1/*
2 * Copyright © 2015 Broadcom
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 */
23
24/**
25 * Implements most of the fixed function fragment pipeline in shader code.
26 *
27 * VC4 doesn't have any hardware support for blending, alpha test, logic ops,
28 * or color mask.  Instead, you read the current contents of the destination
29 * from the tile buffer after having waited for the scoreboard (which is
30 * handled by vc4_qpu_emit.c), then do math using your output color and that
31 * destination value, and update the output color appropriately.
32 *
33 * Once this pass is done, the color write will either have one component (for
34 * single sample) with packed argb8888, or 4 components with the per-sample
35 * argb8888 result.
36 */
37
38/**
39 * Lowers fixed-function blending to a load of the destination color and a
40 * series of ALU operations before the store of the output.
41 */
42#include "util/u_format.h"
43#include "vc4_qir.h"
44#include "compiler/nir/nir_builder.h"
45#include "vc4_context.h"
46
47static bool
48blend_depends_on_dst_color(struct vc4_compile *c)
49{
50        return (c->fs_key->blend.blend_enable ||
51                c->fs_key->blend.colormask != 0xf ||
52                c->fs_key->logicop_func != PIPE_LOGICOP_COPY);
53}
54
55/** Emits a load of the previous fragment color from the tile buffer. */
56static nir_ssa_def *
57vc4_nir_get_dst_color(nir_builder *b, int sample)
58{
59        nir_intrinsic_instr *load =
60                nir_intrinsic_instr_create(b->shader,
61                                           nir_intrinsic_load_input);
62        load->num_components = 1;
63        nir_intrinsic_set_base(load, VC4_NIR_TLB_COLOR_READ_INPUT + sample);
64        load->src[0] = nir_src_for_ssa(nir_imm_int(b, 0));
65        nir_ssa_dest_init(&load->instr, &load->dest, 1, 32, NULL);
66        nir_builder_instr_insert(b, &load->instr);
67        return &load->dest.ssa;
68}
69
70static  nir_ssa_def *
71vc4_nir_srgb_decode(nir_builder *b, nir_ssa_def *srgb)
72{
73        nir_ssa_def *is_low = nir_flt(b, srgb, nir_imm_float(b, 0.04045));
74        nir_ssa_def *low = nir_fmul(b, srgb, nir_imm_float(b, 1.0 / 12.92));
75        nir_ssa_def *high = nir_fpow(b,
76                                     nir_fmul(b,
77                                              nir_fadd(b, srgb,
78                                                       nir_imm_float(b, 0.055)),
79                                              nir_imm_float(b, 1.0 / 1.055)),
80                                     nir_imm_float(b, 2.4));
81
82        return nir_bcsel(b, is_low, low, high);
83}
84
85static  nir_ssa_def *
86vc4_nir_srgb_encode(nir_builder *b, nir_ssa_def *linear)
87{
88        nir_ssa_def *is_low = nir_flt(b, linear, nir_imm_float(b, 0.0031308));
89        nir_ssa_def *low = nir_fmul(b, linear, nir_imm_float(b, 12.92));
90        nir_ssa_def *high = nir_fsub(b,
91                                     nir_fmul(b,
92                                              nir_imm_float(b, 1.055),
93                                              nir_fpow(b,
94                                                       linear,
95                                                       nir_imm_float(b, 0.41666))),
96                                     nir_imm_float(b, 0.055));
97
98        return nir_bcsel(b, is_low, low, high);
99}
100
101static nir_ssa_def *
102vc4_blend_channel_f(nir_builder *b,
103                    nir_ssa_def **src,
104                    nir_ssa_def **dst,
105                    unsigned factor,
106                    int channel)
107{
108        switch(factor) {
109        case PIPE_BLENDFACTOR_ONE:
110                return nir_imm_float(b, 1.0);
111        case PIPE_BLENDFACTOR_SRC_COLOR:
112                return src[channel];
113        case PIPE_BLENDFACTOR_SRC_ALPHA:
114                return src[3];
115        case PIPE_BLENDFACTOR_DST_ALPHA:
116                return dst[3];
117        case PIPE_BLENDFACTOR_DST_COLOR:
118                return dst[channel];
119        case PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE:
120                if (channel != 3) {
121                        return nir_fmin(b,
122                                        src[3],
123                                        nir_fsub(b,
124                                                 nir_imm_float(b, 1.0),
125                                                 dst[3]));
126                } else {
127                        return nir_imm_float(b, 1.0);
128                }
