scanline.cpp revision d82b2a3eb4f4d2385ec508515a95ff9f339ab74f
1/* libs/pixelflinger/scanline.cpp
2**
3** Copyright 2006-2011, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18
19#define LOG_TAG "pixelflinger"
20
21#include <assert.h>
22#include <stdlib.h>
23#include <stdio.h>
24#include <string.h>
25
26#include <cutils/memory.h>
27#include <cutils/log.h>
28
29#ifdef __arm__
30#include <machine/cpu-features.h>
31#endif
32
33#include "buffer.h"
34#include "scanline.h"
35
36#include "codeflinger/CodeCache.h"
37#include "codeflinger/GGLAssembler.h"
38#if defined(__arm__)
39#include "codeflinger/ARMAssembler.h"
40#elif defined(__aarch64__)
41#include "codeflinger/Arm64Assembler.h"
42#elif defined(__mips__)
43#include "codeflinger/MIPSAssembler.h"
44#endif
45//#include "codeflinger/ARMAssemblerOptimizer.h"
46
47// ----------------------------------------------------------------------------
48
49#define ANDROID_CODEGEN_GENERIC     0   // force generic pixel pipeline
50#define ANDROID_CODEGEN_C           1   // hand-written C, fallback generic
51#define ANDROID_CODEGEN_ASM         2   // hand-written asm, fallback generic
52#define ANDROID_CODEGEN_GENERATED   3   // hand-written asm, fallback codegen
53
54#ifdef NDEBUG
55#   define ANDROID_RELEASE
56#   define ANDROID_CODEGEN      ANDROID_CODEGEN_GENERATED
57#else
58#   define ANDROID_DEBUG
59#   define ANDROID_CODEGEN      ANDROID_CODEGEN_GENERATED
60#endif
61
62#if defined(__arm__) || defined(__mips__) || defined(__aarch64__)
63#   define ANDROID_ARM_CODEGEN  1
64#else
65#   define ANDROID_ARM_CODEGEN  0
66#endif
67
68#define DEBUG__CODEGEN_ONLY     0
69
70/* Set to 1 to dump to the log the states that need a new
71 * code-generated scanline callback, i.e. those that don't
72 * have a corresponding shortcut function.
73 */
74#define DEBUG_NEEDS  0
75
76#ifdef __mips__
77#define ASSEMBLY_SCRATCH_SIZE   4096
78#elif defined(__aarch64__)
79#define ASSEMBLY_SCRATCH_SIZE   8192
80#else
81#define ASSEMBLY_SCRATCH_SIZE   2048
82#endif
83
84// ----------------------------------------------------------------------------
85namespace android {
86// ----------------------------------------------------------------------------
87
88static void init_y(context_t*, int32_t);
89static void init_y_noop(context_t*, int32_t);
90static void init_y_packed(context_t*, int32_t);
91static void init_y_error(context_t*, int32_t);
92
93static void step_y__generic(context_t* c);
94static void step_y__nop(context_t*);
95static void step_y__smooth(context_t* c);
96static void step_y__tmu(context_t* c);
97static void step_y__w(context_t* c);
98
99static void scanline(context_t* c);
100static void scanline_perspective(context_t* c);
101static void scanline_perspective_single(context_t* c);
102static void scanline_t32cb16blend(context_t* c);
103static void scanline_t32cb16blend_dither(context_t* c);
104static void scanline_t32cb16blend_srca(context_t* c);
105static void scanline_t32cb16blend_clamp(context_t* c);
106static void scanline_t32cb16blend_clamp_dither(context_t* c);
107static void scanline_t32cb16blend_clamp_mod(context_t* c);
108static void scanline_x32cb16blend_clamp_mod(context_t* c);
109static void scanline_t32cb16blend_clamp_mod_dither(context_t* c);
110static void scanline_x32cb16blend_clamp_mod_dither(context_t* c);
111static void scanline_t32cb16(context_t* c);
112static void scanline_t32cb16_dither(context_t* c);
113static void scanline_t32cb16_clamp(context_t* c);
114static void scanline_t32cb16_clamp_dither(context_t* c);
115static void scanline_col32cb16blend(context_t* c);
116static void scanline_t16cb16_clamp(context_t* c);
117static void scanline_t16cb16blend_clamp_mod(context_t* c);
118static void scanline_memcpy(context_t* c);
119static void scanline_memset8(context_t* c);
120static void scanline_memset16(context_t* c);
121static void scanline_memset32(context_t* c);
122static void scanline_noop(context_t* c);
123static void scanline_set(context_t* c);
124static void scanline_clear(context_t* c);
125
126static void rect_generic(context_t* c, size_t yc);
127static void rect_memcpy(context_t* c, size_t yc);
128
129#if defined( __arm__)
130extern "C" void scanline_t32cb16blend_arm(uint16_t*, uint32_t*, size_t);
131extern "C" void scanline_t32cb16_arm(uint16_t *dst, uint32_t *src, size_t ct);
132extern "C" void scanline_col32cb16blend_neon(uint16_t *dst, uint32_t *col, size_t ct);
133extern "C" void scanline_col32cb16blend_arm(uint16_t *dst, uint32_t col, size_t ct);
134#elif defined(__aarch64__)
135extern "C" void scanline_t32cb16blend_arm64(uint16_t*, uint32_t*, size_t);
136extern "C" void scanline_col32cb16blend_arm64(uint16_t *dst, uint32_t col, size_t ct);
137#elif defined(__mips__)
138extern "C" void scanline_t32cb16blend_mips(uint16_t*, uint32_t*, size_t);
139#endif
140
141// ----------------------------------------------------------------------------
142
143static inline uint16_t  convertAbgr8888ToRgb565(uint32_t  pix)
144{
145    return uint16_t( ((pix << 8) & 0xf800) |
146                      ((pix >> 5) & 0x07e0) |
147                      ((pix >> 19) & 0x001f) );
148}
149
150struct shortcut_t {
151    needs_filter_t  filter;
152    const char*     desc;
153    void            (*scanline)(context_t*);
154    void            (*init_y)(context_t*, int32_t);
155};
156
157// Keep in sync with needs
158
159/* To understand the values here, have a look at:
160 *     system/core/include/private/pixelflinger/ggl_context.h
161 *
162 * Especially the lines defining and using GGL_RESERVE_NEEDS
163 *
164 * Quick reminders:
165 *   - the last nibble of the first value is the destination buffer format.
166 *   - the last nibble of the third value is the source texture format
167 *   - formats: 4=rgb565 1=abgr8888 2=xbgr8888
168 *
169 * In the descriptions below:
170 *
171 *   SRC      means we copy the source pixels to the destination
172 *
173 *   SRC_OVER means we blend the source pixels to the destination
174 *            with dstFactor = 1-srcA, srcFactor=1  (premultiplied source).
175 *            This mode is otherwise called 'blend'.
176 *
177 *   SRCA_OVER means we blend the source pixels to the destination
178 *             with dstFactor=srcA*(1-srcA) srcFactor=srcA (non-premul source).
179 *             This mode is otherwise called 'blend_srca'
180 *
181 *   clamp    means we fetch source pixels from a texture with u/v clamping
182 *
183 *   mod      means the source pixels are modulated (multiplied) by the
184 *            a/r/g/b of the current context's color. Typically used for
185 *            fade-in / fade-out.
186 *
187 *   dither   means we dither 32 bit values to 16 bits
188 */
189static shortcut_t shortcuts[] = {
190    { { { 0x03515104, 0x00000077, { 0x00000A01, 0x00000000 } },
191        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
192        "565 fb, 8888 tx, blend SRC_OVER", scanline_t32cb16blend, init_y_noop },
193    { { { 0x03010104, 0x00000077, { 0x00000A01, 0x00000000 } },
194        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
195        "565 fb, 8888 tx, SRC", scanline_t32cb16, init_y_noop  },
196    /* same as first entry, but with dithering */
197    { { { 0x03515104, 0x00000177, { 0x00000A01, 0x00000000 } },
198        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
199        "565 fb, 8888 tx, blend SRC_OVER dither", scanline_t32cb16blend_dither, init_y_noop },
200    /* same as second entry, but with dithering */
201    { { { 0x03010104, 0x00000177, { 0x00000A01, 0x00000000 } },
202        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
203        "565 fb, 8888 tx, SRC dither", scanline_t32cb16_dither, init_y_noop  },
204    /* this is used during the boot animation - CHEAT: ignore dithering */
205    { { { 0x03545404, 0x00000077, { 0x00000A01, 0x00000000 } },
206        { 0xFFFFFFFF, 0xFFFFFEFF, { 0xFFFFFFFF, 0x0000003F } } },
207        "565 fb, 8888 tx, blend dst:ONE_MINUS_SRCA src:SRCA", scanline_t32cb16blend_srca, init_y_noop },
208    /* special case for arbitrary texture coordinates (think scaling) */
209    { { { 0x03515104, 0x00000077, { 0x00000001, 0x00000000 } },
210        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
211        "565 fb, 8888 tx, SRC_OVER clamp", scanline_t32cb16blend_clamp, init_y },
212    { { { 0x03515104, 0x00000177, { 0x00000001, 0x00000000 } },
213        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
214        "565 fb, 8888 tx, SRC_OVER clamp dither", scanline_t32cb16blend_clamp_dither, init_y },
215    /* another case used during emulation */
216    { { { 0x03515104, 0x00000077, { 0x00001001, 0x00000000 } },
217        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
218        "565 fb, 8888 tx, SRC_OVER clamp modulate", scanline_t32cb16blend_clamp_mod, init_y },
219    /* and this */
220    { { { 0x03515104, 0x00000077, { 0x00001002, 0x00000000 } },
221        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
222        "565 fb, x888 tx, SRC_OVER clamp modulate", scanline_x32cb16blend_clamp_mod, init_y },
223    { { { 0x03515104, 0x00000177, { 0x00001001, 0x00000000 } },
224        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
225        "565 fb, 8888 tx, SRC_OVER clamp modulate dither", scanline_t32cb16blend_clamp_mod_dither, init_y },
226    { { { 0x03515104, 0x00000177, { 0x00001002, 0x00000000 } },
227        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
228        "565 fb, x888 tx, SRC_OVER clamp modulate dither", scanline_x32cb16blend_clamp_mod_dither, init_y },
229    { { { 0x03010104, 0x00000077, { 0x00000001, 0x00000000 } },
230        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
231        "565 fb, 8888 tx, SRC clamp", scanline_t32cb16_clamp, init_y  },
232    { { { 0x03010104, 0x00000077, { 0x00000002, 0x00000000 } },
233        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
234        "565 fb, x888 tx, SRC clamp", scanline_t32cb16_clamp, init_y  },
235    { { { 0x03010104, 0x00000177, { 0x00000001, 0x00000000 } },
236        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
237        "565 fb, 8888 tx, SRC clamp dither", scanline_t32cb16_clamp_dither, init_y  },
238    { { { 0x03010104, 0x00000177, { 0x00000002, 0x00000000 } },
239        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
240        "565 fb, x888 tx, SRC clamp dither", scanline_t32cb16_clamp_dither, init_y  },
241    { { { 0x03010104, 0x00000077, { 0x00000004, 0x00000000 } },
242        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
243        "565 fb, 565 tx, SRC clamp", scanline_t16cb16_clamp, init_y  },
244    { { { 0x03515104, 0x00000077, { 0x00001004, 0x00000000 } },
245        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
