[require] GLSL >= 1.10 [vertex shader] void main() { gl_Position = gl_Vertex; } [fragment shader] uniform vec4 color; void main() { gl_FragColor = vec4(1.0) / sqrt(color.g); } [test] uniform vec4 color 0.0 2.0 0.0 0.0 draw rect -1 -1 2 2 probe all rgba 0.7071 0.7071 0.7071 0.7071