129        case PIPE_BLENDFACTOR_CONST_COLOR:
130                return nir_load_system_value(b,
131                                             nir_intrinsic_load_blend_const_color_r_float +
132                                             channel,
133                                             0);
134        case PIPE_BLENDFACTOR_CONST_ALPHA:
135                return nir_load_blend_const_color_a_float(b);
136        case PIPE_BLENDFACTOR_ZERO:
137                return nir_imm_float(b, 0.0);
138        case PIPE_BLENDFACTOR_INV_SRC_COLOR:
139                return nir_fsub(b, nir_imm_float(b, 1.0), src[channel]);
140        case PIPE_BLENDFACTOR_INV_SRC_ALPHA:
141                return nir_fsub(b, nir_imm_float(b, 1.0), src[3]);
142        case PIPE_BLENDFACTOR_INV_DST_ALPHA:
143                return nir_fsub(b, nir_imm_float(b, 1.0), dst[3]);
144        case PIPE_BLENDFACTOR_INV_DST_COLOR:
145                return nir_fsub(b, nir_imm_float(b, 1.0), dst[channel]);
146        case PIPE_BLENDFACTOR_INV_CONST_COLOR:
147                return nir_fsub(b, nir_imm_float(b, 1.0),
148                                nir_load_system_value(b,
149                                                      nir_intrinsic_load_blend_const_color_r_float +
150                                                      channel,
151                                                      0));
152        case PIPE_BLENDFACTOR_INV_CONST_ALPHA:
153                return nir_fsub(b, nir_imm_float(b, 1.0),
154                                nir_load_blend_const_color_a_float(b));
155
156        default:
157        case PIPE_BLENDFACTOR_SRC1_COLOR:
158        case PIPE_BLENDFACTOR_SRC1_ALPHA:
159        case PIPE_BLENDFACTOR_INV_SRC1_COLOR:
160        case PIPE_BLENDFACTOR_INV_SRC1_ALPHA:
161                /* Unsupported. */
162                fprintf(stderr, "Unknown blend factor %d\n", factor);
163                return nir_imm_float(b, 1.0);
164        }
165}
166
167static nir_ssa_def *
168vc4_nir_set_packed_chan(nir_builder *b, nir_ssa_def *src0, nir_ssa_def *src1,
169                        int chan)
170{
171        unsigned chan_mask = 0xff << (chan * 8);
172        return nir_ior(b,
173                       nir_iand(b, src0, nir_imm_int(b, ~chan_mask)),
174                       nir_iand(b, src1, nir_imm_int(b, chan_mask)));
175}
176
177static nir_ssa_def *
178vc4_blend_channel_i(nir_builder *b,
179                    nir_ssa_def *src,
180                    nir_ssa_def *dst,
181                    nir_ssa_def *src_a,
182                    nir_ssa_def *dst_a,
183                    unsigned factor,
184                    int a_chan)
185{
186        switch (factor) {
187        case PIPE_BLENDFACTOR_ONE:
188                return nir_imm_int(b, ~0);
189        case PIPE_BLENDFACTOR_SRC_COLOR:
190                return src;
191        case PIPE_BLENDFACTOR_SRC_ALPHA:
192                return src_a;
193        case PIPE_BLENDFACTOR_DST_ALPHA:
194                return dst_a;
195        case PIPE_BLENDFACTOR_DST_COLOR:
196                return dst;
197        case PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE:
198                return vc4_nir_set_packed_chan(b,
199                                               nir_umin_4x8(b,
200                                                            src_a,
201                                                            nir_inot(b, dst_a)),
202                                               nir_imm_int(b, ~0),
203                                               a_chan);
204        case PIPE_BLENDFACTOR_CONST_COLOR:
205                return nir_load_blend_const_color_rgba8888_unorm(b);
206        case PIPE_BLENDFACTOR_CONST_ALPHA:
207                return nir_load_blend_const_color_aaaa8888_unorm(b);
208        case PIPE_BLENDFACTOR_ZERO:
209                return nir_imm_int(b, 0);
210        case PIPE_BLENDFACTOR_INV_SRC_COLOR:
211                return nir_inot(b, src);
212        case PIPE_BLENDFACTOR_INV_SRC_ALPHA:
213                return nir_inot(b, src_a);
214        case PIPE_BLENDFACTOR_INV_DST_ALPHA:
215                return nir_inot(b, dst_a);
216        case PIPE_BLENDFACTOR_INV_DST_COLOR:
217                return nir_inot(b, dst);
218        case PIPE_BLENDFACTOR_INV_CONST_COLOR:
219                return nir_inot(b,
220                                nir_load_blend_const_color_rgba8888_unorm(b));
221        case PIPE_BLENDFACTOR_INV_CONST_ALPHA:
222                return nir_inot(b,
223                                nir_load_blend_const_color_aaaa8888_unorm(b));
