hi,
is it possible to ask shader related questions on the pd list? I am
trying to write pix_alpha as a shader, but for now I have problems with
the glsl code. (maybe you can also point me to a shader forum or mailing
list that you know is good?)
I have a fragment shader, which is not working, and I don't know why.
the problem is that "A.a = other" does not set the value correct (it
always sets 0).
If I write A.a = 0.5 for example, then it is working.
The variables are passed correctly, all other variables work too, so I
think it is really a problem of how glsl works, and an error in the
code. what it should do is when the red pixel value is within a certain
range, the alpha value should be set to the pass value, and if it is
outside, it should be set to the other value. (similar to pix_alpha, but
only with red at the moment)
thanks,
marius.
---------
// red pix alpha
uniform sampler2D texture;
varying vec2 texcoord0;
uniform vec4 hithresh; // hi and lo threshold
uniform vec4 lothresh;
uniform float pass;
uniform float other;
void main()
{
vec4 A = texture2D(texture, texcoord0);
A.a = pass;
if ((A.r >= hithresh.r) || (A.r <= lothresh.r))
{
A.a = other;
}
gl_FragColor = A;
}
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