246        "565 fb, 565 tx, SRC_OVER clamp", scanline_t16cb16blend_clamp_mod, init_y  },
247    { { { 0x03515104, 0x00000077, { 0x00000000, 0x00000000 } },
248        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0xFFFFFFFF } } },
249        "565 fb, 8888 fixed color", scanline_col32cb16blend, init_y_packed  },
250    { { { 0x00000000, 0x00000000, { 0x00000000, 0x00000000 } },
251        { 0x00000000, 0x00000007, { 0x00000000, 0x00000000 } } },
252        "(nop) alpha test", scanline_noop, init_y_noop },
253    { { { 0x00000000, 0x00000000, { 0x00000000, 0x00000000 } },
254        { 0x00000000, 0x00000070, { 0x00000000, 0x00000000 } } },
255        "(nop) depth test", scanline_noop, init_y_noop },
256    { { { 0x05000000, 0x00000000, { 0x00000000, 0x00000000 } },
257        { 0x0F000000, 0x00000080, { 0x00000000, 0x00000000 } } },
258        "(nop) logic_op", scanline_noop, init_y_noop },
259    { { { 0xF0000000, 0x00000000, { 0x00000000, 0x00000000 } },
260        { 0xF0000000, 0x00000080, { 0x00000000, 0x00000000 } } },
261        "(nop) color mask", scanline_noop, init_y_noop },
262    { { { 0x0F000000, 0x00000077, { 0x00000000, 0x00000000 } },
263        { 0xFF000000, 0x000000F7, { 0x00000000, 0x00000000 } } },
264        "(set) logic_op", scanline_set, init_y_noop },
265    { { { 0x00000000, 0x00000077, { 0x00000000, 0x00000000 } },
266        { 0xFF000000, 0x000000F7, { 0x00000000, 0x00000000 } } },
267        "(clear) logic_op", scanline_clear, init_y_noop },
268    { { { 0x03000000, 0x00000077, { 0x00000000, 0x00000000 } },
269        { 0xFFFFFF00, 0x000000F7, { 0x00000000, 0x00000000 } } },
270        "(clear) blending 0/0", scanline_clear, init_y_noop },
271    { { { 0x00000000, 0x00000000, { 0x00000000, 0x00000000 } },
272        { 0x0000003F, 0x00000000, { 0x00000000, 0x00000000 } } },
273        "(error) invalid color-buffer format", scanline_noop, init_y_error },
274};
275static const needs_filter_t noblend1to1 = {
276        // (disregard dithering, see below)
277        { 0x03010100, 0x00000077, { 0x00000A00, 0x00000000 } },
278        { 0xFFFFFFC0, 0xFFFFFEFF, { 0xFFFFFFC0, 0x0000003F } }
279};
280static  const needs_filter_t fill16noblend = {
281        { 0x03010100, 0x00000077, { 0x00000000, 0x00000000 } },
282        { 0xFFFFFFC0, 0xFFFFFFFF, { 0x0000003F, 0x0000003F } }
283};
284
285// ----------------------------------------------------------------------------
286
287#if ANDROID_ARM_CODEGEN
288
289#if defined(__mips__)
290static CodeCache gCodeCache(32 * 1024);
291#elif defined(__aarch64__)
292static CodeCache gCodeCache(48 * 1024);
293#else
294static CodeCache gCodeCache(12 * 1024);
295#endif
296
297class ScanlineAssembly : public Assembly {
298    AssemblyKey<needs_t> mKey;
299public:
300    ScanlineAssembly(needs_t needs, size_t size)
301        : Assembly(size), mKey(needs) { }
302    const AssemblyKey<needs_t>& key() const { return mKey; }
303};
304#endif
305
306// ----------------------------------------------------------------------------
307
308void ggl_init_scanline(context_t* c)
309{
310    c->init_y = init_y;
311    c->step_y = step_y__generic;
312    c->scanline = scanline;
313}
314
315void ggl_uninit_scanline(context_t* c)
316{
317    if (c->state.buffers.coverage)
318        free(c->state.buffers.coverage);
319#if ANDROID_ARM_CODEGEN
320    if (c->scanline_as)
321        c->scanline_as->decStrong(c);
322#endif
323}
324
325// ----------------------------------------------------------------------------
326
327static void pick_scanline(context_t* c)
328{
329#if (!defined(DEBUG__CODEGEN_ONLY) || (DEBUG__CODEGEN_ONLY == 0))
330
331#if ANDROID_CODEGEN == ANDROID_CODEGEN_GENERIC
332    c->init_y = init_y;
333    c->step_y = step_y__generic;
334    c->scanline = scanline;
335    return;
336#endif
337
338    //printf("*** needs [%08lx:%08lx:%08lx:%08lx]\n",
339    //    c->state.needs.n, c->state.needs.p,
340    //    c->state.needs.t[0], c->state.needs.t[1]);
341
342    // first handle the special case that we cannot test with a filter
343    const uint32_t cb_format = GGL_READ_NEEDS(CB_FORMAT, c->state.needs.n);
344    if (GGL_READ_NEEDS(T_FORMAT, c->state.needs.t[0]) == cb_format) {
345        if (c->state.needs.match(noblend1to1)) {
346            // this will match regardless of dithering state, since both
347            // src and dest have the same format anyway, there is no dithering
348            // to be done.
349            const GGLFormat* f =
350                &(c->formats[GGL_READ_NEEDS(T_FORMAT, c->state.needs.t[0])]);
351            if ((f->components == GGL_RGB) ||
352                (f->components == GGL_RGBA) ||
353                (f->components == GGL_LUMINANCE) ||
354                (f->components == GGL_LUMINANCE_ALPHA))
355            {
356                // format must have all of RGB components
357                // (so the current color doesn't show through)
358                c->scanline = scanline_memcpy;
359                c->init_y = init_y_noop;
360                return;
361            }
362        }
363    }
364
365    if (c->state.needs.match(fill16noblend)) {
366        c->init_y = init_y_packed;
367        switch (c->formats[cb_format].size) {
368        case 1: c->scanline = scanline_memset8;  return;
369        case 2: c->scanline = scanline_memset16; return;
370        case 4: c->scanline = scanline_memset32; return;
371        }
372    }
373
374    const int numFilters = sizeof(shortcuts)/sizeof(shortcut_t);
375    for (int i=0 ; i<numFilters ; i++) {
376        if (c->state.needs.match(shortcuts[i].filter)) {
377            c->scanline = shortcuts[i].scanline;
378            c->init_y = shortcuts[i].init_y;
379            return;
380        }
381    }
382
383#if DEBUG_NEEDS
384    ALOGI("Needs: n=0x%08x p=0x%08x t0=0x%08x t1=0x%08x",
385         c->state.needs.n, c->state.needs.p,
386         c->state.needs.t[0], c->state.needs.t[1]);
387#endif
388
389#endif // DEBUG__CODEGEN_ONLY
390
391    c->init_y = init_y;
392    c->step_y = step_y__generic;
393
394#if ANDROID_ARM_CODEGEN
395    // we're going to have to generate some code...
396    // here, generate code for our pixel pipeline
397    const AssemblyKey<needs_t> key(c->state.needs);
398    sp<Assembly> assembly = gCodeCache.lookup(key);
399    if (assembly == 0) {
400        // create a new assembly region
401        sp<ScanlineAssembly> a = new ScanlineAssembly(c->state.needs,
402                ASSEMBLY_SCRATCH_SIZE);
403        // initialize our assembler
404#if defined(__arm__)
405        GGLAssembler assembler( new ARMAssembler(a) );
406        //GGLAssembler assembler(
407        //        new ARMAssemblerOptimizer(new ARMAssembler(a)) );
408#endif
409#if defined(__mips__)
410        GGLAssembler assembler( new ArmToMipsAssembler(a) );
411#elif defined(__aarch64__)
412        GGLAssembler assembler( new ArmToArm64Assembler(a) );
413#endif
414        // generate the scanline code for the given needs
415        bool err = assembler.scanline(c->state.needs, c) != 0;
416        if (ggl_likely(!err)) {
417            // finally, cache this assembly
418            err = gCodeCache.cache(a->key(), a) < 0;
419        }
420        if (ggl_unlikely(err)) {
421            ALOGE("error generating or caching assembly. Reverting to NOP.");
422            c->scanline = scanline_noop;
423            c->init_y = init_y_noop;
424            c->step_y = step_y__nop;
425            return;
426        }
427        assembly = a;
428    }
429
430    // release the previous assembly
431    if (c->scanline_as) {
432        c->scanline_as->decStrong(c);
433    }
434
435    //ALOGI("using generated pixel-pipeline");
436    c->scanline_as = assembly.get();
437    c->scanline_as->incStrong(c); //  hold on to assembly
438    c->scanline = (void(*)(context_t* c))assembly->base();
439#else
440//    ALOGW("using generic (slow) pixel-pipeline");
441    c->scanline = scanline;
442#endif
443}
444
445void ggl_pick_scanline(context_t* c)
446{
447    pick_scanline(c);
448    if ((c->state.enables & GGL_ENABLE_W) &&
449        (c->state.enables & GGL_ENABLE_TMUS))
450    {
451        c->span = c->scanline;
452        c->scanline = scanline_perspective;
453        if (!(c->state.enabled_tmu & (c->state.enabled_tmu - 1))) {
454            // only one TMU enabled
455            c->scanline = scanline_perspective_single;
456        }
457    }
458}
459
460// ----------------------------------------------------------------------------
461
462static void blending(context_t* c, pixel_t* fragment, pixel_t* fb);
463static void blend_factor(context_t* c, pixel_t* r, uint32_t factor,
464        const pixel_t* src, const pixel_t* dst);
465static void rescale(uint32_t& u, uint8_t& su, uint32_t& v, uint8_t& sv);
466
467#if ANDROID_ARM_CODEGEN && (ANDROID_CODEGEN == ANDROID_CODEGEN_GENERATED)
468
469// no need to compile the generic-pipeline, it can't be reached
470void scanline(context_t*)
471{
472}
473
474#else
475
476void rescale(uint32_t& u, uint8_t& su, uint32_t& v, uint8_t& sv)
477{
478    if (su && sv) {
479        if (su > sv) {
480            v = ggl_expand(v, sv, su);
481            sv = su;
482        } else if (su < sv) {
483            u = ggl_expand(u, su, sv);
484            su = sv;
485        }
486    }
487}
488
489void blending(context_t* c, pixel_t* fragment, pixel_t* fb)
490{
491    rescale(fragment->c[0], fragment->s[0], fb->c[0], fb->s[0]);
492    rescale(fragment->c[1], fragment->s[1], fb->c[1], fb->s[1]);
493    rescale(fragment->c[2], fragment->s[2], fb->c[2], fb->s[2]);
494    rescale(fragment->c[3], fragment->s[3], fb->c[3], fb->s[3]);
495
496    pixel_t sf, df;
497    blend_factor(c, &sf, c->state.blend.src, fragment, fb);
498    blend_factor(c, &df, c->state.blend.dst, fragment, fb);
499
500    fragment->c[1] =
501            gglMulAddx(fragment->c[1], sf.c[1], gglMulx(fb->c[1], df.c[1]));
502    fragment->c[2] =
503            gglMulAddx(fragment->c[2], sf.c[2], gglMulx(fb->c[2], df.c[2]));
504    fragment->c[3] =
505            gglMulAddx(fragment->c[3], sf.c[3], gglMulx(fb->c[3], df.c[3]));
506
507    if (c->state.blend.alpha_separate) {
508        blend_factor(c, &sf, c->state.blend.src_alpha, fragment, fb);
509        blend_factor(c, &df, c->state.blend.dst_alpha, fragment, fb);
510    }
511
512    fragment->c[0] =
513            gglMulAddx(fragment->c[0], sf.c[0], gglMulx(fb->c[0], df.c[0]));
514
515    // clamp to 1.0
516    if (fragment->c[0] >= (1LU<<fragment->s[0]))
517        fragment->c[0] = (1<<fragment->s[0])-1;
518    if (fragment->c[1] >= (1LU<<fragment->s[1]))
519        fragment->c[1] = (1<<fragment->s[1])-1;
520    if (fragment->c[2] >= (1LU<<fragment->s[2]))
