[require]
GLSL >= 1.10

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

[fragment shader]
uniform vec4 y, x;
void main()
{
	/* This test does two things that glsl-fs-atan-1 doesn't: It
	 * tests behavior at y = 0, x < 0 (the discontinuity), and it
	 * does so using the vec4 variant with some of the same values
	 * used in glsl-fs-atan-1.
	 */
	gl_FragColor = atan(y, x) / (2.0 * 3.1415926) + 0.5;
}

[test]
uniform vec4 y -1.0 -1.0 0.0 1.0
uniform vec4 x 0.0 -1.0 -1.0 -1.0
draw rect -1 -1 2 2
probe all rgba 0.25 0.125 1.0 0.875