mesa: validate sampler uniforms during gluniform calls

Patch fixes 'glsl-2types-of-textures-on-same-unit' in WebGL conformance
test suite. No Piglit regressions, fixes gl-2.0-active-sampler-conflict.

To avoid adding potentially heavy check during draw (valid_to_render),
check is done during uniform updates by inspecting TexturesUsed mask.

A new boolean variable is introduced to cache validation state.

v2: take into account case where 2 uniforms use same unit (curro)
    also do the check only when SSO is not in use, SSO has own
    path for sampler validation.

Signed-off-by: Tapani Pälli <[email protected]>
Reviewed-by: Francisco Jerez <[email protected]>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/mesa/main/uniforms.c b/src/mesa/main/uniforms.c
index 0d0cbf57eb7..598b4d4538f 100644
--- a/src/mesa/main/uniforms.c
+++ b/src/mesa/main/uniforms.c
@@ -75,12 +75,26 @@ _mesa_update_shader_textures_used(struct gl_shader_program *shProg,
    memcpy(prog->SamplerUnits, shader->SamplerUnits, sizeof(prog->SamplerUnits));
    memset(prog->TexturesUsed, 0, sizeof(prog->TexturesUsed));
 
+   shProg->SamplersValidated = GL_TRUE;
+
    for (s = 0; s < MAX_SAMPLERS; s++) {
       if (prog->SamplersUsed & (1 << s)) {
          GLuint unit = shader->SamplerUnits[s];
          GLuint tgt = shader->SamplerTargets[s];
          assert(unit < Elements(prog->TexturesUsed));
          assert(tgt < NUM_TEXTURE_TARGETS);
+
+         /* The types of the samplers associated with a particular texture
+          * unit must be an exact match.  Page 74 (page 89 of the PDF) of the
+          * OpenGL 3.3 core spec says:
+          *
+          *     "It is not allowed to have variables of different sampler
+          *     types pointing to the same texture image unit within a program
+          *     object."
+          */
+         if (prog->TexturesUsed[unit] & ~(1 << tgt))
+            shProg->SamplersValidated = GL_FALSE;
+
          prog->TexturesUsed[unit] |= (1 << tgt);
       }
    }