On 11/01/2013 02:37 PM, Paul Berry wrote:
On 31 October 2013 18:36, Chad Versace <[email protected]> wrote:
Clamp gen7 GL_MAX_SAMPLES to 0, 4, or 8.
Clamp gen6 GL_MAX_SAMPLES to 0 or 4.
Clamp other gens to 0.
CC: Eric Anholt <[email protected]>
Signed-off-by: Chad Versace <[email protected]>
---
src/mesa/drivers/dri/i965/brw_context.c | 35
+++++++++++++++++++++++---------
src/mesa/drivers/dri/i965/intel_screen.c | 1 +
2 files changed, 26 insertions(+), 10 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_context.c
b/src/mesa/drivers/dri/i965/brw_context.c
index 38147e9..60a201f 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -273,6 +273,10 @@ brw_initialize_context_constants(struct brw_context
*brw)
{
struct gl_context *ctx = &brw->ctx;
+ uint32_t max_samples;
+ const uint32_t *legal_max_samples;
+ uint32_t clamp_max_samples;
+
ctx->Const.QueryCounterBits.Timestamp = 36;
ctx->Const.StripTextureBorder = true;
@@ -333,19 +337,30 @@ brw_initialize_context_constants(struct brw_context
*brw)
ctx->Const.AlwaysUseGetTransformFeedbackVertexCount = true;
- if (brw->gen == 6) {
- ctx->Const.MaxSamples = 4;
- ctx->Const.MaxColorTextureSamples = 4;
- ctx->Const.MaxDepthTextureSamples = 4;
- ctx->Const.MaxIntegerSamples = 4;
- } else if (brw->gen >= 7) {
- ctx->Const.MaxSamples = 8;
- ctx->Const.MaxColorTextureSamples = 8;
- ctx->Const.MaxDepthTextureSamples = 8;
- ctx->Const.MaxIntegerSamples = 8;
+ if (brw->gen >= 7) {
+ legal_max_samples = (uint32_t[]){8, 4, 0};
ctx->Const.MaxProgramTextureGatherComponents = 4;
+ } else if (brw->gen == 6) {
+ legal_max_samples = (uint32_t[]){4, 0};
+ } else {
+ legal_max_samples = (uint32_t[]){0};
+ }
+
+ /* Set max_samples = min(max(legal_max_samples), clamp_max_samples). */
I don't think the comment matches your intention. How about this instead?
/* Set max_samples to the first (and hence largest) element of
* legal_max_samples that is <= clamp_max_samples. Or, if
* clamp_max_samples < 0, simply the first element of legal_max_samples.
*/
+ max_samples = 0;
+ clamp_max_samples = driQueryOptioni(&brw->optionCache,
"clamp_max_samples");
+ for (uint32_t i = 0; legal_max_samples[i] != 0; ++i) {
+ if (legal_max_samples[i] <= clamp_max_samples) {
+ max_samples = legal_max_samples[i];
+ break;
+ }
If clamp_max_samples < 0, this code sets max_samples to 0. That's not what
you want; you want it to be set to legal_max_samples[0] in this case.
I tested the code and it works as I intended. If the user sets
clamp_max_samples=-1,
then GL_MAX_SAMPLES remains unclamped.
But... I was accidentally too clever in this code. That's why it actually works
despite appearing otherwise. The cleverness is that driQueryOptioni() returns
an int, but I declared clamp_max_samples as a uint. Therefore, if the user
sets the driconf option clamp_max_samples tonegative, then clamp_max_samples
the variable becomes a very large uint. That cleverness is what makes
this comment true:
/* Set max_samples = min(max(legal_max_samples), clamp_max_samples). */
I object to that sort of cleverness. So expect a new clever-free patch soon.
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