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authorGregory Hainaut <gregory.hainaut@gmail.com>2015-10-25 15:01:37 +0100
committerEmil Velikov <emil.l.velikov@gmail.com>2015-12-12 19:39:01 +0000
commitaa19234943bb254f79f3d3582d3f1fcda2f5b5d6 (patch)
tree02c994810e49a8c648ee0be51d9676d15694e2f3
parent66f216d8ceda75ed0a47512a69af5f8d94ea0172 (diff)
glsl: don't sort varying in separate shader mode
This fixes an issue where the addition of the FLAT qualifier in varying_matches::record() can break the expected varying order. It also avoids a future issue with the relaxing of interpolation qualifier matching constraints in GLSL 4.50. V2: (by Timothy Arceri) * reworked comment slightly Signed-off-by: Gregory Hainaut <gregory.hainaut@gmail.com> Reviewed-by: Timothy Arceri <timothy.arceri@collabora.com> Reviewed-by: Tapani Pälli <tapani.palli@intel.com> (cherry picked from commit 2ab9cd0c4dcefb3e63266cadc1e06079e67c3962) Nominated-by: Timothy Arceri <timothy.arceri@collabora.com>
-rw-r--r--src/glsl/link_varyings.cpp38
1 files changed, 32 insertions, 6 deletions
diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
index c0b4b3e820c..560906a3eaf 100644
--- a/src/glsl/link_varyings.cpp
+++ b/src/glsl/link_varyings.cpp
@@ -766,7 +766,7 @@ public:
gl_shader_stage consumer_stage);
~varying_matches();
void record(ir_variable *producer_var, ir_variable *consumer_var);
- unsigned assign_locations(uint64_t reserved_slots);
+ unsigned assign_locations(uint64_t reserved_slots, bool separate_shader);
void store_locations() const;
private:
@@ -986,11 +986,36 @@ varying_matches::record(ir_variable *producer_var, ir_variable *consumer_var)
* passed to varying_matches::record().
*/
unsigned
-varying_matches::assign_locations(uint64_t reserved_slots)
+varying_matches::assign_locations(uint64_t reserved_slots, bool separate_shader)
{
- /* Sort varying matches into an order that makes them easy to pack. */
- qsort(this->matches, this->num_matches, sizeof(*this->matches),
- &varying_matches::match_comparator);
+ /* We disable varying sorting for separate shader programs for the
+ * following reasons:
+ *
+ * 1/ All programs must sort the code in the same order to guarantee the
+ * interface matching. However varying_matches::record() will change the
+ * interpolation qualifier of some stages.
+ *
+ * 2/ GLSL version 4.50 removes the matching constrain on the interpolation
+ * qualifier.
+ *
+ * From Section 4.5 (Interpolation Qualifiers) of the GLSL 4.40 spec:
+ *
+ * "The type and presence of interpolation qualifiers of variables with
+ * the same name declared in all linked shaders for the same cross-stage
+ * interface must match, otherwise the link command will fail.
+ *
+ * When comparing an output from one stage to an input of a subsequent
+ * stage, the input and output don't match if their interpolation
+ * qualifiers (or lack thereof) are not the same."
+ *
+ * "It is a link-time error if, within the same stage, the interpolation
+ * qualifiers of variables of the same name do not match."
+ */
+ if (!separate_shader) {
+ /* Sort varying matches into an order that makes them easy to pack. */
+ qsort(this->matches, this->num_matches, sizeof(*this->matches),
+ &varying_matches::match_comparator);
+ }
unsigned generic_location = 0;
unsigned generic_patch_location = MAX_VARYING*4;
@@ -1590,7 +1615,8 @@ assign_varying_locations(struct gl_context *ctx,
reserved_varying_slot(producer, ir_var_shader_out) |
reserved_varying_slot(consumer, ir_var_shader_in);
- const unsigned slots_used = matches.assign_locations(reserved_slots);
+ const unsigned slots_used = matches.assign_locations(reserved_slots,
+ prog->SeparateShader);
matches.store_locations();
for (unsigned i = 0; i < num_tfeedback_decls; ++i) {