src/mesa/state_tracker/st_atom_msaa.c

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   3  * Copyright 2010 VMware, Inc.
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  16  * of the Software.
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  27
  28
  29 #include "st_context.h"
  30 #include "pipe/p_context.h"
  31 #include "st_atom.h"
  32
  33 #include "cso_cache/cso_context.h"
  34
  35
  36 /* Second state atom for user clip planes:
  37  */
  38 static void update_sample_mask( struct st_context *st )
  39 {
  40    unsigned sample_mask = 0xffffffff;
  41    unsigned sample_count = 1;
  42    struct pipe_framebuffer_state *framebuffer = &st->state.framebuffer;
  43
  44    /* dependency here on bound surface (or rather, sample count) is worrying */
  45    if (framebuffer->zsbuf)
  46       sample_count = framebuffer->zsbuf->texture->nr_samples;
  47    else if (framebuffer->cbufs[0])
  48       sample_count = framebuffer->cbufs[0]->texture->nr_samples;
  49
  50    if (st->ctx->Multisample.Enabled && sample_count > 1) {
  51    /* unlike in gallium/d3d10 the mask is only active if msaa is enabled */
  52       if (st->ctx->Multisample.SampleCoverage) {
  53          unsigned nr_bits;
  54          nr_bits = st->ctx->Multisample.SampleCoverageValue * (float)sample_count;
  55          /* there's lot of ways how to do this. We just use first few bits,
  56             since we have no knowledge of sample positions here. When
  57             app-supplied mask though is used too might need to be smarter.
  58             Also, there's a interface restriction here in theory it is
  59             encouraged this mask not be the same at each pixel. */
  60          sample_mask = (1 << nr_bits) - 1;
  61          if (st->ctx->Multisample.SampleCoverageInvert)
  62             sample_mask = ~sample_mask;
  63       }
  64       /* TODO merge with app-supplied sample mask */
  65    }
  66
  67    /* mask off unused bits or don't care? */
  68
  69    if (sample_mask != st->state.sample_mask) {
  70       st->state.sample_mask = sample_mask;
  71       cso_set_sample_mask(st->cso_context, sample_mask);
  72    }
  73 }
  74
  75
  76 const struct st_tracked_state st_update_msaa = {
  77    "st_update_msaa",                                    /* name */
  78    {                                                    /* dirty */
  79       (_NEW_MULTISAMPLE | _NEW_BUFFERS),                /* mesa */
  80       ST_NEW_FRAMEBUFFER,                               /* st */
  81    },
  82    update_sample_mask                                   /* update */
  83 };