[require] GLSL >= 1.10 [vertex shader] void main() { gl_Position = gl_Vertex; } [fragment shader] void main() { mat3 matrix3 = mat3(1, 2, 3, 4, 5, 6, 7, 8, 9); gl_FragColor = vec4(ivec4(matrix3)) / 10.0; } [test] draw rect -1 -1 2 2 probe all rgba 0.1 0.2 0.3 0.4