FeedbackCircles.fs

/*{
	"CREDIT" : "FeedbackCircles by paulofalcao",
	"CATEGORIES" : [
		"ci"
	],
	"DESCRIPTION": "",
	"INPUTS": [
		{
			"NAME": "inputImage",
			"TYPE" : "image"
		},
		{
			"NAME": "iZoom",
			"TYPE" : "float",
			"MIN" : 0.1,
			"MAX" : 2.0,
			"DEFAULT" : 1.0
		},
		{
			"NAME": "iSteps",
			"TYPE" : "float",
			"MIN" : 2.0,
			"MAX" : 128.0,
			"DEFAULT" : 64.0
		},
		{
			"NAME": "iTimeMultiplier",
			"TYPE" : "float",
			"MIN" : 0.01,
			"MAX" : 10.0,
			"DEFAULT" : 1.0
		},
		{
			"NAME" :"iMouse",
			"TYPE" : "point2D",
			"DEFAULT" : [0.0, 0.0],
			"MAX" : [640.0, 480.0],
			"MIN" : [0.0, 0.0]
		},
		{
			"NAME": "iColor", 
			"TYPE" : "color", 
			"DEFAULT" : [
				0.9, 
				0.6, 
				0.0, 
				1.0
			]
		}
	],
}
*/

// https://www.shadertoy.com/view/XsyXRK
// by @paulofalcao
//
// Fun with some feedbacks :)

vec3 subImg(in vec2 fCoord, float xs,float ys, float zs){
    vec2 xy=fCoord.xy/RENDERSIZE.xy;
    xy-=0.5;
    xy+=vec2(sin(TIME*xs)*0.1,cos(TIME*ys)*0.1);//move
    xy*=(1.1+sin(TIME*zs)*0.1);//scale
    xy+=0.5;
    return IMG_NORM_PIXEL(inputImage,xy).xyz;
}

vec3 drawCircle(in vec2 xy){
    float l=length(xy);
    return ( l>.233 || l<.184 ) ? vec3(0) : vec3(sin(l*128.0)*.5+0.5);
}

void main(void) {
    //circle zoom and deformation
    vec2 xy=RENDERSIZE.xy;xy=-.5*(xy-2.0*gl_FragCoord.xy)/xy.x;
    xy*=1.0+sin(TIME*4.0)*0.2;
    xy.x+=sin(xy.x*32.0+TIME*16.0)*0.01;
    xy.y+=sin(xy.y*16.0+TIME*8.0)*0.01;
    
    vec3 c=drawCircle(xy);
 
    vec3 fC=
        subImg(gl_FragCoord.xy,3.3,3.1,2.5)*vec3(0.3,0.7,1.0)+
        subImg(gl_FragCoord.xy,2.4,4.3,3.3)*vec3(0.3,1.0,0.7)+
        subImg(gl_FragCoord.xy,2.2,4.2,4.2)*vec3(1.0,0.7,0.3)+
        subImg(gl_FragCoord.xy,3.2,3.2,2.1)*vec3(1.0,0.3,0.7)+
        subImg(gl_FragCoord.xy,2.2,1.2,3.4)*vec3(0.3,0.5,0.7)+
        subImg(gl_FragCoord.xy,5.2,2.2,2.2)*vec3(0.8,0.5,0.1);
    
    fragColor = vec4((fC/3.6+c)*0.95,1.0);;
}