---

/*{
	"CREDIT": "mojovideotech",
	"CATEGORIES": [
		"Automatically Converted"
	],
	"INPUTS": [
		{
			"NAME": "mouse",
			"TYPE": "point2D",
			"MAX": [
				1,
				1
			],
			"MIN": [
				0,
				0
			]
		}
	],
	"DESCRIPTION": "Automatically converted from http://glslsandbox.com/e#1613.0"
}
*/


//Archimedes spiral, antialiased

#ifdef GL_ES
precision mediump float;
#endif


const float PI = 3.1415926;
const float EPSILON = 0.1;

vec2 perspective(vec2 scaled) {
	float z = 1.2-scaled.y+cos((scaled.x)*scaled.y*1.)*.1;
	return vec2((scaled.x-.5)/z,sin((scaled.x-.5)*10./z)*.2+1./z)*.5;
}

float getval(vec2 car) {
	float r = sqrt(car.x * car.x + car.y * car.y);
	float theta = atan(car.y, car.x);

	return fract(TIME) * 2. + theta / (2. * PI) - r * 16.;
}

void main( void ) {
	vec2 mousepersp = perspective(mouse);
	vec2 vec = perspective(isf_FragNormCoord.xy) - mousepersp;
	float val = getval(vec);
	float valx = getval(perspective((gl_FragCoord.xy + vec2(.01,0)) / RENDERSIZE.xy) - mousepersp)-val;
	float valy = getval(perspective((gl_FragCoord.xy + vec2(0,.01)) / RENDERSIZE.xy) - mousepersp)-val;
	float aa = sqrt(valx*valx+valy*valy)*250.;
	aa = aa > 100. ? 0. : tan(min(aa,PI*.4999))*.3;

	vec3 color = vec3(sqrt((1.-smoothstep(EPSILON-aa, EPSILON+aa, abs(fract(val)-.5)))/(1.+dot(vec,vec)*20.)));

	gl_FragColor = vec4(color, 1.0);
}