21_Cosplay.fs

// SaturdayShader Week 21 : Cosplay
// by Joseph Fiola (http://www.joefiola.com)
// 2016-01-09

/*{
    "CREDIT": "Joseph Fiola",
	"DESCRIPTION": "",
	"CATEGORIES": [
			"Generator"
	],
	"INPUTS": [
	
		{
			"NAME": "dotSize",
			"TYPE": "float",
			"DEFAULT": 0.01,
			"MIN": 0.0,
			"MAX": 0.1
		},
		{
			"NAME": "iteration",
			"TYPE": "float",
			"DEFAULT": 100.0,
			"MIN": 0.0,
			"MAX": 100.0
		},
		{
			"NAME": "xAmp",
			"TYPE": "float",
			"DEFAULT": 0.3,
			"MIN": -1.0,
			"MAX": 1.0
		},
		{
			"NAME": "yAmp",
			"TYPE": "float",
			"DEFAULT": 0.1,
			"MIN": -1.0,
			"MAX": 1.0
		},
		{
			"NAME": "xFactor",
			"TYPE": "float",
			"DEFAULT": 0.2,
			"MIN": 0.0,
			"MAX": 10.0
		},		
		{
			"NAME": "yFactor",
			"TYPE": "float",
			"DEFAULT": 0.2,
			"MIN": 0.0,
			"MAX": 10.0
		},
		{
			"NAME": "speed",
			"TYPE": "float",
			"DEFAULT": 0.05,
			"MIN": 0.0,
			"MAX": 0.1
		},
		{
			"NAME": "rotateCanvas",
			"TYPE": "float",
			"DEFAULT": 0.0,
			"MIN": -3.14159265358979323846,
			"MAX": 3.14159265358979323846
		},
		{
			"NAME": "rotateParticles",
			"TYPE": "float",
			"DEFAULT": 1.0,
			"MIN": -1.57079632679489661923,
			"MAX": 1.57079632679489661923
		},
			{
			"NAME": "rotateMultiplier",
			"TYPE": "float",
			"DEFAULT": 10.0,
			"MIN": 0.01,
			"MAX": 10
		},
		{
			"NAME": "pos",
			"TYPE": "point2D",
			"DEFAULT": [
				0.5,
				0.5
			],
			"MIN": [
				0.0,
				0.0
			],
			"MAX": [
				1.0,
				1.0
			]
		}
	]
}*/

#define PI 3.14159265358979323846
#define TWOPI 6.28318530717958



//generic rotation formula
vec2 rot(vec2 uv,float a){
	return vec2(uv.x*cos(a)-uv.y*sin(a),uv.y*cos(a)+uv.x*sin(a));
}

float circle(vec2 uv, float size){
	return  length(uv) > size?0.0:1.0;
}


void main(){

	vec2 uv = gl_FragCoord.xy/RENDERSIZE;
	uv -= vec2(pos);						
	uv.x *= RENDERSIZE.x/RENDERSIZE.y;
	vec3 color = vec3(0);
	
	//rotate canvas
	uv=rot(uv,rotateCanvas);
		
	for (float i = 0.0; i<100.0; i++){
		
		// set max number of iterations
		if (iteration < i) break;
		
		// sin() cos() animation
		vec2 st = uv - vec2(cos(i * xFactor * (TIME*speed)) * xAmp, sin(i * yFactor * (TIME*speed)) * yAmp);
		
		// set dotSize
		float dots = circle((st), dotSize * (i  * 0.01));
		
		//rotate particles
		uv=rot(uv,rotateParticles*rotateMultiplier);

		color += dots;
		}

	gl_FragColor = vec4(vec3(color),1.0);
}