224
225        default:
226        case PIPE_BLENDFACTOR_SRC1_COLOR:
227        case PIPE_BLENDFACTOR_SRC1_ALPHA:
228        case PIPE_BLENDFACTOR_INV_SRC1_COLOR:
229        case PIPE_BLENDFACTOR_INV_SRC1_ALPHA:
230                /* Unsupported. */
231                fprintf(stderr, "Unknown blend factor %d\n", factor);
232                return nir_imm_int(b, ~0);
233        }
234}
235
236static nir_ssa_def *
237vc4_blend_func_f(nir_builder *b, nir_ssa_def *src, nir_ssa_def *dst,
238                 unsigned func)
239{
240        switch (func) {
241        case PIPE_BLEND_ADD:
242                return nir_fadd(b, src, dst);
243        case PIPE_BLEND_SUBTRACT:
244                return nir_fsub(b, src, dst);
245        case PIPE_BLEND_REVERSE_SUBTRACT:
246                return nir_fsub(b, dst, src);
247        case PIPE_BLEND_MIN:
248                return nir_fmin(b, src, dst);
249        case PIPE_BLEND_MAX:
250                return nir_fmax(b, src, dst);
251
252        default:
253                /* Unsupported. */
254                fprintf(stderr, "Unknown blend func %d\n", func);
255                return src;
256
257        }
258}
259
260static nir_ssa_def *
261vc4_blend_func_i(nir_builder *b, nir_ssa_def *src, nir_ssa_def *dst,
262                 unsigned func)
263{
264        switch (func) {
265        case PIPE_BLEND_ADD:
266                return nir_usadd_4x8(b, src, dst);
267        case PIPE_BLEND_SUBTRACT:
268                return nir_ussub_4x8(b, src, dst);
269        case PIPE_BLEND_REVERSE_SUBTRACT:
270                return nir_ussub_4x8(b, dst, src);
271        case PIPE_BLEND_MIN:
272                return nir_umin_4x8(b, src, dst);
273        case PIPE_BLEND_MAX:
274                return nir_umax_4x8(b, src, dst);
275
276        default:
277                /* Unsupported. */
278                fprintf(stderr, "Unknown blend func %d\n", func);
279                return src;
280
281        }
282}
283
284static void
285vc4_do_blending_f(struct vc4_compile *c, nir_builder *b, nir_ssa_def **result,
286                  nir_ssa_def **src_color, nir_ssa_def **dst_color)
287{
288        struct pipe_rt_blend_state *blend = &c->fs_key->blend;
289
290        if (!blend->blend_enable) {
291                for (int i = 0; i < 4; i++)
292                        result[i] = src_color[i];
293                return;
294        }
295
296        /* Clamp the src color to [0, 1].  Dest is already clamped. */
297        for (int i = 0; i < 4; i++)
298                src_color[i] = nir_fsat(b, src_color[i]);
299
300        nir_ssa_def *src_blend[4], *dst_blend[4];
301        for (int i = 0; i < 4; i++) {
302                int src_factor = ((i != 3) ? blend->rgb_src_factor :
303                                  blend->alpha_src_factor);
304                int dst_factor = ((i != 3) ? blend->rgb_dst_factor :
305                                  blend->alpha_dst_factor);
306                src_blend[i] = nir_fmul(b, src_color[i],
307                                        vc4_blend_channel_f(b,
308                                                            src_color, dst_color,
309                                                            src_factor, i));
310                dst_blend[i] = nir_fmul(b, dst_color[i],
311                                        vc4_blend_channel_f(b,
312                                                            src_color, dst_color,
313                                                            dst_factor, i));
314        }
315
316        for (int i = 0; i < 4; i++) {
317                result[i] = vc4_blend_func_f(b, src_blend[i], dst_blend[i],
318                                             ((i != 3) ? blend->rgb_func :
319                                              blend->alpha_func));
320        }
321}
322
323static nir_ssa_def *
324vc4_nir_splat(nir_builder *b, nir_ssa_def *src)
325{
326        nir_ssa_def *or1 = nir_ior(b, src, nir_ishl(b, src, nir_imm_int(b, 8)));
327        return nir_ior(b, or1, nir_ishl(b, or1, nir_imm_int(b, 16)));
328}
329
330static nir_ssa_def *
331vc4_do_blending_i(struct vc4_compile *c, nir_builder *b,
332                  nir_ssa_def *src_color, nir_ssa_def *dst_color,
333                  nir_ssa_def *src_float_a)
334{
335        struct pipe_rt_blend_state *blend = &c->fs_key->blend;
336
337        if (!blend->blend_enable)
338                return src_color;
339
340        enum pipe_format color_format = c->fs_key->color_format;
