src/demos/projtex.c

   1
   2 /* projtex.c - by David Yu and David Blythe, SGI */
   3
   4 /**
   5  ** Demonstrates simple projective texture mapping.
   6  **
   7  ** Button1 changes view, Button2 moves texture.
   8  **
   9  ** (See: Segal, Korobkin, van Widenfelt, Foran, and Haeberli
  10  **  "Fast Shadows and Lighting Effects Using Texture Mapping", SIGGRAPH '92)
  11  **
  12  ** 1994,1995 -- David G Yu
  13  **
  14  ** cc -o projtex projtex.c texture.c -lglut -lGLU -lGL -lX11 -lm
  15  **/
  16
  17 #include <assert.h>
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <math.h>
  21 #include <GL/glew.h>
  22 #include "glut_wrap.h"
  23 #include "readtex.h"
  24
  25
  26 /* Some <math.h> files do not define M_PI... */
  27 #ifndef M_PI
  28 #define M_PI 3.14159265358979323846
  29 #endif
  30
  31 #define MAX_TEX 4
  32 int NumTextures = 1;
  33
  34 int winWidth, winHeight;
  35
  36 GLboolean redrawContinuously = GL_FALSE;
  37
  38 float angle, axis[3];
  39 enum MoveModes {
  40   MoveNone, MoveView, MoveObject, MoveTexture
  41 };
  42 enum MoveModes mode = MoveNone;
  43
  44 GLfloat objectXform[4][4];
  45 GLfloat textureXform[MAX_TEX][4][4];
  46
  47 void (*drawObject) (void);
  48 void (*loadTexture) (void);
  49 GLboolean textureEnabled = GL_TRUE;
  50 GLboolean showProjection = GL_TRUE;
  51 GLboolean linearFilter = GL_TRUE;
  52
  53 char *texFilename[MAX_TEX] = {
  54    DEMOS_DATA_DIR "girl.rgb",
  55    DEMOS_DATA_DIR "tile.rgb",
  56    DEMOS_DATA_DIR "bw.rgb",
  57    DEMOS_DATA_DIR "reflect.rgb"
  58 };
  59
  60
  61 GLfloat zoomFactor = 1.0;
  62
  63 /*****************************************************************/
  64
  65
  66 static void
  67 ActiveTexture(int i)
  68 {
  69    glActiveTextureARB(i);
  70 }
  71
  72
  73 /* matrix = identity */
  74 static void
  75 matrixIdentity(GLfloat matrix[16])
  76 {
  77   matrix[0] = 1.0;
  78   matrix[1] = 0.0;
  79   matrix[2] = 0.0;
  80   matrix[3] = 0.0;
  81   matrix[4] = 0.0;
  82   matrix[5] = 1.0;
  83   matrix[6] = 0.0;
  84   matrix[7] = 0.0;
  85   matrix[8] = 0.0;
  86   matrix[9] = 0.0;
  87   matrix[10] = 1.0;
  88   matrix[11] = 0.0;
  89   matrix[12] = 0.0;
  90   matrix[13] = 0.0;
  91   matrix[14] = 0.0;
  92   matrix[15] = 1.0;
  93 }
  94
  95 /* matrix2 = transpose(matrix1) */
  96 static void
  97 matrixTranspose(GLfloat matrix2[16], GLfloat matrix1[16])
  98 {
  99   matrix2[0] = matrix1[0];
 100   matrix2[1] = matrix1[4];
 101   matrix2[2] = matrix1[8];
 102   matrix2[3] = matrix1[12];
 103
 104   matrix2[4] = matrix1[1];
 105   matrix2[5] = matrix1[5];
 106   matrix2[6] = matrix1[9];
 107   matrix2[7] = matrix1[13];
 108
 109   matrix2[8] = matrix1[2];
 110   matrix2[9] = matrix1[6];
 111   matrix2[10] = matrix1[10];
 112   matrix2[11] = matrix1[14];
 113
 114   matrix2[12] = matrix1[3];
 115   matrix2[13] = matrix1[7];
 116   matrix2[14] = matrix1[14];
 117   matrix2[15] = matrix1[15];
 118 }
 119
 120 /*****************************************************************/
 121
 122 /* load SGI .rgb image (pad with a border of the specified width and color) */
 123 #if 0
 124 static void
 125 imgLoad(char *filenameIn, int borderIn, GLfloat borderColorIn[4],
 126   int *wOut, int *hOut, GLubyte ** imgOut)
 127 {
 128   int border = borderIn;
 129   int width, height;
 130   int w, h;
 131   GLubyte *image, *img, *p;
 132   int i, j, components;
 133
 134   image = (GLubyte *) read_texture(filenameIn, &width, &height, &components);
 135   w = width + 2 * border;
 136   h = height + 2 * border;
 137   img = (GLubyte *) calloc(w * h, 4 * sizeof(unsigned char));
 138
