dbf-halloween2015: 50683c78264e src/meshgen.cc

dbf-halloween2015

view src/meshgen.cc @ 0:50683c78264e

initial commit

author	John Tsiombikas <nuclear@member.fsf.org>
date	Sun, 01 Nov 2015 00:09:12 +0200
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line source

1 #include <stdio.h>

2 #include "meshgen.h"

3 #include "mesh.h"

5 // -------- sphere --------

7 #define SURAD(u) ((u) * 2.0 * M_PI)

8 #define SVRAD(v) ((v) * M_PI)

10 static Vector3 sphvec(float theta, float phi)

11 {

12 return Vector3(sin(theta) * sin(phi),

13 cos(phi),

14 cos(theta) * sin(phi));

15 }

17 void gen_sphere(Mesh *mesh, float rad, int usub, int vsub, float urange, float vrange)

18 {

19 if(usub < 4) usub = 4;

20 if(vsub < 2) vsub = 2;

22 int uverts = usub + 1;

23 int vverts = vsub + 1;

25 int num_verts = uverts * vverts;

26 int num_quads = usub * vsub;

27 int num_tri = num_quads * 2;

29 mesh->clear();

30 Vector3 *varr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_VERTEX, 3, num_verts, 0);

31 Vector3 *narr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_NORMAL, 3, num_verts, 0);

32 Vector3 *tarr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_TANGENT, 3, num_verts, 0);

33 Vector2 *uvarr = (Vector2*)mesh->set_attrib_data(MESH_ATTR_TEXCOORD, 2, num_verts, 0);

34 unsigned int *idxarr = mesh->set_index_data(num_tri * 3, 0);

36 float du = urange / (float)(uverts - 1);

37 float dv = vrange / (float)(vverts - 1);

39 float u = 0.0;

40 for(int i=0; i<uverts; i++) {

41 float theta = u * 2.0 * M_PI;

43 float v = 0.0;

44 for(int j=0; j<vverts; j++) {

45 float phi = v * M_PI;

47 Vector3 pos = sphvec(theta, phi);

49 *varr++ = pos * rad;

50 *narr++ = pos;

51 *tarr++ = (sphvec(theta + 0.1f, (float)M_PI / 2.0f) - sphvec(theta - 0.1f, (float)M_PI / 2.0f)).normalized();

52 *uvarr++ = Vector2(u * urange, v * vrange);

54 if(i < usub && j < vsub) {

55 int idx = i * vverts + j;

56 *idxarr++ = idx;

57 *idxarr++ = idx + 1;

58 *idxarr++ = idx + vverts + 1;

60 *idxarr++ = idx;

61 *idxarr++ = idx + vverts + 1;

62 *idxarr++ = idx + vverts;

63 }

65 v += dv;

66 }

67 u += du;

68 }

69 }

71 // -------- torus -----------

72 static Vector3 torusvec(float theta, float phi, float mr, float rr)

73 {

74 theta = -theta;

76 float rx = -cos(phi) * rr + mr;

77 float ry = sin(phi) * rr;

78 float rz = 0.0;

80 float x = rx * sin(theta) + rz * cos(theta);

81 float y = ry;

82 float z = -rx * cos(theta) + rz * sin(theta);

84 return Vector3(x, y, z);

85 }

87 void gen_torus(Mesh *mesh, float mainrad, float ringrad, int usub, int vsub, float urange, float vrange)

88 {

89 if(usub < 4) usub = 4;

90 if(vsub < 2) vsub = 2;

92 int uverts = usub + 1;

93 int vverts = vsub + 1;

95 int num_verts = uverts * vverts;

96 int num_quads = usub * vsub;

97 int num_tri = num_quads * 2;

99 mesh->clear();

100 Vector3 *varr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_VERTEX, 3, num_verts, 0);

101 Vector3 *narr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_NORMAL, 3, num_verts, 0);

102 Vector3 *tarr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_TANGENT, 3, num_verts, 0);

103 Vector2 *uvarr = (Vector2*)mesh->set_attrib_data(MESH_ATTR_TEXCOORD, 2, num_verts, 0);

104 unsigned int *idxarr = mesh->set_index_data(num_tri * 3, 0);

