progs/demos/terrain.c

   1 /*
   2  * This program is under the GNU GPL.
   3  * Use at your own risk.
   4  *
   5  * written by David Bucciarelli (tech.hmw@plus.it)
   6  *            Humanware s.r.l.
   7  *
   8  * based on a Mikael SkiZoWalker's (MoDEL) / France (Skizo@Hol.Fr) demo
   9  */
  10
  11 #include <stdio.h>
  12 #include <math.h>
  13 #include <stdlib.h>
  14 #include <time.h>
  15
  16 #ifdef WIN32
  17 #include <windows.h>
  18 #endif
  19
  20 #include <GL/glut.h>
  21
  22 #ifdef XMESA
  23 #include "GL/xmesa.h"
  24 static int fullscreen = 1;
  25 #endif
  26
  27 #ifndef M_PI
  28 #define M_PI 3.14159265
  29 #endif
  30
  31 #define heightMnt       450
  32 #define lenghtXmnt      62
  33 #define lenghtYmnt      62
  34
  35 #define stepXmnt     96.0
  36 #define stepYmnt     96.0
  37
  38 #define WIDTH 640
  39 #define HEIGHT 480
  40
  41 #define TSCALE 4
  42
  43 #define FRAME 50
  44
  45 #define FOV 85
  46
  47 static GLfloat terrain[256 * 256];
  48 static GLfloat terraincolor[256 * 256][3];
  49
  50 static int win = 0;
  51
  52 static int fog = 1;
  53 static int bfcull = 1;
  54 static int usetex = 1;
  55 static int poutline = 0;
  56 static int help = 1;
  57 static int joyavailable = 0;
  58 static int joyactive = 0;
  59 static float ModZMnt;
  60 static long GlobalMnt = 0;
  61
  62 static int scrwidth = WIDTH;
  63 static int scrheight = HEIGHT;
  64
  65 #define OBSSTARTX 992.0
  66 #define OBSSTARTY 103.0
  67
  68 static float obs[3] = { OBSSTARTX, heightMnt * 1.3, OBSSTARTY };
  69 static float dir[3], v1[2], v2[2];
  70 static float v = 15.0;
  71 static float alpha = 75.0;
  72 static float beta = 90.0;
  73
  74 static float
  75 gettime(void)
  76 {
  77    static clock_t told = 0;
  78    clock_t tnew, ris;
  79
  80    tnew = clock();
  81
  82    ris = tnew - told;
  83
  84    told = tnew;
  85
  86    return (ris / (float) CLOCKS_PER_SEC);
  87 }
  88
  89 static void
  90 calcposobs(void)
  91 {
  92    float alpha1, alpha2;
  93
  94    dir[0] = sin(alpha * M_PI / 180.0);
  95    dir[2] = cos(alpha * M_PI / 180.0) * sin(beta * M_PI / 180.0);
  96    dir[1] = cos(beta * M_PI / 180.0);
  97
  98    alpha1 = alpha + FOV / 2.0;
  99    v1[0] = sin(alpha1 * M_PI / 180.0);
 100    v1[1] = cos(alpha1 * M_PI / 180.0);
 101
 102    alpha2 = alpha - FOV / 2.0;
 103    v2[0] = sin(alpha2 * M_PI / 180.0);
 104    v2[1] = cos(alpha2 * M_PI / 180.0);
 105
 106    obs[0] += v * dir[0];
 107    obs[1] += v * dir[1];
 108    obs[2] += v * dir[2];
 109
 110    if (obs[1] < 0.0)
 111       obs[1] = 0.0;
 112 }
 113
 114 static void
 115 reshape(int width, int height)
 116 {
 117    scrwidth = width;
 118    scrheight = height;
 119    glViewport(0, 0, (GLint) width, (GLint) height);
 120    glMatrixMode(GL_PROJECTION);
 121    glLoadIdentity();
 122    gluPerspective(50.0, ((GLfloat) width / (GLfloat) height),
 123                   lenghtXmnt * stepYmnt * 0.01, lenghtXmnt * stepYmnt * 0.7);
 124    glMatrixMode(GL_MODELVIEW);
 125    glLoadIdentity();