 139   p = img;
 140   for (j = -border; j < height + border; ++j) {
 141     for (i = -border; i < width + border; ++i) {
 142       if (0 <= j && j <= height - 1 && 0 <= i && i <= width - 1) {
 143         p[0] = image[4 * (j * width + i) + 0];
 144         p[1] = image[4 * (j * width + i) + 1];
 145         p[2] = image[4 * (j * width + i) + 2];
 146         p[3] = 0xff;
 147       } else {
 148         p[0] = borderColorIn[0] * 0xff;
 149         p[1] = borderColorIn[1] * 0xff;
 150         p[2] = borderColorIn[2] * 0xff;
 151         p[3] = borderColorIn[3] * 0xff;
 152       }
 153       p += 4;
 154     }
 155   }
 156   free(image);
 157   *wOut = w;
 158   *hOut = h;
 159   *imgOut = img;
 160 }
 161 #endif
 162
 163
 164 /*****************************************************************/
 165
 166 /* Load the image file specified on the command line as the current texture */
 167 static void
 168 loadImageTextures(void)
 169 {
 170   GLfloat borderColor[4] =
 171   {1.0, 1.0, 1.0, 1.0};
 172   int tex;
 173
 174   for (tex = 0; tex < NumTextures; tex++) {
 175      GLubyte *image, *texData3, *texData4;
 176      GLint imgWidth, imgHeight;
 177      GLenum imgFormat;
 178      int i, j;
 179
 180      printf("loading %s\n", texFilename[tex]);
 181      image = LoadRGBImage(texFilename[tex], &imgWidth, &imgHeight, &imgFormat);
 182      if (!image) {
 183         printf("can't find %s\n", texFilename[tex]);
 184         exit(1);
 185      }
 186      assert(imgFormat == GL_RGB);
 187
 188      /* scale to 256x256 */
 189      texData3 = malloc(256 * 256 * 4);
 190      texData4 = malloc(256 * 256 * 4);
 191      assert(texData3);
 192      assert(texData4);
 193      gluScaleImage(imgFormat, imgWidth, imgHeight, GL_UNSIGNED_BYTE, image,
 194                    256, 256, GL_UNSIGNED_BYTE, texData3);
 195
 196      /* convert to rgba */
 197      for (i = 0; i < 256 * 256; i++) {
 198         texData4[i*4+0] = texData3[i*3+0];
 199         texData4[i*4+1] = texData3[i*3+1];
 200         texData4[i*4+2] = texData3[i*3+2];
 201         texData4[i*4+3] = 128;
 202      }
 203
 204      /* put transparent border around image */
 205      for (i = 0; i < 256; i++) {
 206         texData4[i*4+0] = 255;
 207         texData4[i*4+1] = 255;
 208         texData4[i*4+2] = 255;
 209         texData4[i*4+3] = 0;
 210      }
 211      j = 256 * 255 * 4;
 212      for (i = 0; i < 256; i++) {
 213         texData4[j + i*4+0] = 255;
 214         texData4[j + i*4+1] = 255;
 215         texData4[j + i*4+2] = 255;
 216         texData4[j + i*4+3] = 0;
 217      }
 218      for (i = 0; i < 256; i++) {
 219         j = i * 256 * 4;
 220         texData4[j+0] = 255;
 221         texData4[j+1] = 255;
 222         texData4[j+2] = 255;
 223         texData4[j+3] = 0;
 224      }
 225      for (i = 0; i < 256; i++) {
 226         j = i * 256 * 4 + 255 * 4;
 227         texData4[j+0] = 255;
 228         texData4[j+1] = 255;
 229         texData4[j+2] = 255;
 230         texData4[j+3] = 0;
 231      }
 232
 233      ActiveTexture(GL_TEXTURE0_ARB + tex);
 234      glBindTexture(GL_TEXTURE_2D, tex + 1);
 235
 236      glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 237      glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0,
 238                   GL_RGBA, GL_UNSIGNED_BYTE, texData4);
 239
 240      if (linearFilter) {
 241        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 242        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 243      } else {
 244        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 245        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 246      }