521        fragment->c[2] = (1<<fragment->s[2])-1;
522    if (fragment->c[3] >= (1LU<<fragment->s[3]))
523        fragment->c[3] = (1<<fragment->s[3])-1;
524}
525
526static inline int blendfactor(uint32_t x, uint32_t size, uint32_t def = 0)
527{
528    if (!size)
529        return def;
530
531    // scale to 16 bits
532    if (size > 16) {
533        x >>= (size - 16);
534    } else if (size < 16) {
535        x = ggl_expand(x, size, 16);
536    }
537    x += x >> 15;
538    return x;
539}
540
541void blend_factor(context_t* /*c*/, pixel_t* r,
542        uint32_t factor, const pixel_t* src, const pixel_t* dst)
543{
544    switch (factor) {
545        case GGL_ZERO:
546            r->c[1] =
547            r->c[2] =
548            r->c[3] =
549            r->c[0] = 0;
550            break;
551        case GGL_ONE:
552            r->c[1] =
553            r->c[2] =
554            r->c[3] =
555            r->c[0] = FIXED_ONE;
556            break;
557        case GGL_DST_COLOR:
558            r->c[1] = blendfactor(dst->c[1], dst->s[1]);
559            r->c[2] = blendfactor(dst->c[2], dst->s[2]);
560            r->c[3] = blendfactor(dst->c[3], dst->s[3]);
561            r->c[0] = blendfactor(dst->c[0], dst->s[0]);
562            break;
563        case GGL_SRC_COLOR:
564            r->c[1] = blendfactor(src->c[1], src->s[1]);
565            r->c[2] = blendfactor(src->c[2], src->s[2]);
566            r->c[3] = blendfactor(src->c[3], src->s[3]);
567            r->c[0] = blendfactor(src->c[0], src->s[0]);
568            break;
569        case GGL_ONE_MINUS_DST_COLOR:
570            r->c[1] = FIXED_ONE - blendfactor(dst->c[1], dst->s[1]);
571            r->c[2] = FIXED_ONE - blendfactor(dst->c[2], dst->s[2]);
572            r->c[3] = FIXED_ONE - blendfactor(dst->c[3], dst->s[3]);
573            r->c[0] = FIXED_ONE - blendfactor(dst->c[0], dst->s[0]);
574            break;
575        case GGL_ONE_MINUS_SRC_COLOR:
576            r->c[1] = FIXED_ONE - blendfactor(src->c[1], src->s[1]);
577            r->c[2] = FIXED_ONE - blendfactor(src->c[2], src->s[2]);
578            r->c[3] = FIXED_ONE - blendfactor(src->c[3], src->s[3]);
579            r->c[0] = FIXED_ONE - blendfactor(src->c[0], src->s[0]);
580            break;
581        case GGL_SRC_ALPHA:
582            r->c[1] =
583            r->c[2] =
584            r->c[3] =
585            r->c[0] = blendfactor(src->c[0], src->s[0], FIXED_ONE);
586            break;
587        case GGL_ONE_MINUS_SRC_ALPHA:
588            r->c[1] =
589            r->c[2] =
590            r->c[3] =
591            r->c[0] = FIXED_ONE - blendfactor(src->c[0], src->s[0], FIXED_ONE);
592            break;
593        case GGL_DST_ALPHA:
594            r->c[1] =
595            r->c[2] =
596            r->c[3] =
597            r->c[0] = blendfactor(dst->c[0], dst->s[0], FIXED_ONE);
598            break;
599        case GGL_ONE_MINUS_DST_ALPHA:
600            r->c[1] =
601            r->c[2] =
602            r->c[3] =
603            r->c[0] = FIXED_ONE - blendfactor(dst->c[0], dst->s[0], FIXED_ONE);
604            break;
605        case GGL_SRC_ALPHA_SATURATE:
606            // XXX: GGL_SRC_ALPHA_SATURATE
607            break;
608    }
609}
610
611static GGLfixed wrapping(int32_t coord, uint32_t size, int tx_wrap)
612{
613    GGLfixed d;
614    if (tx_wrap == GGL_REPEAT) {
615        d = (uint32_t(coord)>>16) * size;
616    } else if (tx_wrap == GGL_CLAMP) { // CLAMP_TO_EDGE semantics
617        const GGLfixed clamp_min = FIXED_HALF;
618        const GGLfixed clamp_max = (size << 16) - FIXED_HALF;
619        if (coord < clamp_min)     coord = clamp_min;
620        if (coord > clamp_max)     coord = clamp_max;
621        d = coord;
622    } else { // 1:1
623        const GGLfixed clamp_min = 0;
624        const GGLfixed clamp_max = (size << 16);
625        if (coord < clamp_min)     coord = clamp_min;
626        if (coord > clamp_max)     coord = clamp_max;
627        d = coord;
628    }
629    return d;
630}
631
632static inline
633GGLcolor ADJUST_COLOR_ITERATOR(GGLcolor v, GGLcolor dvdx, int len)
634{
635    const int32_t end = dvdx * (len-1) + v;
636    if (end < 0)
637        v -= end;
638    v &= ~(v>>31);
639    return v;
640}
641
642void scanline(context_t* c)
643{
644    const uint32_t enables = c->state.enables;
645    const int xs = c->iterators.xl;
646    const int x1 = c->iterators.xr;
647	int xc = x1 - xs;
648    const int16_t* covPtr = c->state.buffers.coverage + xs;
649
650    // All iterated values are sampled at the pixel center
651
652    // reset iterators for that scanline...
653    GGLcolor r, g, b, a;
654    iterators_t& ci = c->iterators;
655    if (enables & GGL_ENABLE_SMOOTH) {
656        r = (xs * c->shade.drdx) + ci.ydrdy;
657        g = (xs * c->shade.dgdx) + ci.ydgdy;
658        b = (xs * c->shade.dbdx) + ci.ydbdy;
659        a = (xs * c->shade.dadx) + ci.ydady;
660        r = ADJUST_COLOR_ITERATOR(r, c->shade.drdx, xc);
661        g = ADJUST_COLOR_ITERATOR(g, c->shade.dgdx, xc);
662        b = ADJUST_COLOR_ITERATOR(b, c->shade.dbdx, xc);
663        a = ADJUST_COLOR_ITERATOR(a, c->shade.dadx, xc);
664    } else {
665        r = ci.ydrdy;
666        g = ci.ydgdy;
667        b = ci.ydbdy;
668        a = ci.ydady;
669    }
670
671    // z iterators are 1.31
672    GGLfixed z = (xs * c->shade.dzdx) + ci.ydzdy;
673    GGLfixed f = (xs * c->shade.dfdx) + ci.ydfdy;
674
675    struct {
676        GGLfixed s, t;
677    } tc[GGL_TEXTURE_UNIT_COUNT];
678    if (enables & GGL_ENABLE_TMUS) {
679        for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
680            if (c->state.texture[i].enable) {
681                texture_iterators_t& ti = c->state.texture[i].iterators;
682                if (enables & GGL_ENABLE_W) {
683                    tc[i].s = ti.ydsdy;
684                    tc[i].t = ti.ydtdy;
685                } else {
686                    tc[i].s = (xs * ti.dsdx) + ti.ydsdy;
687                    tc[i].t = (xs * ti.dtdx) + ti.ydtdy;
688                }
689            }
690        }
691    }
692
693    pixel_t fragment;
694    pixel_t texel;
695    pixel_t fb;
696
697	uint32_t x = xs;
698	uint32_t y = c->iterators.y;
699
700	while (xc--) {
701
702        { // just a scope
703
704		// read color (convert to 8 bits by keeping only the integer part)
705        fragment.s[1] = fragment.s[2] =
706        fragment.s[3] = fragment.s[0] = 8;
707        fragment.c[1] = r >> (GGL_COLOR_BITS-8);
708        fragment.c[2] = g >> (GGL_COLOR_BITS-8);
709        fragment.c[3] = b >> (GGL_COLOR_BITS-8);
710        fragment.c[0] = a >> (GGL_COLOR_BITS-8);
711
712		// texturing
713        if (enables & GGL_ENABLE_TMUS) {
714            for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
715                texture_t& tx = c->state.texture[i];
716                if (!tx.enable)
717                    continue;
718                texture_iterators_t& ti = tx.iterators;
719                int32_t u, v;
720
721                // s-coordinate
722                if (tx.s_coord != GGL_ONE_TO_ONE) {
723                    const int w = tx.surface.width;
724                    u = wrapping(tc[i].s, w, tx.s_wrap);
725                    tc[i].s += ti.dsdx;
726                } else {
727                    u = (((tx.shade.is0>>16) + x)<<16) + FIXED_HALF;
728                }
729
730                // t-coordinate
731                if (tx.t_coord != GGL_ONE_TO_ONE) {
732                    const int h = tx.surface.height;
733                    v = wrapping(tc[i].t, h, tx.t_wrap);
734                    tc[i].t += ti.dtdx;
735                } else {
736                    v = (((tx.shade.it0>>16) + y)<<16) + FIXED_HALF;
737                }
738
739                // read texture
740                if (tx.mag_filter == GGL_NEAREST &&
741                    tx.min_filter == GGL_NEAREST)
742                {
743                    u >>= 16;
744                    v >>= 16;
745                    tx.surface.read(&tx.surface, c, u, v, &texel);
746                } else {
747                    const int w = tx.surface.width;
748                    const int h = tx.surface.height;
749                    u -= FIXED_HALF;
750                    v -= FIXED_HALF;
751                    int u0 = u >> 16;
752                    int v0 = v >> 16;
753                    int u1 = u0 + 1;
754                    int v1 = v0 + 1;
755                    if (tx.s_wrap == GGL_REPEAT) {
756                        if (u0<0)  u0 += w;
757                        if (u1<0)  u1 += w;
758                        if (u0>=w) u0 -= w;
759                        if (u1>=w) u1 -= w;
760                    } else {
761                        if (u0<0)  u0 = 0;
762                        if (u1<0)  u1 = 0;
763                        if (u0>=w) u0 = w-1;
764                        if (u1>=w) u1 = w-1;
765                    }
766                    if (tx.t_wrap == GGL_REPEAT) {
767                        if (v0<0)  v0 += h;
768                        if (v1<0)  v1 += h;
769                        if (v0>=h) v0 -= h;
770                        if (v1>=h) v1 -= h;
771                    } else {
772                        if (v0<0)  v0 = 0;
773                        if (v1<0)  v1 = 0;
774                        if (v0>=h) v0 = h-1;
775                        if (v1>=h) v1 = h-1;
776                    }
777                    pixel_t texels[4];
778                    uint32_t mm[4];
779                    tx.surface.read(&tx.surface, c, u0, v0, &texels[0]);
780                    tx.surface.read(&tx.surface, c, u0, v1, &texels[1]);
781                    tx.surface.read(&tx.surface, c, u1, v0, &texels[2]);
782                    tx.surface.read(&tx.surface, c, u1, v1, &texels[3]);
783                    u = (u >> 12) & 0xF;
784                    v = (v >> 12) & 0xF;
785                    u += u>>3;
786                    v += v>>3;
787                    mm[0] = (0x10 - u) * (0x10 - v);
788                    mm[1] = (0x10 - u) * v;
789                    mm[2] = u * (0x10 - v);
790                    mm[3] = 0x100 - (mm[0] + mm[1] + mm[2]);
791                    for (int j=0 ; j<4 ; j++) {
792                        texel.s[j] = texels[0].s[j];
793                        if (!texel.s[j]) continue;
794                        texel.s[j] += 8;
795                        texel.c[j] =    texels[0].c[j]*mm[0] +
796                                        texels[1].c[j]*mm[1] +
797                                        texels[2].c[j]*mm[2] +
798                                        texels[3].c[j]*mm[3] ;
799                    }
800                }
801
802                // Texture environnement...
