[vertex shader]
void main()
{
	gl_Position = gl_Vertex;
}

[fragment shader]
uniform vec4 x;
uniform vec4 y;

void main()
{
	gl_FragColor = 0.25 + clamp(pow(x, y), 0.0, 1.0) * 0.5;
}

[test]
uniform vec4 x 0.5 2.0 0.5 1.0
uniform vec4 y 2.0 0.5 -1.0 1.0

draw rect -1 -1 2 2
probe all rgba 0.375 0.75 0.75 0.75