 247      glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, borderColor);
 248
 249      free(texData3);
 250      free(texData4);
 251      free(image);
 252   }
 253 }
 254
 255 /* Create a simple spotlight pattern and make it the current texture */
 256 static void
 257 loadSpotlightTexture(void)
 258 {
 259   static int texWidth = 64, texHeight = 64;
 260   static GLubyte *texData;
 261   GLfloat borderColor[4] =
 262   {0.1, 0.1, 0.1, 1.0};
 263
 264   if (!texData) {
 265     GLubyte *p;
 266     int i, j;
 267
 268     texData = (GLubyte *) malloc(texWidth * texHeight * 4 * sizeof(GLubyte));
 269
 270     p = texData;
 271     for (j = 0; j < texHeight; ++j) {
 272       float dy = (texHeight * 0.5 - j + 0.5) / (texHeight * 0.5);
 273
 274       for (i = 0; i < texWidth; ++i) {
 275         float dx = (texWidth * 0.5 - i + 0.5) / (texWidth * 0.5);
 276         float r = cos(M_PI / 2.0 * sqrt(dx * dx + dy * dy));
 277         float c;
 278
 279         r = (r < 0) ? 0 : r * r;
 280         c = 0xff * (r + borderColor[0]);
 281         p[0] = (c <= 0xff) ? c : 0xff;
 282         c = 0xff * (r + borderColor[1]);
 283         p[1] = (c <= 0xff) ? c : 0xff;
 284         c = 0xff * (r + borderColor[2]);
 285         p[2] = (c <= 0xff) ? c : 0xff;
 286         c = 0xff * (r + borderColor[3]);
 287         p[3] = (c <= 0xff) ? c : 0xff;
 288         p += 4;
 289       }
 290     }
 291   }
 292   if (linearFilter) {
 293     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 294     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 295   } else {
 296     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 297     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 298   }
 299   glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, borderColor);
 300   gluBuild2DMipmaps(GL_TEXTURE_2D, 4, texWidth, texHeight,
 301     GL_RGBA, GL_UNSIGNED_BYTE, texData);
 302 }
 303
 304 /*****************************************************************/
 305
 306 static void
 307 checkErrors(void)
 308 {
 309   GLenum error;
 310   while ((error = glGetError()) != GL_NO_ERROR) {
 311     fprintf(stderr, "Error: %s\n", (char *) gluErrorString(error));
 312   }
 313 }
 314
 315 static void
 316 drawCube(void)
 317 {
 318   glBegin(GL_QUADS);
 319
 320   glNormal3f(-1.0, 0.0, 0.0);
 321   glColor3f(0.80, 0.50, 0.50);
 322   glVertex3f(-0.5, -0.5, -0.5);
 323   glVertex3f(-0.5, -0.5, 0.5);
 324   glVertex3f(-0.5, 0.5, 0.5);
 325   glVertex3f(-0.5, 0.5, -0.5);
 326
 327   glNormal3f(1.0, 0.0, 0.0);
 328   glColor3f(0.50, 0.80, 0.50);
 329   glVertex3f(0.5, 0.5, 0.5);
 330   glVertex3f(0.5, -0.5, 0.5);
 331   glVertex3f(0.5, -0.5, -0.5);
 332   glVertex3f(0.5, 0.5, -0.5);
 333
 334   glNormal3f(0.0, -1.0, 0.0);
 335   glColor3f(0.50, 0.50, 0.80);
 336   glVertex3f(-0.5, -0.5, -0.5);
 337   glVertex3f(0.5, -0.5, -0.5);
 338   glVertex3f(0.5, -0.5, 0.5);
 339   glVertex3f(-0.5, -0.5, 0.5);
 340
 341   glNormal3f(0.0, 1.0, 0.0);
 342   glColor3f(0.50, 0.80, 0.80);
 343   glVertex3f(0.5, 0.5, 0.5);
 344   glVertex3f(0.5, 0.5, -0.5);
 345   glVertex3f(-0.5, 0.5, -0.5);
 346   glVertex3f(-0.5, 0.5, 0.5);
 347
 348   glNormal3f(0.0, 0.0, -1.0);
 349   glColor3f(0.80, 0.50, 0.80);
 350   glVertex3f(-0.5, -0.5, -0.5);
 351   glVertex3f(-0.5, 0.5, -0.5);
 352   glVertex3f(0.5, 0.5, -0.5);
 353   glVertex3f(0.5, -0.5, -0.5);
 354
 355   glNormal3f(0.0, 0.0, 1.0);
 356   glColor3f(1.00, 0.80, 0.50);
 357   glVertex3f(0.5, 0.5, 0.5);
 358   glVertex3f(-0.5, 0.5, 0.5);
 359   glVertex3f(-0.5, -0.5, 0.5);
 360   glVertex3f(0.5, -0.5, 0.5);
 361   glEnd();
 362 }
 363
