blur.cikernel

kernel vec4 basicBlur(sampler image, float width)
{
    // get coordinates of the current pixel
    vec2 center = samplerCoord(image);
        
    // sum the current pixel and 4 pixels around it
    vec4 result = sample(image, center);
    result += sample(image, samplerTransform(image, samplerCoord(image) + vec2(-width, -width)));
    result += sample(image, samplerTransform(image, samplerCoord(image) + vec2( width, -width)));
    result += sample(image, samplerTransform(image, samplerCoord(image) + vec2( width,  width)));
    result += sample(image, samplerTransform(image, samplerCoord(image) + vec2(-width,  width)));
    
    // scale result
    return result * vec2(0.2);
}