 126 }
 127
 128 int
 129 clipstrip(float y, float *start, float *end)
 130 {
 131    float x1, x2, t1, t2, tmp;
 132
 133    if (v1[1] == 0.0) {
 134       t1 = 0.0;
 135       x1 = -HUGE_VAL;
 136    }
 137    else {
 138       t1 = y / v1[1];
 139       x1 = t1 * v1[0];
 140    }
 141
 142    if (v2[1] == 0.0) {
 143       t2 = 0.0;
 144       x2 = HUGE_VAL;
 145    }
 146    else {
 147       t2 = y / v2[1];
 148       x2 = t2 * v2[0];
 149    }
 150
 151    if (((x1 < -(lenghtXmnt * stepXmnt) / 2) && (t2 <= 0.0)) ||
 152        ((t1 <= 0.0) && (x2 > (lenghtXmnt * stepXmnt) / 2)) ||
 153        ((t1 < 0.0) && (t2 < 0.0)))
 154       return 0;
 155
 156    if ((t1 == 0.0) && (t2 == 0.0)) {
 157       if ((v1[0] < 0.0) && (v1[1] > 0.0) && (v2[0] < 0.0) && (v2[1] < 0.0)) {
 158          *start = -(lenghtXmnt * stepXmnt) / 2;
 159          *end = stepXmnt;
 160          return 1;
 161       }
 162       else {
 163          if ((v1[0] > 0.0) && (v1[1] < 0.0) && (v2[0] > 0.0) && (v2[1] > 0.0)) {
 164             *start = -stepXmnt;
 165             *end = (lenghtXmnt * stepXmnt) / 2;
 166             return 1;
 167          }
 168          else
 169             return 0;
 170       }
 171    }
 172    else {
 173       if (t2 < 0.0) {
 174          if (x1 < 0.0)
 175             x2 = -(lenghtXmnt * stepXmnt) / 2;
 176          else
 177             x2 = (lenghtXmnt * stepXmnt) / 2;
 178       }
 179
 180       if (t1 < 0.0) {
 181          if (x2 < 0.0)
 182             x1 = -(lenghtXmnt * stepXmnt) / 2;
 183          else
 184             x1 = (lenghtXmnt * stepXmnt) / 2;
 185       }
 186    }
 187
 188    if (x1 > x2) {
 189       tmp = x1;
 190       x1 = x2;
 191       x2 = tmp;
 192    }
 193
 194    x1 -= stepXmnt;
 195    if (x1 < -(lenghtXmnt * stepXmnt) / 2)
 196       x1 = -(lenghtXmnt * stepXmnt) / 2;
 197
 198    x2 += stepXmnt;
 199    if (x2 > (lenghtXmnt * stepXmnt) / 2)
 200       x2 = (lenghtXmnt * stepXmnt) / 2;
 201
 202    *start = ((int) (x1 / stepXmnt)) * stepXmnt;
 203    *end = ((int) (x2 / stepXmnt)) * stepXmnt;
 204
 205    return 1;
 206 }
 207
 208 static void
 209 printstring(void *font, char *string)
 210 {
 211    int len, i;
 212
 213    len = (int) strlen(string);
 214    for (i = 0; i < len; i++)
 215       glutBitmapCharacter(font, string[i]);
 216 }
 217
 218 static void
 219 printhelp(void)
 220 {
 221    glEnable(GL_BLEND);
 222    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 223    glColor4f(0.0, 0.0, 0.0, 0.5);
 224    glRecti(40, 40, 600, 440);
 225    glDisable(GL_BLEND);
 226
 227    glColor3f(1.0, 0.0, 0.0);
 228    glRasterPos2i(300, 420);
 229    printstring(GLUT_BITMAP_TIMES_ROMAN_24, "Help");
 230
 231    glRasterPos2i(60, 390);
 232    printstring(GLUT_BITMAP_TIMES_ROMAN_24, "h - Togle Help");
 233    glRasterPos2i(60, 360);
 234    printstring(GLUT_BITMAP_TIMES_ROMAN_24, "t - Togle Textures");
 235    glRasterPos2i(60, 330);
 236    printstring(GLUT_BITMAP_TIMES_ROMAN_24, "f - Togle Fog");
 237    glRasterPos2i(60, 300);
