u_pstipple.c revision 0c4bc1e29223ffec4617999c0c03d722bdcc170a 
1/**************************************************************************
2 *
3 * Copyright 2008 VMware, Inc.
4 * Copyright 2010 VMware, Inc.
5 * All Rights Reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the
9 * "Software"), to deal in the Software without restriction, including
10 * without limitation the rights to use, copy, modify, merge, publish,
11 * distribute, sub license, and/or sell copies of the Software, and to
12 * permit persons to whom the Software is furnished to do so, subject to
13 * the following conditions:
14 *
15 * The above copyright notice and this permission notice (including the
16 * next paragraph) shall be included in all copies or substantial portions
17 * of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
20 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
21 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
22 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
23 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
24 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
25 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
26 *
27 **************************************************************************/
28
29/**
30 * Polygon stipple helper module.  Drivers/GPUs which don't support polygon
31 * stipple natively can use this module to simulate it.
32 *
33 * Basically, modify fragment shader to sample the 32x32 stipple pattern
34 * texture and do a fragment kill for the 'off' bits.
35 *
36 * This was originally a 'draw' module stage, but since we don't need
37 * vertex window coords or anything, it can be a stand-alone utility module.
38 *
39 * Authors:  Brian Paul
40 */
41
42
43#include "pipe/p_context.h"
44#include "pipe/p_defines.h"
45#include "pipe/p_shader_tokens.h"
46#include "util/u_inlines.h"
47
48#include "util/u_format.h"
49#include "util/u_memory.h"
50#include "util/u_pstipple.h"
51#include "util/u_sampler.h"
52
53#include "tgsi/tgsi_transform.h"
54#include "tgsi/tgsi_dump.h"
55#include "tgsi/tgsi_scan.h"
56
57/** Approx number of new tokens for instructions in pstip_transform_inst() */
58#define NUM_NEW_TOKENS 50
59
60
61static void
62util_pstipple_update_stipple_texture(struct pipe_context *pipe,
63                                     struct pipe_resource *tex,
64                                     const uint32_t pattern[32])
65{
66   static const uint bit31 = 1 << 31;
67   struct pipe_transfer *transfer;
68   ubyte *data;
69   int i, j;
70
71   /* map texture memory */
72   data = pipe_transfer_map(pipe, tex, 0, 0,
73                            PIPE_TRANSFER_WRITE, 0, 0, 32, 32, &transfer);
74
75   /*
76    * Load alpha texture.
77    * Note: 0 means keep the fragment, 255 means kill it.
78    * We'll negate the texel value and use KILL_IF which kills if value
79    * is negative.
80    */
81   for (i = 0; i < 32; i++) {
82      for (j = 0; j < 32; j++) {
83         if (pattern[i] & (bit31 >> j)) {
84            /* fragment "on" */
85            data[i * transfer->stride + j] = 0;
86         }
87         else {
88            /* fragment "off" */
89            data[i * transfer->stride + j] = 255;
90         }
91      }
92   }
93
94   /* unmap */
95   pipe->transfer_unmap(pipe, transfer);
96}
97
98
99/**
100 * Create a 32x32 alpha8 texture that encodes the given stipple pattern.
101 */
102struct pipe_resource *
103util_pstipple_create_stipple_texture(struct pipe_context *pipe,
104                                     const uint32_t pattern[32])
105{
106   struct pipe_screen *screen = pipe->screen;
107   struct pipe_resource templat, *tex;
108
109   memset(&templat, 0, sizeof(templat));
110   templat.target = PIPE_TEXTURE_2D;
111   templat.format = PIPE_FORMAT_A8_UNORM;
112   templat.last_level = 0;
113   templat.width0 = 32;
114   templat.height0 = 32;
115   templat.depth0 = 1;
116   templat.array_size = 1;
117   templat.bind = PIPE_BIND_SAMPLER_VIEW;
118
119   tex = screen->resource_create(screen, &templat);
120
121   if (tex)
122      util_pstipple_update_stipple_texture(pipe, tex, pattern);
123
124   return tex;
125}
126
127
128/**
129 * Create sampler view to sample the stipple texture.
