convolve3_fs.glsl

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/**
 * @file
 * @brief convolve3 fragment shader.
 */
 
#ifndef glsl110
    /** After glsl1110 this need to be explicitly declared; used by fixed functionality at the end of the OpenGL pipeline.*/
    out vec4 gl_FragColor;
#endif
 
uniform sampler2D SAMPLER0;
uniform float COEFFICIENTS[3];
uniform vec2 OFFSETS[3];
 
/**
 * @brief Fragment shader that convolves a 3 element filter with the specified texture.
 *
 * Orientation of the filter is controlled by "OFFSETS".
 * The filter itself is specified by "COEFFICIENTS".
 */
void main(void) {
    vec2 inColor = gl_TexCoord[0].st;
    vec4 outColor = vec4(0, 0, 0, 1);
 
    outColor += COEFFICIENTS[0] * texture2D(SAMPLER0, inColor + OFFSETS[0]);
    outColor += COEFFICIENTS[1] * texture2D(SAMPLER0, inColor + OFFSETS[1]);
    outColor += COEFFICIENTS[2] * texture2D(SAMPLER0, inColor + OFFSETS[2]);
 
    gl_FragColor = outColor;
}