 238    printstring(GLUT_BITMAP_TIMES_ROMAN_24, "p - Wire frame");
 239    glRasterPos2i(60, 270);
 240    printstring(GLUT_BITMAP_TIMES_ROMAN_24, "b - Togle Back face culling");
 241    glRasterPos2i(60, 240);
 242    printstring(GLUT_BITMAP_TIMES_ROMAN_24, "Arrow Keys - Rotate");
 243    glRasterPos2i(60, 210);
 244    printstring(GLUT_BITMAP_TIMES_ROMAN_24, "a - Increase velocity");
 245    glRasterPos2i(60, 180);
 246    printstring(GLUT_BITMAP_TIMES_ROMAN_24, "z - Decrease velocity");
 247
 248    glRasterPos2i(60, 150);
 249    if (joyavailable)
 250       printstring(GLUT_BITMAP_TIMES_ROMAN_24,
 251                   "j - Togle jostick control (Joystick control available)");
 252    else
 253       printstring(GLUT_BITMAP_TIMES_ROMAN_24,
 254                   "(No Joystick control available)");
 255 }
 256
 257 void
 258 drawterrain(void)
 259 {
 260    int h, i, idx, ox, oy;
 261    float j, k, start, end;
 262
 263    ox = (int) (obs[0] / stepXmnt);
 264    oy = (int) (obs[2] / stepYmnt);
 265    GlobalMnt = ((ox * TSCALE) & 255) + ((oy * TSCALE) & 255) * 256;
 266
 267    glPushMatrix();
 268    glTranslatef((float) ox * stepXmnt, 0, (float) oy * stepYmnt);
 269
 270    for (h = 0, k = -(lenghtYmnt * stepYmnt) / 2; h < lenghtYmnt;
 271         k += stepYmnt, h++) {
 272       if (!clipstrip(k, &start, &end))
 273          continue;
 274
 275       glBegin(GL_TRIANGLE_STRIP);       /* I hope that the optimizer will be able to improve this code */
 276       for (i = (int) (lenghtXmnt / 2 + start / stepXmnt), j = start; j <= end;
 277            j += stepXmnt, i++) {
 278          idx = (i * TSCALE + h * 256 * TSCALE + GlobalMnt) & 65535;
 279          glColor3fv(terraincolor[idx]);
 280          glTexCoord2f((ox + i) / 8.0, (oy + h) / 8.0);
 281          glVertex3f(j, terrain[idx], k);
 282
 283          idx =
 284             (i * TSCALE + h * 256 * TSCALE + 256 * TSCALE +
 285              GlobalMnt) & 65535;
 286          glColor3fv(terraincolor[idx]);
 287          glTexCoord2f((ox + i) / 8.0, (oy + h + 1) / 8.0);
 288          glVertex3f(j, terrain[idx], k + stepYmnt);
 289       }
 290       glEnd();
 291    }
 292
 293    glDisable(GL_CULL_FACE);
 294    glDisable(GL_TEXTURE_2D);
 295    glEnable(GL_BLEND);
 296    glBegin(GL_QUADS);
 297    glColor4f(0.1, 0.7, 1.0, 0.4);
 298    glVertex3f(-(lenghtXmnt * stepXmnt) / 2.0, heightMnt * 0.6,
 299               -(lenghtYmnt * stepYmnt) / 2.0);
 300    glVertex3f(-(lenghtXmnt * stepXmnt) / 2.0, heightMnt * 0.6,
 301               (lenghtYmnt * stepYmnt) / 2.0);
 302    glVertex3f((lenghtXmnt * stepXmnt) / 2.0, heightMnt * 0.6,
 303               (lenghtYmnt * stepYmnt) / 2.0);
 304    glVertex3f((lenghtXmnt * stepXmnt) / 2.0, heightMnt * 0.6,
 305               -(lenghtYmnt * stepYmnt) / 2.0);
 306    glEnd();
 307    glDisable(GL_BLEND);
 308    if (bfcull)
 309       glEnable(GL_CULL_FACE);
 310    glEnable(GL_TEXTURE_2D);
 311
 312    glPopMatrix();
 313
 314 }
 315
 316 static void
 317 dojoy(void)
 318 {
 319 #ifdef WIN32
