voxfract: 8171de5a000b src/main.c

voxfract

view src/main.c @ 0:8171de5a000b

initial commit

author	John Tsiombikas <nuclear@member.fsf.org>
date	Wed, 14 Jun 2017 18:03:57 +0300
parents
children	d0297d001505

line source

1 #include <stdio.h>

2 #include <stdlib.h>

3 #include <math.h>

4 #include <assert.h>

5 #include <GL/glut.h>

6 #include <metasurf.h>

8 struct quat {

9 float x, y, z, w;

10 };

12 int init(void);

13 void cleanup(void);

14 void display(void);

15 void reshape(int x, int y);

16 void keypress(unsigned char key, int x, int y);

17 void mouse(int bn, int st, int x, int y);

18 void motion(int x, int y);

20 float eval(struct metasurface *ms, float x, float y, float z);

21 void vertex(struct metasurface *ms, float x, float y, float z);

23 int julia(struct quat *qres, struct quat *qprime, struct quat *q, struct quat *seed, int max_iter);

24 float julia_dist(struct quat *z, struct quat *seed, int max_iter);

25 void julia_grad(float *grad, float dist, struct quat *q, struct quat *seed, int max_iter);

27 void show_waitscr(void);

29 float cam_theta, cam_phi = 25, cam_dist = 5;

30 int grid_size = 350;

31 float grid_scale = 1.7;

32 struct quat seed = {0.4, 0.0, 0.0, -0.8};

33 int max_iter = 9;

35 struct metasurface *msurf;

36 int dlist;

37 FILE *fp;

39 int main(int argc, char **argv)

40 {

41 glutInit(&argc, argv);

42 glutInitWindowSize(800, 600);

43 glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);

44 glutCreateWindow("voxel fractals");

46 glutDisplayFunc(display);

47 glutReshapeFunc(reshape);

48 glutKeyboardFunc(keypress);

49 glutMouseFunc(mouse);

50 glutMotionFunc(motion);

52 if(init() == -1) {

53 return 1;

54 }

55 atexit(cleanup);

57 glutMainLoop();

58 return 0;

59 }

61 int init(void)

62 {

63 glEnable(GL_DEPTH_TEST);

64 glEnable(GL_CULL_FACE);

65 glEnable(GL_LIGHTING);

66 glEnable(GL_LIGHT0);

67 /*glShadeModel(GL_FLAT);*/

69 fp = fopen("julia.obj", "wb");

71 if(!(msurf = msurf_create())) {

72 return -1;

73 }

74 msurf_eval_func(msurf, eval);

75 msurf_vertex_func(msurf, vertex);

76 msurf_set_resolution(msurf, grid_size, grid_size, grid_size);

77 msurf_set_threshold(msurf, 0.0);

78 msurf_set_inside(msurf, MSURF_LESS);

80 show_waitscr();

82 dlist = glGenLists(1);

83 glNewList(dlist, GL_COMPILE);

85 glBegin(GL_TRIANGLES);

86 msurf_polygonize(msurf);

87 glEnd();

89 glEndList();

91 if(fp) {

92 fclose(fp);

93 }

95 glClearColor(0.05, 0.05, 0.05, 1);

97 return 0;

98 }

100 void cleanup(void)

101 {

102 msurf_free(msurf);

103 }

104

105 void display(void)

106 {

107 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

108

109 glMatrixMode(GL_MODELVIEW);

110 glLoadIdentity();

111 glTranslatef(0, 0, -cam_dist);

112 glRotatef(cam_phi, 1, 0, 0);

113 glRotatef(cam_theta, 0, 1, 0);

114

115 glCallList(dlist);

116

117 assert(glGetError() == GL_NO_ERROR);

118 glutSwapBuffers();

119 }

120

121 void reshape(int x, int y)

122 {

123 glViewport(0, 0, x, y);

124 glMatrixMode(GL_PROJECTION);

125 glLoadIdentity();

126 gluPerspective(50.0, (float)x / (float)y, 0.5, 500.0);

127 }

128

129 void keypress(unsigned char key, int x, int y)

130 {

131 switch(key) {

132 case 27:

133 exit(0);

134 }

135 }

136

137 int prev_x, prev_y;

138 int bnstate[8];

139

140 void mouse(int bn, int st, int x, int y)

141 {

142 bnstate[bn - GLUT_LEFT_BUTTON] = st == GLUT_DOWN;

143 prev_x = x;

144 prev_y = y;

145 }

146

147 void motion(int x, int y)

148 {

149 int dx = x - prev_x;

150 int dy = y - prev_y;

151 prev_x = x;

152 prev_y = y;

153

154 if(!dx && !dy) return;

155

156 if(bnstate[0]) {

157 cam_theta += dx * 0.5;

158 cam_phi += dy * 0.5;

159

160 if(cam_phi < -90) cam_phi = -90;

161 if(cam_phi > 90) cam_phi = 90;

162 glutPostRedisplay();

163 }

164 if(bnstate[2]) {

165 cam_dist += dy * 0.1;

166

167 if(cam_dist < 0.0) cam_dist = 0.0;

168 glutPostRedisplay();

169 }

170 }

171

172 float eval(struct metasurface *ms, float x, float y, float z)

173 {

174 struct quat q;

175

176 q.w = grid_scale * x;

177 q.x = grid_scale * y;

178 q.y = grid_scale * z;

179 q.z = 0.0f;

180

181 return julia_dist(&q, &seed, max_iter);

182 }

183

184 void vertex(struct metasurface *ms, float x, float y, float z)

