the following simple fragment shader code fails, leaving me with an uninformative message in the log:
ERROR: 0:1: 'gl_Color' : syntax error syntax error
void main()
{
vec4 myOutputColor(gl_Color);
gl_FragColor = myOutputColor;
}
while the following one works:
void main()
{
glFragColor = gl_Color;
}
This boggles my mind, as in Lighthouse3D's tutorial gl_Color is said to be a vec4. Why can't I assign it to another vec4?
Try normal assignment. Like this:
void main()
{
vec4 myOutputColor = gl_Color;
gl_FragColor = myOutputColor;
}
Edit:
The second answer is just as correct really, but there isn't any need to use the vec4() constructor, since both are of the same type. If you had lets say a (r,g,b,w) tuple you could write:
vec4 myOutputColor = vec4(r, g, b, w);
or
// assuming myRgbColor is a vec3
vec4 myOutputColor = vec4(myRgbColor, w);
etc
Aparrently you should use slightly different syntax
(see OpenGL Shading Language Specification )
vec4 myOutputColor = vec4(gl_Color);
gl_FragColor = myOutputColor;
this unlike your sample compiles fine on my mashine (Windows, Nvidia card)