 320    static UINT max[2] = { 0, 0 };
 321    static UINT min[2] = { 0xffffffff, 0xffffffff }, center[2];
 322    MMRESULT res;
 323    JOYINFO joy;
 324
 325    res = joyGetPos(JOYSTICKID1, &joy);
 326
 327    if (res == JOYERR_NOERROR) {
 328       joyavailable = 1;
 329
 330       if (max[0] < joy.wXpos)
 331          max[0] = joy.wXpos;
 332       if (min[0] > joy.wXpos)
 333          min[0] = joy.wXpos;
 334       center[0] = (max[0] + min[0]) / 2;
 335
 336       if (max[1] < joy.wYpos)
 337          max[1] = joy.wYpos;
 338       if (min[1] > joy.wYpos)
 339          min[1] = joy.wYpos;
 340       center[1] = (max[1] + min[1]) / 2;
 341
 342       if (joyactive) {
 343          if (fabs(center[0] - (float) joy.wXpos) > 0.1 * (max[0] - min[0]))
 344             alpha +=
 345                2.5 * (center[0] - (float) joy.wXpos) / (max[0] - min[0]);
 346          if (fabs(center[1] - (float) joy.wYpos) > 0.1 * (max[1] - min[1]))
 347             beta += 2.5 * (center[1] - (float) joy.wYpos) / (max[1] - min[1]);
 348
 349          if (joy.wButtons & JOY_BUTTON1)
 350             v += 0.5;
 351          if (joy.wButtons & JOY_BUTTON2)
 352             v -= 0.5;
 353       }
 354    }
 355    else
 356       joyavailable = 0;
 357 #endif
 358 }
 359
 360 void
 361 drawscene(void)
 362 {
 363    static int count = 0;
 364    static char frbuf[80];
 365    float fr;
 366
 367    dojoy();
 368
 369    glShadeModel(GL_SMOOTH);
 370    glEnable(GL_DEPTH_TEST);
 371
 372    if (usetex)
 373       glEnable(GL_TEXTURE_2D);
 374    else
 375       glDisable(GL_TEXTURE_2D);
 376
 377    if (fog)
 378       glEnable(GL_FOG);
 379    else
 380       glDisable(GL_FOG);
 381
 382    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 383
 384    glPushMatrix();
 385
 386    calcposobs();
 387    gluLookAt(obs[0], obs[1], obs[2],
 388              obs[0] + dir[0], obs[1] + dir[1], obs[2] + dir[2],
 389              0.0, 1.0, 0.0);
 390
 391    drawterrain();
 392    glPopMatrix();
 393
 394    if ((count % FRAME) == 0) {
 395       fr = gettime();
 396       sprintf(frbuf, "Frame rate: %.3f", FRAME / fr);
 397    }
 398
 399    glDisable(GL_TEXTURE_2D);
 400    glDisable(GL_DEPTH_TEST);
 401    glDisable(GL_FOG);
 402    glShadeModel(GL_FLAT);
 403
 404    glMatrixMode(GL_PROJECTION);
 405    glLoadIdentity();
 406    glOrtho(-0.5, 639.5, -0.5, 479.5, -1.0, 1.0);
 407    glMatrixMode(GL_MODELVIEW);
 408    glLoadIdentity();
 409
 410    glColor3f(1.0, 0.0, 0.0);
 411    glRasterPos2i(10, 10);
 412    printstring(GLUT_BITMAP_HELVETICA_18, frbuf);
 413    glRasterPos2i(350, 470);
 414    printstring(GLUT_BITMAP_HELVETICA_10,
 415                "Terrain V1.2 Written by David Bucciarelli (tech.hmw@plus.it)");
 416    glRasterPos2i(434, 457);
 417    printstring(GLUT_BITMAP_HELVETICA_10,
 418                "Based on a Mickael's demo (Skizo@Hol.Fr)");
 419
 420    if (help)
 421       printhelp();
 422
 423    reshape(scrwidth, scrheight);
 424
 425    glutSwapBuffers();
 426
 427    count++;
 428 }
 429
