doc/testspecs/GLES31/functional.uniform_location.txt

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drawElements Quality Program Test Specification
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    Explicit uniform location tests

Tests:
 + dEQP-GLES31.functional.uniform_location.*

Includes:
 + Location for all primitive types
 + Location for (nested) structs and their members
 + Location for (nested) arrays and all their elements
 + Minimum and maximum location
   - With all primitive types
 + Linkage with locations defined in the vertex shader, fragment shader, both or neither
   - Primitive types only
 + Negative tests
   - Duplicate location with various linkage and usage
   - Overlapping structs and arrays with various linkage and usage

Excludes:
 + Samplers with dimensionality other than two or less than four color channels
 + Deeply nested structs/arrays

Description:

All cases create a shader with suitable uniforms, some of which have layout
qualifiers with a location specified. Locations of all uniforms in the shader
are verified to match the given ones with glGetUniformLocation. Generated
textures with a flat randomized color are bound to samplers. Other uniforms
are assigned similarly randomized values.
The shader contains hardcoded comparisons to these randomized values for each
uniform that is being checked. It outputs white if all of the assigned uniform
values match the hardcoded values. A quad is rendered and the output of the
shader is verified to be fully white.

All cases excluding negative and min/max use randomized locations between the
spec defined minimum and maximum values [0, 1024) for all uniforms.

Basic primitive type, array, nested array and min/max cases test with all basic
types. Tests are done in both vertex and fragment shaders but with trivial
linkage.

Min/max cases assign a single primitive either the largest valid location as
reported by the implementation or the smallest valid location (0) but are
otherwise identical to the basic primitive type cases.

Struct, nested struct and linkage cases are randomized.
These cases do not necessarily use every declared uniform.
These cases have declarations, locations specifiers and verification
randomly split between the vertex and fragment shaders on a per-uniform basis.
This includes leaving some locations unassigned.
All primitive types used in these tests are randomized.
Struct cases have a fixed number of members with a fixed nesting structure.

Negative cases are not generated and share no logic with the other cases,
instead expecting compile or link failures.