mask.c revision f44b0ff84338c2184ef4f2cbb752bf62f4fff1fc
1/**************************************************************************
2 *
3 * Copyright 2009 VMware, Inc.  All Rights Reserved.
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the
7 * "Software"), to deal in the Software without restriction, including
8 * without limitation the rights to use, copy, modify, merge, publish,
9 * distribute, sub license, and/or sell copies of the Software, and to
10 * permit persons to whom the Software is furnished to do so, subject to
11 * the following conditions:
12 *
13 * The above copyright notice and this permission notice (including the
14 * next paragraph) shall be included in all copies or substantial portions
15 * of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
19 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
20 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
21 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
22 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
23 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
24 *
25 **************************************************************************/
26
27#include "mask.h"
28
29#include "path.h"
30#include "image.h"
31#include "shaders_cache.h"
32#include "renderer.h"
33#include "asm_util.h"
34#include "st_inlines.h"
35
36#include "pipe/p_context.h"
37#include "pipe/p_screen.h"
38#include "pipe/p_inlines.h"
39#include "util/u_format.h"
40#include "util/u_memory.h"
41
42struct vg_mask_layer {
43   struct vg_object base;
44
45   VGint width;
46   VGint height;
47
48   struct pipe_texture *texture;
49};
50
51static INLINE struct pipe_surface *
52alpha_mask_surface(struct vg_context *ctx, int usage)
53{
54   struct pipe_screen *screen = ctx->pipe->screen;
55   struct st_framebuffer *stfb = ctx->draw_buffer;
56   return screen->get_tex_surface(screen,
57                                  stfb->alpha_mask,
58                                  0, 0, 0,
59                                  usage);
60}
61
62static INLINE VGboolean
63intersect_rectangles(VGint dwidth, VGint dheight,
64                     VGint swidth, VGint sheight,
65                     VGint tx, VGint ty,
66                     VGint twidth, VGint theight,
67                     VGint *offsets,
68                     VGint *location)
69{
70   if (tx + twidth <= 0 || tx >= dwidth)
71      return VG_FALSE;
72   if (ty + theight <= 0 || ty >= dheight)
73      return VG_FALSE;
74
75   offsets[0] = 0;
76   offsets[1] = 0;
77   location[0] = tx;
78   location[1] = ty;
79
80   if (tx < 0) {
81      offsets[0] -= tx;
82      location[0] = 0;
83
84      location[2] = MIN2(tx + swidth, MIN2(dwidth, tx + twidth));
85      offsets[2] = location[2];
86   } else {
87      offsets[2] = MIN2(twidth, MIN2(dwidth - tx, swidth ));
88      location[2] = offsets[2];
89   }
90
91   if (ty < 0) {
92      offsets[1] -= ty;
93      location[1] = 0;
94
95      location[3] = MIN2(ty + sheight, MIN2(dheight, ty + theight));
96      offsets[3] = location[3];
97   } else {
98      offsets[3] = MIN2(theight, MIN2(dheight - ty, sheight));
99      location[3] = offsets[3];
100   }
101
102   return VG_TRUE;
103}
104
105#if DEBUG_MASKS
106static void read_alpha_mask(void * data, VGint dataStride,
107                            VGImageFormat dataFormat,
108                            VGint sx, VGint sy,
109                            VGint width, VGint height)
110{
111   struct vg_context *ctx = vg_current_context();
112   struct pipe_context *pipe = ctx->pipe;
113   struct pipe_screen *screen = pipe->screen;
114
115   struct st_framebuffer *stfb = ctx->draw_buffer;
