rayfract: 03022062c464 sdr/julia.p.glsl

rayfract

view sdr/julia.p.glsl @ 1:03022062c464

lalal

author	John Tsiombikas <nuclear@siggraph.org>
date	Tue, 26 Oct 2010 08:45:37 +0300
parents	09bb67c000bc
children	dfe7c98cf373

line source

1 /* vim: set ft=glsl:ts=4:sw=4 */

2 uniform vec4 seed;

3 uniform sampler2D ray_tex;

4 uniform float err_thres;

5 uniform int iter;

6 uniform float reflectivity;

7 uniform vec3 diffuse_color;

9 #define quat(s, x, y, z) vec4(x, y, z, s)

10 #define quat_identity() vec4(0.0, 0.0, 0.0, 1.0)

12 #define vec2quat(v) (v).wxyz

14 struct Ray {

15 vec3 origin;

16 vec3 dir;

17 };

19 struct Julia {

20 bool inside;

21 vec4 q;

22 vec4 qprime;

23 };

25 struct Material {

26 vec3 kd, ks;

27 float spow;

28 float kr;

29 };

31 struct ISect {

32 bool hit;

33 float t;

34 vec3 pos;

35 vec3 normal;

36 Material mat;

37 };

39 ISect find_intersection(Ray ray);

40 vec3 shade(Ray ray, ISect isect);

41 float amboc(ISect isect);

42 vec3 sky(Ray ray);

43 Julia julia(vec4 q, vec4 c);

44 float julia_dist(vec4 z);

45 vec3 julia_grad(vec4 z);

46 vec4 quat_mul(vec4 q1, vec4 q2);

47 vec4 quat_sq(vec4 q);

48 float quat_length_sq(vec4 q);

49 ISect ray_julia(Ray ray);

50 ISect ray_sphere(Ray ray, float rad);

51 ISect ray_floor(Ray ray);

52 Ray get_primary_ray();

54 vec3 steps_color(int steps);

56 void main()

57 {

58 Ray ray = get_primary_ray();

60 float energy = 1.0;

61 vec3 color = vec3(0.0, 0.0, 0.0);

63 while(energy > 0.001) {

64 ISect res = find_intersection(ray);

66 if(res.hit) {

67 color += shade(ray, res) * energy;

68 energy *= res.mat.kr;

70 ray.origin = res.pos;

71 ray.dir = reflect(ray.dir, res.normal);

72 } else {

73 color += sky(ray) * energy;

74 break;

75 }

76 }

78 gl_FragColor = vec4(color, 1.0);

79 }

82 ISect find_intersection(Ray ray)

83 {

84 ISect res;

85 res.hit = false;

87 ISect bhit = ray_sphere(ray, 2.0);

88 if(bhit.hit) {

89 ray.origin = bhit.pos;

90 res = ray_julia(ray);

91 }

93 if(!res.hit) {

94 res = ray_floor(ray);

95 }

96 return res;

97 }

99 vec3 shade(Ray ray, ISect isect)

100 {

101 vec3 ldir = normalize(vec3(10.0, 10.0, -10.0) - isect.pos);

102 vec3 vdir = -ray.dir;

103 vec3 hdir = normalize(ldir + vdir);

104

105 float ndotl = dot(ldir, isect.normal);

106 float ndoth = dot(hdir, isect.normal);

107

108 vec3 dcol = isect.mat.kd;// * abs(ndotl);

109 vec3 scol = isect.mat.ks * pow(abs(ndoth), isect.mat.spow);

110

111 return vec3(0.05, 0.05, 0.05) + dcol + scol;

112 }

113

114 #define AO_STEP 0.04

115 #define AO_MAGIC 8.0

116 float amboc(ISect isect)

117 {

118 float sum = 0.0;

119

120 for(float fi=0.0; fi<5.0; fi+=1.0) {

121 float sample_dist = fi * AO_STEP;

122 vec3 pt = isect.pos + isect.normal * sample_dist;

123 float jdist = julia_dist(quat(pt.x, pt.y, pt.z, 0.0));

124

125 sum += 1.0 / pow(2.0, fi) * (sample_dist - jdist);

126 }

127

128 float res = 1.0 - AO_MAGIC * sum;

129 return clamp(res, 0.0, 1.0);

130 }

131

132 vec3 sky(Ray ray)

133 {

134 vec3 col1 = vec3(0.75, 0.78, 0.8);

135 vec3 col2 = vec3(0.56, 0.7, 1.0);

136

137 float t = max(ray.dir.y, -0.5);

138 return mix(col1, col2, t);

139 }

140

141 Julia julia(vec4 q, vec4 c)

142 {

143 Julia res;

144 res.inside = true;

145

146 res.q = q;

147 res.qprime = quat_identity();

148

149 for(int i=0; i<iter; i++) {

150 res.qprime = 2.0 * quat_mul(res.q, res.qprime);

151 res.q = quat_sq(res.q) + c;

152

153 if(dot(res.q, res.q) > 8.0) {

154 res.inside = false;

155 break;

156 }

157 }

158 return res;

159 }

160

161 float julia_dist(vec4 z)

162 {

163 Julia jres = julia(z, seed);

164

165 float lenq = length(jres.q);

166 float lenqprime = length(jres.qprime);

167

168 return 0.5 * lenq * log(lenq) / lenqprime;

169 }

170

171 #define OFFS 1e-4

172 vec3 julia_grad(vec4 z)

173 {

174 vec3 grad;

175 grad.x = julia_dist(z + quat(OFFS, 0.0, 0.0, 0.0)) - julia_dist(z - quat(OFFS, 0.0, 0.0, 0.0));

176 grad.y = julia_dist(z + quat(0.0, OFFS, 0.0, 0.0)) - julia_dist(z - quat(0.0, OFFS, 0.0, 0.0));

