[Mesa-dev] [PATCH] glsl: add varyings to resource list only with SSO

Tapani Pälli tapani.palli at intel.com
Wed Oct 7 00:04:06 PDT 2015

Varyings can be considered inputs or outputs of a program only when
SSO is in use. With multi-stage programs, inputs contain only inputs
for first stage and outputs contains outputs of the final shader stage.

I've tested that fix works for Assault Android Cactus (demo version)
and does not cause Piglit or CTS regressions in glGetProgramiv tests.

Following ES 3.1 CTS separate shader tests that do query properties
of varyings in SSO shader programs pass:


Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92122
 src/glsl/linker.cpp | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index 6df8d61..a97b4ef 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -3421,10 +3421,13 @@ build_program_resource_list(struct gl_shader_program *shProg)
    if (input_stage == MESA_SHADER_STAGES && output_stage == 0)
-   if (!add_packed_varyings(shProg, input_stage))
-      return;
-   if (!add_packed_varyings(shProg, output_stage))
-      return;
+   /* Program interface needs to expose varyings in case of SSO. */
+   if (shProg->SeparateShader) {
+      if (!add_packed_varyings(shProg, input_stage))
+         return;
+      if (!add_packed_varyings(shProg, output_stage))
+         return;
+   }
    /* Add inputs and outputs to the resource list. */
    if (!add_interface_variables(shProg, shProg->_LinkedShaders[input_stage]->ir,

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