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annotate 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
rev   line source
nuclear@0 1 /*
nuclear@0 2 256-color 3D graphics hack for real-mode DOS.
nuclear@0 3 Copyright (C) 2011 John Tsiombikas <nuclear@member.fsf.org>
nuclear@0 4
nuclear@0 5 This program is free software: you can redistribute it and/or modify
nuclear@0 6 it under the terms of the GNU General Public License as published by
nuclear@0 7 the Free Software Foundation, either version 3 of the License, or
nuclear@0 8 (at your option) any later version.
nuclear@0 9
nuclear@0 10 This program is distributed in the hope that it will be useful,
nuclear@0 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@0 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@0 13 GNU General Public License for more details.
nuclear@0 14
nuclear@0 15 You should have received a copy of the GNU General Public License
nuclear@0 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
nuclear@0 17 */
nuclear@0 18 #include <stdio.h>
nuclear@0 19 #include <stdlib.h>
nuclear@0 20 #include <string.h>
nuclear@0 21 #include <math.h>
nuclear@0 22 #include <assert.h>
nuclear@0 23 #include "mingl.h"
nuclear@0 24 #include "mglimpl.h"
nuclear@0 25
nuclear@3 26
nuclear@0 27 #define DOT(a, b) ((a).x * (b).x + (a).y * (b).y + (a).z * (b).z)
nuclear@0 28
nuclear@0 29 static void transform(vec4_t *res, vec4_t *v, float *mat);
nuclear@0 30 static void transform3(vec3_t *res, vec3_t *v, float *mat);
nuclear@0 31 static void vertex_proc(struct vertex *vert);
nuclear@3 32 static int calc_shiftmask(int val, int *shiftp, unsigned int *maskp);
nuclear@0 33
nuclear@0 34 static struct state st;
nuclear@0 35 static struct framebuffer fb;
nuclear@0 36
nuclear@0 37 int mgl_init(int width, int height)
nuclear@0 38 {
nuclear@0 39 int i;
nuclear@0 40
nuclear@0 41 st.flags = 0;
nuclear@0 42 st.mmode = 0;
nuclear@0 43
nuclear@0 44 mgl_front_face(MGL_CCW);
nuclear@0 45 mgl_cull_face(MGL_BACK);
nuclear@0 46
nuclear@0 47 st.curv.cidx = 0;
nuclear@0 48 st.curv.energy = 1.0;
nuclear@0 49 st.curv.norm.x = st.curv.norm.y = st.curv.norm.z = 0.0;
nuclear@0 50
nuclear@0 51 if(!(fb.pixels = malloc(width * height))) {
nuclear@0 52 return -1;
nuclear@0 53 }
nuclear@0 54 fb.width = width;
nuclear@0 55 fb.height = height;
nuclear@0 56 fb.zbuf = 0;
nuclear@0 57
nuclear@0 58 if(mgl_rast_init(&st, &fb) == -1) {
nuclear@0 59 free(fb.pixels);
nuclear@0 60 return -1;
nuclear@0 61 }
nuclear@0 62
nuclear@0 63 st.mtop[0] = st.mtop[1] = 0;
nuclear@0 64
nuclear@0 65 mgl_matrix_mode(MGL_MODELVIEW);
nuclear@0 66 mgl_load_identity();