341        const uint8_t *format_swiz = vc4_get_format_swizzle(color_format);
342        nir_ssa_def *imm_0xff = nir_imm_int(b, 0xff);
343        nir_ssa_def *src_a = nir_pack_unorm_4x8(b, src_float_a);
344        nir_ssa_def *dst_a;
345        int alpha_chan;
346        for (alpha_chan = 0; alpha_chan < 4; alpha_chan++) {
347                if (format_swiz[alpha_chan] == 3)
348                        break;
349        }
350        if (alpha_chan != 4) {
351                nir_ssa_def *shift = nir_imm_int(b, alpha_chan * 8);
352                dst_a = vc4_nir_splat(b, nir_iand(b, nir_ushr(b, dst_color,
353                                                              shift), imm_0xff));
354        } else {
355                dst_a = nir_imm_int(b, ~0);
356        }
357
358        nir_ssa_def *src_factor = vc4_blend_channel_i(b,
359                                                      src_color, dst_color,
360                                                      src_a, dst_a,
361                                                      blend->rgb_src_factor,
362                                                      alpha_chan);
363        nir_ssa_def *dst_factor = vc4_blend_channel_i(b,
364                                                      src_color, dst_color,
365                                                      src_a, dst_a,
366                                                      blend->rgb_dst_factor,
367                                                      alpha_chan);
368
369        if (alpha_chan != 4 &&
370            blend->alpha_src_factor != blend->rgb_src_factor) {
371                nir_ssa_def *src_alpha_factor =
372                        vc4_blend_channel_i(b,
373                                            src_color, dst_color,
374                                            src_a, dst_a,
375                                            blend->alpha_src_factor,
376                                            alpha_chan);
377                src_factor = vc4_nir_set_packed_chan(b, src_factor,
378                                                     src_alpha_factor,
379                                                     alpha_chan);
380        }
381        if (alpha_chan != 4 &&
382            blend->alpha_dst_factor != blend->rgb_dst_factor) {
383                nir_ssa_def *dst_alpha_factor =
384                        vc4_blend_channel_i(b,
385                                            src_color, dst_color,
386                                            src_a, dst_a,
387                                            blend->alpha_dst_factor,
388                                            alpha_chan);
389                dst_factor = vc4_nir_set_packed_chan(b, dst_factor,
390                                                     dst_alpha_factor,
391                                                     alpha_chan);
392        }
393        nir_ssa_def *src_blend = nir_umul_unorm_4x8(b, src_color, src_factor);
394        nir_ssa_def *dst_blend = nir_umul_unorm_4x8(b, dst_color, dst_factor);
395
396        nir_ssa_def *result =
397                vc4_blend_func_i(b, src_blend, dst_blend, blend->rgb_func);
398        if (alpha_chan != 4 && blend->alpha_func != blend->rgb_func) {
399                nir_ssa_def *result_a = vc4_blend_func_i(b,
400                                                         src_blend,
401                                                         dst_blend,
402                                                         blend->alpha_func);
403                result = vc4_nir_set_packed_chan(b, result, result_a,
404                                                 alpha_chan);
405        }
406        return result;
407}
408
409static nir_ssa_def *
410vc4_logicop(nir_builder *b, int logicop_func,
411            nir_ssa_def *src, nir_ssa_def *dst)
412{
413        switch (logicop_func) {
414        case PIPE_LOGICOP_CLEAR:
415                return nir_imm_int(b, 0);
416        case PIPE_LOGICOP_NOR:
417                return nir_inot(b, nir_ior(b, src, dst));
418        case PIPE_LOGICOP_AND_INVERTED:
419                return nir_iand(b, nir_inot(b, src), dst);
420        case PIPE_LOGICOP_COPY_INVERTED:
421                return nir_inot(b, src);
422        case PIPE_LOGICOP_AND_REVERSE:
423                return nir_iand(b, src, nir_inot(b, dst));
424        case PIPE_LOGICOP_INVERT:
425                return nir_inot(b, dst);
426        case PIPE_LOGICOP_XOR:
427                return nir_ixor(b, src, dst);
428        case PIPE_LOGICOP_NAND:
