/*
{
  "CATEGORIES" : [
    "Feedback"
  ],
  "DESCRIPTION" : "",
  "ISFVSN" : "2",
  "INPUTS" : [
    {
      "NAME" : "inputImage",
      "TYPE" : "image"
    },
    {
      "NAME" : "maskRadius",
      "TYPE" : "float",
      "MAX" : 1,
      "DEFAULT" : 0.25,
      "MIN" : 0
    },
    {
      "NAME" : "feedbackRate",
      "TYPE" : "float",
      "MAX" : 16,
      "DEFAULT" : 1,
      "MIN" : 0
    },
    {
      "NAME" : "twirlAmount",
      "TYPE" : "float",
      "MAX" : 0.25,
      "DEFAULT" : 0,
      "MIN" : -0.25
    },
    {
      "NAME" : "fadeRate",
      "TYPE" : "float",
      "MAX" : 1,
      "DEFAULT" : 0,
      "MIN" : 0
    },
    {
      "NAME" : "centerFeedback",
      "TYPE" : "float",
      "MAX" : 1,
      "DEFAULT" : 0,
      "MIN" : 0
    },
    {
      "NAME" : "feedbackCenter",
      "TYPE" : "point2D",
      "MAX" : [
        1,
        1
      ],
      "DEFAULT" : [
        0.5,
        0.5
      ],
      "MIN" : [
        0,
        0
      ]
    },
    {
      "LABELS" : [
        "Mask",
        "CenteredMask",
        "Scaled",
        "Wrap",
        "MirrorWrap",
        "InvertedMask"
      ],
      "NAME" : "styleMode",
      "TYPE" : "long",
      "DEFAULT" : 2,
      "VALUES" : [
        0,
        1,
        2,
        3,
        4,
        5
      ]
    },
    {
      "NAME" : "clearBuffer",
      "TYPE" : "event"
    }
  ],
  "PASSES" : [
    {
      "TARGET" : "feedbackBuffer",
      "PERSISTENT" : true
    }
  ],
  "CREDIT" : "VIDVOX"
}
*/

const float pi = 3.1415926535897932384626433832795;
const float tau =  6.2831853071795864769252867665590;


void main()	{
	vec4		inputPixelColor = vec4(0.0);
	vec2		loc = gl_FragCoord.xy;
	vec2		locCenter = feedbackCenter * RENDERSIZE;
	float		scaledRadius = maskRadius * min(RENDERSIZE.x,RENDERSIZE.y);
	float		dist = distance(locCenter,loc);
	bool		invertMask = (styleMode == 5);
	//	if within the shape, just do the shape
	if (((dist>scaledRadius)&&(invertMask))||((dist<scaledRadius)&&(invertMask==false)))	{
		if (styleMode == 1)	{
			loc -= (locCenter-RENDERSIZE/2.0);
		}
		else if (styleMode == 2)	{
			loc -= (locCenter-RENDERSIZE/2.0);
			loc -= RENDERSIZE/2.0;
			loc /= (2.0 * maskRadius);
			loc += RENDERSIZE/2.0;
		}
		else if (styleMode == 3)	{
			float	r = distance(locCenter,loc);
			float 	a = atan((loc.y-locCenter.y),(loc.x-locCenter.x));	
			a = (a + pi)/(tau);
			a = mod(a+0.75,1.0);
			r /= scaledRadius;
			loc = RENDERSIZE * vec2(a,r);
		}
		else if (styleMode == 4)	{
			float	r = distance(locCenter,loc);
			float 	a = atan((loc.y-locCenter.y),(loc.x-locCenter.x));	
			a = (a + pi)/(tau);
			a = mod(a+0.75,1.0);
			a = (a < 0.5) ? a * 2.0 : 2.0 - a * 2.0;
			r /= scaledRadius;
			loc = RENDERSIZE * vec2(a,r);
		}
		inputPixelColor = IMG_PIXEL(inputImage,loc);
		if ((centerFeedback > 0.0)&&(clearBuffer == false))	{
			inputPixelColor = mix(inputPixelColor,IMG_THIS_PIXEL(feedbackBuffer),centerFeedback);	
		}
		//inputPixelColor = vec4(loc.x,loc.y,0.0,1.0);
	}
	else if (clearBuffer == false)	{
		//float	r = distance(RENDERSIZE/2.0,loc);
		float 	a = atan((loc.y-locCenter.y),(loc.x-locCenter.x));
		float	shiftAmount = -1.0 * feedbackRate;
		vec2	shift = shiftAmount * vec2(cos(a + twirlAmount * tau), sin(a + twirlAmount * tau));
		loc = (invertMask) ? loc - shift : loc + shift;
		inputPixelColor = IMG_PIXEL(feedbackBuffer,loc);
		inputPixelColor.a -= fadeRate / 50.0;
		//inputPixelColor = vec4((a+pi)/(2.0*pi),2.0*r/RENDERSIZE.x,0.0,1.0);
		//inputPixelColor = vec4(shift.x*2.0-1.0,shift.y*2.0-1.0,0.0,1.0);
	}
	
	gl_FragColor = inputPixelColor;
}