Maybe you forget to generate 3D mipmaps ? Try to set the magnification and minification sampling to GL_LINEAR.
better check for the color interval :
float3 colorXYZ = tex2D( testTexture, sUV).rgb;
if (colorXYZ.r <0.0) {
output.pixel = ‘blue’;
} else if (colorXYZ.r <=1.0) {
output.pixel = ‘red’;
} else {
output.pixel = ‘green’;
}
the output should be green. do it for all the color components.
I don’t think I want mip-maps as I am happy with only GL_LINEAR interpolation. I have tried with both GL_LINEAR and GL_NEAREST and still get black so I think my problem lies elsewhere.
I just tried with your colour interval test.
I get the Red output, which should mean that the value lies between 0.0 and 1.0, correct? Which should be good in this case?
I find it strange that my both other above tests work but not in the combination I need it to.