[Mesa-dev] [PATCH 1/2] blorp: Don't try to use R32_UNORM for R24_UNORM_X8_TYPELESS rendering.

[Kenneth Graunke]

The hardware doesn't support rendering to R24_UNORM_X8_TYPELESS, so
Jason decided to fake it with a bit of shader math and R32_UNORM RTs.

The only problem is that R32_UNORM isn't renderable either...so we've
just traded one bad format for another.

This patch makes us use R32_UINT instead.
---
 src/intel/blorp/blorp_blit.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/intel/blorp/blorp_blit.c b/src/intel/blorp/blorp_blit.c
index c85ec8543a9..7b49f9afa35 100644
--- a/src/intel/blorp/blorp_blit.c
+++ b/src/intel/blorp/blorp_blit.c
@@ -984,14 +984,15 @@ convert_color(struct nir_builder *b, nir_ssa_def *color,
    nir_ssa_def *value;
 
    if (key->dst_format == ISL_FORMAT_R24_UNORM_X8_TYPELESS) {
-      /* The destination image is bound as R32_UNORM but the data needs to be
+      /* The destination image is bound as R32_UINT but the data needs to be
        * in R24_UNORM_X8_TYPELESS.  The bottom 24 are the actual data and the
        * top 8 need to be zero.  We can accomplish this by simply multiplying
        * by a factor to scale things down.
        */
-      float factor = (float)((1 << 24) - 1) / (float)UINT32_MAX;
-      value = nir_fmul(b, nir_fsat(b, nir_channel(b, color, 0)),
-                          nir_imm_float(b, factor));
+      unsigned factor = (1 << 24) - 1;
+      value = nir_fsat(b, nir_channel(b, color, 0));
+      value = nir_fmul(b, value, nir_imm_float(b, factor));
+      value = nir_iand(b, nir_f2i32(b, value), nir_imm_int(b, factor));
    } else if (key->dst_format == ISL_FORMAT_L8_UNORM_SRGB) {
       value = nir_format_linear_to_srgb(b, nir_channel(b, color, 0));
    } else if (key->dst_format == ISL_FORMAT_R8G8B8_UNORM_SRGB) {
@@ -1976,7 +1977,7 @@ try_blorp_blit(struct blorp_batch *batch,
          isl_format_rgbx_to_rgba(params->dst.view.format);
    } else if (params->dst.view.format == ISL_FORMAT_R24_UNORM_X8_TYPELESS) {
       wm_prog_key->dst_format = params->dst.view.format;
-      params->dst.view.format = ISL_FORMAT_R32_UNORM;
+      params->dst.view.format = ISL_FORMAT_R32_UINT;
    } else if (params->dst.view.format == ISL_FORMAT_A4B4G4R4_UNORM) {
       params->dst.view.swizzle =
          isl_swizzle_compose(params->dst.view.swizzle,
-- 
2.18.0