 364 static void
 365 drawDodecahedron(void)
 366 {
 367 #define A (0.5 * 1.61803)  /* (sqrt(5) + 1) / 2 */
 368 #define B (0.5 * 0.61803)  /* (sqrt(5) - 1) / 2 */
 369 #define C (0.5 * 1.0)
 370   GLfloat vertexes[20][3] =
 371   {
 372     {-A, 0.0, B},
 373     {-A, 0.0, -B},
 374     {A, 0.0, -B},
 375     {A, 0.0, B},
 376     {B, -A, 0.0},
 377     {-B, -A, 0.0},
 378     {-B, A, 0.0},
 379     {B, A, 0.0},
 380     {0.0, B, -A},
 381     {0.0, -B, -A},
 382     {0.0, -B, A},
 383     {0.0, B, A},
 384     {-C, -C, C},
 385     {-C, -C, -C},
 386     {C, -C, -C},
 387     {C, -C, C},
 388     {-C, C, C},
 389     {-C, C, -C},
 390     {C, C, -C},
 391     {C, C, C},
 392   };
 393 #undef A
 394 #undef B
 395 #undef C
 396   GLint polygons[12][5] =
 397   {
 398     {0, 12, 10, 11, 16},
 399     {1, 17, 8, 9, 13},
 400     {2, 14, 9, 8, 18},
 401     {3, 19, 11, 10, 15},
 402     {4, 14, 2, 3, 15},
 403     {5, 12, 0, 1, 13},
 404     {6, 17, 1, 0, 16},
 405     {7, 19, 3, 2, 18},
 406     {8, 17, 6, 7, 18},
 407     {9, 14, 4, 5, 13},
 408     {10, 12, 5, 4, 15},
 409     {11, 19, 7, 6, 16},
 410   };
 411   int i;
 412
 413   glColor3f(0.75, 0.75, 0.75);
 414   for (i = 0; i < 12; ++i) {
 415     GLfloat *p0, *p1, *p2, d;
 416     GLfloat u[3], v[3], n[3];
 417
 418     p0 = &vertexes[polygons[i][0]][0];
 419     p1 = &vertexes[polygons[i][1]][0];
 420     p2 = &vertexes[polygons[i][2]][0];
 421
 422     u[0] = p2[0] - p1[0];
 423     u[1] = p2[1] - p1[1];
 424     u[2] = p2[2] - p1[2];
 425
 426     v[0] = p0[0] - p1[0];
 427     v[1] = p0[1] - p1[1];
 428     v[2] = p0[2] - p1[2];
 429
 430     n[0] = u[1] * v[2] - u[2] * v[1];
 431     n[1] = u[2] * v[0] - u[0] * v[2];
 432     n[2] = u[0] * v[1] - u[1] * v[0];
 433
 434     d = 1.0 / sqrt(n[0] * n[0] + n[1] * n[1] + n[2] * n[2]);
 435     n[0] *= d;
 436     n[1] *= d;
 437     n[2] *= d;
 438
 439     glBegin(GL_POLYGON);
 440     glNormal3fv(n);
 441     glVertex3fv(p0);
 442     glVertex3fv(p1);
 443     glVertex3fv(p2);
 444     glVertex3fv(vertexes[polygons[i][3]]);
 445     glVertex3fv(vertexes[polygons[i][4]]);
 446     glEnd();
 447   }
 448 }
 449
 450 static void
 451 drawSphere(void)
 452 {
 453   int numMajor = 24;
 454   int numMinor = 32;
 455   float radius = 0.8;
 456   double majorStep = (M_PI / numMajor);
 457   double minorStep = (2.0 * M_PI / numMinor);
 458   int i, j;
 459
 460   glColor3f(0.50, 0.50, 0.50);
 461   for (i = 0; i < numMajor; ++i) {
 462     double a = i * majorStep;
 463     double b = a + majorStep;
 464     double r0 = radius * sin(a);
 465     double r1 = radius * sin(b);
 466     GLfloat z0 = radius * cos(a);
 467     GLfloat z1 = radius * cos(b);
 468
 469     glBegin(GL_TRIANGLE_STRIP);
 470     for (j = 0; j <= numMinor; ++j) {
 471       double c = j * minorStep;
 472       GLfloat x = cos(c);
 473       GLfloat y = sin(c);
 474
 475       glNormal3f((x * r0) / radius, (y * r0) / radius, z0 / radius);
 476       glTexCoord2f(j / (GLfloat) numMinor, i / (GLfloat) numMajor);
 477       glVertex3f(x * r0, y * r0, z0);
 478
 479       glNormal3f((x * r1) / radius, (y * r1) / radius, z1 / radius);
 480       glTexCoord2f(j / (GLfloat) numMinor, (i + 1) / (GLfloat) numMajor);
 481       glVertex3f(x * r1, y * r1, z1);
 482     }
 483     glEnd();
 484   }
 485 }
 486
 487 /*****************************************************************/
 488
 489 float xmin = -0.035, xmax = 0.035;
 490 float ymin = -0.035, ymax = 0.035;
 491 float nnear = 0.1;
 492 float ffar = 1.9;
 493 float distance = -1.0;
 494
 495 static void
 496 loadTextureProjection(int texUnit, GLfloat m[16])
 497 {