nuclear@0 67 mgl_matrix_mode(MGL_PROJECTION);
nuclear@0 68 mgl_load_identity();
nuclear@0 69
nuclear@0 70 /* initial viewport in the size of the framebuffer */
nuclear@0 71 st.vp[0] = st.vp[1] = 0;
nuclear@0 72 st.vp[2] = width;
nuclear@0 73 st.vp[3] = height;
nuclear@0 74
nuclear@0 75 st.col_range = 256;
nuclear@0 76 for(i=0; i<MAX_LIGHTS; i++) {
nuclear@0 77 st.ldir[i].x = st.ldir[i].y = 0.0f;
nuclear@0 78 st.ldir[i].z = 1.0f;
nuclear@0 79 st.lint[i] = 0.0f;
nuclear@0 80 }
nuclear@0 81
nuclear@0 82 return 0;
nuclear@0 83 }
nuclear@0 84
nuclear@0 85 void mgl_free(void)
nuclear@0 86 {
nuclear@9 87 int i;
nuclear@9 88
nuclear@0 89 mgl_rast_cleanup();
nuclear@0 90 free(fb.pixels);
nuclear@9 91 fb.pixels = 0;
nuclear@9 92
nuclear@9 93 if(fb.zbuf) {
nuclear@9 94 for(i=0; i<fb.num_ztiles; i++) {
nuclear@9 95 free(fb.zbuf[i]);
nuclear@9 96 }
nuclear@9 97 free(fb.zbuf);
nuclear@9 98 fb.zbuf = 0;
nuclear@9 99 }
nuclear@0 100 }
nuclear@0 101
nuclear@0 102 unsigned char *mgl_framebuffer(void)
nuclear@0 103 {
nuclear@0 104 return fb.pixels;
nuclear@0 105 }
nuclear@0 106
nuclear@0 107 void mgl_clear(int cidx)
nuclear@0 108 {
nuclear@0 109 memset(fb.pixels, cidx, fb.width * fb.height);
nuclear@0 110 }
nuclear@0 111
nuclear@9 112 void mgl_clear_depth(void)
nuclear@9 113 {
nuclear@9 114 int i;
nuclear@9 115
nuclear@9 116 if(!fb.zbuf) {
nuclear@9 117 long num_pixels = (long)fb.width * (long)fb.height;
nuclear@9 118 fb.num_ztiles = (num_pixels + ZTILE_SIZE - 1) / ZTILE_SIZE;
nuclear@9 119
nuclear@9 120 if(!(fb.zbuf = malloc(fb.num_ztiles * sizeof *fb.zbuf))) {
nuclear@9 121 fprintf(stderr, "failed to allocate ztile array\n");
nuclear@9 122 abort();
nuclear@9 123 }
nuclear@9 124
nuclear@9 125 for(i=0; i<fb.num_ztiles; i++) {
nuclear@9 126 if(!(fb.zbuf[i] = malloc(ZTILE_SIZE * 2))) {
nuclear@9 127 fprintf(stderr, "failed to allocate ztile %d\n", i);
nuclear@9 128 abort();
nuclear@9 129 }
nuclear@9 130 memset(fb.zbuf[i], 0xff, ZTILE_SIZE * 2);
nuclear@9 131 }
nuclear@9 132 return;
nuclear@9 133 }
nuclear@9 134
nuclear@9 135 for(i=0; i<fb.num_ztiles; i++) {
nuclear@9 136 memset(fb.zbuf[i], 0xff, ZTILE_SIZE * 2);
nuclear@9 137 }
nuclear@9 138 }
nuclear@9 139
nuclear@0 140 void mgl_enable(unsigned int bit)
nuclear@0 141 {
nuclear@0 142 st.flags |= bit;
nuclear@0 143 }
nuclear@0 144
nuclear@0 145 void mgl_disable(unsigned int bit)
nuclear@0 146 {
nuclear@0 147 st.flags &= ~bit;
nuclear@0 148 }
nuclear@0 149
nuclear@3 150 int mgl_isenabled(unsigned int bit)
nuclear@3 151 {
nuclear@3 152 return (st.flags & bit) != 0;
nuclear@3 153 }
nuclear@3 154
nuclear@0 155 void mgl_front_face(int ff)
nuclear@0 156 {
nuclear@0 157 st.frontface = ff;