116   struct st_renderbuffer *strb = stfb->alpha_mask;
117   struct pipe_framebuffer_state *fb = &ctx->state.g3d.fb;
118
119   VGfloat temp[VEGA_MAX_IMAGE_WIDTH][4];
120   VGfloat *df = (VGfloat*)temp;
121   VGint y = (fb->height - sy) - 1, yStep = -1;
122   VGint i;
123   VGubyte *dst = (VGubyte *)data;
124   VGint xoffset = 0, yoffset = 0;
125
126   /* make sure rendering has completed */
127   pipe->flush(pipe, PIPE_FLUSH_RENDER_CACHE, NULL);
128   if (sx < 0) {
129      xoffset = -sx;
130      xoffset *= _vega_size_for_format(dataFormat);
131      width += sx;
132      sx = 0;
133   }
134   if (sy < 0) {
135      yoffset = -sy;
136      height += sy;
137      sy = 0;
138      y = (fb->height - sy) - 1;
139      yoffset *= dataStride;
140   }
141
142   {
143      struct pipe_surface *surf;
144
145      surf = screen->get_tex_surface(screen, strb->texture,  0, 0, 0,
146                                     PIPE_BUFFER_USAGE_CPU_READ);
147
148      /* Do a row at a time to flip image data vertically */
149      for (i = 0; i < height; i++) {
150#if 0
151         debug_printf("%d-%d  == %d\n", sy, height, y);
152#endif
153         pipe_get_tile_rgba(surf, sx, y, width, 1, df);
154         y += yStep;
155         _vega_pack_rgba_span_float(ctx, width, temp, dataFormat,
156                                    dst + yoffset + xoffset);
157         dst += dataStride;
158      }
159
160      pipe_surface_reference(&surf, NULL);
161   }
162}
163
164void save_alpha_to_file(const char *filename)
165{
166   struct vg_context *ctx = vg_current_context();
167   struct pipe_framebuffer_state *fb = &ctx->state.g3d.fb;
168   VGint *data;
169   int i, j;
170
171   data = malloc(sizeof(int) * fb->width * fb->height);
172   read_alpha_mask(data, fb->width * sizeof(int),
173                   VG_sRGBA_8888,
174                   0, 0, fb->width, fb->height);
175   fprintf(stderr, "/*---------- start */\n");
176   fprintf(stderr, "const int image_width = %d;\n",
177           fb->width);
178   fprintf(stderr, "const int image_height = %d;\n",
179           fb->height);
180   fprintf(stderr, "const int image_data = {\n");
181   for (i = 0; i < fb->height; ++i) {
182      for (j = 0; j < fb->width; ++j) {
183         int rgba = data[i * fb->height + j];
184         int argb = 0;
185         argb = (rgba >> 8);
186         argb |= ((rgba & 0xff) << 24);
187         fprintf(stderr, "0x%x, ", argb);
188      }
189      fprintf(stderr, "\n");
190   }
191   fprintf(stderr, "};\n");
192   fprintf(stderr, "/*---------- end */\n");
193}
194#endif
195
196static void setup_mask_framebuffer(struct pipe_surface *surf,
197                                   VGint surf_width, VGint surf_height)
198{
199   struct vg_context *ctx = vg_current_context();
200   struct pipe_framebuffer_state fb;
201
202   memset(&fb, 0, sizeof(fb));
203   fb.width = surf_width;
204   fb.height = surf_height;
205   fb.nr_cbufs = 1;
206   fb.cbufs[0] = surf;
207   {
208      VGint i;
209      for (i = 1; i < PIPE_MAX_COLOR_BUFS; ++i)
210         fb.cbufs[i] = 0;
211   }
212   cso_set_framebuffer(ctx->cso_context, &fb);
213}
214
215
216/* setup shader constants */
217static void setup_mask_operation(VGMaskOperation operation)
218{
219   struct vg_context *ctx = vg_current_context();
220   struct pipe_buffer **cbuf = &ctx->mask.cbuf;
221   const VGint param_bytes = 4 * sizeof(VGfloat);
222   const VGfloat ones[4] = {1.f, 1.f, 1.f, 1.f};
223   void *shader = 0;
224
225   /* We always need to get a new buffer, to keep the drivers simple and
226    * avoid gratuitous rendering synchronization.