105

106 float du = urange / (float)(uverts - 1);

107 float dv = vrange / (float)(vverts - 1);

108

109 float u = 0.0;

110 for(int i=0; i<uverts; i++) {

111 float theta = u * 2.0 * M_PI;

112

113 float v = 0.0;

114 for(int j=0; j<vverts; j++) {

115 float phi = v * 2.0 * M_PI;

116

117 Vector3 pos = torusvec(theta, phi, mainrad, ringrad);

118 Vector3 cent = torusvec(theta, phi, mainrad, 0.0);

119

120 *varr++ = pos;

121 *narr++ = (pos - cent) / ringrad;

122

123 Vector3 pprev = torusvec(theta - 0.1f, phi, mainrad, ringrad);

124 Vector3 pnext = torusvec(theta + 0.1f, phi, mainrad, ringrad);

125

126 *tarr++ = (pnext - pprev).normalized();

127 *uvarr++ = Vector2(u * urange, v * vrange);

128

129 if(i < usub && j < vsub) {

130 int idx = i * vverts + j;

131 *idxarr++ = idx;

132 *idxarr++ = idx + 1;

133 *idxarr++ = idx + vverts + 1;

134

135 *idxarr++ = idx;

136 *idxarr++ = idx + vverts + 1;

137 *idxarr++ = idx + vverts;

138 }

139

140 v += dv;

141 }

142 u += du;

143 }

144 }

145

146

147 // -------- cylinder --------

148

149 static Vector3 cylvec(float theta, float height)

150 {

151 return Vector3(sin(theta), height, cos(theta));

152 }

153

154 void gen_cylinder(Mesh *mesh, float rad, float height, int usub, int vsub, int capsub, float urange, float vrange)

155 {

156 if(usub < 4) usub = 4;

157 if(vsub < 1) vsub = 1;

158

159 int uverts = usub + 1;

160 int vverts = vsub + 1;

161

162 int num_body_verts = uverts * vverts;

163 int num_body_quads = usub * vsub;

164 int num_body_tri = num_body_quads * 2;

165

166 int capvverts = capsub ? capsub + 1 : 0;

167 int num_cap_verts = uverts * capvverts;

168 int num_cap_quads = usub * capsub;

169 int num_cap_tri = num_cap_quads * 2;

170

171 int num_verts = num_body_verts + num_cap_verts * 2;

172 int num_tri = num_body_tri + num_cap_tri * 2;

173

174 mesh->clear();

175 Vector3 *varr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_VERTEX, 3, num_verts, 0);

176 Vector3 *narr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_NORMAL, 3, num_verts, 0);

177 Vector3 *tarr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_TANGENT, 3, num_verts, 0);

178 Vector2 *uvarr = (Vector2*)mesh->set_attrib_data(MESH_ATTR_TEXCOORD, 2, num_verts, 0);

179 unsigned int *idxarr = mesh->set_index_data(num_tri * 3, 0);

180

181 float du = urange / (float)(uverts - 1);

182 float dv = vrange / (float)(vverts - 1);

183

184 float u = 0.0;

185 for(int i=0; i<uverts; i++) {

186 float theta = SURAD(u);

187

188 float v = 0.0;

189 for(int j=0; j<vverts; j++) {

190 float y = (v - 0.5) * height;

191 Vector3 pos = cylvec(theta, y);

192

193 *varr++ = Vector3(pos.x * rad, pos.y, pos.z * rad);

194 *narr++ = Vector3(pos.x, 0.0, pos.z);

195 *tarr++ = (cylvec(theta + 0.1, 0.0) - cylvec(theta - 0.1, 0.0)).normalized();

196 *uvarr++ = Vector2(u * urange, v * vrange);

197

198 if(i < usub && j < vsub) {

199 int idx = i * vverts + j;

200

201 *idxarr++ = idx;

202 *idxarr++ = idx + vverts + 1;

203 *idxarr++ = idx + 1;

204

205 *idxarr++ = idx;

206 *idxarr++ = idx + vverts;

207 *idxarr++ = idx + vverts + 1;

208 }

209

210 v += dv;

211 }

212 u += du;

213 }

214

215

216 // now the cap!