nuclear@0 158 }
nuclear@0 159
nuclear@0 160 void mgl_cull_face(int cf)
nuclear@0 161 {
nuclear@0 162 st.cullface = cf;
nuclear@0 163 }
nuclear@0 164
nuclear@0 165 void mgl_color_range(int rng)
nuclear@0 166 {
nuclear@0 167 st.col_range = rng;
nuclear@0 168 }
nuclear@0 169
nuclear@0 170 void mgl_light_intensity(int ltidx, float intens)
nuclear@0 171 {
nuclear@0 172 assert(ltidx >= 0 && ltidx < MAX_LIGHTS);
nuclear@0 173 st.lint[ltidx] = intens;
nuclear@0 174 }
nuclear@0 175
nuclear@0 176 void mgl_light_direction(int ltidx, float x, float y, float z)
nuclear@0 177 {
nuclear@0 178 vec3_t dir;
nuclear@0 179 float mag;
nuclear@0 180 assert(ltidx >= 0 && ltidx < MAX_LIGHTS);
nuclear@0 181
nuclear@0 182 dir.x = x;
nuclear@0 183 dir.y = y;
nuclear@0 184 dir.z = z;
nuclear@0 185 transform3(&st.ldir[ltidx], &dir, st.matrix[MGL_MODELVIEW][st.mtop[MGL_MODELVIEW]]);
nuclear@0 186
nuclear@0 187 mag = sqrt(DOT(st.ldir[ltidx], st.ldir[ltidx]));
nuclear@0 188 if(fabs(mag) < 1e-6) {
nuclear@0 189 mag = 1.0f;
nuclear@0 190 }
nuclear@0 191 st.ldir[ltidx].x /= mag;
nuclear@0 192 st.ldir[ltidx].y /= mag;
nuclear@0 193 st.ldir[ltidx].z /= mag;
nuclear@0 194 }
nuclear@0 195
nuclear@0 196 void mgl_begin(int prim)
nuclear@0 197 {
nuclear@0 198 st.prim = prim;
nuclear@0 199 st.vidx = 0;
nuclear@0 200
nuclear@0 201 st.ord = st.frontface;
nuclear@0 202 if(st.cullface == MGL_FRONT) {
nuclear@0 203 st.ord = st.frontface == MGL_CCW ? MGL_CW : MGL_CCW;
nuclear@0 204 }
nuclear@0 205
nuclear@0 206 /* select the correct rasterizer according to state */
nuclear@0 207 mgl_rast_prepare();
nuclear@0 208 }
nuclear@0 209
nuclear@0 210 void mgl_end(void)
nuclear@0 211 {
nuclear@0 212 }
nuclear@0 213
nuclear@0 214 void mgl_vertex2f(float x, float y)
nuclear@0 215 {
nuclear@0 216 mgl_vertex4f(x, y, 0.0f, 1.0f);
nuclear@0 217 }
nuclear@0 218
nuclear@0 219 void mgl_vertex3f(float x, float y, float z)
nuclear@0 220 {
nuclear@0 221 mgl_vertex4f(x, y, z, 1.0f);
nuclear@0 222 }
nuclear@0 223
nuclear@0 224 void mgl_vertex4f(float x, float y, float z, float w)
nuclear@0 225 {
nuclear@0 226 st.v[st.vidx].pos.x = x;
nuclear@0 227 st.v[st.vidx].pos.y = y;
nuclear@0 228 st.v[st.vidx].pos.z = z;
nuclear@0 229 st.v[st.vidx].pos.w = w;
nuclear@0 230 st.v[st.vidx].cidx = st.curv.cidx;
nuclear@0 231 st.v[st.vidx].energy = st.curv.energy;
nuclear@0 232 st.v[st.vidx].norm = st.curv.norm;
nuclear@0 233 st.v[st.vidx].tc = st.curv.tc;
nuclear@0 234
nuclear@0 235 vertex_proc(st.v + st.vidx);
nuclear@0 236
nuclear@0 237 if(++st.vidx >= st.prim) {
nuclear@0 238 switch(st.prim) {
nuclear@0 239 case MGL_POINTS:
nuclear@0 240 mgl_draw_point(st.v);
