clmpr

//Archimedes spiral, antialiased

#ifdef GL_ES
precision mediump float;
#endif

uniform float time;
uniform vec2 mouse;
uniform vec2 resolution;

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*6.)*.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(gl_FragCoord.xy / resolution.xy) - mousepersp;
float val = getval(vec);
float valx = getval(perspective((gl_FragCoord.xy + vec2(.01,0)) / resolution.xy) - mousepersp)-val;
float valy = getval(perspective((gl_FragCoord.xy + vec2(0,.01)) / resolution.xy) - mousepersp)-val;
float aa = sqrt(valx*valx+valy*valy)*250.;
aa = aa > 200. ? 0. : atan(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);
}

glsl