 498   GLfloat mInverse[4][4];
 499
 500   /* Should use true inverse, but since m consists only of rotations, we can
 501      just use the transpose. */
 502   matrixTranspose((GLfloat *) mInverse, m);
 503
 504   ActiveTexture(GL_TEXTURE0_ARB + texUnit);
 505   glMatrixMode(GL_TEXTURE);
 506   glLoadIdentity();
 507   glTranslatef(0.5, 0.5, 0.0);
 508   glScalef(0.5, 0.5, 1.0);
 509   glFrustum(xmin, xmax, ymin, ymax, nnear, ffar);
 510   glTranslatef(0.0, 0.0, distance);
 511   glMultMatrixf((GLfloat *) mInverse);
 512   glMatrixMode(GL_MODELVIEW);
 513 }
 514
 515 static void
 516 drawTextureProjection(void)
 517 {
 518   float t = ffar / nnear;
 519   GLfloat n[4][3];
 520   GLfloat f[4][3];
 521
 522   n[0][0] = xmin;
 523   n[0][1] = ymin;
 524   n[0][2] = -(nnear + distance);
 525
 526   n[1][0] = xmax;
 527   n[1][1] = ymin;
 528   n[1][2] = -(nnear + distance);
 529
 530   n[2][0] = xmax;
 531   n[2][1] = ymax;
 532   n[2][2] = -(nnear + distance);
 533
 534   n[3][0] = xmin;
 535   n[3][1] = ymax;
 536   n[3][2] = -(nnear + distance);
 537
 538   f[0][0] = xmin * t;
 539   f[0][1] = ymin * t;
 540   f[0][2] = -(ffar + distance);
 541
 542   f[1][0] = xmax * t;
 543   f[1][1] = ymin * t;
 544   f[1][2] = -(ffar + distance);
 545
 546   f[2][0] = xmax * t;
 547   f[2][1] = ymax * t;
 548   f[2][2] = -(ffar + distance);
 549
 550   f[3][0] = xmin * t;
 551   f[3][1] = ymax * t;
 552   f[3][2] = -(ffar + distance);
 553
 554   glColor3f(1.0, 1.0, 0.0);
 555   glBegin(GL_LINE_LOOP);
 556   glVertex3fv(n[0]);
 557   glVertex3fv(n[1]);
 558   glVertex3fv(n[2]);
 559   glVertex3fv(n[3]);
 560   glVertex3fv(f[3]);
 561   glVertex3fv(f[2]);
 562   glVertex3fv(f[1]);
 563   glVertex3fv(f[0]);
 564   glVertex3fv(n[0]);
 565   glVertex3fv(n[1]);
 566   glVertex3fv(f[1]);
 567   glVertex3fv(f[0]);
 568   glVertex3fv(f[3]);
 569   glVertex3fv(f[2]);
 570   glVertex3fv(n[2]);
 571   glVertex3fv(n[3]);
 572   glEnd();
 573 }
 574
 575 /*****************************************************************/
 576
 577 static void
 578 initialize(void)
 579 {
 580   GLfloat light0Pos[4] =
 581   {0.3, 0.3, 0.0, 1.0};
 582   GLfloat matAmb[4] =
 583   {0.01, 0.01, 0.01, 1.00};
 584   GLfloat matDiff[4] =
 585   {0.65, 0.65, 0.65, 1.00};
 586   GLfloat matSpec[4] =
 587   {0.30, 0.30, 0.30, 1.00};
 588   GLfloat matShine = 10.0;
 589   GLfloat eyePlaneS[] =
 590   {1.0, 0.0, 0.0, 0.0};
 591   GLfloat eyePlaneT[] =
 592   {0.0, 1.0, 0.0, 0.0};
 593   GLfloat eyePlaneR[] =
 594   {0.0, 0.0, 1.0, 0.0};
 595   GLfloat eyePlaneQ[] =
 596   {0.0, 0.0, 0.0, 1.0};
 597   int i;
 598
 599   /* Setup Misc.  */
 600   glClearColor(0.41, 0.41, 0.31, 0.0);
 601
 602   glEnable(GL_DEPTH_TEST);
 603
 604   /*  glLineWidth(2.0);*/
 605
 606   glCullFace(GL_FRONT);
 607   glEnable(GL_CULL_FACE);
 608
 609   glMatrixMode(GL_PROJECTION);
 610   glFrustum(-0.5, 0.5, -0.5, 0.5, 1, 3);
 611   glMatrixMode(GL_MODELVIEW);
 612   glTranslatef(0, 0, -2);
 613
 614   matrixIdentity((GLfloat *) objectXform);
 615   for (i = 0; i < NumTextures; i++) {
 616      matrixIdentity((GLfloat *) textureXform[i]);
 617   }
 618
 619   glMatrixMode(GL_PROJECTION);
 620   glPushMatrix();
 621   glLoadIdentity();
 622   glOrtho(0, 1, 0, 1, -1, 1);
 623   glMatrixMode(GL_MODELVIEW);
 624   glPushMatrix();
 625   glLoadIdentity();
 626
 627   glRasterPos2i(0, 0);
 628
 629   glPopMatrix();
 630   glMatrixMode(GL_PROJECTION);
 631   glPopMatrix();
 632   glMatrixMode(GL_MODELVIEW);
 633
 634   /* Setup Lighting */
 635   glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, matAmb);
 636   glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, matDiff);