177 grad.z = julia_dist(z + quat(0.0, 0.0, OFFS, 0.0)) - julia_dist(z - quat(0.0, 0.0, OFFS, 0.0));

178 return grad;

179 }

180

181 vec4 quat_mul(vec4 q1, vec4 q2)

182 {

183 vec4 res;

184 res.w = q1.w * q2.w - dot(q1.xyz, q2.xyz);

185 res.xyz = q1.w * q2.xyz + q2.w * q1.xyz + cross(q1.xyz, q2.xyz);

186 return res;

187 }

188

189 vec4 quat_sq(vec4 q)

190 {

191 vec4 res;

192 res.w = q.w * q.w - dot(q.xyz, q.xyz);

193 res.xyz = 2.0 * q.w * q.xyz;

194 return res;

195 }

196

197 #define MIN_STEP 0.001

198 ISect ray_julia(Ray inray)

199 {

200 float dist_acc = 0.0;

201 Ray ray = inray;

202 ISect res;

203

204 int i = 0;

205 for(float fi=0.0; ; fi+=0.1) {

206 i++;

207 vec4 q = quat(ray.origin.x, ray.origin.y, ray.origin.z, 0.0);

208

209 float dist = max(julia_dist(q), MIN_STEP);

210

211 ray.origin += ray.dir * dist;

212 dist_acc += dist;

213

214 if(dist < err_thres) {

215 res.hit = true;

216 res.t = dist_acc;

217 res.pos = ray.origin;

218 res.normal = normalize(julia_grad(quat(res.pos.x, res.pos.y, res.pos.z, 0.0)));

219 res.mat.kr = reflectivity;

220 res.mat.kd = diffuse_color * amboc(res) * (1.0 - res.mat.kr);

221 res.mat.ks = vec3(0.4, 0.4, 0.4);//vec3(res.mat.kr, res.mat.kr, res.mat.kr);

222 res.mat.spow = 50.0;

223 break;

224 }

225

226 if(dot(ray.origin, ray.origin) > 100.0) {

227 res.hit = false;

228 break;

229 }

230 }

231

232 return res;

233 }

234

235 ISect ray_sphere(Ray ray, float rad)

236 {

237 ISect res;

238 res.hit = false;

239

240 float a = dot(ray.dir, ray.dir);

241 float b = 2.0 * dot(ray.dir, ray.origin);

242 float c = dot(ray.origin, ray.origin) - rad * rad;

243

244 float d = b * b - 4.0 * a * c;

245 if(d < 0.0) return res;

246

247 float sqrt_d = sqrt(d);

248 float t1 = (-b + sqrt_d) / (2.0 * a);

249 float t2 = (-b - sqrt_d) / (2.0 * a);

250

251 if((t1 >= 0.0 || t2 >= 0.0)) {

252 if(t1 < 0.0) t1 = t2;

253 if(t2 < 0.0) t2 = t1;

254

255 res.hit = true;

256 res.t = min(t1, t2);

257 res.pos = ray.origin + ray.dir * res.t;

258 //res.mat.kd = vec3(1.0, 0.3, 0.2);

259 //res.normal = res.pos / rad;

260 }

261

262 return res;

263 }

264

265 #define FLOOR_HEIGHT (-2.0)

266

267 ISect ray_floor(Ray ray)

268 {

269 ISect res;

270 res.hit = false;

271

272 if(ray.origin.y < FLOOR_HEIGHT || ray.dir.y >= 0.0) {

273 return res;

274 }

275

276 res.normal = vec3(0.0, 1.0, 0.0);

277 float ndotdir = dot(res.normal, ray.dir);

278

279 float t = (FLOOR_HEIGHT - ray.origin.y) / ndotdir;

280 res.pos = ray.origin + ray.dir * t;

281

282 if(abs(res.pos.x) > 8.0 || abs(res.pos.z) > 8.0) {

283 res.hit = false;

284 } else {

285 res.hit = true;

286

287 float chess = mod(floor(res.pos.x) + floor(res.pos.z), 2.0);

288 res.mat.kd = mix(vec3(0.498, 0.165, 0.149), vec3(0.776, 0.851, 0.847), chess);

289 res.mat.ks = vec3(0.0, 0.0, 0.0);

290 res.mat.spow = 1.0;

291 res.mat.kr = 0.0;

292 }

293 return res;

294 }

295

296 Ray get_primary_ray()

297 {

298 Ray ray;

299 vec2 tc = gl_TexCoord[0].xy;

300 ray.dir = gl_NormalMatrix * normalize(texture2D(ray_tex, tc).xyz);

301 ray.origin = (gl_ModelViewMatrix * vec4(0.0, 0.0, 0.0, 1.0)).xyz;

302 return ray;

303 }

304

305

306 vec3 steps_color(int steps)

307 {

308 if(steps <= 1) {

309 return vec3(0.0, 0.5, 0.0);

310 } else if(steps == 2) {

311 return vec3(0.0, 1.0, 0.0);

312 } else if(steps == 3) {

313 return vec3(0.0, 0.0, 0.5);

314 } else if(steps == 4) {

315 return vec3(0.0, 0.0, 1.0);

316 } else if(steps == 5) {

317 return vec3(0.0, 0.5, 0.5);

318 } else if(steps == 6) {

319 return vec3(0.0, 1.0, 1.0);

320 } else if(steps == 7) {

321 return vec3(0.5, 0.0, 0.5);

322 } else if(steps == 8) {

323 return vec3(1.0, 0.0, 1.0);

324 } else if(steps == 9) {

325 return vec3(0.5, 0.0, 0.0);

326 }

327 return vec3(0.5 + float(steps - 9) / 10.0, 0.0, 0.0);

328 }