git.hungrycats.org Git - xscreensaver/blob - hacks/glx/cage.c

   1 /* -*- Mode: C; tab-width: 4 -*- */
   2 /* cage --- the Impossible Cage, an Escher like scene. */
   3
   4 #if !defined( lint ) && !defined( SABER )
   5 static const char sccsid[] = "@(#)cage.c        4.07 98/01/04 xlockmore";
   6
   7 #endif
   8
   9 #undef DEBUG_LISTS
  10
  11 /*-
  12  * Permission to use, copy, modify, and distribute this software and its
  13  * documentation for any purpose and without fee is hereby granted,
  14  * provided that the above copyright notice appear in all copies and that
  15  * both that copyright notice and this permission notice appear in
  16  * supporting documentation.
  17  *
  18  * This file is provided AS IS with no warranties of any kind.  The author
  19  * shall have no liability with respect to the infringement of copyrights,
  20  * trade secrets or any patents by this file or any part thereof.  In no
  21  * event will the author be liable for any lost revenue or profits or
  22  * other special, indirect and consequential damages.
  23  *
  24  * The RotateAroundU() routine was adapted from the book
  25  *    "Computer Graphics Principles and Practice
  26  *     Foley - vanDam - Feiner - Hughes
  27  *     Second Edition" Pag. 227, exercise 5.15.
  28  *
  29  * This mode shows some interesting scenes that are impossible OR very
  30  * wierd to build in the real universe. Much of the scenes are inspirated
  31  * on Mauritz Cornelis Escher's works which derivated the mode's name.
  32  * M.C. Escher (1898-1972) was a dutch artist and many people prefer to
  33  * say he was a mathematician.
  34  *
  35  * Thanks goes to Brian Paul for making it possible and inexpensive to use
  36  * OpenGL at home.
  37  *
  38  * Since I'm not a native English speaker, my apologies for any grammatical
  39  * mistake.
  40  *
  41  * My e-mail address is
  42  * m-vianna@usa.net
  43  *
  44  * Marcelo F. Vianna (Jun-01-1997)
  45  *
  46  * Revision History:
  47  * 01-Jan-98: Mode separated from escher and renamed
  48  * 08-Jun-97: New scene implemented: "Impossible Cage" based in a M.C. Escher's
  49  *            painting with the same name (quite similar). The first GL mode
  50  *            to use texture mapping.
  51  *            The "Impossible Cage" scene doesn't use DEPTH BUFFER, the
  52  *            wood planks are drawn consistently using GL_CULL_FACE, and
  53  *            the painter's algorithm is used to sort the planks.
  54  *            Marcelo F. Vianna.
  55  * 07-Jun-97: Speed ups in Moebius Strip using GL_CULL_FACE.
  56  *            Marcelo F. Vianna.
  57  * 03-Jun-97: Initial Release (Only one scene: "Moebius Strip")
  58  *            The Moebius Strip scene was inspirated in a M.C. Escher's
  59  *            painting named Moebius Strip II in wich ants walk across a
  60  *            Moebius Strip path, sometimes meeting each other and sometimes
  61  *            being in "opposite faces" (note that the moebius strip has
  62  *            only one face and one edge).
  63  *            Marcelo F. Vianna.
  64  *
  65  */
  66
  67 /*-
  68  * Texture mapping is only available on RGBA contexts, Mono and color index
  69  * visuals DO NOT support texture mapping in OpenGL.
  70  *
  71  * BUT Mesa do implements RGBA contexts in pseudo color visuals, so texture
  72  * mapping shuld work on PseudoColor, DirectColor, TrueColor using Mesa. Mono
  73  * is not officially supported for both OpenGL and Mesa, but seems to not crash
  74  * Mesa.
  75  *
  76  * In real OpenGL, PseudoColor DO NOT support texture map (as far as I know).