803                for (int j=0 ; j<4 ; j++) {
804                    uint32_t& Cf = fragment.c[j];
805                    uint32_t& Ct = texel.c[j];
806                    uint8_t& sf  = fragment.s[j];
807                    uint8_t& st  = texel.s[j];
808                    uint32_t At = texel.c[0];
809                    uint8_t sat = texel.s[0];
810                    switch (tx.env) {
811                    case GGL_REPLACE:
812                        if (st) {
813                            Cf = Ct;
814                            sf = st;
815                        }
816                        break;
817                    case GGL_MODULATE:
818                        if (st) {
819                            uint32_t factor = Ct + (Ct>>(st-1));
820                            Cf = (Cf * factor) >> st;
821                        }
822                        break;
823                    case GGL_DECAL:
824                        if (sat) {
825                            rescale(Cf, sf, Ct, st);
826                            Cf += ((Ct - Cf) * (At + (At>>(sat-1)))) >> sat;
827                        }
828                        break;
829                    case GGL_BLEND:
830                        if (st) {
831                            uint32_t Cc = tx.env_color[i];
832                            if (sf>8)       Cc = (Cc * ((1<<sf)-1))>>8;
833                            else if (sf<8)  Cc = (Cc - (Cc>>(8-sf)))>>(8-sf);
834                            uint32_t factor = Ct + (Ct>>(st-1));
835                            Cf = ((((1<<st) - factor) * Cf) + Ct*Cc)>>st;
836                        }
837                        break;
838                    case GGL_ADD:
839                        if (st) {
840                            rescale(Cf, sf, Ct, st);
841                            Cf += Ct;
842                        }
843                        break;
844                    }
845                }
846            }
847		}
848
849        // coverage application
850        if (enables & GGL_ENABLE_AA) {
851            int16_t cf = *covPtr++;
852            fragment.c[0] = (int64_t(fragment.c[0]) * cf) >> 15;
853        }
854
855        // alpha-test
856        if (enables & GGL_ENABLE_ALPHA_TEST) {
857            GGLcolor ref = c->state.alpha_test.ref;
858            GGLcolor alpha = (uint64_t(fragment.c[0]) *
859                    ((1<<GGL_COLOR_BITS)-1)) / ((1<<fragment.s[0])-1);
860            switch (c->state.alpha_test.func) {
861            case GGL_NEVER:     goto discard;
862            case GGL_LESS:      if (alpha<ref)  break; goto discard;
863            case GGL_EQUAL:     if (alpha==ref) break; goto discard;
864            case GGL_LEQUAL:    if (alpha<=ref) break; goto discard;
865            case GGL_GREATER:   if (alpha>ref)  break; goto discard;
866            case GGL_NOTEQUAL:  if (alpha!=ref) break; goto discard;
867            case GGL_GEQUAL:    if (alpha>=ref) break; goto discard;
868            }
869        }
870
871        // depth test
872        if (c->state.buffers.depth.format) {
873            if (enables & GGL_ENABLE_DEPTH_TEST) {
874                surface_t* cb = &(c->state.buffers.depth);
875                uint16_t* p = (uint16_t*)(cb->data)+(x+(cb->stride*y));
876                uint16_t zz = uint32_t(z)>>(16);
877                uint16_t depth = *p;
878                switch (c->state.depth_test.func) {
879                case GGL_NEVER:     goto discard;
880                case GGL_LESS:      if (zz<depth)    break; goto discard;
881                case GGL_EQUAL:     if (zz==depth)   break; goto discard;
882                case GGL_LEQUAL:    if (zz<=depth)   break; goto discard;
883                case GGL_GREATER:   if (zz>depth)    break; goto discard;
884                case GGL_NOTEQUAL:  if (zz!=depth)   break; goto discard;
885                case GGL_GEQUAL:    if (zz>=depth)   break; goto discard;
886                }
887                // depth buffer is not enabled, if depth-test is not enabled
888/*
889        fragment.s[1] = fragment.s[2] =
890        fragment.s[3] = fragment.s[0] = 8;
891        fragment.c[1] =
892        fragment.c[2] =
893        fragment.c[3] =
894        fragment.c[0] = 255 - (zz>>8);
895*/
896                if (c->state.mask.depth) {
897                    *p = zz;
898                }
899            }
900        }
901
902        // fog
903        if (enables & GGL_ENABLE_FOG) {
904            for (int i=1 ; i<=3 ; i++) {
905                GGLfixed fc = (c->state.fog.color[i] * 0x10000) / 0xFF;
906                uint32_t& c = fragment.c[i];
907                uint8_t& s  = fragment.s[i];
908                c = (c * 0x10000) / ((1<<s)-1);
909                c = gglMulAddx(c, f, gglMulx(fc, 0x10000 - f));
910                s = 16;
911            }
912        }
913
914        // blending
915        if (enables & GGL_ENABLE_BLENDING) {
916            fb.c[1] = fb.c[2] = fb.c[3] = fb.c[0] = 0; // placate valgrind
917            fb.s[1] = fb.s[2] = fb.s[3] = fb.s[0] = 0;
918            c->state.buffers.color.read(
919                    &(c->state.buffers.color), c, x, y, &fb);
920            blending( c, &fragment, &fb );
921        }
922
923		// write
924        c->state.buffers.color.write(
925                &(c->state.buffers.color), c, x, y, &fragment);
926        }
927
928discard:
929		// iterate...
930        x += 1;
931        if (enables & GGL_ENABLE_SMOOTH) {
932            r += c->shade.drdx;
933            g += c->shade.dgdx;
934            b += c->shade.dbdx;
935            a += c->shade.dadx;
936        }
937        z += c->shade.dzdx;
938        f += c->shade.dfdx;
939	}
940}
941
942#endif // ANDROID_ARM_CODEGEN && (ANDROID_CODEGEN == ANDROID_CODEGEN_GENERATED)
943
944// ----------------------------------------------------------------------------
945#if 0
946#pragma mark -
947#pragma mark Scanline
948#endif
949
950/* Used to parse a 32-bit source texture linearly. Usage is:
951 *
952 * horz_iterator32  hi(context);
953 * while (...) {
954 *    uint32_t  src_pixel = hi.get_pixel32();
955 *    ...
956 * }
957 *
958 * Use only for one-to-one texture mapping.
959 */
960struct horz_iterator32 {
961    horz_iterator32(context_t* c) {
962        const int x = c->iterators.xl;
963        const int y = c->iterators.y;
964        texture_t& tx = c->state.texture[0];
965        const int32_t u = (tx.shade.is0>>16) + x;
966        const int32_t v = (tx.shade.it0>>16) + y;
967        m_src = reinterpret_cast<uint32_t*>(tx.surface.data)+(u+(tx.surface.stride*v));
968    }
969    uint32_t  get_pixel32() {
970        return *m_src++;
971    }
972protected:
973    uint32_t* m_src;
974};
975
976/* A variant for 16-bit source textures. */
977struct horz_iterator16 {
978    horz_iterator16(context_t* c) {
979        const int x = c->iterators.xl;
980        const int y = c->iterators.y;
981        texture_t& tx = c->state.texture[0];
982        const int32_t u = (tx.shade.is0>>16) + x;
983        const int32_t v = (tx.shade.it0>>16) + y;
984        m_src = reinterpret_cast<uint16_t*>(tx.surface.data)+(u+(tx.surface.stride*v));
985    }
986    uint16_t  get_pixel16() {
987        return *m_src++;
988    }
989protected:
990    uint16_t* m_src;
991};
992
993/* A clamp iterator is used to iterate inside a texture with GGL_CLAMP.
994 * After initialization, call get_src16() or get_src32() to get the current
995 * texture pixel value.
996 */
997struct clamp_iterator {
998    clamp_iterator(context_t* c) {
999        const int xs = c->iterators.xl;
1000        texture_t& tx = c->state.texture[0];
1001        texture_iterators_t& ti = tx.iterators;
1002        m_s = (xs * ti.dsdx) + ti.ydsdy;
1003        m_t = (xs * ti.dtdx) + ti.ydtdy;
1004        m_ds = ti.dsdx;
1005        m_dt = ti.dtdx;
1006        m_width_m1 = tx.surface.width - 1;
1007        m_height_m1 = tx.surface.height - 1;
1008        m_data = tx.surface.data;
1009        m_stride = tx.surface.stride;
1010    }
1011    uint16_t get_pixel16() {
1012        int  u, v;
1013        get_uv(u, v);
1014        uint16_t* src = reinterpret_cast<uint16_t*>(m_data) + (u + (m_stride*v));
1015        return src[0];
1016    }
1017    uint32_t get_pixel32() {
1018        int  u, v;
1019        get_uv(u, v);
1020        uint32_t* src = reinterpret_cast<uint32_t*>(m_data) + (u + (m_stride*v));
1021        return src[0];
1022    }
1023private:
1024    void   get_uv(int& u, int& v) {
1025        int  uu = m_s >> 16;
1026        int  vv = m_t >> 16;
1027        if (uu < 0)
1028            uu = 0;
1029        if (uu > m_width_m1)
1030            uu = m_width_m1;
1031        if (vv < 0)
1032            vv = 0;
1033        if (vv > m_height_m1)
1034            vv = m_height_m1;
1035        u = uu;
1036        v = vv;
1037        m_s += m_ds;
1038        m_t += m_dt;
1039    }
1040
1041    GGLfixed  m_s, m_t;
1042    GGLfixed  m_ds, m_dt;
1043    int       m_width_m1, m_height_m1;
1044    uint8_t*  m_data;
1045    int       m_stride;
1046};
1047
1048/*
1049 * The 'horizontal clamp iterator' variant corresponds to the case where
1050 * the 'v' coordinate doesn't change. This is useful to avoid one mult and
1051 * extra adds / checks per pixels, if the blending/processing operation after
1052 * this is very fast.
1053 */
1054static int is_context_horizontal(const context_t* c) {
1055    return (c->state.texture[0].iterators.dtdx == 0);
1056}
1057
1058struct horz_clamp_iterator {
1059    uint16_t  get_pixel16() {
1060        int  u = m_s >> 16;
1061        m_s += m_ds;
1062        if (u < 0)
1063            u = 0;
1064        if (u > m_width_m1)
1065            u = m_width_m1;
1066        const uint16_t* src = reinterpret_cast<const uint16_t*>(m_data);
1067        return src[u];
1068    }
1069    uint32_t  get_pixel32() {
1070        int  u = m_s >> 16;
1071        m_s += m_ds;
1072        if (u < 0)
1073            u = 0;
1074        if (u > m_width_m1)
1075            u = m_width_m1;
1076        const uint32_t* src = reinterpret_cast<const uint32_t*>(m_data);
1077        return src[u];
1078    }
1079protected:
1080    void init(const context_t* c, int shift);
1081    GGLfixed       m_s;
1082    GGLfixed       m_ds;
1083    int            m_width_m1;
1084    const uint8_t* m_data;
1085};
1086
1087void horz_clamp_iterator::init(const context_t* c, int shift)
1088{
1089    const int xs = c->iterators.xl;
1090    const texture_t& tx = c->state.texture[0];
1091    const texture_iterators_t& ti = tx.iterators;
1092    m_s = (xs * ti.dsdx) + ti.ydsdy;
1093    m_ds = ti.dsdx;
1094    m_width_m1 = tx.surface.width-1;
1095    m_data = tx.surface.data;
1096
1097    GGLfixed t = (xs * ti.dtdx) + ti.ydtdy;
1098    int      v = t >> 16;
1099    if (v < 0)
1100        v = 0;
1101    else if (v >= (int)tx.surface.height)
1102        v = (int)tx.surface.height-1;
1103
1104    m_data += (tx.surface.stride*v) << shift;
1105}
1106
1107struct horz_clamp_iterator16 : horz_clamp_iterator {
1108    horz_clamp_iterator16(const context_t* c) {
1109        init(c,1);
1110    };
1111};
1112
1113struct horz_clamp_iterator32 : horz_clamp_iterator {
1114    horz_clamp_iterator32(context_t* c) {
1115        init(c,2);
1116    };
1117};
1118
1119/* This is used to perform dithering operations.
1120 */
1121struct ditherer {
1122    ditherer(const context_t* c) {
1123        const int x = c->iterators.xl;
1124        const int y = c->iterators.y;
1125        m_line = &c->ditherMatrix[ ((y & GGL_DITHER_MASK)<<GGL_DITHER_ORDER_SHIFT) ];
1126        m_index = x & GGL_DITHER_MASK;
1127    }
1128    void step(void) {
1129        m_index++;
1130    }
1131    int  get_value(void) {
1132        int ret = m_line[m_index & GGL_DITHER_MASK];
1133        m_index++;
1134        return ret;
1135    }
1136    uint16_t abgr8888ToRgb565(uint32_t s) {
1137        uint32_t r = s & 0xff;
1138        uint32_t g = (s >> 8) & 0xff;
1139        uint32_t b = (s >> 16) & 0xff;
1140        return rgb888ToRgb565(r,g,b);
1141    }
1142    /* The following assumes that r/g/b are in the 0..255 range each */
1143    uint16_t rgb888ToRgb565(uint32_t& r, uint32_t& g, uint32_t &b) {
1144        int threshold = get_value();
1145        /* dither in on GGL_DITHER_BITS, and each of r, g, b is on 8 bits */
1146        r += (threshold >> (GGL_DITHER_BITS-8 +5));
1147        g += (threshold >> (GGL_DITHER_BITS-8 +6));
1148        b += (threshold >> (GGL_DITHER_BITS-8 +5));
1149        if (r > 0xff)
1150            r = 0xff;
1151        if (g > 0xff)
1152            g = 0xff;
1153        if (b > 0xff)
1154            b = 0xff;
1155        return uint16_t(((r & 0xf8) << 8) | ((g & 0xfc) << 3) | (b >> 3));
1156    }
1157protected:
1158    const uint8_t* m_line;
1159    int            m_index;
1160};
1161
1162/* This structure is used to blend (SRC_OVER) 32-bit source pixels
1163 * onto 16-bit destination ones. Usage is simply:
1164 *
1165 *   blender.blend(<32-bit-src-pixel-value>,<ptr-to-16-bit-dest-pixel>)
1166 */
1167struct blender_32to16 {
1168    blender_32to16(context_t* /*c*/) { }
1169    void write(uint32_t s, uint16_t* dst) {
1170        if (s == 0)
1171            return;
1172        s = GGL_RGBA_TO_HOST(s);
1173        int sA = (s>>24);
1174        if (sA == 0xff) {
1175            *dst = convertAbgr8888ToRgb565(s);
1176        } else {
1177            int f = 0x100 - (sA + (sA>>7));
1178            int sR = (s >> (   3))&0x1F;
1179            int sG = (s >> ( 8+2))&0x3F;
1180            int sB = (s >> (16+3))&0x1F;
1181            uint16_t d = *dst;
1182            int dR = (d>>11)&0x1f;
1183            int dG = (d>>5)&0x3f;
1184            int dB = (d)&0x1f;
1185            sR += (f*dR)>>8;
1186            sG += (f*dG)>>8;
1187            sB += (f*dB)>>8;
1188            *dst = uint16_t((sR<<11)|(sG<<5)|sB);
1189        }
1190    }
1191    void write(uint32_t s, uint16_t* dst, ditherer& di) {
1192        if (s == 0) {
1193            di.step();
1194            return;
1195        }
1196        s = GGL_RGBA_TO_HOST(s);
1197        int sA = (s>>24);
1198        if (sA == 0xff) {
1199            *dst = di.abgr8888ToRgb565(s);
1200        } else {
1201            int threshold = di.get_value() << (8 - GGL_DITHER_BITS);
1202            int f = 0x100 - (sA + (sA>>7));
1203            int sR = (s >> (   3))&0x1F;
1204            int sG = (s >> ( 8+2))&0x3F;
1205            int sB = (s >> (16+3))&0x1F;
1206            uint16_t d = *dst;
1207            int dR = (d>>11)&0x1f;
1208            int dG = (d>>5)&0x3f;
1209            int dB = (d)&0x1f;
1210            sR = ((sR << 8) + f*dR + threshold)>>8;
1211            sG = ((sG << 8) + f*dG + threshold)>>8;
1212            sB = ((sB << 8) + f*dB + threshold)>>8;
1213            if (sR > 0x1f) sR = 0x1f;
1214            if (sG > 0x3f) sG = 0x3f;
1215            if (sB > 0x1f) sB = 0x1f;
1216            *dst = uint16_t((sR<<11)|(sG<<5)|sB);
1217        }
1218    }
1219};
1220
1221/* This blender does the same for the 'blend_srca' operation.