429                return nir_inot(b, nir_iand(b, src, dst));
430        case PIPE_LOGICOP_AND:
431                return nir_iand(b, src, dst);
432        case PIPE_LOGICOP_EQUIV:
433                return nir_inot(b, nir_ixor(b, src, dst));
434        case PIPE_LOGICOP_NOOP:
435                return dst;
436        case PIPE_LOGICOP_OR_INVERTED:
437                return nir_ior(b, nir_inot(b, src), dst);
438        case PIPE_LOGICOP_OR_REVERSE:
439                return nir_ior(b, src, nir_inot(b, dst));
440        case PIPE_LOGICOP_OR:
441                return nir_ior(b, src, dst);
442        case PIPE_LOGICOP_SET:
443                return nir_imm_int(b, ~0);
444        default:
445                fprintf(stderr, "Unknown logic op %d\n", logicop_func);
446                /* FALLTHROUGH */
447        case PIPE_LOGICOP_COPY:
448                return src;
449        }
450}
451
452static nir_ssa_def *
453vc4_nir_pipe_compare_func(nir_builder *b, int func,
454                          nir_ssa_def *src0, nir_ssa_def *src1)
455{
456        switch (func) {
457        default:
458                fprintf(stderr, "Unknown compare func %d\n", func);
459                /* FALLTHROUGH */
460        case PIPE_FUNC_NEVER:
461                return nir_imm_int(b, 0);
462        case PIPE_FUNC_ALWAYS:
463                return nir_imm_int(b, ~0);
464        case PIPE_FUNC_EQUAL:
465                return nir_feq(b, src0, src1);
466        case PIPE_FUNC_NOTEQUAL:
467                return nir_fne(b, src0, src1);
468        case PIPE_FUNC_GREATER:
469                return nir_flt(b, src1, src0);
470        case PIPE_FUNC_GEQUAL:
471                return nir_fge(b, src0, src1);
472        case PIPE_FUNC_LESS:
473                return nir_flt(b, src0, src1);
474        case PIPE_FUNC_LEQUAL:
475                return nir_fge(b, src1, src0);
476        }
477}
478
479static void
480vc4_nir_emit_alpha_test_discard(struct vc4_compile *c, nir_builder *b,
481                                nir_ssa_def *alpha)
482{
483        if (!c->fs_key->alpha_test)
484                return;
485
486        nir_ssa_def *condition =
487                vc4_nir_pipe_compare_func(b, c->fs_key->alpha_test_func,
488                                          alpha,
489                                          nir_load_alpha_ref_float(b));
490
491        nir_intrinsic_instr *discard =
492                nir_intrinsic_instr_create(b->shader,
493                                           nir_intrinsic_discard_if);
494        discard->num_components = 1;
495        discard->src[0] = nir_src_for_ssa(nir_inot(b, condition));
496        nir_builder_instr_insert(b, &discard->instr);
497        c->s->info->fs.uses_discard = true;
498}
499
500static nir_ssa_def *
501vc4_nir_swizzle_and_pack(struct vc4_compile *c, nir_builder *b,
502                         nir_ssa_def **colors)
503{
504        enum pipe_format color_format = c->fs_key->color_format;
505        const uint8_t *format_swiz = vc4_get_format_swizzle(color_format);
506
507        nir_ssa_def *swizzled[4];
508        for (int i = 0; i < 4; i++) {
509                swizzled[i] = vc4_nir_get_swizzled_channel(b, colors,
510                                                           format_swiz[i]);
511        }
512
513        return nir_pack_unorm_4x8(b,
514                                  nir_vec4(b,
515                                           swizzled[0], swizzled[1],
516                                           swizzled[2], swizzled[3]));
517
518}
519
520static nir_ssa_def *
521vc4_nir_blend_pipeline(struct vc4_compile *c, nir_builder *b, nir_ssa_def *src,
522                       int sample)
523{
524        enum pipe_format color_format = c->fs_key->color_format;
525        const uint8_t *format_swiz = vc4_get_format_swizzle(color_format);
526        bool srgb = util_format_is_srgb(color_format);
527
528        /* Pull out the float src/dst color components. */
529        nir_ssa_def *packed_dst_color = vc4_nir_get_dst_color(b, sample);
530        nir_ssa_def *dst_vec4 = nir_unpack_unorm_4x8(b, packed_dst_color);
531        nir_ssa_def *src_color[4], *unpacked_dst_color[4];
532        for (unsigned i = 0; i < 4; i++) {
533                src_color[i] = nir_channel(b, src, i);
534                unpacked_dst_color[i] = nir_channel(b, dst_vec4, i);
535        }
536
537        if (c->fs_key->sample_alpha_to_one && c->fs_key->msaa)
538                src_color[3] = nir_imm_float(b, 1.0);
539
540        vc4_nir_emit_alpha_test_discard(c, b, src_color[3]);
541
542        nir_ssa_def *packed_color;