217 if(!capsub) {

218 return;

219 }

220

221 dv = 1.0 / (float)(capvverts - 1);

222

223 u = 0.0;

224 for(int i=0; i<uverts; i++) {

225 float theta = SURAD(u);

226

227 float v = 0.0;

228 for(int j=0; j<capvverts; j++) {

229 float r = v * rad;

230

231 Vector3 pos = cylvec(theta, height / 2.0) * r;

232 pos.y = height / 2.0;

233 Vector3 tang = (cylvec(theta + 0.1, 0.0) - cylvec(theta - 0.1, 0.0)).normalized();

234

235 *varr++ = pos;

236 *narr++ = Vector3(0, 1, 0);

237 *tarr++ = tang;

238 *uvarr++ = Vector2(u * urange, v);

239

240 pos.y = -height / 2.0;

241 *varr++ = pos;

242 *narr++ = Vector3(0, -1, 0);

243 *tarr++ = -tang;

244 *uvarr++ = Vector2(u * urange, v);

245

246 if(i < usub && j < capsub) {

247 unsigned int idx = num_body_verts + (i * capvverts + j) * 2;

248

249 unsigned int vidx[4] = {

250 idx,

251 idx + capvverts * 2,

252 idx + (capvverts + 1) * 2,

253 idx + 2

254 };

255

256 *idxarr++ = vidx[0];

257 *idxarr++ = vidx[2];

258 *idxarr++ = vidx[1];

259 *idxarr++ = vidx[0];

260 *idxarr++ = vidx[3];

261 *idxarr++ = vidx[2];

262

263 *idxarr++ = vidx[0] + 1;

264 *idxarr++ = vidx[1] + 1;

265 *idxarr++ = vidx[2] + 1;

266 *idxarr++ = vidx[0] + 1;

267 *idxarr++ = vidx[2] + 1;

268 *idxarr++ = vidx[3] + 1;

269 }

270

271 v += dv;

272 }

273 u += du;

274 }

275 }

276

277 // -------- cone --------

278

279 static Vector3 conevec(float theta, float y, float height)

280 {

281 float scale = 1.0 - y / height;

282 return Vector3(sin(theta) * scale, y, cos(theta) * scale);

283 }

284

285 void gen_cone(Mesh *mesh, float rad, float height, int usub, int vsub, int capsub, float urange, float vrange)

286 {

287 if(usub < 4) usub = 4;

288 if(vsub < 1) vsub = 1;

289

290 int uverts = usub + 1;

291 int vverts = vsub + 1;

292

293 int num_body_verts = uverts * vverts;

294 int num_body_quads = usub * vsub;

295 int num_body_tri = num_body_quads * 2;

296

297 int capvverts = capsub ? capsub + 1 : 0;

298 int num_cap_verts = uverts * capvverts;

299 int num_cap_quads = usub * capsub;

300 int num_cap_tri = num_cap_quads * 2;

301

302 int num_verts = num_body_verts + num_cap_verts;

303 int num_tri = num_body_tri + num_cap_tri;

304

305 mesh->clear();

306 Vector3 *varr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_VERTEX, 3, num_verts, 0);

307 Vector3 *narr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_NORMAL, 3, num_verts, 0);

308 Vector3 *tarr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_TANGENT, 3, num_verts, 0);

309 Vector2 *uvarr = (Vector2*)mesh->set_attrib_data(MESH_ATTR_TEXCOORD, 2, num_verts, 0);

310 unsigned int *idxarr = mesh->set_index_data(num_tri * 3, 0);

311

312 float du = urange / (float)(uverts - 1);

313 float dv = vrange / (float)(vverts - 1);

314

315 float u = 0.0;

316 for(int i=0; i<uverts; i++) {

317 float theta = SURAD(u);

318

319 float v = 0.0;

320 for(int j=0; j<vverts; j++) {

321 float y = v * height;

322 Vector3 pos = conevec(theta, y, height);

323

324 Vector3 tang = (conevec(theta + 0.1, 0.0, height) - conevec(theta - 0.1, 0.0, height)).normalized();

325 Vector3 bitang = (conevec(theta, y + 0.1, height) - pos).normalized();

326

327 *varr++ = Vector3(pos.x * rad, pos.y, pos.z * rad);

