On 16 December 2011 11:09, Ian Romanick <<a href="mailto:idr@freedesktop.org">idr@freedesktop.org</a>> wrote: <div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div class="im">On 12/16/2011 10:44 AM, Paul Berry wrote: </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im"> On 16 December 2011 10:04, Paul Berry <<a href="mailto:stereotype441@gmail.com" target="_blank">stereotype441@gmail.com</a> </div><div class="im"> <mailto:<a href="mailto:stereotype441@gmail.com" target="_blank">stereotype441@gmail.com</a>>> wrote: On 15 December 2011 15:20, Kenneth Graunke <<a href="mailto:kenneth@whitecape.org" target="_blank">kenneth@whitecape.org</a> </div><div class="im"> <mailto:<a href="mailto:kenneth@whitecape.org" target="_blank">kenneth@whitecape.org</a>>> wrote: Signed-off-by: Kenneth Graunke <<a href="mailto:kenneth@whitecape.org" target="_blank">kenneth@whitecape.org</a> </div> <mailto:<a href="mailto:kenneth@whitecape.org" target="_blank">kenneth@whitecape.org</a>>><div><div class="h5"> --- 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. </div></div></blockquote> Do we have piglit test cases for these edge conditions? If we don't, we need them. :) </blockquote><div> This one was caught by piglit tests that I'm hoping to send to the list today. </div></div>