# [description]
# This test exercises a corner case of copy propagation found in Mesa:
# double negation of a value should restore the original value.

[require]
GLSL >= 1.10

[vertex shader]
#version 110

uniform float x;

void main(void)
{
	gl_Position = gl_Vertex;

	float y = -x;
	float z = -y;
	gl_FrontColor = vec4(0.5 + x, 0.5 + y, 0.5 + z, 1.0);
}

[fragment shader]
#version 110
void main(void)
{
	gl_FragColor = gl_Color;
}

[test]
uniform float x 0.25
draw rect -1 -1 2 2
probe all rgba 0.75 0.25 0.75 1.0