nuclear@0 241 break;
nuclear@0 242 case MGL_LINES:
nuclear@0 243 mgl_draw_line(st.v, st.v + 1);
nuclear@0 244 break;
nuclear@0 245 case MGL_TRIANGLES:
nuclear@0 246 case MGL_QUADS:
nuclear@0 247 mgl_draw_poly(st.v, st.prim);
nuclear@0 248 break;
nuclear@0 249 default:
nuclear@0 250 fprintf(stderr, "invalid primitive: %d\n", st.prim);
nuclear@0 251 abort();
nuclear@0 252 }
nuclear@0 253 st.vidx = 0;
nuclear@0 254 }
nuclear@0 255 }
nuclear@0 256
nuclear@0 257 void mgl_color1f(float energy)
nuclear@0 258 {
nuclear@0 259 st.curv.energy = energy;
nuclear@0 260 }
nuclear@0 261
nuclear@0 262 void mgl_index(int c)
nuclear@0 263 {
nuclear@0 264 st.curv.cidx = c;
nuclear@0 265 }
nuclear@0 266
nuclear@0 267 void mgl_normal(float x, float y, float z)
nuclear@0 268 {
nuclear@0 269 st.curv.norm.x = x;
nuclear@0 270 st.curv.norm.y = y;
nuclear@0 271 st.curv.norm.z = z;
nuclear@0 272 }
nuclear@0 273
nuclear@0 274 void mgl_texcoord2f(float x, float y)
nuclear@0 275 {
nuclear@0 276 st.curv.tc.x = x;
nuclear@0 277 st.curv.tc.y = y;
nuclear@0 278 }
nuclear@0 279
nuclear@0 280 static void transform(vec4_t *res, vec4_t *v, float *mat)
nuclear@0 281 {
nuclear@0 282 res->x = mat[0] * v->x + mat[4] * v->y + mat[8] * v->z + mat[12] * v->w;
nuclear@0 283 res->y = mat[1] * v->x + mat[5] * v->y + mat[9] * v->z + mat[13] * v->w;
nuclear@0 284 res->z = mat[2] * v->x + mat[6] * v->y + mat[10] * v->z + mat[14] * v->w;
nuclear@0 285 res->w = mat[3] * v->x + mat[7] * v->y + mat[11] * v->z + mat[15] * v->w;
nuclear@0 286 }
nuclear@0 287
nuclear@0 288 /* the matrix is 4x4 (16 floats), just ignoring anything out of the 3x3 */
nuclear@0 289 static void transform3(vec3_t *res, vec3_t *v, float *mat)
nuclear@0 290 {
nuclear@0 291 res->x = mat[0] * v->x + mat[4] * v->y + mat[8] * v->z;
nuclear@0 292 res->y = mat[1] * v->x + mat[5] * v->y + mat[9] * v->z;
nuclear@0 293 res->z = mat[2] * v->x + mat[6] * v->y + mat[10] * v->z;
nuclear@0 294 }
nuclear@0 295
nuclear@0 296 static void vertex_proc(struct vertex *vert)
nuclear@0 297 {
nuclear@0 298 vec4_t pview, pclip;
nuclear@0 299
nuclear@0 300 float *mvmat = st.matrix[MGL_MODELVIEW][st.mtop[MGL_MODELVIEW]];
nuclear@0 301 float *pmat = st.matrix[MGL_PROJECTION][st.mtop[MGL_PROJECTION]];
nuclear@0 302
nuclear@0 303 /* modelview transformation */
nuclear@0 304 transform(&pview, &vert->pos, mvmat);
nuclear@0 305
nuclear@0 306 if(st.flags & MGL_LIGHTING) {
nuclear@0 307 if((st.flags & MGL_SMOOTH) || st.vidx == 0) {
nuclear@0 308 int i;
nuclear@0 309 vec3_t norm;
nuclear@0 310 float irrad = 0.0f;
nuclear@0 311
nuclear@0 312 transform3(&norm, &vert->norm, mvmat);
nuclear@0 313