130 */
131struct pipe_sampler_view *
132util_pstipple_create_sampler_view(struct pipe_context *pipe,
133                                  struct pipe_resource *tex)
134{
135   struct pipe_sampler_view templat, *sv;
136
137   u_sampler_view_default_template(&templat, tex, tex->format);
138   sv = pipe->create_sampler_view(pipe, tex, &templat);
139
140   return sv;
141}
142
143
144/**
145 * Create the sampler CSO that'll be used for stippling.
146 */
147void *
148util_pstipple_create_sampler(struct pipe_context *pipe)
149{
150   struct pipe_sampler_state templat;
151   void *s;
152
153   memset(&templat, 0, sizeof(templat));
154   templat.wrap_s = PIPE_TEX_WRAP_REPEAT;
155   templat.wrap_t = PIPE_TEX_WRAP_REPEAT;
156   templat.wrap_r = PIPE_TEX_WRAP_REPEAT;
157   templat.min_mip_filter = PIPE_TEX_MIPFILTER_NONE;
158   templat.min_img_filter = PIPE_TEX_FILTER_NEAREST;
159   templat.mag_img_filter = PIPE_TEX_FILTER_NEAREST;
160   templat.normalized_coords = 1;
161   templat.min_lod = 0.0f;
162   templat.max_lod = 0.0f;
163
164   s = pipe->create_sampler_state(pipe, &templat);
165   return s;
166}
167
168
169
170/**
171 * Subclass of tgsi_transform_context, used for transforming the
172 * user's fragment shader to add the extra texture sample and fragment kill
173 * instructions.
174 */
175struct pstip_transform_context {
176   struct tgsi_transform_context base;
177   struct tgsi_shader_info info;
178   uint tempsUsed;  /**< bitmask */
179   int wincoordInput;
180   int maxInput;
181   uint samplersUsed;  /**< bitfield of samplers used */
182   int freeSampler;  /** an available sampler for the pstipple */
183   int texTemp;  /**< temp registers */
184   int numImmed;
185   boolean firstInstruction;
186   uint coordOrigin;
187};
188
189
190/**
191 * TGSI declaration transform callback.
192 * Track samplers used, temps used, inputs used.
193 */
194static void
195pstip_transform_decl(struct tgsi_transform_context *ctx,
196                     struct tgsi_full_declaration *decl)
197{
198   struct pstip_transform_context *pctx =
199      (struct pstip_transform_context *) ctx;
200
201   /* XXX we can use tgsi_shader_info instead of some of this */
202
203   if (decl->Declaration.File == TGSI_FILE_SAMPLER) {
204      uint i;
205      for (i = decl->Range.First; i <= decl->Range.Last; i++) {
206         pctx->samplersUsed |= 1 << i;
207      }
208   }
209   else if (decl->Declaration.File == TGSI_FILE_INPUT) {
210      pctx->maxInput = MAX2(pctx->maxInput, (int) decl->Range.Last);
211      if (decl->Semantic.Name == TGSI_SEMANTIC_POSITION)
212         pctx->wincoordInput = (int) decl->Range.First;
213   }
214   else if (decl->Declaration.File == TGSI_FILE_TEMPORARY) {
215      uint i;
216      for (i = decl->Range.First; i <= decl->Range.Last; i++) {
217         pctx->tempsUsed |= (1 << i);
218      }
219   }
220
221   ctx->emit_declaration(ctx, decl);
222}
223
224
225static void
226pstip_transform_immed(struct tgsi_transform_context *ctx,
227                      struct tgsi_full_immediate *immed)
228{
229   struct pstip_transform_context *pctx =
230      (struct pstip_transform_context *) ctx;
231   pctx->numImmed++;
232}
233
234
235/**
236 * Find the lowest zero bit in the given word, or -1 if bitfield is all ones.
237 */
238static int
239free_bit(uint bitfield)
240{
241   return ffs(~bitfield) - 1;
242}
243
244
245/**
246 * TGSI instruction transform callback.
247 * Before the first instruction, insert our new code to sample the
248 * stipple texture (using the fragment coord register) then kill the
249 * fragment if the stipple texture bit is off.
250 *
251 * Insert:
252 *   declare new registers
253 *   MUL texTemp, INPUT[wincoord], 1/32;
254 *   TEX texTemp, texTemp, sampler;
255 *   KILL_IF -texTemp;   # if -texTemp < 0, kill fragment
256 *   [...original code...]
