On 12/16/2011 10:44 AM, Paul Berry wrote:
On 16 December 2011 10:04, Paul Berry <stereotype...@gmail.com
<mailto:stereotype...@gmail.com>> wrote:
On 15 December 2011 15:20, Kenneth Graunke <kenn...@whitecape.org
<mailto:kenn...@whitecape.org>> wrote:
Signed-off-by: Kenneth Graunke <kenn...@whitecape.org
<mailto:kenn...@whitecape.org>>
---
src/mesa/drivers/dri/i965/brw_context.c | 1 +
src/mesa/drivers/dri/i965/brw_context.h | 3 ++
src/mesa/drivers/dri/i965/brw_gs_emit.c | 10 ++++++++
src/mesa/drivers/dri/i965/gen6_sol.c | 38
+++++++++++++++++++++++++++++++
4 files changed, 52 insertions(+), 0 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_context.c
b/src/mesa/drivers/dri/i965/brw_context.c
index 7d360b0..fd60853 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -117,6 +117,7 @@ static void brwInitDriverFunctions( struct
dd_function_table *functions )
brw_init_queryobj_functions(functions);
functions->PrepareExecBegin = brwPrepareExecBegin;
+ functions->BeginTransformFeedback =
brw_begin_transform_feedback;
functions->EndTransformFeedback = brw_end_transform_feedback;
}
diff --git a/src/mesa/drivers/dri/i965/brw_context.h
b/src/mesa/drivers/dri/i965/brw_context.h
index 8e52488..20623d4 100644
--- a/src/mesa/drivers/dri/i965/brw_context.h
+++ b/src/mesa/drivers/dri/i965/brw_context.h
@@ -1073,6 +1073,9 @@ brw_fprog_uses_noperspective(const struct
gl_fragment_program *fprog);
/* gen6_sol.c */
void
+brw_begin_transform_feedback(struct gl_context *ctx,
+ struct gl_transform_feedback_object
*obj);
+void
brw_end_transform_feedback(struct gl_context *ctx,
struct gl_transform_feedback_object
*obj);
diff --git a/src/mesa/drivers/dri/i965/brw_gs_emit.c
b/src/mesa/drivers/dri/i965/brw_gs_emit.c
index 72d4eca..5dd3734 100644
--- a/src/mesa/drivers/dri/i965/brw_gs_emit.c
+++ b/src/mesa/drivers/dri/i965/brw_gs_emit.c
@@ -352,6 +352,15 @@ gen6_sol_program(struct brw_gs_compile *c,
struct brw_gs_prog_key *key,
*/
brw_MOV(p, get_element_ud(c->reg.header, 5),
get_element_ud(c->reg.SVBI, 0));
+
+ /* Make sure that the buffers have enough room for all
the vertices. */
+ brw_ADD(p, get_element_ud(c->reg.temp, 0),
+ get_element_ud(c->reg.SVBI, 0),
brw_imm_ud(num_verts));
+ brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_L,
+ get_element_ud(c->reg.temp, 0),
+ get_element_ud(c->reg.SVBI, 4));
+ brw_IF(p, BRW_EXECUTE_1);
+
Whoops, one other correction. There's an off-by-one error--this should
be BRW_CONDITIONAL_LE.
For example, let's say we're outputting triangles, the transform
feedback buffer is large enough to hold 6 vertices, and we've output 3
vertices already. In that case num_verts is 3, SVBI.0 is 3, and SVBI.4
is 6. The above logic compares SVBI.0 + num_verts < SVBI.4 (6 < 6), so
it concludes that there isn't room for the second triangle. It should
be computing SVBI.0 + num_verts <= SVBI.4 (6 <= 6), because there is
just barely room for the second triangle.
Do we have piglit test cases for these edge conditions? If we don't, we
need them. :)
/* For each vertex, generate code to output each varying
using the
* appropriate binding table entry.
*/
@@ -392,6 +401,7 @@ gen6_sol_program(struct brw_gs_compile *c,
struct brw_gs_prog_key *key,
get_element_ud(c->reg.header, 5),
brw_imm_ud(1));
}
}
+ brw_ENDIF(p);
/* Now, reinitialize the header register from R0 to
restore the parts of
* the register that we overwrote while streaming out
transform feedback
diff --git a/src/mesa/drivers/dri/i965/gen6_sol.c
b/src/mesa/drivers/dri/i965/gen6_sol.c
index b11bce2..56d4a6a 100644
--- a/src/mesa/drivers/dri/i965/gen6_sol.c
+++ b/src/mesa/drivers/dri/i965/gen6_sol.c
@@ -26,6 +26,7 @@
* Code to initialize the binding table entries used by
transform feedback.
*/
+#include "main/macros.h"
#include "brw_context.h"
#include "intel_buffer_objects.h"
#include "intel_batchbuffer.h"
@@ -101,6 +102,43 @@ const struct brw_tracked_state
gen6_sol_surface = {
};
void
+brw_begin_transform_feedback(struct gl_context *ctx,
+ struct gl_transform_feedback_object
*obj)
+{
+ struct intel_context *intel = intel_context(ctx);
+ const struct gl_shader_program *vs_prog =
+ ctx->Shader.CurrentVertexProgram;
+ const struct gl_transform_feedback_info *linked_xfb_info =
+ &vs_prog->LinkedTransformFeedback;
+ struct gl_transform_feedback_object *xfb_obj =
+ ctx->TransformFeedback.CurrentObject;
+
+ unsigned max_index = 0xffffffff;
+
+ /* Compute the maximum number of vertices that we can write
without
+ * overflowing any of the buffers currently being used for
feedback.
+ */
+ for (int i = 0; i < MAX_FEEDBACK_ATTRIBS; ++i) {
Minor nit: MAX_FEEDBACK_ATTRIBS (32) is the correct bound for
generic Mesa code, but in i965, we only support 4 buffers, so this
loop bound should probably be BRW_MAX_SOL_BUFFERS.
+ unsigned stride = linked_xfb_info->BufferStride[i];
+
+ /* Skip any inactive buffers, which have a stride of 0. */
+ if (stride == 0)
+ continue;
+
+ unsigned max_for_this_buffer = xfb_obj->Size[i] / (4 *
stride);
+ max_index = MIN2(max_index, max_for_this_buffer);
+ }
+
+ /* Initialize the SVBI 0 register to zero and set the
maximum index. */
+ BEGIN_BATCH(4);
+ OUT_BATCH(_3DSTATE_GS_SVB_INDEX << 16 | (4 - 2));
+ OUT_BATCH(0); /* SVBI 0 */
+ OUT_BATCH(0);
+ OUT_BATCH(max_index);
+ ADVANCE_BATCH();
+}
+
+void
brw_end_transform_feedback(struct gl_context *ctx,
struct gl_transform_feedback_object
*obj)
{
--
1.7.7.3
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Other than that one minor comment, this patch is:
Reviewed-by: Paul Berry <stereotype...@gmail.com
<mailto:stereotype...@gmail.com>>
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