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);
26 const Material mtl_sph = Material(vec3(1.0, 0.0, 0.0), vec3(1.0, 1.0, 1.0), 80.0);
27 const Material mtl_floor = Material(vec3(0.5, 0.5, 0.5), vec3(0.0, 0.0, 0.0), 1.0);
29 const vec3 light_pos = vec3(-20, 20, 30);
33 vec3 rdir = normalize(v_rdir);
34 gl_FragColor.rgb = backdrop(rdir);
37 if(isect_scene(v_rorg, rdir, hit)) {
38 gl_FragColor.rgb = shade(v_rorg, rdir, hit);
40 gl_FragColor.rgb = backdrop(rdir);
45 vec3 shade(in vec3 ro, in vec3 rd, in HitPoint hit)
48 vec3 ldir = light_pos - hit.pos;
50 vec3 col = vec3(0.03, 0.03, 0.03); // ambient
52 if(!isect_scene(hit.pos + hit.norm * 0.01, ldir, shadow_hit) || shadow_hit.dist > 1.0) {
53 vec3 l = normalize(ldir);
54 vec3 v = normalize(-rd);
55 vec3 h = normalize(v + l);
56 float ndotl = max(dot(hit.norm, l), 0.0);
57 float ndoth = max(dot(hit.norm, h), 0.0);
59 col += hit.mtl.diffuse * ndotl + hit.mtl.specular * pow(ndoth, hit.mtl.shin);
65 #define M_PI 3.1415926
66 #define M_2PI (M_PI * 2.0)
68 vec3 backdrop(in vec3 dir)
70 return mix(vec3(0.8, 0.3, 0.2), vec3(0.2, 0.3, 0.8), smoothstep(-0.1, 0.1, dir.y));
73 bool isect_scene(in vec3 ro, in vec3 rd, out HitPoint hit_res)
75 HitPoint hit, nearest;
77 nearest.dist = 10000.0;
79 if(isect_sphere(ro, rd, vec3(0.0, 0.0, 0.0), 1.0, hit)) {
81 nearest.mtl = mtl_sph;
84 if(isect_floor(ro, rd, 5.0, hit) && hit.dist < nearest.dist) {
86 nearest.mtl = mtl_floor;
89 if(nearest.dist >= 10000.0) {
97 #define FLOOR_OFFS vec3(2.0, 0.0, 0.0)
99 bool isect_floor(in vec3 ro, in vec3 rd, float rad, out HitPoint hit)
101 if(!isect_plane(ro - FLOOR_OFFS, rd, vec4(0.0, 1.0, 0.0, -1.0), hit)) {
105 float d = max(abs(hit.pos.x), abs(hit.pos.z));
106 if(d >= rad) return false;
108 hit.pos += FLOOR_OFFS;
112 bool isect_plane(in vec3 ro, in vec3 rd, in vec4 plane, out HitPoint hit)
114 float ndotrd = dot(rd, plane.xyz);
116 if(abs(ndotrd) < 1e-6) {
120 vec3 pp = plane.xyz * plane.w;
122 float t = dot(pdir, plane.xyz) / ndotrd;
129 hit.pos = ro + rd * t;
130 hit.norm = plane.xyz;
131 hit.surfpos = hit.pos.xz; /* XXX */
135 bool isect_sphere(in vec3 ro, in vec3 rd, in vec3 pos, float rad, out HitPoint hit)
137 float a = dot(rd, rd);
138 float b = dot(rd * 2.0, (ro - pos));
139 float c = dot(ro, ro) + dot(pos, pos) - 2.0 * dot(ro, pos) - rad * rad;
141 float d = b * b - 4.0 * a * c;
146 float t0 = (-b + sqrt(d)) / (2.0 * a);
147 float t1 = (-b - sqrt(d)) / (2.0 * a);
149 if(t0 < 0.0) t0 = t1;
150 if(t1 < 0.0) t1 = t0;
151 float t = min(t0, t1);
158 hit.pos = ro + rd * t;
159 hit.norm = normalize(hit.pos - pos);
160 hit.surfpos.x = atan(hit.norm.z, hit.norm.x);
161 hit.surfpos.y = acos(hit.norm.y);