  77  */
  78
  79 #include <X11/Intrinsic.h>
  80
  81 #ifdef STANDALONE
  82 # define PROGCLASS                      "Cage"
  83 # define HACK_INIT                      init_cage
  84 # define HACK_DRAW                      draw_cage
  85 # define cage_opts                      xlockmore_opts
  86 # define DEFAULTS                       "*cycles:               1       \n"                     \
  87                                                         "*delay:                1000    \n"                     \
  88                                                         "*wireframe:    False   \n"
  89 # include "xlockmore.h"         /* from the xscreensaver distribution */
  90 #else /* !STANDALONE */
  91 # include "xlock.h"             /* from the xlockmore distribution */
  92
  93 #endif /* !STANDALONE */
  94
  95 #ifdef USE_GL
  96
  97
  98 #include <GL/glu.h>
  99 #include "e_textures.h"
 100
 101 ModeSpecOpt cage_opts =
 102 {0, NULL, 0, NULL, NULL};
 103
 104 #ifdef USE_MODULES
 105 ModStruct   cage_description =
 106 {"cage", "init_cage", "draw_cage", "release_cage",
 107  "draw_cage", "change_cage", NULL, &cage_opts,
 108  1000, 1, 1, 1, 1.0, 4, "",
 109  "Shows the Impossible Cage, an Escher-like GL scene", 0, NULL};
 110
 111 #endif
 112
 113 #define Scale4Window               0.3
 114 #define Scale4Iconic               0.4
 115
 116 #define sqr(A)                     ((A)*(A))
 117
 118 #ifndef Pi
 119 #define Pi                         M_PI
 120 #endif
 121
 122 /*************************************************************************/
 123
 124 typedef struct {
 125         GLint       WindH, WindW;
 126         GLfloat     step;
 127         int         AreObjectsDefined[1];
 128         GLXContext *glx_context;
 129 } cagestruct;
 130
 131 static float front_shininess[] =
 132 {60.0};
 133 static float front_specular[] =
 134 {0.7, 0.7, 0.7, 1.0};
 135 static float ambient[] =
 136 {0.0, 0.0, 0.0, 1.0};
 137 static float diffuse[] =
 138 {1.0, 1.0, 1.0, 1.0};
 139 static float position0[] =
 140 {1.0, 1.0, 1.0, 0.0};
 141 static float position1[] =
 142 {-1.0, -1.0, 1.0, 0.0};
 143 static float lmodel_ambient[] =
 144 {0.5, 0.5, 0.5, 1.0};
 145 static float lmodel_twoside[] =
 146 {GL_TRUE};
 147
 148 static float MaterialWhite[] =
 149 {0.7, 0.7, 0.7, 1.0};
 150
 151 static cagestruct *cage = NULL;
 152 static GLuint objects;
 153
 154 #define ObjWoodPlank    0
 155
 156 #define PlankWidth      3.0
 157 #define PlankHeight     0.35
 158 #define PlankThickness  0.15
 159
 160 static void
 161 draw_woodplank(cagestruct * cp)
 162 {
 163         if (!cp->AreObjectsDefined[ObjWoodPlank]) {
 164                 glNewList(objects + ObjWoodPlank, GL_COMPILE_AND_EXECUTE);
 165                 glBegin(GL_QUADS);
 166                 glNormal3f(0, 0, 1);
 167                 glTexCoord2f(0, 0);
 168                 glVertex3f(-PlankWidth, -PlankHeight, PlankThickness);
 169                 glTexCoord2f(1, 0);
 170                 glVertex3f(PlankWidth, -PlankHeight, PlankThickness);
 171                 glTexCoord2f(1, 1);
 172                 glVertex3f(PlankWidth, PlankHeight, PlankThickness);
 173                 glTexCoord2f(0, 1);
 174                 glVertex3f(-PlankWidth, PlankHeight, PlankThickness);
 175                 glNormal3f(0, 0, -1);
 176                 glTexCoord2f(0, 0);
 177                 glVertex3f(-PlankWidth, PlankHeight, -PlankThickness);
 178                 glTexCoord2f(1, 0);
 179                 glVertex3f(PlankWidth, PlankHeight, -PlankThickness);
 180                 glTexCoord2f(1, 1);
 181                 glVertex3f(PlankWidth, -PlankHeight, -PlankThickness);
 182                 glTexCoord2f(0, 1);
 183                 glVertex3f(-PlankWidth, -PlankHeight, -PlankThickness);
 184                 glNormal3f(0, 1, 0);
 185                 glTexCoord2f(0, 0);
 186                 glVertex3f(-PlankWidth, PlankHeight, PlankThickness);
 187                 glTexCoord2f(1, 0);
 188                 glVertex3f(PlankWidth, PlankHeight, PlankThickness);
 189                 glTexCoord2f(1, 1);
 190                 glVertex3f(PlankWidth, PlankHeight, -PlankThickness);
 191                 glTexCoord2f(0, 1);
 192                 glVertex3f(-PlankWidth, PlankHeight, -PlankThickness);
 193                 glNormal3f(0, -1, 0);
 194                 glTexCoord2f(0, 0);
 195                 glVertex3f(-PlankWidth, -PlankHeight, -PlankThickness);
 196                 glTexCoord2f(1, 0);
 197                 glVertex3f(PlankWidth, -PlankHeight, -PlankThickness);
 198                 glTexCoord2f(1, 1);
 199                 glVertex3f(PlankWidth, -PlankHeight, PlankThickness);
 200                 glTexCoord2f(0, 1);