 637   glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, matSpec);
 638   glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, matShine);
 639
 640   glEnable(GL_COLOR_MATERIAL);
 641
 642   glLightfv(GL_LIGHT0, GL_POSITION, light0Pos);
 643   glEnable(GL_LIGHT0);
 644
 645   glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_TRUE);
 646   glEnable(GL_LIGHTING);
 647
 648   /* Setup Texture */
 649
 650   (*loadTexture) ();
 651
 652
 653   for (i = 0; i < NumTextures; i++) {
 654      ActiveTexture(GL_TEXTURE0_ARB + i);
 655
 656      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
 657      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
 658      glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 659
 660      glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
 661      glTexGenfv(GL_S, GL_EYE_PLANE, eyePlaneS);
 662
 663      glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
 664      glTexGenfv(GL_T, GL_EYE_PLANE, eyePlaneT);
 665
 666      glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
 667      glTexGenfv(GL_R, GL_EYE_PLANE, eyePlaneR);
 668
 669      glTexGeni(GL_Q, GL_TEXTURE_GEN_MODE, GL_EYE_LINEAR);
 670      glTexGenfv(GL_Q, GL_EYE_PLANE, eyePlaneQ);
 671   }
 672 }
 673
 674 static void
 675 display(void)
 676 {
 677   int i;
 678
 679   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 680
 681   if (textureEnabled) {
 682     if (mode == MoveTexture || mode == MoveView) {
 683       /* Have OpenGL compute the new transformation (simple but slow). */
 684       for (i = 0; i < NumTextures; i++) {
 685         glPushMatrix();
 686         glLoadIdentity();
 687 #if 0
 688         if (i & 1)
 689            glRotatef(angle, axis[0], axis[1], axis[2]);
 690         else
 691 #endif
 692            glRotatef(angle*(i+1), axis[0], axis[1], axis[2]);
 693
 694         glMultMatrixf((GLfloat *) textureXform[i]);
 695         glGetFloatv(GL_MODELVIEW_MATRIX, (GLfloat *) textureXform[i]);
 696         glPopMatrix();
 697       }
 698     }
 699     for (i = 0; i < NumTextures; i++) {
 700        loadTextureProjection(i, (GLfloat *) textureXform[i]);
 701     }
 702
 703     if (showProjection) {
 704       for (i = 0; i < NumTextures; i++) {
 705         ActiveTexture(GL_TEXTURE0_ARB + i);
 706         glPushMatrix();
 707         glMultMatrixf((GLfloat *) textureXform[i]);
 708         glDisable(GL_LIGHTING);
 709         drawTextureProjection();
 710         glEnable(GL_LIGHTING);
 711         glPopMatrix();
 712       }
 713     }
 714     for (i = 0; i < NumTextures; i++) {
 715       ActiveTexture(GL_TEXTURE0_ARB + i);
 716       glEnable(GL_TEXTURE_2D);
 717       glEnable(GL_TEXTURE_GEN_S);
 718       glEnable(GL_TEXTURE_GEN_T);
 719       glEnable(GL_TEXTURE_GEN_R);
 720       glEnable(GL_TEXTURE_GEN_Q);
 721     }
 722   }
 723   if (mode == MoveObject || mode == MoveView) {
 724     /* Have OpenGL compute the new transformation (simple but slow). */
 725     glPushMatrix();
 726     glLoadIdentity();
 727     glRotatef(angle, axis[0], axis[1], axis[2]);
 728     glMultMatrixf((GLfloat *) objectXform);
 729     glGetFloatv(GL_MODELVIEW_MATRIX, (GLfloat *) objectXform);
 730     glPopMatrix();
 731   }
 732   glPushMatrix();
 733   glMultMatrixf((GLfloat *) objectXform);
 734   (*drawObject) ();
 735   glPopMatrix();
 736
 737   for (i = 0; i < NumTextures; i++) {
 738     ActiveTexture(GL_TEXTURE0_ARB + i);
 739     glDisable(GL_TEXTURE_2D);
 740     glDisable(GL_TEXTURE_GEN_S);
 741     glDisable(GL_TEXTURE_GEN_T);
 742     glDisable(GL_TEXTURE_GEN_R);
 743     glDisable(GL_TEXTURE_GEN_Q);
