dos3d: bce78aaafc68 src/mingl.c

dos3d

view src/mingl.c @ 9:bce78aaafc68

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author	John Tsiombikas <nuclear@member.fsf.org>
date	Sat, 26 Nov 2011 03:59:48 +0200
parents	0e781cc43178
children	0909996838ff

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

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

31 static void vertex_proc(struct vertex *vert);

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

34 static struct state st;

35 static struct framebuffer fb;

37 int mgl_init(int width, int height)

38 {

39 int i;

41 st.flags = 0;

42 st.mmode = 0;

44 mgl_front_face(MGL_CCW);

45 mgl_cull_face(MGL_BACK);

47 st.curv.cidx = 0;

48 st.curv.energy = 1.0;

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

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

52 return -1;

53 }

54 fb.width = width;

55 fb.height = height;

56 fb.zbuf = 0;

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

59 free(fb.pixels);

60 return -1;

61 }

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

65 mgl_matrix_mode(MGL_MODELVIEW);

66 mgl_load_identity();

67 mgl_matrix_mode(MGL_PROJECTION);

68 mgl_load_identity();

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

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

72 st.vp[2] = width;

73 st.vp[3] = height;

75 st.col_range = 256;

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

77 st.ldir[i].x = st.ldir[i].y = 0.0f;

78 st.ldir[i].z = 1.0f;

79 st.lint[i] = 0.0f;

80 }

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 bit)

141 {

142 st.flags |= bit;

143 }

144

145 void mgl_disable(unsigned int bit)

146 {

147 st.flags &= ~bit;

148 }

149

150 int mgl_isenabled(unsigned int bit)

151 {

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

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_color_range(int rng)

166 {

167 st.col_range = rng;

168 }

169

170 void mgl_light_intensity(int ltidx, float intens)

171 {

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

173 st.lint[ltidx] = intens;

174 }

175

176 void mgl_light_direction(int ltidx, float x, float y, float z)

177 {

178 vec3_t dir;

179 float mag;

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

181

182 dir.x = x;

183 dir.y = y;

184 dir.z = z;

185 transform3(&st.ldir[ltidx], &dir, st.matrix[MGL_MODELVIEW][st.mtop[MGL_MODELVIEW]]);

186

187 mag = sqrt(DOT(st.ldir[ltidx], st.ldir[ltidx]));

188 if(fabs(mag) < 1e-6) {

189 mag = 1.0f;

190 }

191 st.ldir[ltidx].x /= mag;

192 st.ldir[ltidx].y /= mag;

193 st.ldir[ltidx].z /= mag;

194 }

195

196 void mgl_begin(int prim)

197 {

198 st.prim = prim;

199 st.vidx = 0;

200

201 st.ord = st.frontface;

202 if(st.cullface == MGL_FRONT) {

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

204 }

205

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

207 mgl_rast_prepare();

208 }

209

210 void mgl_end(void)

211 {

212 }

213

214 void mgl_vertex2f(float x, float y)

215 {

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

217 }

218

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

220 {

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

222 }

223

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

225 {

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

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

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

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

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

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

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

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

234

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

236

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

238 switch(st.prim) {

239 case MGL_POINTS:

240 mgl_draw_point(st.v);

241 break;

242 case MGL_LINES:

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

244 break;

245 case MGL_TRIANGLES:

246 case MGL_QUADS:

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

248 break;

249 default:

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

251 abort();

252 }

253 st.vidx = 0;

254 }

255 }

256

257 void mgl_color1f(float energy)

258 {

259 st.curv.energy = energy;

260 }

261

262 void mgl_index(int c)

263 {

264 st.curv.cidx = c;

265 }

266

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

268 {

269 st.curv.norm.x = x;

270 st.curv.norm.y = y;

271 st.curv.norm.z = z;

272 }

273

274 void mgl_texcoord2f(float x, float y)

275 {

276 st.curv.tc.x = x;

277 st.curv.tc.y = y;

