[Mesa-dev] [PATCH 7/7] i965: Enable ARB_transform_feedback2 on Sandybridge.
Kenneth Graunke
kenneth at whitecape.org
Fri Feb 17 09:56:21 UTC 2017
The only feature over and above ES 3.0 is DrawTransformFeedback().
We already have to do the whole SOL_NUM_PRIMS_WRITTEN counter dance in
order to compute the SVBI value for ResumeTransformFeedback(), at which
point our existing GetTransformFeedbackVertexCount() implementation will
do the trick (though with a stall to CPU map the buffer).
Someday, we could probably implement DrawTransformFeedback() more
efficiently, using the "Load Internal Vertex Count" feature of
3DSTATE_SVB_INDEX and the 3DPRIMITIVE indirect vertex count bit.
Rumor has it this allows people to use WebGL 2.0 on Sandybridge.
Note that we don't need pipelined register writes like Gen7+ because
we use the 3DSTATE_SVB_INDEX command rather than MI_LOAD_REGISTER_MEM.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99842
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
src/mesa/drivers/dri/i965/brw_context.c | 2 ++
src/mesa/drivers/dri/i965/intel_extensions.c | 3 +++
2 files changed, 5 insertions(+)
diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 977c59c1c3e..17800e3fd60 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -483,6 +483,8 @@ brw_init_driver_functions(struct brw_context *brw,
functions->EndTransformFeedback = brw_end_transform_feedback;
functions->PauseTransformFeedback = brw_pause_transform_feedback;
functions->ResumeTransformFeedback = brw_resume_transform_feedback;
+ functions->GetTransformFeedbackVertexCount =
+ brw_get_transform_feedback_vertex_count;
}
if (brw->gen >= 6)
diff --git a/src/mesa/drivers/dri/i965/intel_extensions.c b/src/mesa/drivers/dri/i965/intel_extensions.c
index f1290bf7b49..ec7ff02be84 100644
--- a/src/mesa/drivers/dri/i965/intel_extensions.c
+++ b/src/mesa/drivers/dri/i965/intel_extensions.c
@@ -158,6 +158,9 @@ intelInitExtensions(struct gl_context *ctx)
ctx->Extensions.EXT_timer_query = true;
}
+ if (brw->gen == 6)
+ ctx->Extensions.ARB_transform_feedback2 = true;
+
if (brw->gen >= 6) {
ctx->Extensions.ARB_blend_func_extended =
!driQueryOptionb(&brw->optionCache, "disable_blend_func_extended");
--
2.11.1
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