nuclear@0 314 for(i=0; i<MAX_LIGHTS; i++) {
nuclear@0 315 if(st.lint[i] > 1e-6f) {
nuclear@0 316 float ndotl = DOT(norm, st.ldir[i]);
nuclear@0 317 if(ndotl < 0.0) {
nuclear@0 318 ndotl = 0.0;
nuclear@0 319 }
nuclear@0 320 irrad += ndotl * st.lint[i];
nuclear@0 321 }
nuclear@0 322 }
nuclear@0 323 vert->energy = irrad;
nuclear@0 324 } else {
nuclear@0 325 vert->energy = st.v[0].energy;
nuclear@0 326 }
nuclear@0 327 }
nuclear@0 328
nuclear@0 329 transform(&pclip, &pview, pmat);
nuclear@0 330 /* TODO clipping in homogenous clip space */
nuclear@0 331
nuclear@0 332 if(pclip.w < 1e-6 && pclip.w > -1e-6) {
nuclear@0 333 vert->pos.x = vert->pos.y = vert->pos.z = vert->pos.w = 0.0f;
nuclear@0 334 return;
nuclear@0 335 }
nuclear@0 336
nuclear@0 337 /* perspective division */
nuclear@0 338 vert->pos.x = pclip.x / pclip.w;
nuclear@0 339 vert->pos.y = pclip.y / pclip.w;
nuclear@0 340 vert->pos.z = pclip.z / pclip.w;
nuclear@0 341 vert->pos.w = pclip.w;
nuclear@0 342
nuclear@0 343 /* viewport transformation */
nuclear@0 344 vert->pos.x = st.vp[0] + st.vp[2] * (vert->pos.x * 0.5 + 0.5);
nuclear@0 345 vert->pos.y = st.vp[1] + st.vp[3] * (-vert->pos.y * 0.5 + 0.5);
nuclear@0 346 }
nuclear@0 347
nuclear@0 348 void mgl_viewport(int x, int y, int width, int height)
nuclear@0 349 {
nuclear@0 350 st.vp[0] = x;
nuclear@0 351 st.vp[1] = y;
nuclear@0 352 st.vp[2] = width;
nuclear@0 353 st.vp[3] = height;
nuclear@0 354 }
nuclear@0 355
nuclear@0 356 void mgl_matrix_mode(int mmode)
nuclear@0 357 {
nuclear@0 358 st.mmode = mmode;
nuclear@0 359 }
nuclear@0 360
nuclear@0 361 void mgl_push_matrix(void)
nuclear@0 362 {
nuclear@0 363 float *topmat;
nuclear@0 364 if(st.mtop[st.mmode] >= MATRIX_STACK_SIZE - 1) {
nuclear@0 365 fprintf(stderr, "mgl_push_matrix: stack overflow\n");
nuclear@0 366 abort();
nuclear@0 367 }
nuclear@0 368
nuclear@0 369 topmat = st.matrix[st.mmode][st.mtop[st.mmode]];
nuclear@0 370 memcpy(topmat + 16, topmat, 16 * sizeof *topmat);
nuclear@0 371 st.mmode++;
nuclear@0 372 }
nuclear@0 373
nuclear@0 374 void mgl_pop_matrix(void)
nuclear@0 375 {
nuclear@0 376 if(st.mtop[st.mmode] <= 0) {
nuclear@0 377 fprintf(stderr, "mgl_pop_matrix: stack underflow\n");
nuclear@0 378 abort();
nuclear@0 379 }
nuclear@0 380 st.mtop[st.mmode]--;
nuclear@0 381 }
nuclear@0 382
nuclear@0 383 void mgl_load_matrix(float *mat)
nuclear@0 384 {
nuclear@0 385 float *dest = st.matrix[st.mmode][st.mtop[st.mmode]];
nuclear@0 386 memcpy(dest, mat, 16 * sizeof *dest);
nuclear@0 387 }
nuclear@0 388
nuclear@0 389 #define M(i,j) (((j) << 2) + (i))
nuclear@0 390 void mgl_mult_matrix(float *m2)
nuclear@0 391 {
nuclear@0 392 int i, j;