227    */
228   pipe_buffer_reference(cbuf, NULL);
229
230   *cbuf = pipe_buffer_create(ctx->pipe->screen, 1,
231                              PIPE_BUFFER_USAGE_CONSTANT,
232                              param_bytes);
233   if (*cbuf) {
234      st_no_flush_pipe_buffer_write(ctx, *cbuf,
235                                    0, param_bytes, ones);
236   }
237
238   ctx->pipe->set_constant_buffer(ctx->pipe, PIPE_SHADER_FRAGMENT, 0, *cbuf);
239   switch (operation) {
240   case VG_UNION_MASK: {
241      if (!ctx->mask.union_fs) {
242         ctx->mask.union_fs = shader_create_from_text(ctx->pipe,
243                                                      union_mask_asm,
244                                                      200,
245                                                      PIPE_SHADER_FRAGMENT);
246      }
247      shader = ctx->mask.union_fs->driver;
248   }
249      break;
250   case VG_INTERSECT_MASK: {
251      if (!ctx->mask.intersect_fs) {
252         ctx->mask.intersect_fs = shader_create_from_text(ctx->pipe,
253                                                          intersect_mask_asm,
254                                                          200,
255                                                          PIPE_SHADER_FRAGMENT);
256      }
257      shader = ctx->mask.intersect_fs->driver;
258   }
259      break;
260   case VG_SUBTRACT_MASK: {
261      if (!ctx->mask.subtract_fs) {
262         ctx->mask.subtract_fs = shader_create_from_text(ctx->pipe,
263                                                         subtract_mask_asm,
264                                                         200,
265                                                         PIPE_SHADER_FRAGMENT);
266      }
267      shader = ctx->mask.subtract_fs->driver;
268   }
269      break;
270   case VG_SET_MASK: {
271      if (!ctx->mask.set_fs) {
272         ctx->mask.set_fs = shader_create_from_text(ctx->pipe,
273                                                    set_mask_asm,
274                                                    200,
275                                                    PIPE_SHADER_FRAGMENT);
276      }
277      shader = ctx->mask.set_fs->driver;
278   }
279      break;
280   default:
281         assert(0);
282      break;
283   }
284   cso_set_fragment_shader_handle(ctx->cso_context, shader);
285}
286
287static void setup_mask_samplers(struct pipe_texture *umask)
288{
289   struct vg_context *ctx = vg_current_context();
290   struct pipe_sampler_state *samplers[PIPE_MAX_SAMPLERS];
291   struct pipe_texture *textures[PIPE_MAX_SAMPLERS];
292   struct st_framebuffer *fb_buffers = ctx->draw_buffer;
293   struct pipe_texture *uprev = NULL;
294   struct pipe_sampler_state sampler;
295
296   uprev = fb_buffers->blend_texture;
297   sampler = ctx->mask.sampler;
298   sampler.normalized_coords = 1;
299
300   samplers[0] = NULL;
301   samplers[1] = NULL;
302   samplers[2] = NULL;
303   textures[0] = NULL;
304   textures[1] = NULL;
305   textures[2] = NULL;
306
307   samplers[0] = &sampler;
308   samplers[1] = &ctx->mask.sampler;
309
310   textures[0] = umask;
311   textures[1] = uprev;
312
313   cso_set_samplers(ctx->cso_context, 2,
314                    (const struct pipe_sampler_state **)samplers);
315   cso_set_sampler_textures(ctx->cso_context, 2, textures);
316}
317
318
319/* setup shader constants */
320static void setup_mask_fill(const VGfloat color[4])
321{
322   struct vg_context *ctx = vg_current_context();
323   struct pipe_buffer **cbuf = &ctx->mask.cbuf;
324   const VGint param_bytes = 4 * sizeof(VGfloat);
325
326   /* We always need to get a new buffer, to keep the drivers simple and
327    * avoid gratuitous rendering synchronization.
