deepstone: 11d14f688485 src/mingl.c

deepstone

view src/mingl.c @ 28:11d14f688485

added clipping

author	John Tsiombikas <nuclear@member.fsf.org>
date	Sun, 22 Sep 2013 06:38:08 +0300
parents	00d84ab1ef26
children	17a5107b6fa4

line source

1 #include <stdio.h>

2 #include <stdlib.h>

3 #include <string.h>

4 #include <math.h>

5 #include <limits.h>

6 #include <assert.h>

7 #include "vmath.h"

8 #include "mingl.h"

9 #include "mglimpl.h"

12 #define DOT(a, b) ((a).x * (b).x + (a).y * (b).y + (a).z * (b).z)

14 #define NORMALIZE(v) \

15 do { \

16 float mag = sqrt(DOT(v, v)); \

17 if(fabs(mag) > 1e-6) { \

18 float invmag = 1.0 / mag; \

19 (v).x *= invmag; \

20 (v).y *= invmag; \

21 (v).z *= invmag; \

22 } \

23 } while(0)

25 static void transform(vec4_t *res, vec4_t *v, float *mat);

26 static void transform3(vec3_t *res, vec3_t *v, float *mat);

27 static void vertex_proc_view(struct vertex *vert);

28 static int vertex_proc_proj(struct vertex *vert);

29 static int calc_shiftmask(int val, int *shiftp, unsigned int *maskp);

31 static struct state st;

32 static struct framebuffer fb;

34 int mgl_init(int width, int height)

35 {

36 int i;

38 st.flags = 0;

39 st.mmode = 0;

41 mgl_front_face(MGL_CCW);

42 mgl_cull_face(MGL_BACK);

44 st.curv.cidx = 0;

45 st.curv.energy = 1.0;

46 st.curv.norm.x = st.curv.norm.y = st.curv.norm.z = 0.0;

48 if(!(fb.pixels = malloc(width * height))) {

49 return -1;

50 }

51 fb.width = width;

52 fb.height = height;

53 fb.zbuf = 0;

55 if(mgl_rast_init(&st, &fb) == -1) {

56 free(fb.pixels);

57 return -1;

58 }

60 st.mtop[0] = st.mtop[1] = 0;

62 mgl_matrix_mode(MGL_MODELVIEW);

63 mgl_load_identity();

64 mgl_matrix_mode(MGL_PROJECTION);

65 mgl_load_identity();

67 /* initial viewport in the size of the framebuffer */

68 st.vp[0] = st.vp[1] = 0;

69 st.vp[2] = width;

70 st.vp[3] = height;

72 st.col_range = 256;

73 for(i=0; i<MAX_LIGHTS; i++) {

74 st.lpos[i].x = st.lpos[i].y = st.lpos[i].w = 0.0f;

75 st.lpos[i].z = 1.0f;

76 st.lint[i] = 0.0f;

77 }

79 st.ambient = 0.1;

81 mgl_clip_init(&st);

82 return 0;

83 }

85 void mgl_free(void)

86 {

87 int i;

89 mgl_rast_cleanup();

90 free(fb.pixels);

91 fb.pixels = 0;

93 if(fb.zbuf) {

94 for(i=0; i<fb.num_ztiles; i++) {

95 free(fb.zbuf[i]);

96 }

97 free(fb.zbuf);

98 fb.zbuf = 0;

99 }

100 }

101

102 unsigned char *mgl_framebuffer(void)

103 {

104 return fb.pixels;

105 }

106

107 void mgl_clear(int cidx)

108 {

109 memset(fb.pixels, cidx, fb.width * fb.height);

110 }

111

112 void mgl_clear_depth(void)

113 {

114 int i;

115

116 if(!fb.zbuf) {

117 long num_pixels = (long)fb.width * (long)fb.height;

118 fb.num_ztiles = (num_pixels + ZTILE_SIZE - 1) / ZTILE_SIZE;

119

120 if(!(fb.zbuf = malloc(fb.num_ztiles * sizeof *fb.zbuf))) {

121 fprintf(stderr, "failed to allocate ztile array\n");

122 abort();

