  uniform sampler2D u_image;
        uniform vec2 u_dimensions;
        uniform float u_radius;

        in vec2 v_texCoord;
        out vec4 out_color;

        float localMaximum(vec2 p, vec2 onePixel, float value, float radius)
        {
            int size = int(radius);

            for(int x = -size; x <= size; x++)
            {
                for(int y = -size; y <= size; y++)
                {
                    if (x == 0 && y == 0) continue;

                    if (PIXEL_AT(x, y).r >= value)
