dos3d: 4a0e9ab12ad0 src/mingl.c

dos3d

view src/mingl.c @ 15:4a0e9ab12ad0

separated vec2/vec3/vec4 in a different header file

author	John Tsiombikas <nuclear@member.fsf.org>
date	Tue, 29 Nov 2011 07:23:12 +0200
parents	0909996838ff
children	1e9f0b3616fa

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 NORMALIZE(st.lpos[ltidx]);

200 } else {

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

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

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

204 }

205 }

206

207 void mgl_begin(int prim)

208 {

209 st.prim = prim;

210 st.vidx = 0;

211

212 st.ord = st.frontface;

213 if(st.cullface == MGL_FRONT) {

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

215 }

216

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

218 mgl_rast_prepare();

219 }

220

221 void mgl_end(void)

222 {

223 }

224

225 void mgl_vertex2f(float x, float y)

226 {

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

228 }

229

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

231 {

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

233 }

234

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

236 {

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

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

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

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

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

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

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

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

245

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

247

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

249 switch(st.prim) {

250 case MGL_POINTS:

251 mgl_draw_point(st.v);

252 break;

253 case MGL_LINES:

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

255 break;

256 case MGL_TRIANGLES:

257 case MGL_QUADS:

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

259 break;

260 default:

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

262 abort();

263 }

264 st.vidx = 0;

265 }

266 }

267

268 void mgl_color1f(float energy)

269 {

270 st.curv.energy = energy;

271 }

272

273 void mgl_index(int c)

274 {

275 st.curv.cidx = c;

276 }

277

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

279 {

280 st.curv.norm.x = x;

281 st.curv.norm.y = y;

282 st.curv.norm.z = z;

283 }

284

285 void mgl_texcoord2f(float x, float y)

286 {

287 st.curv.tc.x = x;

288 st.curv.tc.y = y;

289 }

290

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

292 {

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

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

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

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

297 }

298

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

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

301 {

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

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

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

305 }

306

307 static void vertex_proc(struct vertex *vert)

308 {

309 vec4_t pview, pclip;

310

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

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

313

314 /* modelview transformation */

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

316

317 if(st.flags & MGL_LIGHTING) {

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

319 int i;

320 vec3_t norm;

321 float irrad = 0.0f;

322

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

324

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

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

327 float ndotl;

328 vec3_t ldir;

329

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

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

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

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

334 } else {

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

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

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

338

339 NORMALIZE(ldir);

340 }

341

342 ndotl = DOT(norm, ldir);

343 if(ndotl < 0.0) {

344 ndotl = 0.0;

345 }

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

347 }

348 }

349 vert->energy = irrad;

350 } else {

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

352 }

353 }

354

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

356 /* TODO clipping in homogenous clip space */

357

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

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

360 return;

361 }

362

363 /* perspective division */

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

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

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

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

368

369 /* viewport transformation */

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

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

372 }

373

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

375 {

376 st.vp[0] = x;

377 st.vp[1] = y;

378 st.vp[2] = width;

379 st.vp[3] = height;

380 }

381

382 void mgl_matrix_mode(int mmode)

383 {

384 st.mmode = mmode;

385 }

386

387 void mgl_push_matrix(void)

388 {

389 float *topmat;

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

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

392 abort();

393 }

394

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

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

397 st.mmode++;

398 }

399

400 void mgl_pop_matrix(void)

401 {

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

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

404 abort();

405 }

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

407 }

408

409 void mgl_load_matrix(float *mat)

410 {

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

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

413 }

414

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

416 void mgl_mult_matrix(float *m2)

417 {

418 int i, j;

419 float m1[16];

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

421

422 memcpy(m1, dest, sizeof m1);

423

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

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

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

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

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

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

430 }

431 }

432 }

433

434 void mgl_load_identity(void)

435 {

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

437 mgl_load_matrix((float*)id);

438 }

439

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

441 {

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

443 xform[12] = x;

444 xform[13] = y;

445 xform[14] = z;

446 mgl_mult_matrix(xform);

447 }

448

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

450 {

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

452

453 float angle = M_PI * deg / 180.0f;

454 float sina = sin(angle);

455 float cosa = cos(angle);

456 float one_minus_cosa = 1.0f - cosa;

457 float nxsq = x * x;

458 float nysq = y * y;

459 float nzsq = z * z;

460

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

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

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

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

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

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

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

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

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

470

471 mgl_mult_matrix(xform);

472 }

473

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

475 {

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

477 xform[0] = x;

478 xform[5] = y;

479 xform[10] = z;

480 mgl_mult_matrix(xform);

481 }

482

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

484 {

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

486

487 float dx = right - left;

488 float dy = top - bottom;

489 float dz = fr - nr;

490

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

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

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

494

495 float sx = 2.0 / dx;

496 float sy = 2.0 / dy;

497 float sz = -2.0 / dz;

498

499 xform[0] = sx;

500 xform[5] = sy;

501 xform[10] = sz;

502 xform[12] = tx;

503 xform[13] = ty;

504 xform[14] = tz;

505

506 mgl_mult_matrix(xform);

507 }

508

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

510 {

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

512

513 float dx = right - left;

514 float dy = top - bottom;

515 float dz = fr - nr;

516

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

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

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

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

521

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

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

524 xform[8] = a;

525 xform[9] = b;

526 xform[10] = c;

527 xform[11] = -1.0f;

528 xform[14] = d;

529

530 mgl_mult_matrix(xform);

531 }

532

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

534 {

535 float vfov_rad = M_PI * vfov / 180.0;

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

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

538 }

539

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

541 {

542 st.tex.width = width;

543 st.tex.height = height;

544 st.tex.pixels = pixels;

545

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

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

548 st.tex.pixels = 0;

549 }

550 }

551

552 #define MAX_SHIFT 12

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

554 {

555 int i;

556

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

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

559 *shiftp = i;

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

561 return 0;

562 }

563 }

564 return -1;

565 }