nuclear@0 393 float m1[16];
nuclear@0 394 float *dest = st.matrix[st.mmode][st.mtop[st.mmode]];
nuclear@0 395
nuclear@0 396 memcpy(m1, dest, sizeof m1);
nuclear@0 397
nuclear@0 398 for(i=0; i<4; i++) {
nuclear@0 399 for(j=0; j<4; j++) {
nuclear@0 400 dest[M(i,j)] = m1[M(0,j)] * m2[M(i,0)] +
nuclear@0 401 m1[M(1,j)] * m2[M(i,1)] +
nuclear@0 402 m1[M(2,j)] * m2[M(i,2)] +
nuclear@0 403 m1[M(3,j)] * m2[M(i,3)];
nuclear@0 404 }
nuclear@0 405 }
nuclear@0 406 }
nuclear@0 407
nuclear@0 408 void mgl_load_identity(void)
nuclear@0 409 {
nuclear@0 410 static float id[] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1};
nuclear@0 411 mgl_load_matrix((float*)id);
nuclear@0 412 }
nuclear@0 413
nuclear@0 414 void mgl_translate(float x, float y, float z)
nuclear@0 415 {
nuclear@0 416 float xform[] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1};
nuclear@0 417 xform[12] = x;
nuclear@0 418 xform[13] = y;
nuclear@0 419 xform[14] = z;
nuclear@0 420 mgl_mult_matrix(xform);
nuclear@0 421 }
nuclear@0 422
nuclear@0 423 void mgl_rotate(float deg, float x, float y, float z)
nuclear@0 424 {
nuclear@0 425 float xform[] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1};
nuclear@0 426
nuclear@0 427 float angle = M_PI * deg / 180.0f;
nuclear@0 428 float sina = sin(angle);
nuclear@0 429 float cosa = cos(angle);
nuclear@0 430 float one_minus_cosa = 1.0f - cosa;
nuclear@0 431 float nxsq = x * x;
nuclear@0 432 float nysq = y * y;
nuclear@0 433 float nzsq = z * z;
nuclear@0 434
nuclear@0 435 xform[0] = nxsq + (1.0f - nxsq) * cosa;
nuclear@0 436 xform[4] = x * y * one_minus_cosa - z * sina;
nuclear@0 437 xform[8] = x * z * one_minus_cosa + y * sina;
nuclear@0 438 xform[1] = x * y * one_minus_cosa + z * sina;
nuclear@0 439 xform[5] = nysq + (1.0 - nysq) * cosa;
nuclear@0 440 xform[9] = y * z * one_minus_cosa - x * sina;
nuclear@0 441 xform[2] = x * z * one_minus_cosa - y * sina;
nuclear@0 442 xform[6] = y * z * one_minus_cosa + x * sina;
nuclear@0 443 xform[10] = nzsq + (1.0 - nzsq) * cosa;
nuclear@0 444
nuclear@0 445 mgl_mult_matrix(xform);
nuclear@0 446 }
nuclear@0 447
nuclear@0 448 void mgl_scale(float x, float y, float z)
nuclear@0 449 {
nuclear@0 450 float xform[] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1};
nuclear@0 451 xform[0] = x;
nuclear@0 452 xform[5] = y;
nuclear@0 453 xform[10] = z;
nuclear@0 454 mgl_mult_matrix(xform);
nuclear@0 455 }
nuclear@0 456
nuclear@0 457 void gl_ortho(float left, float right, float bottom, float top, float nr, float fr)
nuclear@0 458 {
nuclear@0 459 float xform[] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1};
nuclear@0 460
nuclear@0 461 float dx = right - left;