123 }

124

125 for(i=0; i<fb.num_ztiles; i++) {

126 if(!(fb.zbuf[i] = malloc(ZTILE_SIZE * 2))) {

127 fprintf(stderr, "failed to allocate ztile %d\n", i);

128 abort();

129 }

130 memset(fb.zbuf[i], 0xff, ZTILE_SIZE * 2);

131 }

132 return;

133 }

134

135 for(i=0; i<fb.num_ztiles; i++) {

136 memset(fb.zbuf[i], 0xff, ZTILE_SIZE * 2);

137 }

138 }

139

140 void mgl_enable(unsigned int what)

141 {

142 st.flags |= (1 << what);

143 }

144

145 void mgl_disable(unsigned int what)

146 {

147 st.flags &= ~(1 << what);

148 }

149

150 int mgl_isenabled(unsigned int what)

151 {

152 return IS_ENABLED(st.flags, what);

153 }

154

155 void mgl_front_face(int ff)

156 {

157 st.frontface = ff;

158 }

159

160 void mgl_cull_face(int cf)

161 {

162 st.cullface = cf;

163 }

164

165 void mgl_set_ambient(float amb)

166 {

167 st.ambient = amb;

168 }

169

170 float mgl_get_ambient(void)

171 {

172 return st.ambient;

173 }

174

175 void mgl_color_range(int rng)

176 {

177 st.col_range = rng;

178 }

179

180 void mgl_light_intensity(int ltidx, float intens)

181 {

182 assert(ltidx >= 0 && ltidx < MAX_LIGHTS);

183 st.lint[ltidx] = intens;

184 }

185

186 void mgl_light_position(int ltidx, float x, float y, float z, float w)

187 {

188 vec4_t pos;

189 assert(ltidx >= 0 && ltidx < MAX_LIGHTS);

190

191 pos.x = x;

192 pos.y = y;

193 pos.z = z;

194 pos.w = w;

195 transform(&st.lpos[ltidx], &pos, st.matrix[MGL_MODELVIEW][st.mtop[MGL_MODELVIEW]]);

196

197 if(fabs(st.lpos[ltidx].w) < 1e-6) {

198 NORMALIZE(st.lpos[ltidx]);

199 } else {

200 st.lpos[ltidx].x /= st.lpos[ltidx].w;

201 st.lpos[ltidx].y /= st.lpos[ltidx].w;

202 st.lpos[ltidx].z /= st.lpos[ltidx].w;

203 }

204 }

205

206 void mgl_begin(int prim)

207 {

208 st.prim = prim;

209 st.vidx = 0;

210

211 st.ord = st.frontface;

212 if(st.cullface == MGL_FRONT) {

213 st.ord = st.frontface == MGL_CCW ? MGL_CW : MGL_CCW;

214 }

215

216 /* select the correct rasterizer according to state */

217 mgl_rast_prepare();

218 }

219

220 void mgl_end(void)

221 {

222 }

223

224 void mgl_vertex2f(float x, float y)

225 {

226 mgl_vertex4f(x, y, 0.0f, 1.0f);

227 }

228

229 void mgl_vertex3f(float x, float y, float z)

230 {

231 mgl_vertex4f(x, y, z, 1.0f);

232 }

233

234 void mgl_vertex4f(float x, float y, float z, float w)

235 {

236 st.v[st.vidx].pos.x = x;

237 st.v[st.vidx].pos.y = y;

238 st.v[st.vidx].pos.z = z;

239 st.v[st.vidx].pos.w = w;

240 st.v[st.vidx].cidx = st.curv.cidx;

241 st.v[st.vidx].energy = st.curv.energy;

242 st.v[st.vidx].norm = st.curv.norm;

243 st.v[st.vidx].tc = st.curv.tc;

244

245 /* T&L up to view space, to perform user-clipping */

246 vertex_proc_view(st.v + st.vidx);

247

248 if(++st.vidx >= st.prim) {

249 st.vidx = 0;

250

251 switch(st.prim) {

252 case MGL_POINTS:

253 vertex_proc_proj(st.v);

254 mgl_draw_point(st.v);

255 break;

256 case MGL_LINES:

257 vertex_proc_proj(st.v);

258 vertex_proc_proj(st.v + 1);