328 *narr++ = cross_product(tang, bitang);

329 *tarr++ = tang;

330 *uvarr++ = Vector2(u * urange, v * vrange);

331

332 if(i < usub && j < vsub) {

333 int idx = i * vverts + j;

334

335 *idxarr++ = idx;

336 *idxarr++ = idx + vverts + 1;

337 *idxarr++ = idx + 1;

338

339 *idxarr++ = idx;

340 *idxarr++ = idx + vverts;

341 *idxarr++ = idx + vverts + 1;

342 }

343

344 v += dv;

345 }

346 u += du;

347 }

348

349

350 // now the bottom cap!

351 if(!capsub) {

352 return;

353 }

354

355 dv = 1.0 / (float)(capvverts - 1);

356

357 u = 0.0;

358 for(int i=0; i<uverts; i++) {

359 float theta = SURAD(u);

360

361 float v = 0.0;

362 for(int j=0; j<capvverts; j++) {

363 float r = v * rad;

364

365 Vector3 pos = conevec(theta, 0.0, height) * r;

366 Vector3 tang = (cylvec(theta + 0.1, 0.0) - cylvec(theta - 0.1, 0.0)).normalized();

367

368 *varr++ = pos;

369 *narr++ = Vector3(0, -1, 0);

370 *tarr++ = tang;

371 *uvarr++ = Vector2(u * urange, v);

372

373 if(i < usub && j < capsub) {

374 unsigned int idx = num_body_verts + i * capvverts + j;

375

376 unsigned int vidx[4] = {

377 idx,

378 idx + capvverts,

379 idx + (capvverts + 1),

380 idx + 1

381 };

382

383 *idxarr++ = vidx[0];

384 *idxarr++ = vidx[1];

385 *idxarr++ = vidx[2];

386 *idxarr++ = vidx[0];

387 *idxarr++ = vidx[2];

388 *idxarr++ = vidx[3];

389 }

390

391 v += dv;

392 }

393 u += du;

394 }

395 }

396

397

398 // -------- plane --------

399

400 void gen_plane(Mesh *mesh, float width, float height, int usub, int vsub)

401 {

402 gen_heightmap(mesh, width, height, usub, vsub, 0);

403 }

404

405

406 // ----- heightmap ------

407

408 void gen_heightmap(Mesh *mesh, float width, float height, int usub, int vsub, float (*hf)(float, float, void*), void *hfdata)

409 {

410 if(usub < 1) usub = 1;

411 if(vsub < 1) vsub = 1;

412

413 mesh->clear();

414

415 int uverts = usub + 1;

416 int vverts = vsub + 1;

417 int num_verts = uverts * vverts;

418

419 int num_quads = usub * vsub;

420 int num_tri = num_quads * 2;

421

422 Vector3 *varr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_VERTEX, 3, num_verts, 0);

423 Vector3 *narr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_NORMAL, 3, num_verts, 0);

424 Vector3 *tarr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_TANGENT, 3, num_verts, 0);

425 Vector2 *uvarr = (Vector2*)mesh->set_attrib_data(MESH_ATTR_TEXCOORD, 2, num_verts, 0);

426 unsigned int *idxarr = mesh->set_index_data(num_tri * 3, 0);

427

428 float du = 1.0 / (float)usub;

429 float dv = 1.0 / (float)vsub;

430

431 float u = 0.0;

432 for(int i=0; i<uverts; i++) {

433 float v = 0.0;

434 for(int j=0; j<vverts; j++) {

435 float x = (u - 0.5) * width;

436 float y = (v - 0.5) * height;

437 float z = hf ? hf(u, v, hfdata) : 0.0;

438

439 Vector3 normal = Vector3(0, 0, 1);

440 if(hf) {

441 float u1z = hf(u + du, v, hfdata);

442 float v1z = hf(u, v + dv, hfdata);

443

444 Vector3 tang = Vector3(du * width, 0, u1z - z);

445 Vector3 bitan = Vector3(0, dv * height, v1z - z);

446 normal = cross_product(tang, bitan).normalized();

447 }

448

449 *varr++ = Vector3(x, y, z);

450 *narr++ = normal;

451 *tarr++ = Vector3(1, 0, 0);

