#version 450 struct Foo { int a; }; layout(location = 0) in vec4 vColor; layout(location = 0) out vec4 FragColor; int uninit_int = 0; ivec4 uninit_vector = ivec4(0); mat4 uninit_matrix = mat4(vec4(0.0), vec4(0.0), vec4(0.0), vec4(0.0)); Foo uninit_foo = Foo(0); void main() { int uninit_function_int = 0; if (vColor.x > 10.0) { uninit_function_int = 10; } else { uninit_function_int = 20; } FragColor = vColor; }