 744   }
 745
 746   if (zoomFactor > 1.0) {
 747     glDisable(GL_DEPTH_TEST);
 748     glCopyPixels(0, 0, winWidth / zoomFactor, winHeight / zoomFactor, GL_COLOR);
 749     glEnable(GL_DEPTH_TEST);
 750   }
 751   glFlush();
 752   glutSwapBuffers();
 753   checkErrors();
 754 }
 755
 756 /*****************************************************************/
 757
 758 /* simple trackball-like motion control */
 759 static float lastPos[3];
 760 static int lastTime;
 761
 762 static void
 763 ptov(int x, int y, int width, int height, float v[3])
 764 {
 765   float d, a;
 766
 767   /* project x,y onto a hemi-sphere centered within width, height */
 768   v[0] = (2.0 * x - width) / width;
 769   v[1] = (height - 2.0 * y) / height;
 770   d = sqrt(v[0] * v[0] + v[1] * v[1]);
 771   v[2] = cos((M_PI / 2.0) * ((d < 1.0) ? d : 1.0));
 772   a = 1.0 / sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
 773   v[0] *= a;
 774   v[1] *= a;
 775   v[2] *= a;
 776 }
 777
 778 static void
 779 startMotion(int x, int y, int but, int time)
 780 {
 781   if (but == GLUT_LEFT_BUTTON) {
 782     mode = MoveView;
 783   } else if (but == GLUT_MIDDLE_BUTTON) {
 784     mode = MoveTexture;
 785   } else {
 786     return;
 787   }
 788
 789   lastTime = time;
 790   ptov(x, y, winWidth, winHeight, lastPos);
 791 }
 792
 793 static void
 794 animate(void)
 795 {
 796   glutPostRedisplay();
 797 }
 798
 799 static void
 800 vis(int visible)
 801 {
 802   if (visible == GLUT_VISIBLE) {
 803     if (redrawContinuously)
 804       glutIdleFunc(animate);
 805   } else {
 806     if (redrawContinuously)
 807       glutIdleFunc(NULL);
 808   }
 809 }
 810
 811 static void
 812 stopMotion(int but, int time)
 813 {
 814   if ((but == GLUT_LEFT_BUTTON && mode == MoveView) ||
 815     (but == GLUT_MIDDLE_BUTTON && mode == MoveTexture)) {
 816   } else {
 817     return;
 818   }
 819
 820   if (time == lastTime) {
 821      /*    redrawContinuously = GL_TRUE;*/
 822     glutIdleFunc(animate);
 823   } else {
 824     angle = 0.0;
 825     redrawContinuously = GL_FALSE;
 826     glutIdleFunc(0);
 827   }
 828   if (!redrawContinuously) {
 829     mode = MoveNone;
 830   }
 831 }
 832
 833 static void
 834 trackMotion(int x, int y)
 835 {
 836   float curPos[3], dx, dy, dz;
 837
 838   ptov(x, y, winWidth, winHeight, curPos);
 839
 840   dx = curPos[0] - lastPos[0];
 841   dy = curPos[1] - lastPos[1];
 842   dz = curPos[2] - lastPos[2];
 843   angle = 90.0 * sqrt(dx * dx + dy * dy + dz * dz);
 844
 845   axis[0] = lastPos[1] * curPos[2] - lastPos[2] * curPos[1];
 846   axis[1] = lastPos[2] * curPos[0] - lastPos[0] * curPos[2];
 847   axis[2] = lastPos[0] * curPos[1] - lastPos[1] * curPos[0];
 848
 849   lastTime = glutGet(GLUT_ELAPSED_TIME);
 850   lastPos[0] = curPos[0];
 851   lastPos[1] = curPos[1];
 852   lastPos[2] = curPos[2];
 853   glutPostRedisplay();
 854 }
 855
 856 /*****************************************************************/
 857
 858 static void
 859 object(void)
 860 {
 861   static int object;
 862
 863   object++;
 864   object %= 3;
 865   switch (object) {
 866   case 0:
 867     drawObject = drawCube;
 868     break;
 869   case 1:
 870     drawObject = drawDodecahedron;
 871     break;
 872   case 2:
 873     drawObject = drawSphere;
 874     break;
 875   default:
 876     break;
 877   }
 878 }
 879
 880 static void
 881 nop(void)
 882 {
 883 }
 884
 885 static void
 886 texture(void)
 887 {
 888   static int texture = 0;
 889
 890   texture++;
 891   texture %= 3;
 892   if (texture == 1 && texFilename == NULL) {
 893     /* Skip file texture if not loaded. */