328    */
329   pipe_buffer_reference(cbuf, NULL);
330
331   *cbuf = pipe_buffer_create(ctx->pipe->screen, 1,
332                              PIPE_BUFFER_USAGE_CONSTANT,
333                              param_bytes);
334   if (*cbuf) {
335      st_no_flush_pipe_buffer_write(ctx, *cbuf, 0, param_bytes, color);
336   }
337
338   ctx->pipe->set_constant_buffer(ctx->pipe, PIPE_SHADER_FRAGMENT, 0, *cbuf);
339   cso_set_fragment_shader_handle(ctx->cso_context,
340                                  shaders_cache_fill(ctx->sc,
341                                                     VEGA_SOLID_FILL_SHADER));
342}
343
344static void setup_mask_viewport()
345{
346   struct vg_context *ctx = vg_current_context();
347   vg_set_viewport(ctx, VEGA_Y0_TOP);
348}
349
350static void setup_mask_blend()
351{
352   struct vg_context *ctx = vg_current_context();
353
354   struct pipe_blend_state blend;
355
356   memset(&blend, 0, sizeof(struct pipe_blend_state));
357   blend.blend_enable = 1;
358   blend.colormask |= PIPE_MASK_R;
359   blend.colormask |= PIPE_MASK_G;
360   blend.colormask |= PIPE_MASK_B;
361   blend.colormask |= PIPE_MASK_A;
362   blend.rgb_src_factor = PIPE_BLENDFACTOR_ONE;
363   blend.alpha_src_factor = PIPE_BLENDFACTOR_ONE;
364   blend.rgb_dst_factor = PIPE_BLENDFACTOR_ZERO;
365   blend.alpha_dst_factor = PIPE_BLENDFACTOR_ZERO;
366
367   cso_set_blend(ctx->cso_context, &blend);
368}
369
370
371static void surface_fill(struct pipe_surface *surf,
372                         int surf_width, int surf_height,
373                         int x, int y, int width, int height,
374                         const VGfloat color[4])
375{
376   struct vg_context *ctx = vg_current_context();
377
378   if (x < 0) {
379      width += x;
380      x = 0;
381   }
382   if (y < 0) {
383      height += y;
384      y = 0;
385   }
386
387   cso_save_framebuffer(ctx->cso_context);
388   cso_save_blend(ctx->cso_context);
389   cso_save_fragment_shader(ctx->cso_context);
390   cso_save_viewport(ctx->cso_context);
391
392   setup_mask_blend();
393   setup_mask_fill(color);
394   setup_mask_framebuffer(surf, surf_width, surf_height);
395   setup_mask_viewport();
396
397   renderer_draw_quad(ctx->renderer, x, y,
398                      x + width, y + height, 0.0f/*depth should be disabled*/);
399
400
401   /* make sure rendering has completed */
402   ctx->pipe->flush(ctx->pipe,
403                    PIPE_FLUSH_RENDER_CACHE | PIPE_FLUSH_FRAME,
404                    NULL);
405
406#if DEBUG_MASKS
407   save_alpha_to_file(0);
408#endif
409
410   cso_restore_blend(ctx->cso_context);
411   cso_restore_framebuffer(ctx->cso_context);
412   cso_restore_fragment_shader(ctx->cso_context);
413   cso_restore_viewport(ctx->cso_context);
414}
415
416
417static void mask_using_texture(struct pipe_texture *texture,
418                               VGMaskOperation operation,
419                               VGint x, VGint y,
420                               VGint width, VGint height)
421{
422   struct vg_context *ctx = vg_current_context();
423   struct pipe_surface *surface =
424      alpha_mask_surface(ctx, PIPE_BUFFER_USAGE_GPU_WRITE);
425   VGint offsets[4], loc[4];
426
427   if (!surface)
428      return;
429   if (!intersect_rectangles(surface->width, surface->height,
430                             texture->width0, texture->height0,
431                             x, y, width, height,
432                             offsets, loc))
433      return;
434#if 0
435   debug_printf("Offset = [%d, %d, %d, %d]\n", offsets[0],
436                offsets[1], offsets[2], offsets[3]);
437   debug_printf("Locati = [%d, %d, %d, %d]\n", loc[0],
438                loc[1], loc[2], loc[3]);
439#endif
440
441   /* prepare our blend surface */
442   vg_prepare_blend_surface_from_mask(ctx);
443
444   cso_save_samplers(ctx->cso_context);
445   cso_save_sampler_textures(ctx->cso_context);
446   cso_save_framebuffer(ctx->cso_context);