257 */
258static void
259pstip_transform_inst(struct tgsi_transform_context *ctx,
260                     struct tgsi_full_instruction *inst)
261{
262   struct pstip_transform_context *pctx =
263      (struct pstip_transform_context *) ctx;
264
265   if (pctx->firstInstruction) {
266      /* emit our new declarations before the first instruction */
267
268      struct tgsi_full_declaration decl;
269      struct tgsi_full_instruction newInst;
270      uint i;
271      int wincoordInput;
272
273      /* find free texture sampler */
274      pctx->freeSampler = free_bit(pctx->samplersUsed);
275      if (pctx->freeSampler >= PIPE_MAX_SAMPLERS)
276         pctx->freeSampler = PIPE_MAX_SAMPLERS - 1;
277
278      if (pctx->wincoordInput < 0)
279         wincoordInput = pctx->maxInput + 1;
280      else
281         wincoordInput = pctx->wincoordInput;
282
283      /* find one free temp register */
284      for (i = 0; i < 32; i++) {
285         if ((pctx->tempsUsed & (1 << i)) == 0) {
286            /* found a free temp */
287            if (pctx->texTemp < 0)
288               pctx->texTemp  = i;
289            else
290               break;
291         }
292      }
293      assert(pctx->texTemp >= 0);
294
295      if (pctx->wincoordInput < 0) {
296         /* declare new position input reg */
297         decl = tgsi_default_full_declaration();
298         decl.Declaration.File = TGSI_FILE_INPUT;
299         decl.Declaration.Interpolate = 1;
300         decl.Declaration.Semantic = 1;
301         decl.Semantic.Name = TGSI_SEMANTIC_POSITION;
302         decl.Semantic.Index = 0;
303         decl.Range.First =
304            decl.Range.Last = wincoordInput;
305         decl.Interp.Interpolate = TGSI_INTERPOLATE_LINEAR;
306         ctx->emit_declaration(ctx, &decl);
307      }
308
309      /* declare new sampler */
310      decl = tgsi_default_full_declaration();
311      decl.Declaration.File = TGSI_FILE_SAMPLER;
312      decl.Range.First =
313      decl.Range.Last = pctx->freeSampler;
314      ctx->emit_declaration(ctx, &decl);
315
316      /* declare new temp regs */
317      decl = tgsi_default_full_declaration();
318      decl.Declaration.File = TGSI_FILE_TEMPORARY;
319      decl.Range.First =
320      decl.Range.Last = pctx->texTemp;
321      ctx->emit_declaration(ctx, &decl);
322
323      /* emit immediate = {1/32, 1/32, 1, 1}
324       * The index/position of this immediate will be pctx->numImmed
325       */
326      {
327         static const float value[4] = { 1.0/32, 1.0/32, 1.0, 1.0 };
328         struct tgsi_full_immediate immed;
329         uint size = 4;
330         immed = tgsi_default_full_immediate();
331         immed.Immediate.NrTokens = 1 + size; /* one for the token itself */
332         immed.u[0].Float = value[0];
333         immed.u[1].Float = value[1];
334         immed.u[2].Float = value[2];
335         immed.u[3].Float = value[3];
336         ctx->emit_immediate(ctx, &immed);
337      }
338
339      pctx->firstInstruction = FALSE;
340
341
342      /*
343       * Insert new MUL/TEX/KILL_IF instructions at start of program
344       * Take gl_FragCoord, divide by 32 (stipple size), sample the
345       * texture and kill fragment if needed.
346       *
347       * We'd like to use non-normalized texcoords to index into a RECT
348       * texture, but we can only use REPEAT wrap mode with normalized
349       * texcoords.  Darn.
