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i965: Let driconf clamp_max_samples affect context version 

Commit 2f89662 added the driconf option 'clamp_max_samples'.  In that
commit, the option did not alter the context version. The neglect to
alter the context version is a fatal issue for some apps.

For example, consider running Chromium with clamp_max_samples=0.
Pre-patch, Mesa creates a GL 3.0 context but clamps GL_MAX_SAMPLES to
0. This violates the GL 3.0 spec, which requires GL_MAX_SAMPLES >= 4.
The spec violation causes WebGL context creation to fail in many
scenarios because Chromium correctly assumes that a GL 3.0 context
supports at least 4 samples.

Since the driconf option was introduced largely for Chromium, the issue
really needs fixing.

This patch fixes calculation of the context version to respect the
post-clamped value of GL_MAX_SAMPLES. This in turn fixes WebGL on
Chromium when clamp_max_samples=0.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Chad Versace <chad.versace@linux.intel.com>
This commit is contained in:
Chad Versace 2013-11-06 19:52:11 -08:00
parent 95ebabbc5f
commit 315b06ff62
1 changed files with 20 additions and 40 deletions
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60
src/mesa/drivers/dri/i965/brw_context.c
View File

@ -277,38 +277,6 @@ brw_init_driver_functions(struct brw_context *brw,
functions->GetSamplePosition = gen6_get_sample_position;
}
/**
* Override GL_MAX_SAMPLES and related constants according to value of driconf
* option 'clamp_max_samples'.
*/
static void
brw_override_max_samples(struct brw_context *brw)
{
const int clamp_max_samples = driQueryOptioni(&brw->optionCache,
"clamp_max_samples");
if (clamp_max_samples < 0)
return;
const int *supported_msaa_modes =
intel_supported_msaa_modes(brw->intelScreen);
int max_samples = 0;
/* Select the largest supported MSAA mode that does not exceed
* clamp_max_samples.
*/
for (int i = 0; supported_msaa_modes[i] != -1; ++i) {
if (supported_msaa_modes[i] <= clamp_max_samples) {
max_samples = supported_msaa_modes[i];
break;
}
}
brw->ctx.Const.MaxSamples = max_samples;
brw->ctx.Const.MaxColorTextureSamples = max_samples;
brw->ctx.Const.MaxDepthTextureSamples = max_samples;
brw->ctx.Const.MaxIntegerSamples = max_samples;
}
static void
brw_initialize_context_constants(struct brw_context *brw)
{
@ -374,8 +342,26 @@ brw_initialize_context_constants(struct brw_context *brw)
ctx->Const.AlwaysUseGetTransformFeedbackVertexCount = true;
const int max_samples =
intel_supported_msaa_modes(brw->intelScreen)[0];
int max_samples;
const int *msaa_modes = intel_supported_msaa_modes(brw->intelScreen);
const int clamp_max_samples =
driQueryOptioni(&brw->optionCache, "clamp_max_samples");
if (clamp_max_samples < 0) {
max_samples = msaa_modes[0];
} else {
/* Select the largest supported MSAA mode that does not exceed
* clamp_max_samples.
*/
max_samples = 0;
for (int i = 0; msaa_modes[i] != 0; ++i) {
if (msaa_modes[i] <= clamp_max_samples) {
max_samples = msaa_modes[i];
break;
}
}
}
ctx->Const.MaxSamples = max_samples;
ctx->Const.MaxColorTextureSamples = max_samples;
ctx->Const.MaxDepthTextureSamples = max_samples;
@ -775,12 +761,6 @@ brwCreateContext(gl_api api,
_mesa_compute_version(ctx);
/* Here we override context constants. We apply the overrides after
* calculation of the context version because we do not want the overridden
* constants to change the version.
*/
brw_override_max_samples(brw);
_mesa_initialize_dispatch_tables(ctx);
_mesa_initialize_vbo_vtxfmt(ctx);