543        if (srgb) {
544                /* Unswizzle the destination color. */
545                nir_ssa_def *dst_color[4];
546                for (unsigned i = 0; i < 4; i++) {
547                        dst_color[i] = vc4_nir_get_swizzled_channel(b,
548                                                                    unpacked_dst_color,
549                                                                    format_swiz[i]);
550                }
551
552                /* Turn dst color to linear. */
553                for (int i = 0; i < 3; i++)
554                        dst_color[i] = vc4_nir_srgb_decode(b, dst_color[i]);
555
556                nir_ssa_def *blend_color[4];
557                vc4_do_blending_f(c, b, blend_color, src_color, dst_color);
558
559                /* sRGB encode the output color */
560                for (int i = 0; i < 3; i++)
561                        blend_color[i] = vc4_nir_srgb_encode(b, blend_color[i]);
562
563                packed_color = vc4_nir_swizzle_and_pack(c, b, blend_color);
564        } else {
565                nir_ssa_def *packed_src_color =
566                        vc4_nir_swizzle_and_pack(c, b, src_color);
567
568                packed_color =
569                        vc4_do_blending_i(c, b,
570                                          packed_src_color, packed_dst_color,
571                                          src_color[3]);
572        }
573
574        packed_color = vc4_logicop(b, c->fs_key->logicop_func,
575                                   packed_color, packed_dst_color);
576
577        /* If the bit isn't set in the color mask, then just return the
578         * original dst color, instead.
579         */
580        uint32_t colormask = 0xffffffff;
581        for (int i = 0; i < 4; i++) {
582                if (format_swiz[i] < 4 &&
583                    !(c->fs_key->blend.colormask & (1 << format_swiz[i]))) {
584                        colormask &= ~(0xff << (i * 8));
585                }
586        }
587
588        return nir_ior(b,
589                       nir_iand(b, packed_color,
590                                nir_imm_int(b, colormask)),
591                       nir_iand(b, packed_dst_color,
592                                nir_imm_int(b, ~colormask)));
593}
594
595static int
596vc4_nir_next_output_driver_location(nir_shader *s)
597{
598        int maxloc = -1;
599
600        nir_foreach_variable(var, &s->outputs)
601                maxloc = MAX2(maxloc, (int)var->data.driver_location);
602
603        return maxloc + 1;
604}
605
606static void
607vc4_nir_store_sample_mask(struct vc4_compile *c, nir_builder *b,
608                          nir_ssa_def *val)
609{
610        nir_variable *sample_mask = nir_variable_create(c->s, nir_var_shader_out,
611                                                        glsl_uint_type(),
612                                                        "sample_mask");
613        sample_mask->data.driver_location =
614                vc4_nir_next_output_driver_location(c->s);
615        sample_mask->data.location = FRAG_RESULT_SAMPLE_MASK;
616
617        nir_intrinsic_instr *intr =
618                nir_intrinsic_instr_create(c->s, nir_intrinsic_store_output);
619        intr->num_components = 1;
620        nir_intrinsic_set_base(intr, sample_mask->data.driver_location);
621
622        intr->src[0] = nir_src_for_ssa(val);
623        intr->src[1] = nir_src_for_ssa(nir_imm_int(b, 0));
624        nir_builder_instr_insert(b, &intr->instr);
625}
626
627static void
628vc4_nir_lower_blend_instr(struct vc4_compile *c, nir_builder *b,
629                          nir_intrinsic_instr *intr)
630{
631        nir_ssa_def *frag_color = intr->src[0].ssa;
632
633        if (c->fs_key->sample_coverage) {
634                nir_intrinsic_instr *load =
635                        nir_intrinsic_instr_create(b->shader,
636                                                   nir_intrinsic_load_sample_mask_in);
637                load->num_components = 1;
638                nir_ssa_dest_init(&load->instr, &load->dest, 1, 32, NULL);
639                nir_builder_instr_insert(b, &load->instr);
640
641                nir_ssa_def *bitmask = &load->dest.ssa;
642
643                vc4_nir_store_sample_mask(c, b, bitmask);
644        } else if (c->fs_key->sample_alpha_to_coverage) {
645                nir_ssa_def *a = nir_channel(b, frag_color, 3);
646
647                /* XXX: We should do a nice dither based on the fragment
648                 * coordinate, instead.
