precision mediump float;

uniform float iGlobalTime;

uniform vec3 iResolution;

vec2 doModel(vec3 p);

#pragma glslify: camera = require('glsl-turntable-camera')

#pragma glslify: noise = require('glsl-noise/simplex/4d')

#pragma glslify: raytrace = require('glsl-raytrace', map = doModel, steps = 90)

#pragma glslify: normal = require('glsl-sdf-normal', map = doModel)

vec2 doModel(vec3 p) {

float r = 1.0 + noise(vec4(p, iGlobalTime)) * 0.25;

float d = length(p) - r;

float id = 0.0;

return vec2(d, id);

}

void main() {

vec3 color = vec3(0.0);

vec3 ro, rd;

float rotation = iGlobalTime;

float height = 0.0;

float dist = 4.0;

camera(rotation, height, dist, iResolution.xy, ro, rd);

vec2 t = raytrace(ro, rd);

if (t.x > -0.5) {

vec3 pos = ro + rd * t.x;

vec3 nor = normal(pos);

color = nor * 0.5 + 0.5;

}

gl_FragColor.rgb = color;

gl_FragColor.a = 1.0;

}