deepstone: f04884489bad src/mingl.c

deepstone

view src/mingl.c @ 0:f04884489bad

dos3d initial import

author	John Tsiombikas <nuclear@member.fsf.org>
date	Mon, 21 Nov 2011 06:14:01 +0200
parents
children	0e781cc43178

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"

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

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

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

30 static void vertex_proc(struct vertex *vert);

32 static struct state st;

33 static struct framebuffer fb;

35 int mgl_init(int width, int height)

36 {

37 int i;

39 st.flags = 0;

40 st.mmode = 0;

42 mgl_front_face(MGL_CCW);

43 mgl_cull_face(MGL_BACK);

45 st.curv.cidx = 0;

46 st.curv.energy = 1.0;

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

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

50 return -1;

51 }

52 fb.width = width;

53 fb.height = height;

54 fb.zbuf = 0;

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

57 free(fb.pixels);

58 return -1;

59 }

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

63 mgl_matrix_mode(MGL_MODELVIEW);

64 mgl_load_identity();

65 mgl_matrix_mode(MGL_PROJECTION);

66 mgl_load_identity();

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

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

70 st.vp[2] = width;

71 st.vp[3] = height;

73 st.col_range = 256;

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

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

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

77 st.lint[i] = 0.0f;

78 }

80 return 0;

81 }

83 void mgl_free(void)

84 {

85 mgl_rast_cleanup();

86 free(fb.pixels);

87 }

89 unsigned char *mgl_framebuffer(void)

90 {

91 return fb.pixels;

92 }

94 void mgl_clear(int cidx)

95 {

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

97 }

99 void mgl_enable(unsigned int bit)

100 {

101 st.flags |= bit;

102 }

103

104 void mgl_disable(unsigned int bit)

105 {

106 st.flags &= ~bit;

107 }

108

109 void mgl_front_face(int ff)

110 {

111 st.frontface = ff;

112 }

113

114 void mgl_cull_face(int cf)

115 {

116 st.cullface = cf;

117 }

118

119 void mgl_color_range(int rng)

120 {

121 st.col_range = rng;

122 }

123

124 void mgl_light_intensity(int ltidx, float intens)

125 {

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

127 st.lint[ltidx] = intens;

128 }

129

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

131 {

132 vec3_t dir;

133 float mag;

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

135

136 dir.x = x;

137 dir.y = y;

138 dir.z = z;

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

140

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

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

143 mag = 1.0f;

144 }

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

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

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

148 }

149

150 void mgl_begin(int prim)

151 {

152 st.prim = prim;

153 st.vidx = 0;

154

155 st.ord = st.frontface;

156 if(st.cullface == MGL_FRONT) {

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

158 }

159

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

161 mgl_rast_prepare();

162 }

163

164 void mgl_end(void)

165 {

166 }

167

168 void mgl_vertex2f(float x, float y)

169 {

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

171 }

172

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

174 {

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

176 }

177

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

179 {

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

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

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

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

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

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

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

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

188

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

190

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

192 switch(st.prim) {

193 case MGL_POINTS:

194 mgl_draw_point(st.v);

195 break;

196 case MGL_LINES:

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

198 break;

199 case MGL_TRIANGLES:

200 case MGL_QUADS:

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

202 break;

203 default:

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

205 abort();

206 }

207 st.vidx = 0;

208 }

209 }

210

211 void mgl_color1f(float energy)

212 {

213 st.curv.energy = energy;

214 }

215

216 void mgl_index(int c)

217 {

218 st.curv.cidx = c;

219 }

220

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

222 {

223 st.curv.norm.x = x;

224 st.curv.norm.y = y;

225 st.curv.norm.z = z;

226 }

227

228 void mgl_texcoord2f(float x, float y)

229 {

230 st.curv.tc.x = x;

231 st.curv.tc.y = y;

232 }

233

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

235 {

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

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

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

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

240 }

241

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

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

244 {

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

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

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

248 }

249

250 static void vertex_proc(struct vertex *vert)

251 {

252 vec4_t pview, pclip;

253

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

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

256

257 /* modelview transformation */

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

259

260 if(st.flags & MGL_LIGHTING) {

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

262 int i;

263 vec3_t norm;

264 float irrad = 0.0f;

265

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

267

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

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

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

271 if(ndotl < 0.0) {

272 ndotl = 0.0;

273 }

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

275 }

276 }

277 vert->energy = irrad;

278 } else {

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

280 }

281 }

282

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

284 /* TODO clipping in homogenous clip space */

285

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

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

288 return;

289 }

290

291 /* perspective division */

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

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

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

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

296

297 /* viewport transformation */

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

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

300 }

301

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

303 {

304 st.vp[0] = x;

305 st.vp[1] = y;

306 st.vp[2] = width;

307 st.vp[3] = height;

308 }

309

310 void mgl_matrix_mode(int mmode)

311 {

312 st.mmode = mmode;

313 }

314

315 void mgl_push_matrix(void)

316 {

317 float *topmat;

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

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

320 abort();

321 }

322

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

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

325 st.mmode++;

326 }

327

328 void mgl_pop_matrix(void)

329 {

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

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

332 abort();

333 }

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

335 }

336

337 void mgl_load_matrix(float *mat)

338 {

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

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

341 }

342

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

344 void mgl_mult_matrix(float *m2)

345 {

346 int i, j;

347 float m1[16];

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

349

350 memcpy(m1, dest, sizeof m1);

351

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

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

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

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

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

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

358 }

359 }

360 }

361

362 void mgl_load_identity(void)

363 {

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

365 mgl_load_matrix((float*)id);

366 }

367

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

369 {

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

371 xform[12] = x;

372 xform[13] = y;

373 xform[14] = z;

374 mgl_mult_matrix(xform);

375 }

376

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

378 {

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

380

381 float angle = M_PI * deg / 180.0f;

382 float sina = sin(angle);

383 float cosa = cos(angle);

384 float one_minus_cosa = 1.0f - cosa;

385 float nxsq = x * x;

386 float nysq = y * y;

387 float nzsq = z * z;

388

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

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

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

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

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

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

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

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

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

398

399 mgl_mult_matrix(xform);

400 }

401

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

403 {

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

405 xform[0] = x;

406 xform[5] = y;

407 xform[10] = z;

408 mgl_mult_matrix(xform);

409 }

410

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

412 {

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

414

415 float dx = right - left;

416 float dy = top - bottom;

417 float dz = fr - nr;

418

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

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

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

422

423 float sx = 2.0 / dx;

424 float sy = 2.0 / dy;

425 float sz = -2.0 / dz;

426

427 xform[0] = sx;

428 xform[5] = sy;

429 xform[10] = sz;

430 xform[12] = tx;

431 xform[13] = ty;

432 xform[14] = tz;

433

434 mgl_mult_matrix(xform);

435 }

436

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

438 {

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

440

441 float dx = right - left;

442 float dy = top - bottom;

443 float dz = fr - nr;

444

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

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

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

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

449

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

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

452 xform[8] = a;

453 xform[9] = b;

454 xform[10] = c;

455 xform[11] = -1.0f;

456 xform[14] = d;

457

458 mgl_mult_matrix(xform);

459 }

460

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

462 {

463 float vfov_rad = M_PI * vfov / 180.0;

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

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

466 }