649                 */
650                nir_ssa_def *num_samples = nir_imm_float(b, VC4_MAX_SAMPLES);
651                nir_ssa_def *num_bits = nir_f2i(b, nir_fmul(b, a, num_samples));
652                nir_ssa_def *bitmask = nir_isub(b,
653                                                nir_ishl(b,
654                                                         nir_imm_int(b, 1),
655                                                         num_bits),
656                                                nir_imm_int(b, 1));
657                vc4_nir_store_sample_mask(c, b, bitmask);
658        }
659
660        /* The TLB color read returns each sample in turn, so if our blending
661         * depends on the destination color, we're going to have to run the
662         * blending function separately for each destination sample value, and
663         * then output the per-sample color using TLB_COLOR_MS.
664         */
665        nir_ssa_def *blend_output;
666        if (c->fs_key->msaa && blend_depends_on_dst_color(c)) {
667                c->msaa_per_sample_output = true;
668
669                nir_ssa_def *samples[4];
670                for (int i = 0; i < VC4_MAX_SAMPLES; i++)
671                        samples[i] = vc4_nir_blend_pipeline(c, b, frag_color, i);
672                blend_output = nir_vec4(b,
673                                        samples[0], samples[1],
674                                        samples[2], samples[3]);
675        } else {
676                blend_output = vc4_nir_blend_pipeline(c, b, frag_color, 0);
677        }
678
679        nir_instr_rewrite_src(&intr->instr, &intr->src[0],
680                              nir_src_for_ssa(blend_output));
681        intr->num_components = blend_output->num_components;
682}
683
684static bool
685vc4_nir_lower_blend_block(nir_block *block, struct vc4_compile *c)
686{
687        nir_foreach_instr_safe(instr, block) {
688                if (instr->type != nir_instr_type_intrinsic)
689                        continue;
690                nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
691                if (intr->intrinsic != nir_intrinsic_store_output)
692                        continue;
693
694                nir_variable *output_var = NULL;
695                nir_foreach_variable(var, &c->s->outputs) {
696                        if (var->data.driver_location ==
697                            nir_intrinsic_base(intr)) {
698                                output_var = var;
699                                break;
700                        }
701                }
702                assert(output_var);
703
704                if (output_var->data.location != FRAG_RESULT_COLOR &&
705                    output_var->data.location != FRAG_RESULT_DATA0) {
706                        continue;
707                }
708
709                nir_function_impl *impl =
710                        nir_cf_node_get_function(&block->cf_node);
711                nir_builder b;
712                nir_builder_init(&b, impl);
713                b.cursor = nir_before_instr(&intr->instr);
714                vc4_nir_lower_blend_instr(c, &b, intr);
715        }
716        return true;
717}
718
719void
720vc4_nir_lower_blend(nir_shader *s, struct vc4_compile *c)
721{
722        nir_foreach_function(function, s) {
723                if (function->impl) {
724                        nir_foreach_block(block, function->impl) {
725                                vc4_nir_lower_blend_block(block, c);
726                        }
727
728                        nir_metadata_preserve(function->impl,
729                                              nir_metadata_block_index |
730                                              nir_metadata_dominance);
731                }
732        }
733}
734