9_7_octahedron

Code 9.7, 9.8, Figure 9.13:

9_7_octahedron.frag

#version 300 es precision highp float; precision highp int; out vec4 fragColor; uniform float u_time; uniform vec2 u_resolution; //begin rot vec2 rot2(vec2 p, float t){ return vec2(cos(t) * p.x -sin(t) * p.y, sin(t) * p.x + cos(t) * p.y); } vec3 rotX(vec3 p, float t){ return vec3(p.x, rot2(p.yz, t)); } vec3 rotY(vec3 p, float t){ return vec3(p.y, rot2(p.zx, t)).zxy; } vec3 rotZ(vec3 p, float t){ return vec3(rot2(p.xy, t), p.z); } vec3 euler(vec3 p, vec3 t){ return rotZ(rotY(rotX(p, t.x), t.y), t.z); } //end rot float smin(float d1, float d2, float r){ float c = clamp(0.5 + (d2 - d1) * (0.5 / r), 0.0, 1.0); return mix(d2, d1, c) - r * c * (1.0 - c); } float sphereSDF(vec3 p, vec3 c, float r){ return length(p - c) - r; } float planeSDF(vec3 p, vec3 n, float s){ return dot(normalize(n), p) - s; } float octaSDF(vec3 p, float s){ return planeSDF(abs(p), vec3(1.0), s); } float sceneSDF(vec3 p){ float t = 0.3 + 0.2 * sin(u_time); float d1 = octaSDF(p, 0.5); float d2 = sphereSDF(abs(p), vec3(t), 0.1); return smin(d1, d2, 0.1); } vec3 gradSDF(vec3 p){ float eps = 0.001; return normalize(vec3( sceneSDF(p + vec3(eps, 0.0, 0.0)) - sceneSDF(p - vec3(eps, 0.0, 0.0)), sceneSDF(p + vec3(0.0, eps, 0.0)) - sceneSDF(p - vec3(0.0, eps, 0.0)), sceneSDF(p + vec3(0.0, 0.0, eps)) - sceneSDF(p - vec3(0.0, 0.0, eps)) )); } void main(){ vec2 p = (gl_FragCoord.xy * 2.0 - u_resolution) / min(u_resolution.x, u_resolution.y); vec3 t = vec3(u_time * 0.3); vec3 cPos = euler(vec3(0.0, 0.0, 2.0), t); vec3 cDir = euler(vec3(0.0, 0.0, - 1.0), t); vec3 cUp = euler(vec3(0.0, 1.0, 0.0), t); vec3 cSide = cross(cDir, cUp); float targetDepth = 1.0; vec3 lDir = euler(vec3(0.0, 0.0, 1.0), t); vec3 ray = cSide * p.x + cUp * p.y + cDir * targetDepth; vec3 rPos = ray + cPos; ray = normalize(ray); fragColor.rgb = vec3(0.0); for(int i = 0; i < 50; i ++ ){ if (sceneSDF(rPos) > 0.001){ rPos += sceneSDF(rPos) * ray; } else { float amb = 0.1; float diff = 0.9 * max(dot(normalize(lDir), gradSDF(rPos)), 0.0); vec3 col = vec3(0.0, 1.0, 1.0); fragColor.rgb = col * (diff + amb); break; } } fragColor.a = 1.0; }

#version 300 es
precision highp float;
precision highp int;
out vec4 fragColor;
uniform float u_time;
uniform vec2 u_resolution;

//begin rot
vec2 rot2(vec2 p, float t){
  return vec2(cos(t) * p.x -sin(t) * p.y, sin(t) * p.x + cos(t) * p.y);
}

vec3 rotX(vec3 p, float t){
  return vec3(p.x, rot2(p.yz, t));
}

vec3 rotY(vec3 p, float t){
  return vec3(p.y, rot2(p.zx, t)).zxy;
}

vec3 rotZ(vec3 p, float t){
  return vec3(rot2(p.xy, t), p.z);
}

vec3 euler(vec3 p, vec3 t){
  return rotZ(rotY(rotX(p, t.x), t.y), t.z);
}
//end rot

float smin(float d1, float d2, float r){
  float c = clamp(0.5 + (d2 - d1) * (0.5 / r), 0.0, 1.0);
  return mix(d2, d1, c) - r * c * (1.0 - c);
}

float sphereSDF(vec3 p, vec3 c, float r){
  return length(p - c) - r;
}

float planeSDF(vec3 p, vec3 n, float s){
  return dot(normalize(n), p) - s;
}

float octaSDF(vec3 p, float s){
  return planeSDF(abs(p), vec3(1.0), s);
}

float sceneSDF(vec3 p){
  float t = 0.3 + 0.2 * sin(u_time);
  float d1 = octaSDF(p, 0.5);
  float d2 = sphereSDF(abs(p), vec3(t), 0.1);
  return smin(d1, d2, 0.1);
}

vec3 gradSDF(vec3 p){
  float eps = 0.001;
  return normalize(vec3(
    sceneSDF(p + vec3(eps, 0.0, 0.0)) - sceneSDF(p - vec3(eps, 0.0, 0.0)),
    sceneSDF(p + vec3(0.0, eps, 0.0)) - sceneSDF(p - vec3(0.0, eps, 0.0)),
    sceneSDF(p + vec3(0.0, 0.0, eps)) - sceneSDF(p - vec3(0.0, 0.0, eps))
  ));
}

void main(){
  vec2 p = (gl_FragCoord.xy * 2.0 - u_resolution) / min(u_resolution.x, u_resolution.y);
  
  vec3 t = vec3(u_time * 0.3);
  vec3 cPos = euler(vec3(0.0, 0.0, 2.0), t);
  vec3 cDir = euler(vec3(0.0, 0.0, - 1.0), t);
  vec3 cUp = euler(vec3(0.0, 1.0, 0.0), t);
  vec3 cSide = cross(cDir, cUp);
  
  float targetDepth = 1.0;
  
  vec3 lDir = euler(vec3(0.0, 0.0, 1.0), t);
  
  vec3 ray = cSide * p.x + cUp * p.y + cDir * targetDepth;
  vec3 rPos = ray + cPos;
  ray = normalize(ray);
  fragColor.rgb = vec3(0.0);
  for(int i = 0; i < 50; i ++ ){
    if (sceneSDF(rPos) > 0.001){
      rPos += sceneSDF(rPos) * ray;
    } else {
      float amb = 0.1;
      float diff = 0.9 * max(dot(normalize(lDir), gradSDF(rPos)), 0.0);
      vec3 col = vec3(0.0, 1.0, 1.0);
      fragColor.rgb = col * (diff + amb);
      break;
    }
  }
  fragColor.a = 1.0;
}