 894     texture++;
 895   }
 896   switch (texture) {
 897   case 0:
 898     loadTexture = nop;
 899     textureEnabled = GL_FALSE;
 900     break;
 901   case 1:
 902     loadTexture = loadImageTextures;
 903     (*loadTexture) ();
 904     textureEnabled = GL_TRUE;
 905     break;
 906   case 2:
 907     loadTexture = loadSpotlightTexture;
 908     (*loadTexture) ();
 909     textureEnabled = GL_TRUE;
 910     break;
 911   default:
 912     break;
 913   }
 914 }
 915
 916 static void
 917 help(void)
 918 {
 919   printf("'h'   - help\n");
 920   printf("'l'   - toggle linear/nearest filter\n");
 921   printf("'s'   - toggle projection frustum\n");
 922   printf("'t'   - toggle projected texture\n");
 923   printf("'o'   - toggle object\n");
 924   printf("'z'   - increase zoom factor\n");
 925   printf("'Z'   - decrease zoom factor\n");
 926   printf("left mouse     - move view\n");
 927   printf("middle mouse   - move projection\n");
 928 }
 929
 930 /* ARGSUSED1 */
 931 static void
 932 key(unsigned char key, int x, int y)
 933 {
 934   switch (key) {
 935   case '\033':
 936     exit(0);
 937     break;
 938   case 'l':
 939     linearFilter = !linearFilter;
 940     (*loadTexture) ();
 941     break;
 942   case 's':
 943     showProjection = !showProjection;
 944     break;
 945   case 't':
 946     texture();
 947     break;
 948   case 'o':
 949     object();
 950     break;
 951   case 'z':
 952     zoomFactor += 1.0;
 953     glPixelZoom(zoomFactor, zoomFactor);
 954     glViewport(0, 0, winWidth / zoomFactor, winHeight / zoomFactor);
 955     break;
 956   case 'Z':
 957     zoomFactor -= 1.0;
 958     if (zoomFactor < 1.0)
 959       zoomFactor = 1.0;
 960     glPixelZoom(zoomFactor, zoomFactor);
 961     glViewport(0, 0, winWidth / zoomFactor, winHeight / zoomFactor);
 962     break;
 963   case 'h':
 964     help();
 965     break;
 966   }
 967   glutPostRedisplay();
 968 }
 969
 970 static void
 971 mouse(int button, int state, int x, int y)
 972 {
 973   if (state == GLUT_DOWN)
 974     startMotion(x, y, button, glutGet(GLUT_ELAPSED_TIME));
 975   else if (state == GLUT_UP)
 976     stopMotion(button, glutGet(GLUT_ELAPSED_TIME));
 977   glutPostRedisplay();
 978 }
 979
 980 static void
 981 reshape(int w, int h)
 982 {
 983   winWidth = w;
 984   winHeight = h;
 985   glViewport(0, 0, w / zoomFactor, h / zoomFactor);
 986 }
 987
 988
 989 static void
 990 menu(int selection)
 991 {
 992   if (selection == 666) {
 993     exit(0);
 994   }
 995   key((unsigned char) selection, 0, 0);
 996 }
 997
 998 int
 999 main(int argc, char **argv)
1000 {
1001   glutInitWindowSize(500,500);
1002   glutInit(&argc, argv);
1003   glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE);
1004   (void) glutCreateWindow("projtex");
1005   glewInit();
1006
1007   if (argc > 1) {
1008      NumTextures = atoi(argv[1]);
1009   }
1010   assert(NumTextures <= MAX_TEX);
1011
1012   loadTexture = loadImageTextures;
1013   drawObject = drawCube;
1014   initialize();
1015   glutDisplayFunc(display);
1016   glutKeyboardFunc(key);
1017   glutReshapeFunc(reshape);
1018   glutMouseFunc(mouse);
1019   glutMotionFunc(trackMotion);
1020   glutVisibilityFunc(vis);
1021   glutCreateMenu(menu);
1022   glutAddMenuEntry("Toggle showing projection", 's');
1023   glutAddMenuEntry("Switch texture", 't');
1024   glutAddMenuEntry("Switch object", 'o');
1025   glutAddMenuEntry("Toggle filtering", 'l');
1026   glutAddMenuEntry("Quit", 666);
1027   glutAttachMenu(GLUT_RIGHT_BUTTON);
1028   texture();
1029   glutMainLoop();
1030   return 0;             /* ANSI C requires main to return int. */
1031 }