src/gallium/drivers/softpipe/sp_quad_stipple.c

   1
   2 /**
   3  * quad polygon stipple stage
   4  */
   5
   6 #include "sp_context.h"
   7 #include "sp_quad.h"
   8 #include "sp_quad_pipe.h"
   9 #include "pipe/p_defines.h"
  10 #include "util/u_memory.h"
  11
  12
  13 /**
  14  * Apply polygon stipple to quads produced by triangle rasterization
  15  */
  16 static void
  17 stipple_quad(struct quad_stage *qs, struct quad_header *quad)
  18 {
  19    static const uint bit31 = 1 << 31;
  20    static const uint bit30 = 1 << 30;
  21
  22    if (quad->input.prim == QUAD_PRIM_TRI) {
  23       struct softpipe_context *softpipe = qs->softpipe;
  24       /* need to invert Y to index into OpenGL's stipple pattern */
  25       const int col0 = quad->input.x0 % 32;
  26       const int y0 = quad->input.y0;
  27       const int y1 = y0 + 1;
  28       const uint stipple0 = softpipe->poly_stipple.stipple[y0 % 32];
  29       const uint stipple1 = softpipe->poly_stipple.stipple[y1 % 32];
  30
  31       /* turn off quad mask bits that fail the stipple test */
  32       if ((stipple0 & (bit31 >> col0)) == 0)
  33          quad->inout.mask &= ~MASK_TOP_LEFT;
  34
  35       if ((stipple0 & (bit30 >> col0)) == 0)
  36          quad->inout.mask &= ~MASK_TOP_RIGHT;
  37
  38       if ((stipple1 & (bit31 >> col0)) == 0)
  39          quad->inout.mask &= ~MASK_BOTTOM_LEFT;
  40
  41       if ((stipple1 & (bit30 >> col0)) == 0)
  42          quad->inout.mask &= ~MASK_BOTTOM_RIGHT;
  43
  44       if (!quad->inout.mask) {
  45          /* all fragments failed stipple test, end of quad pipeline */
  46          return;
  47       }
  48    }
  49
  50    qs->next->run(qs->next, quad);
  51 }
  52
  53
  54 static void stipple_begin(struct quad_stage *qs)
  55 {
  56    qs->next->begin(qs->next);
  57 }
  58
  59
  60 static void stipple_destroy(struct quad_stage *qs)
  61 {
  62    FREE( qs );
  63 }
  64
  65
  66 struct quad_stage *
  67 sp_quad_polygon_stipple_stage( struct softpipe_context *softpipe )
  68 {
  69    struct quad_stage *stage = CALLOC_STRUCT(quad_stage);
  70
  71    stage->softpipe = softpipe;
  72    stage->begin = stipple_begin;
  73    stage->run = stipple_quad;
  74    stage->destroy = stipple_destroy;
  75
  76    return stage;
  77 }