1222 * where dstFactor=srcA*(1-srcA) srcFactor=srcA
1223 */
1224struct blender_32to16_srcA {
1225    blender_32to16_srcA(const context_t* /*c*/) { }
1226    void write(uint32_t s, uint16_t* dst) {
1227        if (!s) {
1228            return;
1229        }
1230        uint16_t d = *dst;
1231        s = GGL_RGBA_TO_HOST(s);
1232        int sR = (s >> (   3))&0x1F;
1233        int sG = (s >> ( 8+2))&0x3F;
1234        int sB = (s >> (16+3))&0x1F;
1235        int sA = (s>>24);
1236        int f1 = (sA + (sA>>7));
1237        int f2 = 0x100-f1;
1238        int dR = (d>>11)&0x1f;
1239        int dG = (d>>5)&0x3f;
1240        int dB = (d)&0x1f;
1241        sR = (f1*sR + f2*dR)>>8;
1242        sG = (f1*sG + f2*dG)>>8;
1243        sB = (f1*sB + f2*dB)>>8;
1244        *dst = uint16_t((sR<<11)|(sG<<5)|sB);
1245    }
1246};
1247
1248/* Common init code the modulating blenders */
1249struct blender_modulate {
1250    void init(const context_t* c) {
1251        const int r = c->iterators.ydrdy >> (GGL_COLOR_BITS-8);
1252        const int g = c->iterators.ydgdy >> (GGL_COLOR_BITS-8);
1253        const int b = c->iterators.ydbdy >> (GGL_COLOR_BITS-8);
1254        const int a = c->iterators.ydady >> (GGL_COLOR_BITS-8);
1255        m_r = r + (r >> 7);
1256        m_g = g + (g >> 7);
1257        m_b = b + (b >> 7);
1258        m_a = a + (a >> 7);
1259    }
1260protected:
1261    int m_r, m_g, m_b, m_a;
1262};
1263
1264/* This blender does a normal blend after modulation.
1265 */
1266struct blender_32to16_modulate : blender_modulate {
1267    blender_32to16_modulate(const context_t* c) {
1268        init(c);
1269    }
1270    void write(uint32_t s, uint16_t* dst) {
1271        // blend source and destination
1272        if (!s) {
1273            return;
1274        }
1275        s = GGL_RGBA_TO_HOST(s);
1276
1277        /* We need to modulate s */
1278        uint32_t  sA = (s >> 24);
1279        uint32_t  sB = (s >> 16) & 0xff;
1280        uint32_t  sG = (s >> 8) & 0xff;
1281        uint32_t  sR = s & 0xff;
1282
1283        sA = (sA*m_a) >> 8;
1284        /* Keep R/G/B scaled to 5.8 or 6.8 fixed float format */
1285        sR = (sR*m_r) >> (8 - 5);
1286        sG = (sG*m_g) >> (8 - 6);
1287        sB = (sB*m_b) >> (8 - 5);
1288
1289        /* Now do a normal blend */
1290        int f = 0x100 - (sA + (sA>>7));
1291        uint16_t d = *dst;
1292        int dR = (d>>11)&0x1f;
1293        int dG = (d>>5)&0x3f;
1294        int dB = (d)&0x1f;
1295        sR = (sR + f*dR)>>8;
1296        sG = (sG + f*dG)>>8;
1297        sB = (sB + f*dB)>>8;
1298        *dst = uint16_t((sR<<11)|(sG<<5)|sB);
1299    }
1300    void write(uint32_t s, uint16_t* dst, ditherer& di) {
1301        // blend source and destination
1302        if (!s) {
1303            di.step();
1304            return;
1305        }
1306        s = GGL_RGBA_TO_HOST(s);
1307
1308        /* We need to modulate s */
1309        uint32_t  sA = (s >> 24);
1310        uint32_t  sB = (s >> 16) & 0xff;
1311        uint32_t  sG = (s >> 8) & 0xff;
1312        uint32_t  sR = s & 0xff;
1313
1314        sA = (sA*m_a) >> 8;
1315        /* keep R/G/B scaled to 5.8 or 6.8 fixed float format */
1316        sR = (sR*m_r) >> (8 - 5);
1317        sG = (sG*m_g) >> (8 - 6);
1318        sB = (sB*m_b) >> (8 - 5);
1319
1320        /* Scale threshold to 0.8 fixed float format */
1321        int threshold = di.get_value() << (8 - GGL_DITHER_BITS);
1322        int f = 0x100 - (sA + (sA>>7));
1323        uint16_t d = *dst;
1324        int dR = (d>>11)&0x1f;
1325        int dG = (d>>5)&0x3f;
1326        int dB = (d)&0x1f;
1327        sR = (sR + f*dR + threshold)>>8;
1328        sG = (sG + f*dG + threshold)>>8;
1329        sB = (sB + f*dB + threshold)>>8;
1330        if (sR > 0x1f) sR = 0x1f;
1331        if (sG > 0x3f) sG = 0x3f;
1332        if (sB > 0x1f) sB = 0x1f;
1333        *dst = uint16_t((sR<<11)|(sG<<5)|sB);
1334    }
1335};
1336
1337/* same as 32to16_modulate, except that the input is xRGB, instead of ARGB */
1338struct blender_x32to16_modulate : blender_modulate {
1339    blender_x32to16_modulate(const context_t* c) {
1340        init(c);
1341    }
1342    void write(uint32_t s, uint16_t* dst) {
1343        s = GGL_RGBA_TO_HOST(s);
1344
1345        uint32_t  sB = (s >> 16) & 0xff;
1346        uint32_t  sG = (s >> 8) & 0xff;
1347        uint32_t  sR = s & 0xff;
1348
1349        /* Keep R/G/B in 5.8 or 6.8 format */
1350        sR = (sR*m_r) >> (8 - 5);
1351        sG = (sG*m_g) >> (8 - 6);
1352        sB = (sB*m_b) >> (8 - 5);
1353
1354        int f = 0x100 - m_a;
1355        uint16_t d = *dst;
1356        int dR = (d>>11)&0x1f;
1357        int dG = (d>>5)&0x3f;
1358        int dB = (d)&0x1f;
1359        sR = (sR + f*dR)>>8;
1360        sG = (sG + f*dG)>>8;
1361        sB = (sB + f*dB)>>8;
1362        *dst = uint16_t((sR<<11)|(sG<<5)|sB);
1363    }
1364    void write(uint32_t s, uint16_t* dst, ditherer& di) {
1365        s = GGL_RGBA_TO_HOST(s);
1366
1367        uint32_t  sB = (s >> 16) & 0xff;
1368        uint32_t  sG = (s >> 8) & 0xff;
1369        uint32_t  sR = s & 0xff;
1370
1371        sR = (sR*m_r) >> (8 - 5);
1372        sG = (sG*m_g) >> (8 - 6);
1373        sB = (sB*m_b) >> (8 - 5);
1374
1375        /* Now do a normal blend */
1376        int threshold = di.get_value() << (8 - GGL_DITHER_BITS);
1377        int f = 0x100 - m_a;
1378        uint16_t d = *dst;
1379        int dR = (d>>11)&0x1f;
1380        int dG = (d>>5)&0x3f;
1381        int dB = (d)&0x1f;
1382        sR = (sR + f*dR + threshold)>>8;
1383        sG = (sG + f*dG + threshold)>>8;
1384        sB = (sB + f*dB + threshold)>>8;
1385        if (sR > 0x1f) sR = 0x1f;
1386        if (sG > 0x3f) sG = 0x3f;
1387        if (sB > 0x1f) sB = 0x1f;
1388        *dst = uint16_t((sR<<11)|(sG<<5)|sB);
1389    }
1390};
1391
1392/* Same as above, but source is 16bit rgb565 */
1393struct blender_16to16_modulate : blender_modulate {
1394    blender_16to16_modulate(const context_t* c) {
1395        init(c);
1396    }
1397    void write(uint16_t s16, uint16_t* dst) {
1398        uint32_t  s = s16;
1399
1400        uint32_t  sR = s >> 11;
1401        uint32_t  sG = (s >> 5) & 0x3f;
1402        uint32_t  sB = s & 0x1f;
1403
1404        sR = (sR*m_r);
1405        sG = (sG*m_g);
1406        sB = (sB*m_b);
1407
1408        int f = 0x100 - m_a;
1409        uint16_t d = *dst;
1410        int dR = (d>>11)&0x1f;
1411        int dG = (d>>5)&0x3f;
1412        int dB = (d)&0x1f;
1413        sR = (sR + f*dR)>>8;
1414        sG = (sG + f*dG)>>8;
1415        sB = (sB + f*dB)>>8;
1416        *dst = uint16_t((sR<<11)|(sG<<5)|sB);
1417    }
1418};
1419
1420/* This is used to iterate over a 16-bit destination color buffer.
