On August 10, 2018 13:25:04 Kenneth Graunke <[email protected]> wrote:
On Friday, August 10, 2018 8:34:12 AM PDT Jason Ekstrand wrote:
On August 10, 2018 03:19:18 Kenneth Graunke <[email protected]> wrote:
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));
Do we really need the and?
Probably not - without it, we'll just leave garbage in the X8 bits
instead of zeroing them. But that's probably fine, unless it affects
HiZ compression somehow? I was mostly borrowing from u_format_zs.c
code to do this without thinking too hard.
That would only matter of mul(sat(x), factor) produces something outside
the range [0, factor+1). I really don't think it's doing anything useful.
--Jason
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