452 *uvarr++ = Vector2(u, v);

453

454 if(i < usub && j < vsub) {

455 int idx = i * vverts + j;

456

457 *idxarr++ = idx;

458 *idxarr++ = idx + vverts + 1;

459 *idxarr++ = idx + 1;

460

461 *idxarr++ = idx;

462 *idxarr++ = idx + vverts;

463 *idxarr++ = idx + vverts + 1;

464 }

465

466 v += dv;

467 }

468 u += du;

469 }

470 }

471

472 // ----- box ------

473 void gen_box(Mesh *mesh, float xsz, float ysz, float zsz, int usub, int vsub)

474 {

475 static const float face_angles[][2] = {

476 {0, 0},

477 {M_PI / 2.0, 0},

478 {M_PI, 0},

479 {3.0 * M_PI / 2.0, 0},

480 {0, M_PI / 2.0},

481 {0, -M_PI / 2.0}

482 };

483

484 if(usub < 1) usub = 1;

485 if(vsub < 1) vsub = 1;

486

487 mesh->clear();

488

489 for(int i=0; i<6; i++) {

490 Matrix4x4 xform, dir_xform;

491 Mesh m;

492

493 gen_plane(&m, 1, 1, usub, vsub);

494 xform.rotate(Vector3(face_angles[i][1], face_angles[i][0], 0));

495 dir_xform = xform;

496 xform.translate(Vector3(0, 0, 0.5));

497 m.apply_xform(xform, dir_xform);

498

499 mesh->append(m);

500 }

501

502 Matrix4x4 scale;

503 scale.set_scaling(Vector3(xsz, ysz, zsz));

504 mesh->apply_xform(scale, Matrix4x4::identity);

505 }

506

507 /*

508 void gen_box(Mesh *mesh, float xsz, float ysz, float zsz)

509 {

510 mesh->clear();

511

512 const int num_faces = 6;

513 int num_verts = num_faces * 4;

514 int num_tri = num_faces * 2;

515

516 float x = xsz / 2.0;

517 float y = ysz / 2.0;

518 float z = zsz / 2.0;

519

520 Vector3 *varr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_VERTEX, 3, num_verts, 0);

521 Vector3 *narr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_NORMAL, 3, num_verts, 0);

522 Vector3 *tarr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_TANGENT, 3, num_verts, 0);

523 Vector2 *uvarr = (Vector2*)mesh->set_attrib_data(MESH_ATTR_TEXCOORD, 2, num_verts, 0);

524 unsigned int *idxarr = mesh->set_index_data(num_tri * 3, 0);

525

526 static const Vector2 uv[] = { Vector2(0, 0), Vector2(1, 0), Vector2(1, 1), Vector2(0, 1) };

527

528 // front

529 for(int i=0; i<4; i++) {

530 *narr++ = Vector3(0, 0, 1);

531 *tarr++ = Vector3(1, 0, 0);

532 *uvarr++ = uv[i];

533 }

534 *varr++ = Vector3(-x, -y, z);

535 *varr++ = Vector3(x, -y, z);

536 *varr++ = Vector3(x, y, z);

537 *varr++ = Vector3(-x, y, z);

538 // right

539 for(int i=0; i<4; i++) {

540 *narr++ = Vector3(1, 0, 0);

541 *tarr++ = Vector3(0, 0, -1);

542 *uvarr++ = uv[i];

543 }

544 *varr++ = Vector3(x, -y, z);

545 *varr++ = Vector3(x, -y, -z);

546 *varr++ = Vector3(x, y, -z);

547 *varr++ = Vector3(x, y, z);

548 // back

549 for(int i=0; i<4; i++) {

550 *narr++ = Vector3(0, 0, -1);

551 *tarr++ = Vector3(-1, 0, 0);

552 *uvarr++ = uv[i];

553 }

554 *varr++ = Vector3(x, -y, -z);

555 *varr++ = Vector3(-x, -y, -z);

556 *varr++ = Vector3(-x, y, -z);

557 *varr++ = Vector3(x, y, -z);

558 // left

559 for(int i=0; i<4; i++) {

560 *narr++ = Vector3(-1, 0, 0);

561 *tarr++ = Vector3(0, 0, 1);

