Question

When adding a float attribute to my opengl fragment (i want to find to it later), when I compile, I get:

ERROR: 0:1: Invalid qualifiers 'attribute' in global variable context

Here’s my code:

const char * sChromaKeyFragment = _STRINGIFY(
                                             attribute float threshold;

                                             varying highp vec2 coordinate;
                                             precision mediump float;

                                             uniform sampler2D videoframe;
                                             uniform sampler2D videosprite;
                                             uniform vec4 mask;



                                             vec3 normalize(vec3 color, float meanr)
{
    return color*vec3(0.75 + meanr, 1., 1. - meanr);
}

                                             void main()
{
} 

New to OpenGL. Any help would be great. Thanks!

Answer 1

Is that a fragment shader? Attribute’s can be use only in vertex shader. You need to pass all needed information in varying’s from vertex shader to fragment shader.