259 mgl_draw_line(st.v, st.v + 1);

260 break;

261 case MGL_TRIANGLES:

262 case MGL_QUADS:

263 {

264 int nverts = mgl_clip_poly(st.v, st.prim);

265 if(nverts > 0) {

266 int i;

267 /* passed clipping, perform projection for all verts and draw */

268 for(i=0; i<nverts; i++) {

269 if(vertex_proc_proj(st.v + i) == -1) {

270 printf("this shouldn't happen!\n");

271 return;

272 }

273 }

274 mgl_draw_poly(st.v, nverts);

275 }

276 }

277 break;

278 default:

279 fprintf(stderr, "invalid primitive: %d\n", st.prim);

280 abort();

281 }

282 }

283 }

284

285 void mgl_color1f(float energy)

286 {

287 st.curv.energy = energy;

288 }

289

290 void mgl_index(int c)

291 {

292 st.curv.cidx = c;

293 }

294

295 void mgl_normal(float x, float y, float z)

296 {

297 st.curv.norm.x = x;

298 st.curv.norm.y = y;

299 st.curv.norm.z = z;

300 }

301

302 void mgl_texcoord2f(float x, float y)

303 {

304 st.curv.tc.x = x;

305 st.curv.tc.y = y;

306 }

307

308 static void transform(vec4_t *res, vec4_t *v, float *mat)

309 {

310 res->x = mat[0] * v->x + mat[4] * v->y + mat[8] * v->z + mat[12] * v->w;

311 res->y = mat[1] * v->x + mat[5] * v->y + mat[9] * v->z + mat[13] * v->w;

312 res->z = mat[2] * v->x + mat[6] * v->y + mat[10] * v->z + mat[14] * v->w;

313 res->w = mat[3] * v->x + mat[7] * v->y + mat[11] * v->z + mat[15] * v->w;

314 }

315

316 /* the matrix is 4x4 (16 floats), just ignoring anything out of the 3x3 */

317 static void transform3(vec3_t *res, vec3_t *v, float *mat)

318 {

319 res->x = mat[0] * v->x + mat[4] * v->y + mat[8] * v->z;

320 res->y = mat[1] * v->x + mat[5] * v->y + mat[9] * v->z;

321 res->z = mat[2] * v->x + mat[6] * v->y + mat[10] * v->z;

322 }

323

324 static void vertex_proc_view(struct vertex *vert)

325 {

326 vec4_t pview;

327

328 float *mvmat = st.matrix[MGL_MODELVIEW][st.mtop[MGL_MODELVIEW]];

329

330 /* modelview transformation */

331 transform(&pview, &vert->pos, mvmat);

332

333 if(mgl_isenabled(MGL_LIGHTING)) {

334 if(mgl_isenabled(MGL_SMOOTH) || st.vidx == 0) {

335 int i;

336 vec3_t norm;

337 float irrad = st.ambient;

338

339 transform3(&norm, &vert->norm, mvmat);

340

341 for(i=0; i<MAX_LIGHTS; i++) {

342 if(st.lint[i] > 1e-6f) {

343 float ndotl;

344 vec3_t ldir;

345

346 if(st.lpos[i].w == 0.0) {

347 ldir.x = st.lpos[i].x;

348 ldir.y = st.lpos[i].y;

349 ldir.z = st.lpos[i].z;

350 } else {

351 ldir.x = st.lpos[i].x - pview.x;

352 ldir.y = st.lpos[i].y - pview.y;

353 ldir.z = st.lpos[i].z - pview.z;

354

355 NORMALIZE(ldir);

356 }

357

358 ndotl = DOT(norm, ldir);

359 if(ndotl < 0.0) {

360 ndotl = 0.0;

361 }

362 irrad += ndotl * st.lint[i];

363 }

364 }

365 vert->energy = irrad > 1.0 ? 1.0 : irrad;

366 } else {

367 vert->energy = st.v[0].energy;

368 }

369 }

370

371 vert->pos = pview;

372 }

373

374 static int vertex_proc_proj(struct vertex *vert)

375 {

376 vec4_t pclip;

377

378 float *pmat = st.matrix[MGL_PROJECTION][st.mtop[MGL_PROJECTION]];

