src/mesa/pipe/softpipe/sp_quad_bufloop.c

   1
   2 #include "pipe/p_util.h"
   3 #include "sp_context.h"
   4 #include "sp_headers.h"
   5 #include "sp_surface.h"
   6 #include "sp_quad.h"
   7
   8
   9 /**
  10  * Loop over colorbuffers, passing quad to next stage each time.
  11  */
  12 static void
  13 cbuf_loop_quad(struct quad_stage *qs, struct quad_header *quad)
  14 {
  15    struct softpipe_context *softpipe = qs->softpipe;
  16    float tmp[4][QUAD_SIZE];
  17    unsigned i;
  18
  19    assert(sizeof(quad->outputs.color) == sizeof(tmp));
  20    assert(softpipe->framebuffer.num_cbufs <= PIPE_MAX_COLOR_BUFS);
  21
  22    /* make copy of original colors since they can get modified
  23     * by blending and masking.
  24     * XXX we won't have to do this if the fragment program actually emits
  25     * N separate colors and we're drawing to N color buffers (MRT).
  26     * But if we emitted one color and glDrawBuffer(GL_FRONT_AND_BACK) is
  27     * in effect, we need to save/restore colors like this.
  28     */
  29    memcpy(tmp, quad->outputs.color, sizeof(tmp));
  30
  31    for (i = 0; i < softpipe->framebuffer.num_cbufs; i++) {
  32       /* set current cbuffer */
  33       softpipe->cbuf = softpipe->framebuffer.cbufs[i];
  34
  35       /* pass blended quad to next stage */
  36       qs->next->run(qs->next, quad);
  37
  38       /* restore quad's colors for next buffer */
  39       memcpy(quad->outputs.color, tmp, sizeof(tmp));
  40    }
  41
  42    softpipe->cbuf = NULL; /* prevent accidental use */
  43 }
  44
  45
  46 static void cbuf_loop_begin(struct quad_stage *qs)
  47 {
  48    if (qs->next)
  49       qs->next->begin(qs->next);
  50 }
  51
  52
  53 /**
  54  * Create the colorbuffer loop stage.
  55  * This is used to implement multiple render targets and GL_FRONT_AND_BACK
  56  * rendering.
  57  */
  58 struct quad_stage *sp_quad_bufloop_stage( struct softpipe_context *softpipe )
  59 {
  60    struct quad_stage *stage = CALLOC_STRUCT(quad_stage);
  61
  62    stage->softpipe = softpipe;
  63    stage->begin = cbuf_loop_begin;
  64    stage->run = cbuf_loop_quad;
  65
  66    return stage;
  67 }
  68