562 *uvarr++ = uv[i];

563 }

564 *varr++ = Vector3(-x, -y, -z);

565 *varr++ = Vector3(-x, -y, z);

566 *varr++ = Vector3(-x, y, z);

567 *varr++ = Vector3(-x, y, -z);

568 // top

569 for(int i=0; i<4; i++) {

570 *narr++ = Vector3(0, 1, 0);

571 *tarr++ = Vector3(1, 0, 0);

572 *uvarr++ = uv[i];

573 }

574 *varr++ = Vector3(-x, y, z);

575 *varr++ = Vector3(x, y, z);

576 *varr++ = Vector3(x, y, -z);

577 *varr++ = Vector3(-x, y, -z);

578 // bottom

579 for(int i=0; i<4; i++) {

580 *narr++ = Vector3(0, -1, 0);

581 *tarr++ = Vector3(1, 0, 0);

582 *uvarr++ = uv[i];

583 }

584 *varr++ = Vector3(-x, -y, -z);

585 *varr++ = Vector3(x, -y, -z);

586 *varr++ = Vector3(x, -y, z);

587 *varr++ = Vector3(-x, -y, z);

588

589 // index array

590 static const int faceidx[] = {0, 1, 2, 0, 2, 3};

591 for(int i=0; i<num_faces; i++) {

592 for(int j=0; j<6; j++) {

593 *idxarr++ = faceidx[j] + i * 4;

594 }

595 }

596 }

597 */

598

599 static inline Vector3 rev_vert(float u, float v, Vector2 (*rf)(float, float, void*), void *cls)

600 {

601 Vector2 pos = rf(u, v, cls);

602

603 float angle = u * 2.0 * M_PI;

604 float x = pos.x * cos(angle);

605 float y = pos.y;

606 float z = pos.x * sin(angle);

607

608 return Vector3(x, y, z);

609 }

610

611 // ------ surface of revolution -------

612 void gen_revol(Mesh *mesh, int usub, int vsub, Vector2 (*rfunc)(float, float, void*), void *cls)

613 {

614 gen_revol(mesh, usub, vsub, rfunc, 0, cls);

615 }

616

617 void gen_revol(Mesh *mesh, int usub, int vsub, Vector2 (*rfunc)(float, float, void*),

618 Vector2 (*nfunc)(float, float, void*), void *cls)

619 {

620 if(!rfunc) return;

621 if(usub < 3) usub = 3;

622 if(vsub < 1) vsub = 1;

623

624 mesh->clear();

625

626 int uverts = usub + 1;

627 int vverts = vsub + 1;

628 int num_verts = uverts * vverts;

629

630 int num_quads = usub * vsub;

631 int num_tri = num_quads * 2;

632

633 Vector3 *varr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_VERTEX, 3, num_verts, 0);

634 Vector3 *narr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_NORMAL, 3, num_verts, 0);

635 Vector3 *tarr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_TANGENT, 3, num_verts, 0);

636 Vector2 *uvarr = (Vector2*)mesh->set_attrib_data(MESH_ATTR_TEXCOORD, 2, num_verts, 0);

637 unsigned int *idxarr = mesh->set_index_data(num_tri * 3, 0);

638

639 float du = 1.0 / (float)(uverts - 1);

640 float dv = 1.0 / (float)(vverts - 1);

641

642 float u = 0.0;

643 for(int i=0; i<uverts; i++) {

644 float v = 0.0;

645 for(int j=0; j<vverts; j++) {

646 Vector3 pos = rev_vert(u, v, rfunc, cls);

647

648 Vector3 nextu = rev_vert(fmod(u + du, 1.0), v, rfunc, cls);

649 Vector3 tang = nextu - pos;

650 if(tang.length_sq() < 1e-6) {

651 float new_v = v > 0.5 ? v - dv * 0.25 : v + dv * 0.25;

652 nextu = rev_vert(fmod(u + du, 1.0), new_v, rfunc, cls);

653 tang = nextu - pos;

654 }

655

656 Vector3 normal;

657 if(nfunc) {

658 normal = rev_vert(u, v, nfunc, cls);