379

380 transform(&pclip, &vert->pos, pmat);

381 /* TODO clipping in homogenous clip space */

382

383 if(pclip.w < 1e-6) {

384 vert->pos.x = vert->pos.y = vert->pos.z = vert->pos.w = 0.0f;

385 return -1;

386 }

387

388 /* perspective division */

389 vert->pos.x = pclip.x / pclip.w;

390 vert->pos.y = pclip.y / pclip.w;

391 vert->pos.z = pclip.z / pclip.w;

392 vert->pos.w = pclip.w;

393

394 /* viewport transformation */

395 vert->pos.x = st.vp[0] + st.vp[2] * (vert->pos.x * 0.5 + 0.5);

396 vert->pos.y = st.vp[1] + st.vp[3] * (-vert->pos.y * 0.5 + 0.5);

397

398 return 0;

399 }

400

401 void mgl_viewport(int x, int y, int width, int height)

402 {

403 st.vp[0] = x;

404 st.vp[1] = y;

405 st.vp[2] = width;

406 st.vp[3] = height;

407 }

408

409 void mgl_matrix_mode(int mmode)

410 {

411 st.mmode = mmode;

412 }

413

414 void mgl_push_matrix(void)

415 {

416 float *topmat;

417 if(st.mtop[st.mmode] >= MATRIX_STACK_SIZE - 1) {

418 fprintf(stderr, "mgl_push_matrix: stack overflow\n");

419 abort();

420 }

421

422 topmat = st.matrix[st.mmode][st.mtop[st.mmode]];

423 memcpy(topmat + 16, topmat, 16 * sizeof *topmat);

424 st.mmode++;

425 }

426

427 void mgl_pop_matrix(void)

428 {

429 if(st.mtop[st.mmode] <= 0) {

430 fprintf(stderr, "mgl_pop_matrix: stack underflow\n");

431 abort();

432 }

433 st.mtop[st.mmode]--;

434 }

435

436 void mgl_load_matrix(float *mat)

437 {

438 float *dest = st.matrix[st.mmode][st.mtop[st.mmode]];

439 memcpy(dest, mat, 16 * sizeof *dest);

440 }

441

442 #define M(i,j) (((i) << 2) + (j))

443 void mgl_mult_matrix(float *m2)

444 {

445 int i, j;

446 float m1[16];

447 float *dest = st.matrix[st.mmode][st.mtop[st.mmode]];

448

449 memcpy(m1, dest, sizeof m1);

450

451 for(i=0; i<4; i++) {

452 for(j=0; j<4; j++) {

453 dest[M(i,j)] = m1[M(0,j)] * m2[M(i,0)] +

454 m1[M(1,j)] * m2[M(i,1)] +

455 m1[M(2,j)] * m2[M(i,2)] +

456 m1[M(3,j)] * m2[M(i,3)];

457 }

458 }

459 }

460

461 void mgl_load_identity(void)

462 {

463 static float id[] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1};

464 mgl_load_matrix((float*)id);

465 }

466

467 void mgl_translate(float x, float y, float z)

468 {

469 float xform[] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1};

470 xform[12] = x;

471 xform[13] = y;

472 xform[14] = z;

473 mgl_mult_matrix(xform);

474 }

475

476 void mgl_rotate(float deg, float x, float y, float z)

477 {

478 float xform[] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1};

479

480 float angle = M_PI * deg / 180.0f;

481 float sina = sin(angle);

482 float cosa = cos(angle);

483 float one_minus_cosa = 1.0f - cosa;

484 float nxsq = x * x;

485 float nysq = y * y;

486 float nzsq = z * z;

487

488 xform[0] = nxsq + (1.0f - nxsq) * cosa;

489 xform[4] = x * y * one_minus_cosa - z * sina;

490 xform[8] = x * z * one_minus_cosa + y * sina;

491 xform[1] = x * y * one_minus_cosa + z * sina;

492 xform[5] = nysq + (1.0 - nysq) * cosa;

493 xform[9] = y * z * one_minus_cosa - x * sina;

494 xform[2] = x * z * one_minus_cosa - y * sina;