 201                 glVertex3f(-PlankWidth, -PlankHeight, PlankThickness);
 202                 glNormal3f(1, 0, 0);
 203                 glTexCoord2f(0, 0);
 204                 glVertex3f(PlankWidth, -PlankHeight, PlankThickness);
 205                 glTexCoord2f(1, 0);
 206                 glVertex3f(PlankWidth, -PlankHeight, -PlankThickness);
 207                 glTexCoord2f(1, 1);
 208                 glVertex3f(PlankWidth, PlankHeight, -PlankThickness);
 209                 glTexCoord2f(0, 1);
 210                 glVertex3f(PlankWidth, PlankHeight, PlankThickness);
 211                 glNormal3f(-1, 0, 0);
 212                 glTexCoord2f(0, 0);
 213                 glVertex3f(-PlankWidth, PlankHeight, PlankThickness);
 214                 glTexCoord2f(1, 0);
 215                 glVertex3f(-PlankWidth, PlankHeight, -PlankThickness);
 216                 glTexCoord2f(1, 1);
 217                 glVertex3f(-PlankWidth, -PlankHeight, -PlankThickness);
 218                 glTexCoord2f(0, 1);
 219                 glVertex3f(-PlankWidth, -PlankHeight, PlankThickness);
 220                 glEnd();
 221                 glEndList();
 222                 cp->AreObjectsDefined[ObjWoodPlank] = 1;
 223 #ifdef DEBUG_LISTS
 224                 (void) printf("WoodPlank drawn SLOWLY\n");
 225 #endif
 226         } else {
 227                 glCallList(objects + ObjWoodPlank);
 228 #ifdef DEBUG_LISTS
 229                 (void) printf("WoodPlank drawn quickly\n");
 230 #endif
 231         }
 232 }
 233
 234 static void
 235 draw_impossiblecage(cagestruct * cp)
 236 {
 237         glPushMatrix();
 238         glRotatef(90, 0, 1, 0);
 239         glTranslatef(0.0, PlankHeight - PlankWidth, -PlankThickness - PlankWidth);
 240         draw_woodplank(cp);
 241         glPopMatrix();
 242         glPushMatrix();
 243         glRotatef(90, 0, 0, 1);
 244         glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth - PlankThickness);
 245         draw_woodplank(cp);
 246         glPopMatrix();
 247         glPushMatrix();
 248         glRotatef(90, 0, 1, 0);
 249         glTranslatef(0.0, PlankWidth - PlankHeight, -PlankThickness - PlankWidth);
 250         draw_woodplank(cp);
 251         glPopMatrix();
 252         glPushMatrix();
 253         glTranslatef(0.0, PlankWidth - PlankHeight, 3 * PlankThickness - PlankWidth);
 254         draw_woodplank(cp);
 255         glPopMatrix();
 256         glPushMatrix();
 257         glRotatef(90, 0, 0, 1);
 258         glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth - PlankThickness);
 259         draw_woodplank(cp);
 260         glPopMatrix();
 261         glPushMatrix();
 262         glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth - 3 * PlankThickness);
 263         draw_woodplank(cp);
 264         glPopMatrix();
 265         glPushMatrix();
 266         glTranslatef(0.0, PlankHeight - PlankWidth, 3 * PlankThickness - PlankWidth);
 267         draw_woodplank(cp);
 268         glPopMatrix();
 269         glPushMatrix();
 270         glRotatef(90, 0, 0, 1);
 271         glTranslatef(0.0, PlankHeight - PlankWidth, PlankThickness - PlankWidth);
 272         draw_woodplank(cp);
 273         glPopMatrix();
 274         glPushMatrix();
 275         glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth - 3 * PlankThickness);
 276         draw_woodplank(cp);
 277         glPopMatrix();
 278         glPushMatrix();
 279         glRotatef(90, 0, 1, 0);
 280         glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth + PlankThickness);
 281         draw_woodplank(cp);
 282         glPopMatrix();
 283         glPushMatrix();
 284         glRotatef(90, 0, 0, 1);
 285         glTranslatef(0.0, PlankWidth - PlankHeight, PlankThickness - PlankWidth);
 286         draw_woodplank(cp);
 287         glPopMatrix();
 288         glPushMatrix();
 289         glRotatef(90, 0, 1, 0);
 290         glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth + PlankThickness);
 291         draw_woodplank(cp);
 292         glPopMatrix();
 293 }
 294
 295 static void
 296 reshape(ModeInfo * mi, int width, int height)
 297 {
 298         cagestruct *cp = &cage[MI_SCREEN(mi)];
 299
 300         glViewport(0, 0, cp->WindW = (GLint) width, cp->WindH = (GLint) height);
 301         glMatrixMode(GL_PROJECTION);
 302         glLoadIdentity();
 303         glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 15.0);
 304         glMatrixMode(GL_MODELVIEW);
 305         if (width >= 1024) {
 306                 glLineWidth(3);
 307                 glPointSize(3);
 308         } else if (width >= 512) {
 309                 glLineWidth(2);
 310                 glPointSize(2);
 311         } else {
