[require] GLSL >= 1.20 [vertex shader] void main() { gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex; } [fragment shader] void main() { const int x = int(degrees(3.1415926535)); if (x == 180) gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0); else gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0); } [test] draw rect -1 -1 2 2 probe all rgb 0.0 1.0 0.0