2 vec3 diffuse, specular;
13 varying vec3 v_rorg, v_rdir;
16 vec3 shade(in vec3 ro, in vec3 rd, in HitPoint hit);
17 vec3 backdrop(in vec3 dir);
19 bool isect_scene(in vec3 ro, in vec3 rd, out HitPoint hit);
21 bool isect_floor(in vec3 ro, in vec3 rd, float rad, out HitPoint hit);
22 bool isect_plane(in vec3 ro, in vec3 rd, in vec4 plane, out HitPoint hit);
23 bool isect_sphere(in vec3 ro, in vec3 rd, in vec3 pos, float rad, out HitPoint hit);
28 vec3 rdir = normalize(v_rdir);
29 gl_FragColor.rgb = backdrop(rdir);
32 if(isect_scene(v_rorg, rdir, hit)) {
33 gl_FragColor.rgb = shade(v_rorg, rdir, hit);
35 gl_FragColor.rgb = backdrop(rdir);
40 vec3 shade(in vec3 ro, in vec3 rd, in HitPoint hit)
42 return (hit.norm * 0.5 + 0.5) * hit.mtl.diffuse;
45 #define M_PI 3.1415926
46 #define M_2PI (M_PI * 2.0)
48 vec3 backdrop(in vec3 dir)
50 return mix(vec3(0.8, 0.3, 0.2), vec3(0.2, 0.3, 0.8), smoothstep(-0.1, 0.1, dir.y));
53 const Material mtl_sph = Material(vec3(1.0, 0.0, 0.0), vec3(1.0, 1.0, 1.0), 80.0);
54 const Material mtl_floor = Material(vec3(0.5, 0.5, 0.5), vec3(0.0, 0.0, 0.0), 1.0);
56 bool isect_scene(in vec3 ro, in vec3 rd, out HitPoint hit_res)
58 HitPoint hit, nearest;
60 nearest.dist = 10000.0;
62 if(isect_sphere(ro, rd, vec3(0.0, 0.0, 0.0), 1.0, hit)) {
64 nearest.mtl = mtl_sph;
67 if(isect_floor(ro, rd, 5.0, hit) && hit.dist < nearest.dist) {
69 nearest.mtl = mtl_floor;
72 if(nearest.dist >= 10000.0) {
80 bool isect_floor(in vec3 ro, in vec3 rd, float rad, out HitPoint hit)
82 if(!isect_plane(ro, rd, vec4(0.0, 1.0, 0.0, -1.0), hit)) {
86 float d = max(abs(hit.pos.x), abs(hit.pos.z));
87 if(d >= rad) return false;
92 bool isect_plane(in vec3 ro, in vec3 rd, in vec4 plane, out HitPoint hit)
94 float ndotrd = dot(rd, plane.xyz);
96 if(abs(ndotrd) < 1e-6) {
100 vec3 pp = plane.xyz * plane.w;
102 float t = dot(pdir, plane.xyz) / ndotrd;
105 hit.pos = ro + rd * t;
106 hit.norm = plane.xyz;
107 hit.surfpos = hit.pos.xz; /* XXX */
111 bool isect_sphere(in vec3 ro, in vec3 rd, in vec3 pos, float rad, out HitPoint hit)
113 float a = dot(rd, rd);
114 float b = dot(rd * 2.0, (ro - pos));
115 float c = dot(ro, ro) + dot(pos, pos) - 2.0 * dot(ro, pos) - rad * rad;
117 float d = b * b - 4.0 * a * c;
122 float t0 = (-b + sqrt(d)) / (2.0 * a);
123 float t1 = (-b - sqrt(d)) / (2.0 * a);
125 if(t0 < 0.0) t0 = t1;
126 if(t1 < 0.0) t1 = t0;
127 float t = min(t0, t1);
134 hit.pos = ro + rd * t;
135 hit.norm = normalize(hit.pos - pos);
136 hit.surfpos.x = atan(hit.norm.z, hit.norm.x);
137 hit.surfpos.y = acos(hit.norm.y);