opengl es - glsl Expected token ')', found 'identifier' with function mix

Friday, April 8, 2016

I have a Fragment shader that contains:

[...]

float c = texture2D(tex, tc).a;
float alpha = mix(0.0f, 1.0f, c);
gl_FragColor = vec4(1, 1, 1, alpha) * color;

This works fine on my desktop and Nexus 5. However I get an exception while running on a Wiko mobile:

0:22: L0001: Expected token ')', found 'identifier'

Line 22 is the line containing the mix function.

What I'm doing wrong?

Answer

Depending on your driver and GLSL version, the "f" suffix on floats may be illegal. Change to:

float alpha = mix(0.0, 1.0, c);

As always, OS is irrelevant; you really need to say what hardware (in particular what GPU) you have.

Blog