/*{
    "CATEGORIES": [
        "Halftone Effect"
    ],
    "CREDIT": "by VIDVOX",
    "INPUTS": [
        {
            "NAME": "inputImage",
            "TYPE": "image"
        },
        {
            "DEFAULT": 1,
            "MAX": 10,
            "MIN": 0,
            "NAME": "sharpness",
            "TYPE": "float"
        },
        {
            "DEFAULT": 0,
            "MAX": 1,
            "MIN": 0,
            "NAME": "offset",
            "TYPE": "float"
        },
        {
            "DEFAULT": 1,
            "MAX": 2,
            "MIN": 0,
            "NAME": "scale",
            "TYPE": "float"
        },
        {
            "DEFAULT": 0,
            "MAX": 1,
            "MIN": 0,
            "NAME": "colorize",
            "TYPE": "float"
        },
        {
            "DEFAULT": [
                0.5,
                0.5
            ],
            "MAX": [
                1,
                1
            ],
            "MIN": [
                0,
                0
            ],
            "NAME": "center",
            "TYPE": "point2D"
        }
    ],
    "ISFVSN": "2"
}
*/

#if __VERSION__ <= 120
varying vec2 left_coord;
varying vec2 right_coord;
varying vec2 above_coord;
varying vec2 below_coord;

varying vec2 lefta_coord;
varying vec2 righta_coord;
varying vec2 leftb_coord;
varying vec2 rightb_coord;
#else
in vec2 left_coord;
in vec2 right_coord;
in vec2 above_coord;
in vec2 below_coord;

in vec2 lefta_coord;
in vec2 righta_coord;
in vec2 leftb_coord;
in vec2 rightb_coord;
#endif

const float tau = 6.28318530718;

float pattern() {
	float s = 0.0;
	float c = 1.0;
	vec2 tex = isf_FragNormCoord * RENDERSIZE;
	vec2 point = vec2( c * tex.x - s * tex.y, s * tex.x + c * tex.y );
	float d = distance(point, center*RENDERSIZE) * max(scale,0.001);
	return ( sin(d + offset * tau) ) * 4.0;
}

void main() {
	vec4 color = IMG_THIS_PIXEL(inputImage);
	vec4 colorL = IMG_NORM_PIXEL(inputImage, left_coord);
	vec4 colorR = IMG_NORM_PIXEL(inputImage, right_coord);
	vec4 colorA = IMG_NORM_PIXEL(inputImage, above_coord);
	vec4 colorB = IMG_NORM_PIXEL(inputImage, below_coord);

	vec4 colorLA = IMG_NORM_PIXEL(inputImage, lefta_coord);
	vec4 colorRA = IMG_NORM_PIXEL(inputImage, righta_coord);
	vec4 colorLB = IMG_NORM_PIXEL(inputImage, leftb_coord);
	vec4 colorRB = IMG_NORM_PIXEL(inputImage, rightb_coord);

	vec4 final = color + sharpness * (8.0*color - colorL - colorR - colorA - colorB - colorLA - colorRA - colorLB - colorRB);
	
	float average = ( final.r + final.g + final.b ) / 3.0;
	final = vec4( vec3( average * 10.0 - 5.0 + pattern() ), color.a );
	final = mix (color * final, final, 1.0-colorize);
	gl_FragColor = final;
}