1421 * Usage is:
1422 *
1423 *   dst_iterator16  di(context);
1424 *   while (di.count--) {
1425 *       <do stuff with dest pixel at di.dst>
1426 *       di.dst++;
1427 *   }
1428 */
1429struct dst_iterator16 {
1430    dst_iterator16(const context_t* c) {
1431        const int x = c->iterators.xl;
1432        const int width = c->iterators.xr - x;
1433        const int32_t y = c->iterators.y;
1434        const surface_t* cb = &(c->state.buffers.color);
1435        count = width;
1436        dst = reinterpret_cast<uint16_t*>(cb->data) + (x+(cb->stride*y));
1437    }
1438    int        count;
1439    uint16_t*  dst;
1440};
1441
1442
1443static void scanline_t32cb16_clamp(context_t* c)
1444{
1445    dst_iterator16  di(c);
1446
1447    if (is_context_horizontal(c)) {
1448        /* Special case for simple horizontal scaling */
1449        horz_clamp_iterator32 ci(c);
1450        while (di.count--) {
1451            uint32_t s = ci.get_pixel32();
1452            *di.dst++ = convertAbgr8888ToRgb565(s);
1453        }
1454    } else {
1455        /* General case */
1456        clamp_iterator ci(c);
1457        while (di.count--) {
1458            uint32_t s = ci.get_pixel32();
1459            *di.dst++ = convertAbgr8888ToRgb565(s);
1460        }
1461    }
1462}
1463
1464static void scanline_t32cb16_dither(context_t* c)
1465{
1466    horz_iterator32 si(c);
1467    dst_iterator16  di(c);
1468    ditherer        dither(c);
1469
1470    while (di.count--) {
1471        uint32_t s = si.get_pixel32();
1472        *di.dst++ = dither.abgr8888ToRgb565(s);
1473    }
1474}
1475
1476static void scanline_t32cb16_clamp_dither(context_t* c)
1477{
1478    dst_iterator16  di(c);
1479    ditherer        dither(c);
1480
1481    if (is_context_horizontal(c)) {
1482        /* Special case for simple horizontal scaling */
1483        horz_clamp_iterator32 ci(c);
1484        while (di.count--) {
1485            uint32_t s = ci.get_pixel32();
1486            *di.dst++ = dither.abgr8888ToRgb565(s);
1487        }
1488    } else {
1489        /* General case */
1490        clamp_iterator ci(c);
1491        while (di.count--) {
1492            uint32_t s = ci.get_pixel32();
1493            *di.dst++ = dither.abgr8888ToRgb565(s);
1494        }
1495    }
1496}
1497
1498static void scanline_t32cb16blend_dither(context_t* c)
1499{
1500    dst_iterator16 di(c);
1501    ditherer       dither(c);
1502    blender_32to16 bl(c);
1503    horz_iterator32  hi(c);
1504    while (di.count--) {
1505        uint32_t s = hi.get_pixel32();
1506        bl.write(s, di.dst, dither);
1507        di.dst++;
1508    }
1509}
1510
1511static void scanline_t32cb16blend_clamp(context_t* c)
1512{
1513    dst_iterator16  di(c);
1514    blender_32to16  bl(c);
1515
1516    if (is_context_horizontal(c)) {
1517        horz_clamp_iterator32 ci(c);
1518        while (di.count--) {
1519            uint32_t s = ci.get_pixel32();
1520            bl.write(s, di.dst);
1521            di.dst++;
1522        }
1523    } else {
1524        clamp_iterator ci(c);
1525        while (di.count--) {
1526            uint32_t s = ci.get_pixel32();
1527            bl.write(s, di.dst);
1528            di.dst++;
1529        }
1530    }
1531}
1532
1533static void scanline_t32cb16blend_clamp_dither(context_t* c)
1534{
1535    dst_iterator16 di(c);
1536    ditherer       dither(c);
1537    blender_32to16 bl(c);
1538
1539    clamp_iterator ci(c);
1540    while (di.count--) {
1541        uint32_t s = ci.get_pixel32();
1542        bl.write(s, di.dst, dither);
1543        di.dst++;
1544    }
1545}
1546
1547void scanline_t32cb16blend_clamp_mod(context_t* c)
1548{
1549    dst_iterator16 di(c);
1550    blender_32to16_modulate bl(c);
1551
1552    clamp_iterator ci(c);
1553    while (di.count--) {
1554        uint32_t s = ci.get_pixel32();
1555        bl.write(s, di.dst);
1556        di.dst++;
1557    }
1558}
1559
1560void scanline_t32cb16blend_clamp_mod_dither(context_t* c)
1561{
1562    dst_iterator16 di(c);
1563    blender_32to16_modulate bl(c);
1564    ditherer dither(c);
1565
1566    clamp_iterator ci(c);
1567    while (di.count--) {
1568        uint32_t s = ci.get_pixel32();
1569        bl.write(s, di.dst, dither);
1570        di.dst++;
1571    }
1572}
1573
1574/* Variant of scanline_t32cb16blend_clamp_mod with a xRGB texture */
1575void scanline_x32cb16blend_clamp_mod(context_t* c)
1576{
1577    dst_iterator16 di(c);
1578    blender_x32to16_modulate  bl(c);
1579
1580    clamp_iterator ci(c);
1581    while (di.count--) {
1582        uint32_t s = ci.get_pixel32();
1583        bl.write(s, di.dst);
1584        di.dst++;
1585    }
1586}
1587
1588void scanline_x32cb16blend_clamp_mod_dither(context_t* c)
1589{
1590    dst_iterator16 di(c);
1591    blender_x32to16_modulate  bl(c);
1592    ditherer dither(c);
1593
1594    clamp_iterator ci(c);
1595    while (di.count--) {
1596        uint32_t s = ci.get_pixel32();
1597        bl.write(s, di.dst, dither);
1598        di.dst++;
1599    }
1600}
1601
1602void scanline_t16cb16_clamp(context_t* c)
1603{
1604    dst_iterator16  di(c);
1605
1606    /* Special case for simple horizontal scaling */
1607    if (is_context_horizontal(c)) {
1608        horz_clamp_iterator16 ci(c);
1609        while (di.count--) {
1610            *di.dst++ = ci.get_pixel16();
1611        }
1612    } else {
1613        clamp_iterator ci(c);
1614        while (di.count--) {
1615            *di.dst++ = ci.get_pixel16();
1616        }
1617    }
1618}
1619
1620
1621
1622template <typename T, typename U>
1623static inline __attribute__((const))
1624T interpolate(int y, T v0, U dvdx, U dvdy) {
1625    // interpolates in pixel's centers
1626    // v = v0 + (y + 0.5) * dvdy + (0.5 * dvdx)
1627    return (y * dvdy) + (v0 + ((dvdy + dvdx) >> 1));
1628}
1629
1630// ----------------------------------------------------------------------------
1631#if 0
1632#pragma mark -
1633#endif
1634
1635void init_y(context_t* c, int32_t ys)
1636{
1637    const uint32_t enables = c->state.enables;
1638
1639    // compute iterators...
1640    iterators_t& ci = c->iterators;
1641
1642    // sample in the center
1643    ci.y = ys;
1644
1645    if (enables & (GGL_ENABLE_DEPTH_TEST|GGL_ENABLE_W|GGL_ENABLE_FOG)) {
1646        ci.ydzdy = interpolate(ys, c->shade.z0, c->shade.dzdx, c->shade.dzdy);
1647        ci.ydwdy = interpolate(ys, c->shade.w0, c->shade.dwdx, c->shade.dwdy);
1648        ci.ydfdy = interpolate(ys, c->shade.f0, c->shade.dfdx, c->shade.dfdy);
1649    }
1650
1651    if (ggl_unlikely(enables & GGL_ENABLE_SMOOTH)) {
1652        ci.ydrdy = interpolate(ys, c->shade.r0, c->shade.drdx, c->shade.drdy);
1653        ci.ydgdy = interpolate(ys, c->shade.g0, c->shade.dgdx, c->shade.dgdy);
1654        ci.ydbdy = interpolate(ys, c->shade.b0, c->shade.dbdx, c->shade.dbdy);
1655        ci.ydady = interpolate(ys, c->shade.a0, c->shade.dadx, c->shade.dady);
1656        c->step_y = step_y__smooth;
1657    } else {
1658        ci.ydrdy = c->shade.r0;
1659        ci.ydgdy = c->shade.g0;
1660        ci.ydbdy = c->shade.b0;
1661        ci.ydady = c->shade.a0;
1662        // XXX: do only if needed, or make sure this is fast
1663        c->packed = ggl_pack_color(c, c->state.buffers.color.format,
1664                ci.ydrdy, ci.ydgdy, ci.ydbdy, ci.ydady);
1665        c->packed8888 = ggl_pack_color(c, GGL_PIXEL_FORMAT_RGBA_8888,
1666                ci.ydrdy, ci.ydgdy, ci.ydbdy, ci.ydady);
1667    }
1668
1669    // initialize the variables we need in the shader
1670    generated_vars_t& gen = c->generated_vars;
1671    gen.argb[GGLFormat::ALPHA].c  = ci.ydady;
1672    gen.argb[GGLFormat::ALPHA].dx = c->shade.dadx;
1673    gen.argb[GGLFormat::RED  ].c  = ci.ydrdy;
1674    gen.argb[GGLFormat::RED  ].dx = c->shade.drdx;
1675    gen.argb[GGLFormat::GREEN].c  = ci.ydgdy;
1676    gen.argb[GGLFormat::GREEN].dx = c->shade.dgdx;
1677    gen.argb[GGLFormat::BLUE ].c  = ci.ydbdy;
1678    gen.argb[GGLFormat::BLUE ].dx = c->shade.dbdx;
1679    gen.dzdx = c->shade.dzdx;
1680    gen.f    = ci.ydfdy;
1681    gen.dfdx = c->shade.dfdx;
1682
1683    if (enables & GGL_ENABLE_TMUS) {
1684        for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
1685            texture_t& t = c->state.texture[i];
1686            if (!t.enable) continue;
1687
1688            texture_iterators_t& ti = t.iterators;
1689            if (t.s_coord == GGL_ONE_TO_ONE && t.t_coord == GGL_ONE_TO_ONE) {
1690                // we need to set all of these to 0 because in some cases
1691                // step_y__generic() or step_y__tmu() will be used and
1692                // therefore will update dtdy, however, in 1:1 mode
1693                // this is always done by the scanline rasterizer.
1694                ti.dsdx = ti.dsdy = ti.dtdx = ti.dtdy = 0;
1695                ti.ydsdy = t.shade.is0;
1696                ti.ydtdy = t.shade.it0;
1697            } else {
1698                const int adjustSWrap = ((t.s_wrap==GGL_CLAMP)?0:16);
1699                const int adjustTWrap = ((t.t_wrap==GGL_CLAMP)?0:16);
1700                ti.sscale = t.shade.sscale + adjustSWrap;
1701                ti.tscale = t.shade.tscale + adjustTWrap;
1702                if (!(enables & GGL_ENABLE_W)) {
1703                    // S coordinate
1704                    const int32_t sscale = ti.sscale;
1705                    const int32_t sy = interpolate(ys,
1706                            t.shade.is0, t.shade.idsdx, t.shade.idsdy);
1707                    if (sscale>=0) {
1708                        ti.ydsdy= sy            << sscale;
1709                        ti.dsdx = t.shade.idsdx << sscale;
1710                        ti.dsdy = t.shade.idsdy << sscale;
1711                    } else {
1712                        ti.ydsdy= sy            >> -sscale;
1713                        ti.dsdx = t.shade.idsdx >> -sscale;
1714                        ti.dsdy = t.shade.idsdy >> -sscale;
1715                    }
1716                    // T coordinate
1717                    const int32_t tscale = ti.tscale;
1718                    const int32_t ty = interpolate(ys,
1719                            t.shade.it0, t.shade.idtdx, t.shade.idtdy);
1720                    if (tscale>=0) {
1721                        ti.ydtdy= ty            << tscale;
1722                        ti.dtdx = t.shade.idtdx << tscale;
1723                        ti.dtdy = t.shade.idtdy << tscale;
1724                    } else {
1725                        ti.ydtdy= ty            >> -tscale;
1726                        ti.dtdx = t.shade.idtdx >> -tscale;
1727                        ti.dtdy = t.shade.idtdy >> -tscale;
1728                    }
1729                }
1730            }
1731            // mirror for generated code...
