dos3d: 3239511d1a76 src/mingl.c

dos3d

view src/mingl.c @ 7:3239511d1a76

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author	John Tsiombikas <nuclear@member.fsf.org>
date	Mon, 21 Nov 2011 12:12:23 +0200
parents	f04884489bad
children	bce78aaafc68

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 mgl_rast_cleanup();

88 free(fb.pixels);

89 }

91 unsigned char *mgl_framebuffer(void)

92 {

93 return fb.pixels;

94 }

96 void mgl_clear(int cidx)

97 {

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

99 }

100

101 void mgl_enable(unsigned int bit)

102 {

103 st.flags |= bit;

104 }

105

106 void mgl_disable(unsigned int bit)

107 {

108 st.flags &= ~bit;

109 }

110

111 int mgl_isenabled(unsigned int bit)

112 {

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

114 }

115

116 void mgl_front_face(int ff)

117 {

118 st.frontface = ff;

119 }

120

121 void mgl_cull_face(int cf)

122 {

123 st.cullface = cf;

124 }

125

126 void mgl_color_range(int rng)

127 {

128 st.col_range = rng;

129 }

130

131 void mgl_light_intensity(int ltidx, float intens)

132 {

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

134 st.lint[ltidx] = intens;

135 }

136

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

138 {

139 vec3_t dir;

140 float mag;

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

142

143 dir.x = x;

144 dir.y = y;

145 dir.z = z;

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

147

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

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

150 mag = 1.0f;

151 }

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

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

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

155 }

156

157 void mgl_begin(int prim)

158 {

159 st.prim = prim;

160 st.vidx = 0;

161

162 st.ord = st.frontface;

163 if(st.cullface == MGL_FRONT) {

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

165 }

166

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

168 mgl_rast_prepare();

169 }

170

171 void mgl_end(void)

172 {

173 }

174

175 void mgl_vertex2f(float x, float y)

176 {

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

178 }

179

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

181 {

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

183 }

184

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

186 {

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

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

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

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

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

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

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

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

195

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

197

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

199 switch(st.prim) {

200 case MGL_POINTS:

201 mgl_draw_point(st.v);

202 break;

203 case MGL_LINES:

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

205 break;

206 case MGL_TRIANGLES:

207 case MGL_QUADS:

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

209 break;

210 default:

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

212 abort();

213 }

214 st.vidx = 0;

215 }

216 }

217

218 void mgl_color1f(float energy)

219 {

220 st.curv.energy = energy;

221 }

222

223 void mgl_index(int c)

224 {

225 st.curv.cidx = c;

226 }

227

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

229 {

230 st.curv.norm.x = x;

231 st.curv.norm.y = y;

232 st.curv.norm.z = z;

233 }

234

235 void mgl_texcoord2f(float x, float y)

236 {

237 st.curv.tc.x = x;

238 st.curv.tc.y = y;

239 }

240

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

242 {

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

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

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

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

247 }

248

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

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

251 {

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

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

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

255 }

256

257 static void vertex_proc(struct vertex *vert)

258 {

259 vec4_t pview, pclip;

260

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

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

263

264 /* modelview transformation */

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

266

267 if(st.flags & MGL_LIGHTING) {

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

269 int i;

270 vec3_t norm;

271 float irrad = 0.0f;

272

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

274

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

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

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

278 if(ndotl < 0.0) {

279 ndotl = 0.0;

280 }

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

282 }

283 }

284 vert->energy = irrad;

285 } else {

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

287 }

288 }

289

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

291 /* TODO clipping in homogenous clip space */

292

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

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

295 return;

296 }

297

298 /* perspective division */

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

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

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

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

303

304 /* viewport transformation */

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

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

307 }

308

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

310 {

311 st.vp[0] = x;

312 st.vp[1] = y;

313 st.vp[2] = width;

314 st.vp[3] = height;

315 }

316

317 void mgl_matrix_mode(int mmode)

318 {

319 st.mmode = mmode;

320 }

321

322 void mgl_push_matrix(void)

323 {

324 float *topmat;

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

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

327 abort();

328 }

329

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

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

332 st.mmode++;

333 }

334

335 void mgl_pop_matrix(void)

336 {

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

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

339 abort();

340 }

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

342 }

343

344 void mgl_load_matrix(float *mat)

345 {

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

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

348 }

349

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

351 void mgl_mult_matrix(float *m2)

352 {

353 int i, j;

354 float m1[16];

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

356

357 memcpy(m1, dest, sizeof m1);

358

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

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

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

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

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

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

365 }

366 }

367 }

368

369 void mgl_load_identity(void)

370 {

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

372 mgl_load_matrix((float*)id);

373 }

374

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

376 {

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

378 xform[12] = x;

379 xform[13] = y;

380 xform[14] = z;

381 mgl_mult_matrix(xform);

382 }

383

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

385 {

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

387

388 float angle = M_PI * deg / 180.0f;

389 float sina = sin(angle);

390 float cosa = cos(angle);

391 float one_minus_cosa = 1.0f - cosa;

392 float nxsq = x * x;

393 float nysq = y * y;

394 float nzsq = z * z;

395

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

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

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

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

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

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

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

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

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

405

406 mgl_mult_matrix(xform);

407 }

408

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

410 {

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

412 xform[0] = x;

413 xform[5] = y;

414 xform[10] = z;

415 mgl_mult_matrix(xform);

416 }

417

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

419 {

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

421

422 float dx = right - left;

423 float dy = top - bottom;

424 float dz = fr - nr;

425

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

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

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

429

430 float sx = 2.0 / dx;

431 float sy = 2.0 / dy;

432 float sz = -2.0 / dz;

433

434 xform[0] = sx;

435 xform[5] = sy;

436 xform[10] = sz;

437 xform[12] = tx;

438 xform[13] = ty;

439 xform[14] = tz;

440

441 mgl_mult_matrix(xform);

442 }

443

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

445 {

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

447

448 float dx = right - left;

449 float dy = top - bottom;

450 float dz = fr - nr;

451

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

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

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

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

456

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

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

459 xform[8] = a;

460 xform[9] = b;

461 xform[10] = c;

462 xform[11] = -1.0f;

463 xform[14] = d;

464

465 mgl_mult_matrix(xform);

466 }

467

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

469 {

470 float vfov_rad = M_PI * vfov / 180.0;

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

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

473 }

474

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

476 {

477 st.tex.width = width;

478 st.tex.height = height;

479 st.tex.pixels = pixels;

480

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

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

483 st.tex.pixels = 0;

484 }

485 }

486

487 #define MAX_SHIFT 12

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

489 {

490 int i;

491

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

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

494 *shiftp = i;

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

496 return 0;

497 }

498 }

499 return -1;

500 }