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[require]
GLSL >= 1.20
[vertex shader]
uniform vec4 red = vec4(1.0, 0.0, 0.0, 1.0);
uniform vec4 color_delta = vec4(-1.0, 1.0, 0.0, 0.0);
uniform float a = -1.0;
uniform float b = 1.0;
uniform float c = 0.5;
attribute vec4 piglit_vertex;
varying vec4 color;
void main()
{
gl_Position = piglit_vertex;
color = red;
/* This attempts to reproduce a bug in the i965 vec4 backend. Three-
* source instructions, like LRP, cannot write to the null register.
* However, when the result is only used in a condition, the write can be
* (erroneously) eliminated.
*/
if (mix(a, b, c) == 0)
color += color_delta;
}
[fragment shader]
varying vec4 color;
void main()
{
gl_FragColor = color;
}
[test]
draw rect -1 -1 2 2
probe all rgba 0.0 1.0 0.0 1.0
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