1732            generated_tex_vars_t& gen = c->generated_vars.texture[i];
1733            gen.width   = t.surface.width;
1734            gen.height  = t.surface.height;
1735            gen.stride  = t.surface.stride;
1736            gen.data    = uintptr_t(t.surface.data);
1737            gen.dsdx = ti.dsdx;
1738            gen.dtdx = ti.dtdx;
1739        }
1740    }
1741
1742    // choose the y-stepper
1743    c->step_y = step_y__nop;
1744    if (enables & GGL_ENABLE_FOG) {
1745        c->step_y = step_y__generic;
1746    } else if (enables & GGL_ENABLE_TMUS) {
1747        if (enables & GGL_ENABLE_SMOOTH) {
1748            c->step_y = step_y__generic;
1749        } else if (enables & GGL_ENABLE_W) {
1750            c->step_y = step_y__w;
1751        } else {
1752            c->step_y = step_y__tmu;
1753        }
1754    } else {
1755        if (enables & GGL_ENABLE_SMOOTH) {
1756            c->step_y = step_y__smooth;
1757        }
1758    }
1759
1760    // choose the rectangle blitter
1761    c->rect = rect_generic;
1762    if ((c->step_y == step_y__nop) &&
1763        (c->scanline == scanline_memcpy))
1764    {
1765        c->rect = rect_memcpy;
1766    }
1767}
1768
1769void init_y_packed(context_t* c, int32_t y0)
1770{
1771    uint8_t f = c->state.buffers.color.format;
1772    c->packed = ggl_pack_color(c, f,
1773            c->shade.r0, c->shade.g0, c->shade.b0, c->shade.a0);
1774    c->packed8888 = ggl_pack_color(c, GGL_PIXEL_FORMAT_RGBA_8888,
1775            c->shade.r0, c->shade.g0, c->shade.b0, c->shade.a0);
1776    c->iterators.y = y0;
1777    c->step_y = step_y__nop;
1778    // choose the rectangle blitter
1779    c->rect = rect_generic;
1780    if (c->scanline == scanline_memcpy) {
1781        c->rect = rect_memcpy;
1782    }
1783}
1784
1785void init_y_noop(context_t* c, int32_t y0)
1786{
1787    c->iterators.y = y0;
1788    c->step_y = step_y__nop;
1789    // choose the rectangle blitter
1790    c->rect = rect_generic;
1791    if (c->scanline == scanline_memcpy) {
1792        c->rect = rect_memcpy;
1793    }
1794}
1795
1796void init_y_error(context_t* c, int32_t y0)
1797{
1798    // woooops, shoud never happen,
1799    // fail gracefully (don't display anything)
1800    init_y_noop(c, y0);
1801    ALOGE("color-buffer has an invalid format!");
1802}
1803
1804// ----------------------------------------------------------------------------
1805#if 0
1806#pragma mark -
1807#endif
1808
1809void step_y__generic(context_t* c)
1810{
1811    const uint32_t enables = c->state.enables;
1812
1813    // iterate...
1814    iterators_t& ci = c->iterators;
1815    ci.y += 1;
1816
1817    if (enables & GGL_ENABLE_SMOOTH) {
1818        ci.ydrdy += c->shade.drdy;
1819        ci.ydgdy += c->shade.dgdy;
1820        ci.ydbdy += c->shade.dbdy;
1821        ci.ydady += c->shade.dady;
1822    }
1823
1824    const uint32_t mask =
1825            GGL_ENABLE_DEPTH_TEST |
1826            GGL_ENABLE_W |
1827            GGL_ENABLE_FOG;
1828    if (enables & mask) {
1829        ci.ydzdy += c->shade.dzdy;
1830        ci.ydwdy += c->shade.dwdy;
1831        ci.ydfdy += c->shade.dfdy;
1832    }
1833
1834    if ((enables & GGL_ENABLE_TMUS) && (!(enables & GGL_ENABLE_W))) {
1835        for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
1836            if (c->state.texture[i].enable) {
1837                texture_iterators_t& ti = c->state.texture[i].iterators;
1838                ti.ydsdy += ti.dsdy;
1839                ti.ydtdy += ti.dtdy;
1840            }
1841        }
1842    }
1843}
1844
1845void step_y__nop(context_t* c)
1846{
1847    c->iterators.y += 1;
1848    c->iterators.ydzdy += c->shade.dzdy;
1849}
1850
1851void step_y__smooth(context_t* c)
1852{
1853    iterators_t& ci = c->iterators;
1854    ci.y += 1;
1855    ci.ydrdy += c->shade.drdy;
1856    ci.ydgdy += c->shade.dgdy;
1857    ci.ydbdy += c->shade.dbdy;
1858    ci.ydady += c->shade.dady;
1859    ci.ydzdy += c->shade.dzdy;
1860}
1861
1862void step_y__w(context_t* c)
1863{
1864    iterators_t& ci = c->iterators;
1865    ci.y += 1;
1866    ci.ydzdy += c->shade.dzdy;
1867    ci.ydwdy += c->shade.dwdy;
1868}
1869
1870void step_y__tmu(context_t* c)
1871{
1872    iterators_t& ci = c->iterators;
1873    ci.y += 1;
1874    ci.ydzdy += c->shade.dzdy;
1875    for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
1876        if (c->state.texture[i].enable) {
1877            texture_iterators_t& ti = c->state.texture[i].iterators;
1878            ti.ydsdy += ti.dsdy;
1879            ti.ydtdy += ti.dtdy;
1880        }
1881    }
1882}
1883
1884// ----------------------------------------------------------------------------
1885#if 0
1886#pragma mark -
1887#endif
1888
1889void scanline_perspective(context_t* c)
1890{
1891    struct {
1892        union {
1893            struct {
1894                int32_t s, sq;
1895                int32_t t, tq;
1896            } sqtq;
1897            struct {
1898                int32_t v, q;
1899            } st[2];
1900        };
1901    } tc[GGL_TEXTURE_UNIT_COUNT] __attribute__((aligned(16)));
1902
1903    // XXX: we should have a special case when dwdx = 0
1904
1905    // 32 pixels spans works okay. 16 is a lot better,
1906    // but hey, it's a software renderer...
1907    const uint32_t SPAN_BITS = 5;
1908    const uint32_t ys = c->iterators.y;
1909    const uint32_t xs = c->iterators.xl;
1910    const uint32_t x1 = c->iterators.xr;
1911	const uint32_t xc = x1 - xs;
1912    uint32_t remainder = xc & ((1<<SPAN_BITS)-1);
1913    uint32_t numSpans = xc >> SPAN_BITS;
1914
1915    const iterators_t& ci = c->iterators;
1916    int32_t w0 = (xs * c->shade.dwdx) + ci.ydwdy;
1917    int32_t q0 = gglRecipQ(w0, 30);
1918    const int iwscale = 32 - gglClz(q0);
1919
1920    const int32_t dwdx = c->shade.dwdx << SPAN_BITS;
1921    int32_t xl = c->iterators.xl;
1922
1923    // We process s & t with a loop to reduce the code size
1924    // (and i-cache pressure).
1925
1926    for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
1927        const texture_t& tmu = c->state.texture[i];
1928        if (!tmu.enable) continue;
1929        int32_t s =   tmu.shade.is0 +
1930                     (tmu.shade.idsdy * ys) + (tmu.shade.idsdx * xs) +
1931                     ((tmu.shade.idsdx + tmu.shade.idsdy)>>1);
1932        int32_t t =   tmu.shade.it0 +
1933                     (tmu.shade.idtdy * ys) + (tmu.shade.idtdx * xs) +
1934                     ((tmu.shade.idtdx + tmu.shade.idtdy)>>1);
1935        tc[i].sqtq.s  = s;
1936        tc[i].sqtq.t  = t;
1937        tc[i].sqtq.sq = gglMulx(s, q0, iwscale);
1938        tc[i].sqtq.tq = gglMulx(t, q0, iwscale);
1939    }
1940
1941    int32_t span = 0;
1942    do {
1943        int32_t w1;
1944        if (ggl_likely(numSpans)) {
1945            w1 = w0 + dwdx;
1946        } else {
1947            if (remainder) {
1948                // finish off the scanline...
1949                span = remainder;
1950                w1 = (c->shade.dwdx * span) + w0;
1951            } else {
1952                break;
1953            }
1954        }
1955        int32_t q1 = gglRecipQ(w1, 30);
1956        for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
1957            texture_t& tmu = c->state.texture[i];
1958            if (!tmu.enable) continue;
1959            texture_iterators_t& ti = tmu.iterators;
1960
1961            for (int j=0 ; j<2 ; j++) {
1962                int32_t v = tc[i].st[j].v;
1963                if (span)   v += (tmu.shade.st[j].dx)*span;
1964                else        v += (tmu.shade.st[j].dx)<<SPAN_BITS;
1965                const int32_t v0 = tc[i].st[j].q;
1966                const int32_t v1 = gglMulx(v, q1, iwscale);
1967                int32_t dvdx = v1 - v0;
1968                if (span)   dvdx /= span;
1969                else        dvdx >>= SPAN_BITS;
1970                tc[i].st[j].v = v;
1971                tc[i].st[j].q = v1;
1972
1973                const int scale = ti.st[j].scale + (iwscale - 30);
1974                if (scale >= 0) {
1975                    ti.st[j].ydvdy = v0   << scale;
1976                    ti.st[j].dvdx  = dvdx << scale;
1977                } else {
1978                    ti.st[j].ydvdy = v0   >> -scale;
1979                    ti.st[j].dvdx  = dvdx >> -scale;
1980                }
1981            }
1982            generated_tex_vars_t& gen = c->generated_vars.texture[i];
1983            gen.dsdx = ti.st[0].dvdx;
1984            gen.dtdx = ti.st[1].dvdx;
1985        }
1986        c->iterators.xl = xl;
1987        c->iterators.xr = xl = xl + (span ? span : (1<<SPAN_BITS));
1988        w0 = w1;
1989        q0 = q1;
1990        c->span(c);
1991    } while(numSpans--);
1992}
1993
1994void scanline_perspective_single(context_t* c)
1995{
1996    // 32 pixels spans works okay. 16 is a lot better,
1997    // but hey, it's a software renderer...
