dos3d: c29a6e024950 src/mingl.c

dos3d

view src/mingl.c @ 12:c29a6e024950

merged

author	John Tsiombikas <nuclear@member.fsf.org>
date	Mon, 28 Nov 2011 05:03:22 +0200
parents	bce78aaafc68
children	7b574ba5758e

line source

1 /*

2 256-color 3D graphics hack for real-mode DOS.

5 This program is free software: you can redistribute it and/or modify

6 it under the terms of the GNU General Public License as published by

7 the Free Software Foundation, either version 3 of the License, or

8 (at your option) any later version.

10 This program is distributed in the hope that it will be useful,

11 but WITHOUT ANY WARRANTY; without even the implied warranty of

12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

13 GNU General Public License for more details.

15 You should have received a copy of the GNU General Public License

16 along with this program. If not, see <http://www.gnu.org/licenses/>.

17 */

18 #include <stdio.h>

19 #include <stdlib.h>

20 #include <string.h>

21 #include <math.h>

22 #include <assert.h>

23 #include "mingl.h"

24 #include "mglimpl.h"

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

29 #define NORMALIZE(v) \

30 do { \

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

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

33 float invmag = 1.0 / mag; \

34 (v).x *= invmag; \

35 (v).y *= invmag; \

36 (v).z *= invmag; \

37 } \

38 } while(0)

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

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

42 static void vertex_proc(struct vertex *vert);

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

45 static struct state st;

46 static struct framebuffer fb;

48 int mgl_init(int width, int height)

49 {

50 int i;

52 st.flags = 0;

53 st.mmode = 0;

55 mgl_front_face(MGL_CCW);

56 mgl_cull_face(MGL_BACK);

58 st.curv.cidx = 0;

59 st.curv.energy = 1.0;

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

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

63 return -1;

64 }

65 fb.width = width;

66 fb.height = height;

67 fb.zbuf = 0;

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

70 free(fb.pixels);

71 return -1;

72 }

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

76 mgl_matrix_mode(MGL_MODELVIEW);

77 mgl_load_identity();

78 mgl_matrix_mode(MGL_PROJECTION);

79 mgl_load_identity();

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

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

83 st.vp[2] = width;

84 st.vp[3] = height;

86 st.col_range = 256;

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

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

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

90 st.lint[i] = 0.0f;

91 }

93 return 0;

94 }

96 void mgl_free(void)

97 {

98 int i;

100 mgl_rast_cleanup();

101 free(fb.pixels);

102 fb.pixels = 0;

103

104 if(fb.zbuf) {

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

106 free(fb.zbuf[i]);

107 }

108 free(fb.zbuf);

109 fb.zbuf = 0;

110 }

111 }

112

113 unsigned char *mgl_framebuffer(void)

114 {

115 return fb.pixels;

116 }

117

118 void mgl_clear(int cidx)

119 {

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

121 }

122

123 void mgl_clear_depth(void)

124 {

125 int i;

126

127 if(!fb.zbuf) {

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

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

130

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

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

133 abort();

134 }

135

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

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

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

139 abort();

140 }

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

142 }

143 return;

144 }

145

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

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

148 }

149 }

150

151 void mgl_enable(unsigned int bit)

152 {

153 st.flags |= bit;

154 }

155

156 void mgl_disable(unsigned int bit)

157 {

158 st.flags &= ~bit;

159 }

160

161 int mgl_isenabled(unsigned int bit)

162 {

163 return (st.flags & bit) != 0;

164 }

165

166 void mgl_front_face(int ff)

167 {

168 st.frontface = ff;

169 }

170

171 void mgl_cull_face(int cf)

172 {

173 st.cullface = cf;

174 }

175

176 void mgl_color_range(int rng)

177 {

178 st.col_range = rng;

179 }

180

181 void mgl_light_intensity(int ltidx, float intens)

182 {

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

184 st.lint[ltidx] = intens;

185 }

186

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

188 {

189 vec4_t pos;

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

191

192 pos.x = x;

193 pos.y = y;

194 pos.z = z;

195 pos.w = w;

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

197

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

199 st.lpos[ltidx].w = 1.0;

200

201 NORMALIZE(st.lpos[ltidx]);

202 } else {

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

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

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

206 }

207 }

208

209 void mgl_begin(int prim)

210 {

211 st.prim = prim;

212 st.vidx = 0;

213

214 st.ord = st.frontface;

215 if(st.cullface == MGL_FRONT) {

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

217 }

218

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

220 mgl_rast_prepare();

221 }

222

223 void mgl_end(void)

224 {

225 }

226

227 void mgl_vertex2f(float x, float y)

228 {

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

230 }

231

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

233 {

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

235 }

236

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

238 {

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

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

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

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

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

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

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

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

247

248 vertex_proc(st.v + st.vidx);

249

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

251 switch(st.prim) {

252 case MGL_POINTS:

253 mgl_draw_point(st.v);

254 break;

255 case MGL_LINES:

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

257 break;

258 case MGL_TRIANGLES:

259 case MGL_QUADS:

260 mgl_draw_poly(st.v, st.prim);

261 break;

262 default:

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

264 abort();

265 }

266 st.vidx = 0;

267 }

268 }

269

270 void mgl_color1f(float energy)

271 {

272 st.curv.energy = energy;

273 }

274

275 void mgl_index(int c)

276 {

277 st.curv.cidx = c;

278 }

279

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

281 {

282 st.curv.norm.x = x;

283 st.curv.norm.y = y;

284 st.curv.norm.z = z;

285 }

286

287 void mgl_texcoord2f(float x, float y)

288 {

289 st.curv.tc.x = x;

290 st.curv.tc.y = y;

291 }

292

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

294 {

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

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

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

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

299 }

300

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

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

303 {

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

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

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

307 }

308

309 static void vertex_proc(struct vertex *vert)

310 {

311 vec4_t pview, pclip;

312

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

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

315

316 /* modelview transformation */

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

318

319 if(st.flags & MGL_LIGHTING) {

320 if((st.flags & MGL_SMOOTH) || st.vidx == 0) {

321 int i;

322 vec3_t norm;

323 float irrad = 0.0f;

324

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

326

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

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

329 float ndotl;

330 vec3_t ldir;

331

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

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

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

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

336 } else {

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

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

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

340

341 NORMALIZE(ldir);

342 }

343

344 ndotl = DOT(norm, ldir);

345 if(ndotl < 0.0) {

346 ndotl = 0.0;

347 }

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

349 }

350 }

351 vert->energy = irrad;

352 } else {

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

354 }

355 }

356

357 transform(&pclip, &pview, pmat);

358 /* TODO clipping in homogenous clip space */

359

360 if(pclip.w < 1e-6 && pclip.w > -1e-6) {

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

362 return;

363 }

364

365 /* perspective division */

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

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

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

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

370

371 /* viewport transformation */

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

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

374 }

375

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

377 {

378 st.vp[0] = x;

379 st.vp[1] = y;

380 st.vp[2] = width;

381 st.vp[3] = height;

382 }

383

384 void mgl_matrix_mode(int mmode)

385 {

386 st.mmode = mmode;

387 }

388

389 void mgl_push_matrix(void)

390 {

391 float *topmat;

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

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

394 abort();

395 }

396

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

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

399 st.mmode++;

400 }

401

402 void mgl_pop_matrix(void)

403 {

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

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

406 abort();

407 }

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

409 }

410

411 void mgl_load_matrix(float *mat)

412 {

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

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

415 }

416

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

418 void mgl_mult_matrix(float *m2)

419 {

420 int i, j;

421 float m1[16];

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

423

424 memcpy(m1, dest, sizeof m1);

425

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

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

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

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

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

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

432 }

433 }

434 }

435

436 void mgl_load_identity(void)

437 {

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

439 mgl_load_matrix((float*)id);

440 }

441

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

443 {

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

445 xform[12] = x;

446 xform[13] = y;

447 xform[14] = z;

448 mgl_mult_matrix(xform);

449 }

450

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

452 {

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

454

455 float angle = M_PI * deg / 180.0f;

456 float sina = sin(angle);

457 float cosa = cos(angle);

458 float one_minus_cosa = 1.0f - cosa;

459 float nxsq = x * x;

460 float nysq = y * y;

461 float nzsq = z * z;

462

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

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

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

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

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

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

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

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

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

472

473 mgl_mult_matrix(xform);

474 }

475

476 void mgl_scale(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 xform[0] = x;

480 xform[5] = y;

481 xform[10] = z;

482 mgl_mult_matrix(xform);

483 }

484

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

486 {

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

488

489 float dx = right - left;

490 float dy = top - bottom;

491 float dz = fr - nr;

492

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

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

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

496

497 float sx = 2.0 / dx;

498 float sy = 2.0 / dy;

499 float sz = -2.0 / dz;

500

501 xform[0] = sx;

502 xform[5] = sy;

503 xform[10] = sz;

504 xform[12] = tx;

505 xform[13] = ty;

506 xform[14] = tz;

507

508 mgl_mult_matrix(xform);

509 }

510

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

512 {

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

514

515 float dx = right - left;

516 float dy = top - bottom;

517 float dz = fr - nr;

518

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

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

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

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

523

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

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

526 xform[8] = a;

527 xform[9] = b;

528 xform[10] = c;

529 xform[11] = -1.0f;

530 xform[14] = d;

531

532 mgl_mult_matrix(xform);

533 }

534

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

536 {

537 float vfov_rad = M_PI * vfov / 180.0;

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

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

540 }

541

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

543 {

544 st.tex.width = width;

545 st.tex.height = height;

546 st.tex.pixels = pixels;

547

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

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

550 st.tex.pixels = 0;

551 }

552 }

553

554 #define MAX_SHIFT 12

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

556 {

557 int i;

558

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

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

561 *shiftp = i;

562 *maskp = ~(0xffff << i);

563 return 0;

564 }

565 }

566 return -1;

567 }