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, in vec2 sz, 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);
25 vec3 tex_chess(in vec3 col1, in vec3 col2, in vec2 spos);
27 const Material mtl_sph = Material(vec3(1.0, 0.0, 0.0), vec3(1.0, 1.0, 1.0), 80.0);
28 const Material mtl_floor = Material(vec3(0.5, 0.5, 0.5), vec3(0.0, 0.0, 0.0), 1.0);
30 const vec3 light_pos = vec3(-10, 50, 30);
34 vec3 rdir = normalize(v_rdir);
35 gl_FragColor.rgb = backdrop(rdir);
38 if(isect_scene(v_rorg, rdir, hit)) {
39 gl_FragColor.rgb = shade(v_rorg, rdir, hit);
41 gl_FragColor.rgb = backdrop(rdir);
46 vec3 shade(in vec3 ro, in vec3 rd, in HitPoint hit)
49 vec3 ldir = light_pos - hit.pos;
51 vec3 col = vec3(0.03, 0.03, 0.03); // ambient
53 if(!isect_scene(hit.pos + hit.norm * 0.01, ldir, shadow_hit) || shadow_hit.dist > 1.0) {
54 vec3 l = normalize(ldir);
55 vec3 v = normalize(-rd);
56 vec3 h = normalize(v + l);
57 float ndotl = max(dot(hit.norm, l), 0.0);
58 float ndoth = max(dot(hit.norm, h), 0.0);
60 col += hit.mtl.diffuse * ndotl + hit.mtl.specular * pow(ndoth, hit.mtl.shin);
66 #define M_PI 3.1415926
67 #define M_2PI (M_PI * 2.0)
69 vec3 backdrop(in vec3 dir)
71 return mix(vec3(0.8, 0.3, 0.2), vec3(0.2, 0.3, 0.8), smoothstep(-0.1, 0.1, dir.y));
74 #define FLOOR_OFFS vec3(3.0, 0.0, 0.0)
75 #define FLOOR_SIZE vec2(5.5, 15.0)
77 bool isect_scene(in vec3 ro, in vec3 rd, out HitPoint hit_res)
79 HitPoint hit, nearest;
81 nearest.dist = 10000.0;
83 if(isect_sphere(ro, rd, vec3(1.0, 0.0, 0.0), 1.0, hit)) {
85 nearest.mtl = mtl_sph;
88 if(isect_floor(ro, rd, FLOOR_SIZE, hit) && hit.dist < nearest.dist) {
90 nearest.mtl = mtl_floor;
91 nearest.mtl.diffuse = tex_chess(vec3(1.0, 0.0, 0.0), vec3(1.0, 1.0, 0.0), hit.surfpos);
94 if(nearest.dist >= 10000.0) {
102 bool isect_floor(in vec3 ro, in vec3 rd, in vec2 sz, out HitPoint hit)
104 if(!isect_plane(ro - FLOOR_OFFS, rd, vec4(0.0, 1.0, 0.0, -1.8), hit)) {
108 if(abs(hit.pos.x) >= sz.x || abs(hit.pos.z) >= sz.y) {
112 hit.pos += FLOOR_OFFS;
113 hit.surfpos /= sz * 2.0;
117 bool isect_plane(in vec3 ro, in vec3 rd, in vec4 plane, out HitPoint hit)
119 float ndotrd = dot(rd, plane.xyz);
121 if(abs(ndotrd) < 1e-6) {
125 vec3 pp = plane.xyz * plane.w;
127 float t = dot(pdir, plane.xyz) / ndotrd;
134 hit.pos = ro + rd * t;
135 hit.norm = plane.xyz;
136 hit.surfpos = hit.pos.xz; /* XXX */
140 bool isect_sphere(in vec3 ro, in vec3 rd, in vec3 pos, float rad, out HitPoint hit)
142 float a = dot(rd, rd);
143 float b = dot(rd * 2.0, (ro - pos));
144 float c = dot(ro, ro) + dot(pos, pos) - 2.0 * dot(ro, pos) - rad * rad;
146 float d = b * b - 4.0 * a * c;
151 float t0 = (-b + sqrt(d)) / (2.0 * a);
152 float t1 = (-b - sqrt(d)) / (2.0 * a);
154 if(t0 < 0.0) t0 = t1;
155 if(t1 < 0.0) t1 = t0;
156 float t = min(t0, t1);
163 hit.pos = ro + rd * t;
164 hit.norm = normalize(hit.pos - pos);
165 hit.surfpos.x = atan(hit.norm.z, hit.norm.x);
166 hit.surfpos.y = acos(hit.norm.y);
170 vec3 tex_chess(in vec3 col1, in vec3 col2, in vec2 spos)
172 float foo = step(0.5, mod(spos.x * 8.0, 1.0)) * 2.0 - 1.0;
173 float bar = step(0.5, mod(spos.y * 24.0, 1.0)) * 2.0 - 1.0;
175 float xor = (foo * bar) * 0.5 + 0.5;
177 return mix(col1, col2, xor);