495 xform[6] = y * z * one_minus_cosa + x * sina;

496 xform[10] = nzsq + (1.0 - nzsq) * cosa;

497

498 mgl_mult_matrix(xform);

499 }

500

501 void mgl_scale(float x, float y, float z)

502 {

503 float xform[] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1};

504 xform[0] = x;

505 xform[5] = y;

506 xform[10] = z;

507 mgl_mult_matrix(xform);

508 }

509

510 void gl_ortho(float left, float right, float bottom, float top, float nr, float fr)

511 {

512 float xform[] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1};

513

514 float dx = right - left;

515 float dy = top - bottom;

516 float dz = fr - nr;

517

518 float tx = -(right + left) / dx;

519 float ty = -(top + bottom) / dy;

520 float tz = -(fr + nr) / dz;

521

522 float sx = 2.0 / dx;

523 float sy = 2.0 / dy;

524 float sz = -2.0 / dz;

525

526 xform[0] = sx;

527 xform[5] = sy;

528 xform[10] = sz;

529 xform[12] = tx;

530 xform[13] = ty;

531 xform[14] = tz;

532

533 mgl_mult_matrix(xform);

534 }

535

536 void mgl_frustum(float left, float right, float bottom, float top, float nr, float fr)

537 {

538 float xform[] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1};

539

540 float dx = right - left;

541 float dy = top - bottom;

542 float dz = fr - nr;

543

544 float a = (right + left) / dx;

545 float b = (top + bottom) / dy;

546 float c = -(fr + nr) / dz;

547 float d = -2.0 * fr * nr / dz;

548

549 xform[0] = 2.0 * nr / dx;

550 xform[5] = 2.0 * nr / dy;

551 xform[8] = a;

552 xform[9] = b;

553 xform[10] = c;

554 xform[11] = -1.0f;

555 xform[14] = d;

556

557 mgl_mult_matrix(xform);

558 }

559

560 void mgl_perspective(float vfov, float aspect, float nr, float fr)

561 {

562 float vfov_rad = M_PI * vfov / 180.0;

563 float x = nr * tan(vfov_rad / 2.0);

564 mgl_frustum(-aspect * x, aspect * x, -x, x, nr, fr);

565 }

566

567 void mgl_teximage(int width, int height, unsigned char *pixels)

568 {

569 st.tex.width = width;

570 st.tex.height = height;

571 st.tex.pixels = pixels;

572

573 if(calc_shiftmask(width, &st.tex.xshift, &st.tex.xmask) == -1 ||

574 calc_shiftmask(height, &st.tex.yshift, &st.tex.ymask) == -1) {

575 st.tex.pixels = 0;

576 }

577 }

578

579 void mgl_clip_plane(int id, float nx, float ny, float nz, float dist)

580 {

581 id -= MGL_CLIP_PLANE0;

582

583 if(id < 0 || id > MAX_CLIP_PLANES) {

584 return;

585 }

586

587 st.clip_planes[id].normal.x = nx;

588 st.clip_planes[id].normal.y = ny;

589 st.clip_planes[id].normal.z = nz;

590 NORMALIZE(st.clip_planes[id].normal);

591

592 st.clip_planes[id].pt.x = st.clip_planes[id].normal.x * dist;

593 st.clip_planes[id].pt.y = st.clip_planes[id].normal.y * dist;

594 st.clip_planes[id].pt.z = st.clip_planes[id].normal.z * dist;

595

596 printf("set clip plane %d -> n[%f %f %f] p[%f %f %f]\n", id,

597 st.clip_planes[id].normal.x, st.clip_planes[id].normal.y, st.clip_planes[id].normal.z,

598 st.clip_planes[id].pt.x, st.clip_planes[id].pt.y, st.clip_planes[id].pt.z);

599

600 }

601

602 #define MAX_SHIFT 12

603 static int calc_shiftmask(int val, int *shiftp, unsigned int *maskp)

604 {

605 int i;

606

607 for(i=0; i<MAX_SHIFT; i++) {

608 if((val >> i) == 1) {

609 *shiftp = i;

610 *maskp = ~(UINT_MAX << i);

611 return 0;

612 }

613 }

614 return -1;

615 }