SKIP: FAILED #version 310 es precision mediump float; void tint_symbol(vec4 position, bool front_facing, uint sample_index, uint sample_mask) { if (front_facing) { vec4 foo = position; uint bar = (sample_index + sample_mask); } } void main() { tint_symbol(gl_FragCoord, gl_FrontFacing, uint(gl_SampleID), uint(gl_SampleMask[0])); return; } Error parsing GLSL shader: ERROR: 0:12: 'gl_SampleID' : required extension not requested: GL_OES_sample_variables ERROR: 0:12: '' : compilation terminated ERROR: 2 compilation errors. No code generated.