 312                 glLineWidth(1);
 313                 glPointSize(1);
 314         }
 315         cp->AreObjectsDefined[ObjWoodPlank] = 0;
 316 }
 317
 318 static void
 319 pinit(void)
 320 {
 321         glClearDepth(1.0);
 322         glClearColor(0.0, 0.0, 0.0, 1.0);
 323
 324         glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);
 325         glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse);
 326         glLightfv(GL_LIGHT0, GL_POSITION, position0);
 327         glLightfv(GL_LIGHT1, GL_AMBIENT, ambient);
 328         glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuse);
 329         glLightfv(GL_LIGHT1, GL_POSITION, position1);
 330         glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);
 331         glLightModelfv(GL_LIGHT_MODEL_TWO_SIDE, lmodel_twoside);
 332         glEnable(GL_LIGHTING);
 333         glEnable(GL_LIGHT0);
 334         glEnable(GL_LIGHT1);
 335         glEnable(GL_NORMALIZE);
 336         glFrontFace(GL_CCW);
 337         glCullFace(GL_BACK);
 338
 339         /* cage */
 340         glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialWhite);
 341         glShadeModel(GL_FLAT);
 342         glDisable(GL_DEPTH_TEST);
 343         glEnable(GL_TEXTURE_2D);
 344         glEnable(GL_CULL_FACE);
 345
 346         glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 347         gluBuild2DMipmaps(GL_TEXTURE_2D, 3, WoodTextureWidth, WoodTextureHeight,
 348                           GL_RGB, GL_UNSIGNED_BYTE, WoodTextureData);
 349         glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 350         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
 351         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 352         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 353         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 354
 355         glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, front_shininess);
 356         glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, front_specular);
 357 }
 358
 359 void
 360 init_cage(ModeInfo * mi)
 361 {
 362         int         screen = MI_SCREEN(mi);
 363         cagestruct *cp;
 364
 365         if (cage == NULL) {
 366                 if ((cage = (cagestruct *) calloc(MI_NUM_SCREENS(mi),
 367                                                sizeof (cagestruct))) == NULL)
 368                         return;
 369         }
 370         cp = &cage[screen];
 371         cp->step = NRAND(90);
 372
 373         if ((cp->glx_context = init_GL(mi)) != NULL) {
 374
 375                 reshape(mi, MI_WIDTH(mi), MI_HEIGHT(mi));
 376                 glDrawBuffer(GL_BACK);
 377                 if (!glIsList(objects))
 378                         objects = glGenLists(1);
 379                 pinit();
 380         } else {
 381                 MI_CLEARWINDOW(mi);
 382         }
 383 }
 384
 385 void
 386 draw_cage(ModeInfo * mi)
 387 {
 388         cagestruct *cp = &cage[MI_SCREEN(mi)];
 389
 390         Display    *display = MI_DISPLAY(mi);
 391         Window      window = MI_WINDOW(mi);
 392
 393         MI_IS_DRAWN(mi) = True;
 394
 395         if (!cp->glx_context)
 396                 return;
 397
 398         glXMakeCurrent(display, window, *(cp->glx_context));
 399
 400         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 401
 402         glPushMatrix();
 403
 404         glTranslatef(0.0, 0.0, -10.0);
 405
 406         if (!MI_IS_ICONIC(mi)) {
 407                 glScalef(Scale4Window * cp->WindH / cp->WindW, Scale4Window, Scale4Window);
 408         } else {
 409                 glScalef(Scale4Iconic * cp->WindH / cp->WindW, Scale4Iconic, Scale4Iconic);
 410         }
 411
 412         /* cage */
 413         glRotatef(cp->step * 100, 0, 0, 1);
 414         glRotatef(25 + cos(cp->step * 5) * 6, 1, 0, 0);
 415         glRotatef(204.5 - sin(cp->step * 5) * 8, 0, 1, 0);
 416         draw_impossiblecage(cp);
 417
 418         glPopMatrix();
 419
 420         glFlush();
 421
 422         glXSwapBuffers(display, window);
 423
 424         cp->step += 0.025;
 425 }
 426
 427 void
 428 change_cage(ModeInfo * mi)
 429 {
 430         cagestruct *cp = &cage[MI_SCREEN(mi)];
 431
 432         if (!cp->glx_context)
 433                 return;
 434
 435         glXMakeCurrent(MI_DISPLAY(mi), MI_WINDOW(mi), *(cp->glx_context));
 436         pinit();
 437 }
 438
 439 void
 440 release_cage(ModeInfo * mi)
 441 {
 442         if (cage != NULL) {
 443                 (void) free((void *) cage);
 444                 cage = NULL;
 445         }
 446         if (glIsList(objects)) {
 447                 glDeleteLists(objects, 1);
 448         }
 449         FreeAllGL(mi);
 450 }
 451
 452 #endif