278 }

279

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

281 {

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

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

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

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

286 }

287

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

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

290 {

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

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

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

294 }

295

296 static void vertex_proc(struct vertex *vert)

297 {

298 vec4_t pview, pclip;

299

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

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

302

303 /* modelview transformation */

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

305

306 if(st.flags & MGL_LIGHTING) {

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

308 int i;

309 vec3_t norm;

310 float irrad = 0.0f;

311

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

313

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

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

316 float ndotl = DOT(norm, st.ldir[i]);

317 if(ndotl < 0.0) {

318 ndotl = 0.0;

319 }

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

321 }

322 }

323 vert->energy = irrad;

324 } else {

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

326 }

327 }

328

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

330 /* TODO clipping in homogenous clip space */

331

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

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

334 return;

335 }

336

337 /* perspective division */

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

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

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

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

342

343 /* viewport transformation */

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

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

346 }

347

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

349 {

350 st.vp[0] = x;

351 st.vp[1] = y;

352 st.vp[2] = width;

353 st.vp[3] = height;

354 }

355

356 void mgl_matrix_mode(int mmode)

357 {

358 st.mmode = mmode;

359 }

360

361 void mgl_push_matrix(void)

362 {

363 float *topmat;

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

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

366 abort();

367 }

368

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

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

371 st.mmode++;

372 }

373

374 void mgl_pop_matrix(void)

375 {

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

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

378 abort();

379 }

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

381 }

382

383 void mgl_load_matrix(float *mat)

384 {

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

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

387 }

388

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

390 void mgl_mult_matrix(float *m2)

391 {

392 int i, j;

393 float m1[16];

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

395

396 memcpy(m1, dest, sizeof m1);

397

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

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

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

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

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

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

404 }

405 }

406 }

407

408 void mgl_load_identity(void)

409 {

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

411 mgl_load_matrix((float*)id);

412 }

413

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

415 {

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

417 xform[12] = x;

418 xform[13] = y;

419 xform[14] = z;

420 mgl_mult_matrix(xform);

421 }

422

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

424 {

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

426

427 float angle = M_PI * deg / 180.0f;

428 float sina = sin(angle);

429 float cosa = cos(angle);

430 float one_minus_cosa = 1.0f - cosa;

431 float nxsq = x * x;

432 float nysq = y * y;

433 float nzsq = z * z;

434

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

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

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

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

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

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

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

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

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

444

445 mgl_mult_matrix(xform);

446 }

447

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

449 {

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

451 xform[0] = x;

452 xform[5] = y;

453 xform[10] = z;

454 mgl_mult_matrix(xform);

455 }

456

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

458 {

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

460

461 float dx = right - left;

462 float dy = top - bottom;

463 float dz = fr - nr;

464

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

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

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

468

469 float sx = 2.0 / dx;

470 float sy = 2.0 / dy;

471 float sz = -2.0 / dz;

472

473 xform[0] = sx;

474 xform[5] = sy;

475 xform[10] = sz;

476 xform[12] = tx;

477 xform[13] = ty;

478 xform[14] = tz;

479

480 mgl_mult_matrix(xform);

481 }

482

483 void mgl_frustum(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 a = (right + left) / dx;

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

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

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

495

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

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

498 xform[8] = a;

499 xform[9] = b;

500 xform[10] = c;

501 xform[11] = -1.0f;

502 xform[14] = d;

503

504 mgl_mult_matrix(xform);

505 }

506

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

508 {

509 float vfov_rad = M_PI * vfov / 180.0;

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

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

512 }

513

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

515 {

516 st.tex.width = width;

517 st.tex.height = height;

518 st.tex.pixels = pixels;

519

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

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

522 st.tex.pixels = 0;

523 }

524 }

525

526 #define MAX_SHIFT 12

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

528 {

529 int i;

530

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

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

533 *shiftp = i;

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

535 return 0;

536 }

537 }

538 return -1;

539 }