350       */
351
352      /* XXX invert wincoord if origin isn't lower-left... */
353
354      /* MUL texTemp, INPUT[wincoord], 1/32; */
355      newInst = tgsi_default_full_instruction();
356      newInst.Instruction.Opcode = TGSI_OPCODE_MUL;
357      newInst.Instruction.NumDstRegs = 1;
358      newInst.Dst[0].Register.File = TGSI_FILE_TEMPORARY;
359      newInst.Dst[0].Register.Index = pctx->texTemp;
360      newInst.Instruction.NumSrcRegs = 2;
361      newInst.Src[0].Register.File = TGSI_FILE_INPUT;
362      newInst.Src[0].Register.Index = wincoordInput;
363      newInst.Src[1].Register.File = TGSI_FILE_IMMEDIATE;
364      newInst.Src[1].Register.Index = pctx->numImmed;
365      ctx->emit_instruction(ctx, &newInst);
366
367      /* TEX texTemp, texTemp, sampler; */
368      newInst = tgsi_default_full_instruction();
369      newInst.Instruction.Opcode = TGSI_OPCODE_TEX;
370      newInst.Instruction.NumDstRegs = 1;
371      newInst.Dst[0].Register.File = TGSI_FILE_TEMPORARY;
372      newInst.Dst[0].Register.Index = pctx->texTemp;
373      newInst.Instruction.NumSrcRegs = 2;
374      newInst.Instruction.Texture = TRUE;
375      newInst.Texture.Texture = TGSI_TEXTURE_2D;
376      newInst.Src[0].Register.File = TGSI_FILE_TEMPORARY;
377      newInst.Src[0].Register.Index = pctx->texTemp;
378      newInst.Src[1].Register.File = TGSI_FILE_SAMPLER;
379      newInst.Src[1].Register.Index = pctx->freeSampler;
380      ctx->emit_instruction(ctx, &newInst);
381
382      /* KILL_IF -texTemp;   # if -texTemp < 0, kill fragment */
383      newInst = tgsi_default_full_instruction();
384      newInst.Instruction.Opcode = TGSI_OPCODE_KILL_IF;
385      newInst.Instruction.NumDstRegs = 0;
386      newInst.Instruction.NumSrcRegs = 1;
387      newInst.Src[0].Register.File = TGSI_FILE_TEMPORARY;
388      newInst.Src[0].Register.Index = pctx->texTemp;
389      newInst.Src[0].Register.Negate = 1;
390      ctx->emit_instruction(ctx, &newInst);
391   }
392
393   /* emit this instruction */
394   ctx->emit_instruction(ctx, inst);
395}
396
397
398/**
399 * Given a fragment shader, return a new fragment shader which
400 * samples a stipple texture and executes KILL.
401 */
402struct pipe_shader_state *
403util_pstipple_create_fragment_shader(struct pipe_context *pipe,
404                                     struct pipe_shader_state *fs,
405                                     unsigned *samplerUnitOut)
406{
407   struct pipe_shader_state *new_fs;
408   struct pstip_transform_context transform;
409   const uint newLen = tgsi_num_tokens(fs->tokens) + NUM_NEW_TOKENS;
410
411   new_fs = MALLOC(sizeof(*new_fs));
412   if (!new_fs)
413      return NULL;
414
415   new_fs->tokens = tgsi_alloc_tokens(newLen);
416   if (!new_fs->tokens) {
417      FREE(new_fs);
418      return NULL;
419   }
420
421   /* Setup shader transformation info/context.
422    */
423   memset(&transform, 0, sizeof(transform));
424   transform.wincoordInput = -1;
425   transform.maxInput = -1;
426   transform.texTemp = -1;
427   transform.firstInstruction = TRUE;
428   transform.coordOrigin = TGSI_FS_COORD_ORIGIN_UPPER_LEFT;
429   transform.base.transform_instruction = pstip_transform_inst;
430   transform.base.transform_declaration = pstip_transform_decl;
431   transform.base.transform_immediate = pstip_transform_immed;
432
433   tgsi_scan_shader(fs->tokens, &transform.info);
434
435   transform.coordOrigin =
436      transform.info.properties[TGSI_PROPERTY_FS_COORD_ORIGIN];
437
438   tgsi_transform_shader(fs->tokens,
439                         (struct tgsi_token *) new_fs->tokens,
440                         newLen, &transform.base);
441
442#if 0 /* DEBUG */
443   tgsi_dump(fs->tokens, 0);
444   tgsi_dump(new_fs->tokens, 0);
445#endif
446
447   assert(transform.freeSampler < PIPE_MAX_SAMPLERS);
448   *samplerUnitOut = transform.freeSampler;
449
450   return new_fs;
451}
452
453