 430 static void
 431 key(unsigned char k, int x, int y)
 432 {
 433    switch (k) {
 434    case 27:
 435       exit(0);
 436       break;
 437    case 'a':
 438       v += 0.5;
 439       break;
 440    case 'z':
 441       v -= 0.5;
 442       break;
 443    case 'p':
 444       if (poutline) {
 445          glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 446          poutline = 0;
 447       }
 448       else {
 449          glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
 450          poutline = 1;
 451       }
 452       break;
 453    case 'j':
 454       joyactive = (!joyactive);
 455       break;
 456    case 'h':
 457       help = (!help);
 458       break;
 459    case 'f':
 460       fog = (!fog);
 461       break;
 462    case 't':
 463       usetex = (!usetex);
 464       break;
 465    case 'b':
 466       if (bfcull) {
 467          glDisable(GL_CULL_FACE);
 468          bfcull = 0;
 469       }
 470       else {
 471          glEnable(GL_CULL_FACE);
 472          bfcull = 1;
 473       }
 474       break;
 475 #ifdef XMESA
 476    case ' ':
 477       XMesaSetFXmode(fullscreen ? XMESA_FX_FULLSCREEN : XMESA_FX_WINDOW);
 478       fullscreen = (!fullscreen);
 479       break;
 480 #endif
 481    }
 482 }
 483
 484 static void
 485 special(int k, int x, int y)
 486 {
 487    switch (k) {
 488    case GLUT_KEY_LEFT:
 489       alpha += 2.0;
 490       break;
 491    case GLUT_KEY_RIGHT:
 492       alpha -= 2.0;
 493       break;
 494    case GLUT_KEY_DOWN:
 495       beta -= 2.0;
 496       break;
 497    case GLUT_KEY_UP:
 498       beta += 2.0;
 499       break;
 500    }
 501 }
 502
 503 static void
 504 calccolor(GLfloat height, GLfloat c[3])
 505 {
 506    GLfloat color[4][3] = {
 507       {1.0, 1.0, 1.0},
 508       {0.0, 0.8, 0.0},
 509       {1.0, 1.0, 0.3},
 510       {0.0, 0.0, 0.8}
 511    };
 512    GLfloat fact;
 513
 514    height = height * (1.0 / 255.0);
 515
 516    if (height >= 0.9) {
 517       c[0] = color[0][0];
 518       c[1] = color[0][1];
 519       c[2] = color[0][2];
 520       return;
 521    }
 522
 523    if ((height < 0.9) && (height >= 0.7)) {
 524       fact = (height - 0.7) * 5.0;
 525       c[0] = fact * color[0][0] + (1.0 - fact) * color[1][0];
 526       c[1] = fact * color[0][1] + (1.0 - fact) * color[1][1];
 527       c[2] = fact * color[0][2] + (1.0 - fact) * color[1][2];
 528       return;
 529    }
 530
 531    if ((height < 0.7) && (height >= 0.6)) {
 532       fact = (height - 0.6) * 10.0;
 533       c[0] = fact * color[1][0] + (1.0 - fact) * color[2][0];
 534       c[1] = fact * color[1][1] + (1.0 - fact) * color[2][1];
 535       c[2] = fact * color[1][2] + (1.0 - fact) * color[2][2];
 536       return;
 537    }
 538
 539    if ((height < 0.6) && (height >= 0.5)) {
 540       fact = (height - 0.5) * 10.0;
 541       c[0] = fact * color[2][0] + (1.0 - fact) * color[3][0];
 542       c[1] = fact * color[2][1] + (1.0 - fact) * color[3][1];
 543       c[2] = fact * color[2][2] + (1.0 - fact) * color[3][2];
 544       return;