659 } else {

660 Vector3 nextv = rev_vert(u, v + dv, rfunc, cls);

661 Vector3 bitan = nextv - pos;

662 if(bitan.length_sq() < 1e-6) {

663 nextv = rev_vert(u, v - dv, rfunc, cls);

664 bitan = pos - nextv;

665 }

666

667 normal = cross_product(tang, bitan);

668 }

669

670 *varr++ = pos;

671 *narr++ = normal.normalized();

672 *tarr++ = tang.normalized();

673 *uvarr++ = Vector2(u, v);

674

675 if(i < usub && j < vsub) {

676 int idx = i * vverts + j;

677

678 *idxarr++ = idx;

679 *idxarr++ = idx + vverts + 1;

680 *idxarr++ = idx + 1;

681

682 *idxarr++ = idx;

683 *idxarr++ = idx + vverts;

684 *idxarr++ = idx + vverts + 1;

685 }

686

687 v += dv;

688 }

689 u += du;

690 }

691 }

692

693

694 static inline Vector3 sweep_vert(float u, float v, float height, Vector2 (*sf)(float, float, void*), void *cls)

695 {

696 Vector2 pos = sf(u, v, cls);

697

698 float x = pos.x;

699 float y = v * height;

700 float z = pos.y;

701

702 return Vector3(x, y, z);

703 }

704

705 // ---- sweep shape along a path ----

706 void gen_sweep(Mesh *mesh, float height, int usub, int vsub, Vector2 (*sfunc)(float, float, void*), void *cls)

707 {

708 if(!sfunc) return;

709 if(usub < 3) usub = 3;

710 if(vsub < 1) vsub = 1;

711

712 mesh->clear();

713

714 int uverts = usub + 1;

715 int vverts = vsub + 1;

716 int num_verts = uverts * vverts;

717

718 int num_quads = usub * vsub;

719 int num_tri = num_quads * 2;

720

721 Vector3 *varr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_VERTEX, 3, num_verts, 0);

722 Vector3 *narr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_NORMAL, 3, num_verts, 0);

723 Vector3 *tarr = (Vector3*)mesh->set_attrib_data(MESH_ATTR_TANGENT, 3, num_verts, 0);

724 Vector2 *uvarr = (Vector2*)mesh->set_attrib_data(MESH_ATTR_TEXCOORD, 2, num_verts, 0);

725 unsigned int *idxarr = mesh->set_index_data(num_tri * 3, 0);

726

727 float du = 1.0 / (float)(uverts - 1);

728 float dv = 1.0 / (float)(vverts - 1);

729

730 float u = 0.0;

731 for(int i=0; i<uverts; i++) {

732 float v = 0.0;

733 for(int j=0; j<vverts; j++) {

734 Vector3 pos = sweep_vert(u, v, height, sfunc, cls);

735

736 Vector3 nextu = sweep_vert(fmod(u + du, 1.0), v, height, sfunc, cls);

737 Vector3 tang = nextu - pos;

738 if(tang.length_sq() < 1e-6) {

739 float new_v = v > 0.5 ? v - dv * 0.25 : v + dv * 0.25;

740 nextu = sweep_vert(fmod(u + du, 1.0), new_v, height, sfunc, cls);

741 tang = nextu - pos;

742 }

743

744 Vector3 normal;

745 Vector3 nextv = sweep_vert(u, v + dv, height, sfunc, cls);

746 Vector3 bitan = nextv - pos;

747 if(bitan.length_sq() < 1e-6) {

748 nextv = sweep_vert(u, v - dv, height, sfunc, cls);

749 bitan = pos - nextv;

750 }

751

752 normal = cross_product(tang, bitan);

753

754 *varr++ = pos;

755 *narr++ = normal.normalized();

756 *tarr++ = tang.normalized();

757 *uvarr++ = Vector2(u, v);

758

759 if(i < usub && j < vsub) {

760 int idx = i * vverts + j;

761

762 *idxarr++ = idx;

763 *idxarr++ = idx + vverts + 1;

764 *idxarr++ = idx + 1;

765

766 *idxarr++ = idx;

767 *idxarr++ = idx + vverts;

768 *idxarr++ = idx + vverts + 1;

769 }

770

771 v += dv;

772 }

773 u += du;

774 }

775 }