447   cso_save_blend(ctx->cso_context);
448   cso_save_fragment_shader(ctx->cso_context);
449   cso_save_viewport(ctx->cso_context);
450
451   setup_mask_samplers(texture);
452   setup_mask_blend();
453   setup_mask_operation(operation);
454   setup_mask_framebuffer(surface, surface->width, surface->height);
455   setup_mask_viewport();
456
457   /* render the quad to propagate the rendering from stencil */
458   renderer_draw_texture(ctx->renderer, texture,
459                         offsets[0], offsets[1],
460                         offsets[0] + offsets[2], offsets[1] + offsets[3],
461                         loc[0], loc[1], loc[0] + loc[2], loc[1] + loc[3]);
462
463   /* make sure rendering has completed */
464   ctx->pipe->flush(ctx->pipe, PIPE_FLUSH_RENDER_CACHE, NULL);
465   cso_restore_blend(ctx->cso_context);
466   cso_restore_framebuffer(ctx->cso_context);
467   cso_restore_fragment_shader(ctx->cso_context);
468   cso_restore_samplers(ctx->cso_context);
469   cso_restore_sampler_textures(ctx->cso_context);
470   cso_restore_viewport(ctx->cso_context);
471
472   pipe_surface_reference(&surface, NULL);
473}
474
475
476#ifdef OPENVG_VERSION_1_1
477
478struct vg_mask_layer * mask_layer_create(VGint width, VGint height)
479{
480   struct vg_context *ctx = vg_current_context();
481   struct vg_mask_layer *mask = 0;
482
483   mask = CALLOC_STRUCT(vg_mask_layer);
484   vg_init_object(&mask->base, ctx, VG_OBJECT_MASK);
485   mask->width = width;
486   mask->height = height;
487
488   {
489      struct pipe_texture pt;
490      struct pipe_screen *screen = ctx->pipe->screen;
491
492      memset(&pt, 0, sizeof(pt));
493      pt.target = PIPE_TEXTURE_2D;
494      pt.format = PIPE_FORMAT_A8R8G8B8_UNORM;
495      pt.last_level = 0;
496      pt.width0 = width;
497      pt.height0 = height;
498      pt.depth0 = 1;
499      pt.tex_usage = PIPE_TEXTURE_USAGE_SAMPLER;
500      pt.compressed = 0;
501
502      mask->texture = screen->texture_create(screen, &pt);
503   }
504
505   vg_context_add_object(ctx, VG_OBJECT_MASK, mask);
506
507   return mask;
508}
509
510void mask_layer_destroy(struct vg_mask_layer *layer)
511{
512   struct vg_context *ctx = vg_current_context();
513
514   vg_context_remove_object(ctx, VG_OBJECT_MASK, layer);
515   pipe_texture_release(&layer->texture);
516   free(layer);
517}
518
519void mask_layer_fill(struct vg_mask_layer *layer,
520                     VGint x, VGint y,
521                     VGint width, VGint height,
522                     VGfloat value)
523{
524   struct vg_context *ctx = vg_current_context();
525   VGfloat alpha_color[4] = {0, 0, 0, 0};
526   struct pipe_surface *surface;
527
528   alpha_color[3] = value;
529
530   surface = ctx->pipe->screen->get_tex_surface(
531      ctx->pipe->screen, layer->texture,
532      0, 0, 0,
533      PIPE_BUFFER_USAGE_GPU_WRITE);
534
535   surface_fill(surface,
536                layer->width, layer->height,
537                x, y, width, height, alpha_color);
538
539   ctx->pipe->screen->tex_surface_release(ctx->pipe->screen, &surface);
540}
541
542void mask_copy(struct vg_mask_layer *layer,
543               VGint sx, VGint sy,
544               VGint dx, VGint dy,
545               VGint width, VGint height)
546{
547    struct vg_context *ctx = vg_current_context();
548    struct st_framebuffer *fb_buffers = ctx->draw_buffer;
549
550    renderer_copy_texture(ctx->renderer,
551                          layer->texture,
552                          sx, sy,
553                          sx + width, sy + height,
554                          fb_buffers->alpha_mask,
555                          dx, dy,
556                          dx + width, dy + height);
557}
558
559static void mask_layer_render_to(struct vg_mask_layer *layer,
560                                 struct path *path,
561                                 VGbitfield paint_modes)
562{
563   struct vg_context *ctx = vg_current_context();
564   const VGfloat fill_color[4] = {1.f, 1.f, 1.f, 1.f};
