crappySharp.cikernel

/*
A Core Image kernel routine that computes a multiply effect.
The code looks up the source pixel in the sampler and then multiplies it by the value passed to the routine.
*/

kernel vec4 basicSharp(sampler image, float width)
{
    vec2 center = sample(image, samplerCoord(image));
    
    // width = 1.0 /width;

    vec2 _00 = sample(image, samplerTransform(image, samplerCoord(image) + vec2(-width, -width)));
    vec2 _10 = sample(image, samplerTransform(image, samplerCoord(image) + vec2( width, -width)));
    vec2 _11 = sample(image, samplerTransform(image, samplerCoord(image) + vec2(-width,  width)));
    vec2 _01 = sample(image, samplerTransform(image, samplerCoord(image) + vec2( width,  width)));

    return vec4(5.) * center - ( _00 + _10 + _11 + _01);
}