[require]
GLSL >= 1.10

[vertex shader]
uniform float i;

void main()
{
	vec4 color = vec4(0.0);
	color[int(i)] = 1.0;

	gl_FrontColor = color;
	gl_Position = gl_Vertex;
}

[fragment shader file]
glsl-color.frag

[test]
uniform float i 1.0;
draw rect -1 -1 2 2
probe rgb 1 1 0.0 1.0 0.0