src/mesa/pipe/softpipe/sp_quad_alpha_test.c


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77


/**
 * quad alpha test
 */

#include "glheader.h"
#include "imports.h"
#include "sp_context.h"
#include "sp_headers.h"
#include "sp_quad.h"
#include "pipe/p_defines.h"


static void
alpha_test_quad(struct quad_stage *qs, struct quad_header *quad)
{
   struct softpipe_context *softpipe = qs->softpipe;
   GLuint j;
   const GLfloat ref = softpipe->alpha_test.ref;

   switch (softpipe->alpha_test.func) {
   case PIPE_FUNC_NEVER:
      quad->mask = 0x0;
      break;
   case PIPE_FUNC_LESS:
      /*
       * If quad->mask were an array [4] we could do this SIMD-style:
       * quad->mask &= (quad->outputs.color[3] <= vec4(ref));
       */
      for (j = 0; j < QUAD_SIZE; j++) {
         if (quad->mask & (1 << j)) {
            if (quad->outputs.color[3][j] >= ref) {
               /* fail */
               quad->mask &= (1 << j);
            }
         }
      }
      break;
   case PIPE_FUNC_EQUAL:
      for (j = 0; j < QUAD_SIZE; j++) {
         if (quad->mask & (1 << j)) {
            if (quad->outputs.color[3][j] != ref) {
               /* fail */
               quad->mask &= (1 << j);
            }
         }
      }
      break;
   case PIPE_FUNC_LEQUAL:
      for (j = 0; j < QUAD_SIZE; j++) {
         if (quad->mask & (1 << j)) {
            if (quad->outputs.color[3][j] > ref) {
               /* fail */
               quad->mask &= (1 << j);
            }
         }
      }
      break;
      /* XXX fill in remaining cases */
   default:
      abort();
   }

   qs->next->run(qs->next, quad);
}


struct quad_stage *
sp_quad_alpha_test_stage( struct softpipe_context *softpipe )
{
   struct quad_stage *stage = CALLOC_STRUCT(quad_stage);

   stage->softpipe = softpipe;
   stage->run = alpha_test_quad;

   return stage;
}