1998    const uint32_t SPAN_BITS = 5;
1999    const uint32_t ys = c->iterators.y;
2000    const uint32_t xs = c->iterators.xl;
2001    const uint32_t x1 = c->iterators.xr;
2002	const uint32_t xc = x1 - xs;
2003
2004    const iterators_t& ci = c->iterators;
2005    int32_t w = (xs * c->shade.dwdx) + ci.ydwdy;
2006    int32_t iw = gglRecipQ(w, 30);
2007    const int iwscale = 32 - gglClz(iw);
2008
2009    const int i = 31 - gglClz(c->state.enabled_tmu);
2010    generated_tex_vars_t& gen = c->generated_vars.texture[i];
2011    texture_t& tmu = c->state.texture[i];
2012    texture_iterators_t& ti = tmu.iterators;
2013    const int sscale = ti.sscale + (iwscale - 30);
2014    const int tscale = ti.tscale + (iwscale - 30);
2015    int32_t s =   tmu.shade.is0 +
2016                 (tmu.shade.idsdy * ys) + (tmu.shade.idsdx * xs) +
2017                 ((tmu.shade.idsdx + tmu.shade.idsdy)>>1);
2018    int32_t t =   tmu.shade.it0 +
2019                 (tmu.shade.idtdy * ys) + (tmu.shade.idtdx * xs) +
2020                 ((tmu.shade.idtdx + tmu.shade.idtdy)>>1);
2021    int32_t s0 = gglMulx(s, iw, iwscale);
2022    int32_t t0 = gglMulx(t, iw, iwscale);
2023    int32_t xl = c->iterators.xl;
2024
2025    int32_t sq, tq, dsdx, dtdx;
2026    int32_t premainder = xc & ((1<<SPAN_BITS)-1);
2027    uint32_t numSpans = xc >> SPAN_BITS;
2028    if (c->shade.dwdx == 0) {
2029        // XXX: we could choose to do this if the error is small enough
2030        numSpans = 0;
2031        premainder = xc;
2032        goto no_perspective;
2033    }
2034
2035    if (premainder) {
2036        w += c->shade.dwdx   * premainder;
2037        iw = gglRecipQ(w, 30);
2038no_perspective:
2039        s += tmu.shade.idsdx * premainder;
2040        t += tmu.shade.idtdx * premainder;
2041        sq = gglMulx(s, iw, iwscale);
2042        tq = gglMulx(t, iw, iwscale);
2043        dsdx = (sq - s0) / premainder;
2044        dtdx = (tq - t0) / premainder;
2045        c->iterators.xl = xl;
2046        c->iterators.xr = xl = xl + premainder;
2047        goto finish;
2048    }
2049
2050    while (numSpans--) {
2051        w += c->shade.dwdx   << SPAN_BITS;
2052        s += tmu.shade.idsdx << SPAN_BITS;
2053        t += tmu.shade.idtdx << SPAN_BITS;
2054        iw = gglRecipQ(w, 30);
2055        sq = gglMulx(s, iw, iwscale);
2056        tq = gglMulx(t, iw, iwscale);
2057        dsdx = (sq - s0) >> SPAN_BITS;
2058        dtdx = (tq - t0) >> SPAN_BITS;
2059        c->iterators.xl = xl;
2060        c->iterators.xr = xl = xl + (1<<SPAN_BITS);
2061finish:
2062        if (sscale >= 0) {
2063            ti.ydsdy = s0   << sscale;
2064            ti.dsdx  = dsdx << sscale;
2065        } else {
2066            ti.ydsdy = s0   >>-sscale;
2067            ti.dsdx  = dsdx >>-sscale;
2068        }
2069        if (tscale >= 0) {
2070            ti.ydtdy = t0   << tscale;
2071            ti.dtdx  = dtdx << tscale;
2072        } else {
2073            ti.ydtdy = t0   >>-tscale;
2074            ti.dtdx  = dtdx >>-tscale;
2075        }
2076        s0 = sq;
2077        t0 = tq;
2078        gen.dsdx = ti.dsdx;
2079        gen.dtdx = ti.dtdx;
2080        c->span(c);
2081    }
2082}
2083
2084// ----------------------------------------------------------------------------
2085
2086void scanline_col32cb16blend(context_t* c)
2087{
2088    int32_t x = c->iterators.xl;
2089    size_t ct = c->iterators.xr - x;
2090    int32_t y = c->iterators.y;
2091    surface_t* cb = &(c->state.buffers.color);
2092    union {
2093        uint16_t* dst;
2094        uint32_t* dst32;
2095    };
2096    dst = reinterpret_cast<uint16_t*>(cb->data) + (x+(cb->stride*y));
2097
2098#if ((ANDROID_CODEGEN >= ANDROID_CODEGEN_ASM) && defined(__arm__))
2099#if defined(__ARM_HAVE_NEON) && BYTE_ORDER == LITTLE_ENDIAN
2100    scanline_col32cb16blend_neon(dst, &(c->packed8888), ct);
2101#else  // defined(__ARM_HAVE_NEON) && BYTE_ORDER == LITTLE_ENDIAN
2102    scanline_col32cb16blend_arm(dst, GGL_RGBA_TO_HOST(c->packed8888), ct);
2103#endif // defined(__ARM_HAVE_NEON) && BYTE_ORDER == LITTLE_ENDIAN
2104#elif ((ANDROID_CODEGEN >= ANDROID_CODEGEN_ASM) && defined(__aarch64__))
2105    scanline_col32cb16blend_arm64(dst, GGL_RGBA_TO_HOST(c->packed8888), ct);
2106#else
2107    uint32_t s = GGL_RGBA_TO_HOST(c->packed8888);
2108    int sA = (s>>24);
2109    int f = 0x100 - (sA + (sA>>7));
2110    while (ct--) {
2111        uint16_t d = *dst;
2112        int dR = (d>>11)&0x1f;
2113        int dG = (d>>5)&0x3f;
2114        int dB = (d)&0x1f;
2115        int sR = (s >> (   3))&0x1F;
2116        int sG = (s >> ( 8+2))&0x3F;
2117        int sB = (s >> (16+3))&0x1F;
2118        sR += (f*dR)>>8;
2119        sG += (f*dG)>>8;
2120        sB += (f*dB)>>8;
2121        *dst++ = uint16_t((sR<<11)|(sG<<5)|sB);
2122    }
2123#endif
2124
2125}
2126
2127void scanline_t32cb16(context_t* c)
2128{
2129    int32_t x = c->iterators.xl;
2130    size_t ct = c->iterators.xr - x;
2131    int32_t y = c->iterators.y;
2132    surface_t* cb = &(c->state.buffers.color);
2133    union {
2134        uint16_t* dst;
2135        uint32_t* dst32;
2136    };
2137    dst = reinterpret_cast<uint16_t*>(cb->data) + (x+(cb->stride*y));
2138
2139    surface_t* tex = &(c->state.texture[0].surface);
2140    const int32_t u = (c->state.texture[0].shade.is0>>16) + x;
2141    const int32_t v = (c->state.texture[0].shade.it0>>16) + y;
2142    uint32_t *src = reinterpret_cast<uint32_t*>(tex->data)+(u+(tex->stride*v));
2143    int sR, sG, sB;
2144    uint32_t s, d;
2145
2146    if (ct==1 || uintptr_t(dst)&2) {
2147last_one:
2148        s = GGL_RGBA_TO_HOST( *src++ );
2149        *dst++ = convertAbgr8888ToRgb565(s);
2150        ct--;
2151    }
2152
2153    while (ct >= 2) {
2154#if BYTE_ORDER == BIG_ENDIAN
2155        s = GGL_RGBA_TO_HOST( *src++ );
2156        d = convertAbgr8888ToRgb565_hi16(s);
2157
2158        s = GGL_RGBA_TO_HOST( *src++ );
2159        d |= convertAbgr8888ToRgb565(s);
2160#else
2161        s = GGL_RGBA_TO_HOST( *src++ );
2162        d = convertAbgr8888ToRgb565(s);
2163
2164        s = GGL_RGBA_TO_HOST( *src++ );
2165        d |= convertAbgr8888ToRgb565(s) << 16;
2166#endif
2167        *dst32++ = d;
2168        ct -= 2;
2169    }
2170
2171    if (ct > 0) {
2172        goto last_one;
2173    }
2174}
2175
2176void scanline_t32cb16blend(context_t* c)
2177{
2178#if ((ANDROID_CODEGEN >= ANDROID_CODEGEN_ASM) && (defined(__arm__) || defined(__mips__) || defined(__aarch64__)))
2179    int32_t x = c->iterators.xl;
2180    size_t ct = c->iterators.xr - x;
2181    int32_t y = c->iterators.y;
2182    surface_t* cb = &(c->state.buffers.color);
2183    uint16_t* dst = reinterpret_cast<uint16_t*>(cb->data) + (x+(cb->stride*y));
2184
2185    surface_t* tex = &(c->state.texture[0].surface);
2186    const int32_t u = (c->state.texture[0].shade.is0>>16) + x;
2187    const int32_t v = (c->state.texture[0].shade.it0>>16) + y;
2188    uint32_t *src = reinterpret_cast<uint32_t*>(tex->data)+(u+(tex->stride*v));
2189
2190#ifdef __arm__
2191    scanline_t32cb16blend_arm(dst, src, ct);
2192#elif defined(__aarch64__)
2193    scanline_t32cb16blend_arm64(dst, src, ct);
2194#elif defined(__mips__)
2195    scanline_t32cb16blend_mips(dst, src, ct);
2196#endif
2197#else
2198    dst_iterator16  di(c);
2199    horz_iterator32  hi(c);
2200    blender_32to16  bl(c);
2201    while (di.count--) {
2202        uint32_t s = hi.get_pixel32();
2203        bl.write(s, di.dst);
2204        di.dst++;
2205    }
2206#endif
2207}
2208
2209void scanline_t32cb16blend_srca(context_t* c)
2210{
2211    dst_iterator16  di(c);
2212    horz_iterator32  hi(c);
2213    blender_32to16_srcA  blender(c);
2214
2215    while (di.count--) {
2216        uint32_t s = hi.get_pixel32();
2217        blender.write(s,di.dst);
2218        di.dst++;
2219    }
2220}
2221
2222void scanline_t16cb16blend_clamp_mod(context_t* c)
2223{
2224    const int a = c->iterators.ydady >> (GGL_COLOR_BITS-8);
2225    if (a == 0) {
2226        return;
2227    }
2228
2229    if (a == 255) {
2230        scanline_t16cb16_clamp(c);
2231        return;
2232    }
2233
2234    dst_iterator16  di(c);
2235    blender_16to16_modulate  blender(c);
2236    clamp_iterator  ci(c);
2237
2238    while (di.count--) {
2239        uint16_t s = ci.get_pixel16();
2240        blender.write(s, di.dst);
2241        di.dst++;
2242    }
2243}
2244
2245void scanline_memcpy(context_t* c)
2246{
2247    int32_t x = c->iterators.xl;
2248    size_t ct = c->iterators.xr - x;
2249    int32_t y = c->iterators.y;
2250    surface_t* cb = &(c->state.buffers.color);
2251    const GGLFormat* fp = &(c->formats[cb->format]);
2252    uint8_t* dst = reinterpret_cast<uint8_t*>(cb->data) +
2253                            (x + (cb->stride * y)) * fp->size;
2254
2255    surface_t* tex = &(c->state.texture[0].surface);
2256    const int32_t u = (c->state.texture[0].shade.is0>>16) + x;
2257    const int32_t v = (c->state.texture[0].shade.it0>>16) + y;
2258    uint8_t *src = reinterpret_cast<uint8_t*>(tex->data) +
2259                            (u + (tex->stride * v)) * fp->size;
2260
2261    const size_t size = ct * fp->size;
2262    memcpy(dst, src, size);
2263}
2264
2265void scanline_memset8(context_t* c)
2266{
2267    int32_t x = c->iterators.xl;
2268    size_t ct = c->iterators.xr - x;
2269    int32_t y = c->iterators.y;
2270    surface_t* cb = &(c->state.buffers.color);
2271    uint8_t* dst = reinterpret_cast<uint8_t*>(cb->data) + (x+(cb->stride*y));
2272    uint32_t packed = c->packed;
2273    memset(dst, packed, ct);
2274}
2275
2276void scanline_memset16(context_t* c)
2277{
2278    int32_t x = c->iterators.xl;
2279    size_t ct = c->iterators.xr - x;
2280    int32_t y = c->iterators.y;
2281    surface_t* cb = &(c->state.buffers.color);
2282    uint16_t* dst = reinterpret_cast<uint16_t*>(cb->data) + (x+(cb->stride*y));
2283    uint32_t packed = c->packed;
2284    android_memset16(dst, packed, ct*2);
2285}
2286
2287void scanline_memset32(context_t* c)
2288{
2289    int32_t x = c->iterators.xl;
2290    size_t ct = c->iterators.xr - x;
2291    int32_t y = c->iterators.y;
2292    surface_t* cb = &(c->state.buffers.color);
2293    uint32_t* dst = reinterpret_cast<uint32_t*>(cb->data) + (x+(cb->stride*y));
2294    uint32_t packed = GGL_HOST_TO_RGBA(c->packed);
2295    android_memset32(dst, packed, ct*4);
2296}
2297
2298void scanline_clear(context_t* c)
2299{
2300    int32_t x = c->iterators.xl;
2301    size_t ct = c->iterators.xr - x;
2302    int32_t y = c->iterators.y;
2303    surface_t* cb = &(c->state.buffers.color);
2304    const GGLFormat* fp = &(c->formats[cb->format]);
2305    uint8_t* dst = reinterpret_cast<uint8_t*>(cb->data) +
2306                            (x + (cb->stride * y)) * fp->size;
2307    const size_t size = ct * fp->size;
2308    memset(dst, 0, size);
2309}
2310
2311void scanline_set(context_t* c)
2312{
2313    int32_t x = c->iterators.xl;
2314    size_t ct = c->iterators.xr - x;
2315    int32_t y = c->iterators.y;
2316    surface_t* cb = &(c->state.buffers.color);
2317    const GGLFormat* fp = &(c->formats[cb->format]);
2318    uint8_t* dst = reinterpret_cast<uint8_t*>(cb->data) +
2319                            (x + (cb->stride * y)) * fp->size;
2320    const size_t size = ct * fp->size;
2321    memset(dst, 0xFF, size);
2322}
2323
2324void scanline_noop(context_t* /*c*/)
2325{
2326}
2327
2328void rect_generic(context_t* c, size_t yc)
2329{
2330    do {
2331        c->scanline(c);
2332        c->step_y(c);
2333    } while (--yc);
2334}
2335
2336void rect_memcpy(context_t* c, size_t yc)
2337{
2338    int32_t x = c->iterators.xl;
2339    size_t ct = c->iterators.xr - x;
2340    int32_t y = c->iterators.y;
2341    surface_t* cb = &(c->state.buffers.color);
2342    const GGLFormat* fp = &(c->formats[cb->format]);
2343    uint8_t* dst = reinterpret_cast<uint8_t*>(cb->data) +
2344                            (x + (cb->stride * y)) * fp->size;
2345
2346    surface_t* tex = &(c->state.texture[0].surface);
2347    const int32_t u = (c->state.texture[0].shade.is0>>16) + x;
2348    const int32_t v = (c->state.texture[0].shade.it0>>16) + y;
2349    uint8_t *src = reinterpret_cast<uint8_t*>(tex->data) +
2350                            (u + (tex->stride * v)) * fp->size;
2351
2352    if (cb->stride == tex->stride && ct == size_t(cb->stride)) {
2353        memcpy(dst, src, ct * fp->size * yc);
2354    } else {
2355        const size_t size = ct * fp->size;
2356        const size_t dbpr = cb->stride  * fp->size;
2357        const size_t sbpr = tex->stride * fp->size;
2358        do {
2359            memcpy(dst, src, size);
2360            dst += dbpr;
2361            src += sbpr;
2362        } while (--yc);
2363    }
2364}
2365// ----------------------------------------------------------------------------
2366}; // namespace android
2367
2368