nuclear@0 462 float dy = top - bottom;
nuclear@0 463 float dz = fr - nr;
nuclear@0 464
nuclear@0 465 float tx = -(right + left) / dx;
nuclear@0 466 float ty = -(top + bottom) / dy;
nuclear@0 467 float tz = -(fr + nr) / dz;
nuclear@0 468
nuclear@0 469 float sx = 2.0 / dx;
nuclear@0 470 float sy = 2.0 / dy;
nuclear@0 471 float sz = -2.0 / dz;
nuclear@0 472
nuclear@0 473 xform[0] = sx;
nuclear@0 474 xform[5] = sy;
nuclear@0 475 xform[10] = sz;
nuclear@0 476 xform[12] = tx;
nuclear@0 477 xform[13] = ty;
nuclear@0 478 xform[14] = tz;
nuclear@0 479
nuclear@0 480 mgl_mult_matrix(xform);
nuclear@0 481 }
nuclear@0 482
nuclear@0 483 void mgl_frustum(float left, float right, float bottom, float top, float nr, float fr)
nuclear@0 484 {
nuclear@0 485 float xform[] = {1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1};
nuclear@0 486
nuclear@0 487 float dx = right - left;
nuclear@0 488 float dy = top - bottom;
nuclear@0 489 float dz = fr - nr;
nuclear@0 490
nuclear@0 491 float a = (right + left) / dx;
nuclear@0 492 float b = (top + bottom) / dy;
nuclear@0 493 float c = -(fr + nr) / dz;
nuclear@0 494 float d = -2.0 * fr * nr / dz;
nuclear@0 495
nuclear@0 496 xform[0] = 2.0 * nr / dx;
nuclear@0 497 xform[5] = 2.0 * nr / dy;
nuclear@0 498 xform[8] = a;
nuclear@0 499 xform[9] = b;
nuclear@0 500 xform[10] = c;
nuclear@0 501 xform[11] = -1.0f;
nuclear@0 502 xform[14] = d;
nuclear@0 503
nuclear@0 504 mgl_mult_matrix(xform);
nuclear@0 505 }
nuclear@0 506
nuclear@0 507 void mgl_perspective(float vfov, float aspect, float nr, float fr)
nuclear@0 508 {
nuclear@0 509 float vfov_rad = M_PI * vfov / 180.0;
nuclear@0 510 float x = nr * tan(vfov_rad / 2.0);
nuclear@0 511 mgl_frustum(-aspect * x, aspect * x, -x, x, nr, fr);
nuclear@0 512 }
nuclear@3 513
nuclear@3 514 void mgl_teximage(int width, int height, unsigned char *pixels)
nuclear@3 515 {
nuclear@3 516 st.tex.width = width;
nuclear@3 517 st.tex.height = height;
nuclear@3 518 st.tex.pixels = pixels;
nuclear@3 519
nuclear@3 520 if(calc_shiftmask(width, &st.tex.xshift, &st.tex.xmask) == -1 ||
nuclear@3 521 calc_shiftmask(height, &st.tex.yshift, &st.tex.ymask) == -1) {
nuclear@3 522 st.tex.pixels = 0;
nuclear@3 523 }
nuclear@3 524 }
nuclear@3 525
nuclear@3 526 #define MAX_SHIFT 12
nuclear@3 527 static int calc_shiftmask(int val, int *shiftp, unsigned int *maskp)
nuclear@3 528 {
nuclear@3 529 int i;
nuclear@3 530
nuclear@3 531 for(i=0; i<MAX_SHIFT; i++) {
nuclear@3 532 if((val >> i) == 1) {
nuclear@3 533 *shiftp = i;
nuclear@3 534 *maskp = ~(0xffff << i);
nuclear@3 535 return 0;
nuclear@3 536 }
nuclear@3 537 }
nuclear@3 538 return -1;
nuclear@3 539 }