565   struct pipe_screen *screen = ctx->pipe->screen;
566   struct pipe_surface *surface;
567
568   surface = screen->get_tex_surface(screen, layer->texture,  0, 0, 0,
569                                     PIPE_BUFFER_USAGE_GPU_WRITE);
570
571   cso_save_framebuffer(ctx->cso_context);
572   cso_save_fragment_shader(ctx->cso_context);
573   cso_save_viewport(ctx->cso_context);
574
575   setup_mask_blend();
576   setup_mask_fill(fill_color);
577   setup_mask_framebuffer(surface, layer->width, layer->height);
578   setup_mask_viewport();
579
580   if (paint_modes & VG_FILL_PATH) {
581      struct matrix *mat = &ctx->state.vg.path_user_to_surface_matrix;
582      path_fill(path, mat);
583   }
584
585   if (paint_modes & VG_STROKE_PATH){
586      path_stroke(path);
587   }
588
589
590   /* make sure rendering has completed */
591   ctx->pipe->flush(ctx->pipe, PIPE_FLUSH_RENDER_CACHE, NULL);
592
593   cso_restore_framebuffer(ctx->cso_context);
594   cso_restore_fragment_shader(ctx->cso_context);
595   cso_restore_viewport(ctx->cso_context);
596   ctx->state.dirty |= BLEND_DIRTY;
597
598   screen->tex_surface_release(ctx->pipe->screen, &surface);
599}
600
601void mask_render_to(struct path *path,
602                    VGbitfield paint_modes,
603                    VGMaskOperation operation)
604{
605   struct vg_context *ctx = vg_current_context();
606   struct st_framebuffer *fb_buffers = ctx->draw_buffer;
607   struct vg_mask_layer *temp_layer;
608   VGint width, height;
609
610   width = fb_buffers->alpha_mask->width0;
611   height = fb_buffers->alpha_mask->width0;
612
613   temp_layer = mask_layer_create(width, height);
614
615   mask_layer_render_to(temp_layer, path, paint_modes);
616
617   mask_using_layer(temp_layer, 0, 0, width, height,
618                    operation);
619
620   mask_layer_destroy(temp_layer);
621}
622
623void mask_using_layer(struct vg_mask_layer *layer,
624                      VGMaskOperation operation,
625                      VGint x, VGint y,
626                      VGint width, VGint height)
627{
628   mask_using_texture(layer->texture, operation,
629                      x, y, width, height);
630}
631
632VGint mask_layer_width(struct vg_mask_layer *layer)
633{
634   return layer->width;
635}
636
637VGint mask_layer_height(struct vg_mask_layer *layer)
638{
639   return layer->height;
640}
641
642
643#endif
644
645void mask_using_image(struct vg_image *image,
646                      VGMaskOperation operation,
647                      VGint x, VGint y,
648                      VGint width, VGint height)
649{
650   mask_using_texture(image->texture, operation,
651                      x, y, width, height);
652}
653
654void mask_fill(VGint x, VGint y, VGint width, VGint height,
655               VGfloat value)
656{
657   struct vg_context *ctx = vg_current_context();
658   VGfloat alpha_color[4] = {.0f, .0f, .0f, value};
659   struct pipe_surface *surf = alpha_mask_surface(
660      ctx, PIPE_BUFFER_USAGE_GPU_WRITE);
661
662#if DEBUG_MASKS
663   debug_printf("mask_fill(%d, %d, %d, %d) with  rgba(%f, %f, %f, %f)\n",
664                x, y, width, height,
665                alpha_color[0], alpha_color[1],
666                alpha_color[2], alpha_color[3]);
667   debug_printf("XXX %f  === %f \n",
668                alpha_color[3], value);
669#endif
670
671   surface_fill(surf, surf->width, surf->height,
672                x, y, width, height, alpha_color);
673
674   pipe_surface_reference(&surf, NULL);
675}
676
677VGint mask_bind_samplers(struct pipe_sampler_state **samplers,
678                         struct pipe_texture **textures)
679{
680   struct vg_context *ctx = vg_current_context();
681
682   if (ctx->state.vg.masking) {
683      struct st_framebuffer *fb_buffers = ctx->draw_buffer;
684
685      samplers[1] = &ctx->mask.sampler;
686      textures[1] = fb_buffers->alpha_mask;
687      return 1;
688   } else
689      return 0;
690}
691