 545    }
 546
 547    c[0] = color[3][0];
 548    c[1] = color[3][1];
 549    c[2] = color[3][2];
 550 }
 551
 552 static void
 553 loadpic(void)
 554 {
 555    GLubyte bufferter[256 * 256], terrainpic[256 * 256];
 556    FILE *FilePic;
 557    int i, tmp;
 558    GLenum gluerr;
 559
 560    if ((FilePic = fopen("terrain.dat", "r")) == NULL) {
 561       fprintf(stderr, "Error loading Mnt.bin\n");
 562       exit(-1);
 563    }
 564    fread(bufferter, 256 * 256, 1, FilePic);
 565    fclose(FilePic);
 566
 567    for (i = 0; i < (256 * 256); i++) {
 568       terrain[i] = (bufferter[i] * (heightMnt / 255.0f));
 569       calccolor((GLfloat) bufferter[i], terraincolor[i]);
 570       tmp = (((int) bufferter[i]) + 96);
 571       terrainpic[i] = (tmp > 255) ? 255 : tmp;
 572    }
 573
 574    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 575    if ((gluerr = gluBuild2DMipmaps(GL_TEXTURE_2D, 1, 256, 256, GL_LUMINANCE,
 576                                    GL_UNSIGNED_BYTE,
 577                                    (GLvoid *) (&terrainpic[0])))) {
 578       fprintf(stderr, "GLULib%s\n", gluErrorString(gluerr));
 579       exit(-1);
 580    }
 581
 582    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
 583    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 584
 585    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
 586                    GL_LINEAR_MIPMAP_LINEAR);
 587    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 588
 589    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 590    glEnable(GL_TEXTURE_2D);
 591 }
 592
 593 static void
 594 init(void)
 595 {
 596    float fogcolor[4] = { 0.6, 0.7, 0.7, 1.0 };
 597
 598    glClearColor(fogcolor[0], fogcolor[1], fogcolor[2], fogcolor[3]);
 599    glClearDepth(1.0);
 600    glDepthFunc(GL_LEQUAL);
 601    glShadeModel(GL_SMOOTH);
 602    glEnable(GL_DEPTH_TEST);
 603    glEnable(GL_CULL_FACE);
 604
 605    glDisable(GL_BLEND);
 606    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 607
 608    glEnable(GL_FOG);
 609    glFogi(GL_FOG_MODE, GL_EXP2);
 610    glFogfv(GL_FOG_COLOR, fogcolor);
 611    glFogf(GL_FOG_DENSITY, 0.0007);
 612 #ifdef FX
 613    glHint(GL_FOG_HINT, GL_NICEST);
 614 #endif
 615
 616    reshape(scrwidth, scrheight);
 617 }
 618
 619
 620 int
 621 main(int ac, char **av)
 622 {
 623    glutInitWindowPosition(0, 0);
 624    glutInitWindowSize(WIDTH, HEIGHT);
 625    glutInit(&ac, av);
 626
 627    glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
 628
 629    if (!(win = glutCreateWindow("Terrain"))) {
 630       fprintf(stderr, "Error, couldn't open window\n");
 631       return -1;
 632    }
 633
 634    ModZMnt = 0.0f;
 635    loadpic();
 636
 637    init();
 638
 639 #ifndef FX
 640    glDisable(GL_TEXTURE_2D);
 641    usetex = 0;
 642 #endif
 643
 644    glutReshapeFunc(reshape);
 645    glutDisplayFunc(drawscene);
 646    glutKeyboardFunc(key);
 647    glutSpecialFunc(special);
 648    glutIdleFunc(drawscene);
 649
 650    glutMainLoop();
 651
 652    return 0;
 653 }