From 7862bde8af1f63cfe921977ecb112f88885c92a9 Mon Sep 17 00:00:00 2001 From: Paul Berry Date: Sat, 6 Apr 2013 09:36:06 -0700 Subject: glsl/linker: fix varying packing for non-flat integer varyings. Commit dfb57e7 (glsl: Fix error checking on "flat" keyword to match GLSL ES 3.00, GLSL 1.50) relaxed the rules for integral varyings: they only need to be declared as "flat" if they are a fragment shader inputs. This allowed for the possibility of a vertex shader output being a non-flat integer, provided that it was not matched to a fragment shader input. A non-contrived situation where this might arise is if a vertex shader generates some integral outputs which are consumed by tranform feedback, but not by the fragment shader. Unfortunately, lower_packed_varyings assumes that *all* integral varyings are flat, regardless of whether they are consumed by the fragment shader. As a result, attempting to create a non-flat integral vertex output of a size that required packing (i.e. a size other than ivec4 or uvec4) would cause an assertion failure in lower_packed_varyings. This patch prevents the assertion failure by forcing vertex shader outputs to be "flat" whenever they are not consumed by the fragment shader. This should have no effect on rendering since the "flat" keyword only affects the behaviour of fragment shader inputs. Fixes piglit test "spec/EXT_transform_feedback/nonflat-integral". NOTE: This is a candidate for the 9.1 release branch. Reviewed-by: Jordan Justen --- src/glsl/link_varyings.cpp | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp index 04c9fdd7cc6..431d8fd7775 100644 --- a/src/glsl/link_varyings.cpp +++ b/src/glsl/link_varyings.cpp @@ -656,6 +656,10 @@ varying_matches::~varying_matches() * If \c producer_var has already been paired up with a consumer_var, or * producer_var is part of fixed pipeline functionality (and hence already has * a location assigned), this function has no effect. + * + * Note: as a side effect this function may change the interpolation type of + * \c producer_var, but only when the change couldn't possibly affect + * rendering. */ void varying_matches::record(ir_variable *producer_var, ir_variable *consumer_var) @@ -668,6 +672,21 @@ varying_matches::record(ir_variable *producer_var, ir_variable *consumer_var) return; } + if (consumer_var == NULL) { + /* Since there is no consumer_var, the interpolation type of this + * varying cannot possibly affect rendering. Also, since the GL spec + * only requires integer varyings to be "flat" when they are fragment + * shader inputs, it is possible that this variable is non-flat and is + * (or contains) an integer. + * + * lower_packed_varyings requires all integer varyings to flat, + * regardless of where they appear. We can trivially satisfy that + * requirement by changing the interpolation type to flat here. + */ + producer_var->centroid = false; + producer_var->interpolation = INTERP_QUALIFIER_FLAT; + } + if (this->num_matches == this->matches_capacity) { this->matches_capacity *= 2; this->matches = (match *) -- cgit v1.2.3