2TweetsChallenge.fs

/*{
	"CREDIT" : "2TweetsChallenge by Nimitz",
	"CATEGORIES" : [
		"ci"
	],
	"DESCRIPTION": "",
	"INPUTS": [
		{
			"NAME": "inputImage",
			"TYPE" : "image"
		},
		{
			"NAME": "iZoom",
			"TYPE" : "float",
			"MIN" : 0.0,
			"MAX" : 1.0,
			"DEFAULT" : 1.0
		},
		{
			"NAME": "iSteps",
			"TYPE" : "float",
			"MIN" : 2.0,
			"MAX" : 75.0,
			"DEFAULT" : 19.0
		},
		{
			"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/4tl3W8

void main(void)
{
    vec4 p = vec4(gl_FragCoord.xy,0.,1.)/RENDERSIZE.y - vec4(.9,.5,0,0), c=p-p;
    float t=TIME,r=length(p.xy+=sin(t+sin(t*.8))*.4),a=atan(p.y,p.x);
    for (float i = 0.;i<60.;i++)
        c = c*.98 + (sin(i+vec4(5,3,2,1))*.5+.5)*smoothstep(.99, 1., sin(log(r+i*.05)-t-i+sin(a +=t*.01)));
    gl_FragColor = c*r;
}