[require]
GLSL >= 1.10

[vertex shader]
uniform float arg0;
varying vec4 color;

void main()
{
        gl_Position = gl_Vertex;
	color = vec4(0.0, 1.0 - abs(arg0), 0.0, 1.0);
}

[fragment shader]
varying vec4 color;

void main()
{
        gl_FragColor = color;
}

[test]
uniform float arg0 -0.5
draw rect -1 -1 2 2
probe all rgba 0.0 0.5 0.0 1.0