185 {

186 struct quat q;

187 float dist;

188 float norm[3];

189 float norm_len, nscale = 1.0;

190

191 q.w = grid_scale * x;

192 q.x = grid_scale * y;

193 q.y = grid_scale * z;

194 q.z = 0.0f;

195

196 dist = julia_dist(&q, &seed, max_iter);

197

198 julia_grad(norm, dist, &q, &seed, max_iter);

199 norm_len = sqrt(norm[0] * norm[0] + norm[1] * norm[1] + norm[2] * norm[2]);

200

201 if(norm_len != 0.0f) {

202 nscale = 1.0f / norm_len;

203 }

204

205 glNormal3f(norm[0] * nscale, norm[1] * nscale, norm[2] * nscale);

206 glVertex3f(x, y, z);

207

208 if(fp) {

209 static int nverts;

210

211 fprintf(fp, "v %f %f %f\n", x, y, z);

212

213 if((++nverts) % 3 == 0) {

214 fprintf(fp, "f %d %d %d\n", nverts - 2, nverts - 1, nverts);

215 }

216 }

217 }

218

219 void quat_mul(struct quat *res, struct quat *a, struct quat *b)

220 {

221 float w = a->w * b->w - (a->x * b->x + a->y * b->y + a->z * b->z);

222 float x = a->w * b->x + b->w * a->x + (a->y * b->z - a->z * b->y);

223 float y = a->w * b->y + b->w * a->y + (a->z * b->x - a->x * b->z);

224 res->z = a->w * b->z + b->w * a->z + (a->x * b->y - a->y * b->x);

225 res->x = x;

226 res->y = y;

227 res->w = w;

228 }

229

230 void quat_sq(struct quat *q)

231 {

232 float w = q->w * q->w - (q->x * q->x + q->y * q->y + q->z * q->z);

233 float x = 2.0 * q->w * q->x;

234 float y = 2.0 * q->w * q->y;

235 q->z = 2.0 * q->w * q->z;

236 q->x = x;

237 q->y = y;

238 q->w = w;

239 }

240

241 float quat_lensq(struct quat *q)

242 {

243 return q->x * q->x + q->y * q->y + q->z * q->z + q->w * q->w;

244 }

245

246 int julia(struct quat *qres, struct quat *qprime, struct quat *q, struct quat *seed, int max_iter)

247 {

248 int i;

249

250 *qres = *q;

251 qprime->x = qprime->y = qprime->z = 0.0f;

252 qprime->w = 1.0f;

253

254 for(i=0; i<max_iter; i++) {

255 quat_mul(qprime, qres, qprime);

256 qprime->x *= 2.0;

257 qprime->y *= 2.0;

258 qprime->z *= 2.0;

259 qprime->w *= 2.0;

260

261 quat_sq(qres);

262 qres->x += seed->x;

263 qres->y += seed->y;

264 qres->z += seed->z;

265 qres->w += seed->w;

266

267 if(quat_lensq(qres) > 8.0) {

268 return 0;

269 }

270 }

271

272 return 1;

273 }

274

275 float julia_dist(struct quat *z, struct quat *seed, int max_iter)

276 {

277 struct quat qprime, q;

278

279 /* calc julia at z */

280 /*int inside = */julia(&q, &qprime, z, seed, max_iter);

281

282 float lenq = sqrt(quat_lensq(&q));

283 float lenqp = sqrt(quat_lensq(&qprime));

284 return 0.5 * lenq * log(lenq) / lenqp;

285 }

286

287 #define OFFS 1e-4

288 void julia_grad(float *grad, float dist, struct quat *q, struct quat *seed, int max_iter)

289 {

290 struct quat qnext = *q;

291 struct quat qprev = *q;

292

293 qnext.w += OFFS;

294 qprev.w -= OFFS;

295 grad[0] = julia_dist(&qnext, seed, max_iter) - julia_dist(&qprev, seed, max_iter);

296 qnext.w = qprev.w = q->w;

297

298 qnext.x += OFFS;

299 qprev.x -= OFFS;

300 grad[1] = julia_dist(&qnext, seed, max_iter) - julia_dist(&qprev, seed, max_iter);

301 qnext.x = qprev.x = q->x;

302

303 qnext.y += OFFS;

304 qprev.y -= OFFS;

305 grad[2] = julia_dist(&qnext, seed, max_iter) - julia_dist(&qprev, seed, max_iter);

306 }

307

308 void show_waitscr(void)

309 {

310 const char *text = "Please wait, generating fractal...";

311 glClear(GL_COLOR_BUFFER_BIT);

312

313 glPushAttrib(GL_ENABLE_BIT);

314 glDisable(GL_LIGHTING);

315 glDisable(GL_DEPTH_TEST);

316

317 glMatrixMode(GL_PROJECTION);

318 glPushMatrix();

319 glLoadIdentity();

320 glTranslatef(-0.75, 0, 0);

321 glScalef(0.00075, 0.00075, 0.00075);

322 glMatrixMode(GL_MODELVIEW);

323

324 glEnable(GL_LINE_SMOOTH);

325 glEnable(GL_BLEND);

326 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

327

328 glLineWidth(1.5);

329

330 glColor3f(1, 1, 1);

331 while(*text) {

332 glutStrokeCharacter(GLUT_STROKE_ROMAN, *text++);

333 }

334

335 glMatrixMode(GL_PROJECTION);

336 glPopMatrix();

337

338 glPopAttrib();

339

340 glutSwapBuffers();

341 }