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 HACK_RESHAPE                   reshape_cage
  86 # define cage_opts                      xlockmore_opts
  87 # define DEFAULTS                       "*cycles:               1       \n"                     \
  88                                                         "*delay:                25000   \n"                     \
  89                                                         "*showFPS:      False   \n"                     \
  90                                                         "*wireframe:    False   \n"
  91 # include "xlockmore.h"         /* from the xscreensaver distribution */
  92 #else /* !STANDALONE */
  93 # include "xlock.h"             /* from the xlockmore distribution */
  94
  95 #endif /* !STANDALONE */
  96
  97 #ifdef USE_GL
  98
  99
 100 #include <GL/glu.h>
 101 #include "e_textures.h"
 102
 103 ModeSpecOpt cage_opts =
 104 {0, NULL, 0, NULL, NULL};
 105
 106 #ifdef USE_MODULES
 107 ModStruct   cage_description =
 108 {"cage", "init_cage", "draw_cage", "release_cage",
 109  "draw_cage", "change_cage", NULL, &cage_opts,
 110  1000, 1, 1, 1, 1.0, 4, "",
 111  "Shows the Impossible Cage, an Escher-like GL scene", 0, NULL};
 112
 113 #endif
 114
 115 #define Scale4Window               0.3
 116 #define Scale4Iconic               0.4
 117
 118 #define sqr(A)                     ((A)*(A))
 119
 120 #ifndef Pi
 121 #define Pi                         M_PI
 122 #endif
 123
 124 /*************************************************************************/
 125
 126 typedef struct {
 127         GLint       WindH, WindW;
 128         GLfloat     step;
 129         int         AreObjectsDefined[1];
 130         GLXContext *glx_context;
 131 } cagestruct;
 132
 133 static float front_shininess[] =
 134 {60.0};
 135 static float front_specular[] =
 136 {0.7, 0.7, 0.7, 1.0};
 137 static float ambient[] =
 138 {0.0, 0.0, 0.0, 1.0};
 139 static float diffuse[] =
 140 {1.0, 1.0, 1.0, 1.0};
 141 static float position0[] =
 142 {1.0, 1.0, 1.0, 0.0};
 143 static float position1[] =
 144 {-1.0, -1.0, 1.0, 0.0};
 145 static float lmodel_ambient[] =
 146 {0.5, 0.5, 0.5, 1.0};
 147 static float lmodel_twoside[] =
 148 {GL_TRUE};
 149
 150 static float MaterialWhite[] =
 151 {0.7, 0.7, 0.7, 1.0};
 152
 153 static cagestruct *cage = NULL;
 154 static GLuint objects;
 155
 156 #define ObjWoodPlank    0
 157
 158 #define PlankWidth      3.0
 159 #define PlankHeight     0.35
 160 #define PlankThickness  0.15
 161
 162 static void
 163 draw_woodplank(cagestruct * cp)
 164 {
 165         if (!cp->AreObjectsDefined[ObjWoodPlank]) {
 166                 glNewList(objects + ObjWoodPlank, GL_COMPILE_AND_EXECUTE);
 167                 glBegin(GL_QUADS);
 168                 glNormal3f(0, 0, 1);
 169                 glTexCoord2f(0, 0);
 170                 glVertex3f(-PlankWidth, -PlankHeight, PlankThickness);
 171                 glTexCoord2f(1, 0);
 172                 glVertex3f(PlankWidth, -PlankHeight, PlankThickness);
 173                 glTexCoord2f(1, 1);
 174                 glVertex3f(PlankWidth, PlankHeight, PlankThickness);
 175                 glTexCoord2f(0, 1);
 176                 glVertex3f(-PlankWidth, PlankHeight, PlankThickness);
 177                 glNormal3f(0, 0, -1);
 178                 glTexCoord2f(0, 0);
 179                 glVertex3f(-PlankWidth, PlankHeight, -PlankThickness);
 180                 glTexCoord2f(1, 0);
 181                 glVertex3f(PlankWidth, PlankHeight, -PlankThickness);
 182                 glTexCoord2f(1, 1);
 183                 glVertex3f(PlankWidth, -PlankHeight, -PlankThickness);
 184                 glTexCoord2f(0, 1);
 185                 glVertex3f(-PlankWidth, -PlankHeight, -PlankThickness);
 186                 glNormal3f(0, 1, 0);
 187                 glTexCoord2f(0, 0);
 188                 glVertex3f(-PlankWidth, PlankHeight, PlankThickness);
 189                 glTexCoord2f(1, 0);
 190                 glVertex3f(PlankWidth, PlankHeight, PlankThickness);
 191                 glTexCoord2f(1, 1);
 192                 glVertex3f(PlankWidth, PlankHeight, -PlankThickness);
 193                 glTexCoord2f(0, 1);
 194                 glVertex3f(-PlankWidth, PlankHeight, -PlankThickness);
 195                 glNormal3f(0, -1, 0);
 196                 glTexCoord2f(0, 0);
 197                 glVertex3f(-PlankWidth, -PlankHeight, -PlankThickness);
 198                 glTexCoord2f(1, 0);
 199                 glVertex3f(PlankWidth, -PlankHeight, -PlankThickness);
 200                 glTexCoord2f(1, 1);
 201                 glVertex3f(PlankWidth, -PlankHeight, PlankThickness);
 202                 glTexCoord2f(0, 1);
 203                 glVertex3f(-PlankWidth, -PlankHeight, PlankThickness);
 204                 glNormal3f(1, 0, 0);
 205                 glTexCoord2f(0, 0);
 206                 glVertex3f(PlankWidth, -PlankHeight, PlankThickness);
 207                 glTexCoord2f(1, 0);
 208                 glVertex3f(PlankWidth, -PlankHeight, -PlankThickness);
 209                 glTexCoord2f(1, 1);
 210                 glVertex3f(PlankWidth, PlankHeight, -PlankThickness);
 211                 glTexCoord2f(0, 1);
 212                 glVertex3f(PlankWidth, PlankHeight, PlankThickness);
 213                 glNormal3f(-1, 0, 0);
 214                 glTexCoord2f(0, 0);
 215                 glVertex3f(-PlankWidth, PlankHeight, PlankThickness);
 216                 glTexCoord2f(1, 0);
 217                 glVertex3f(-PlankWidth, PlankHeight, -PlankThickness);
 218                 glTexCoord2f(1, 1);
 219                 glVertex3f(-PlankWidth, -PlankHeight, -PlankThickness);
 220                 glTexCoord2f(0, 1);
 221                 glVertex3f(-PlankWidth, -PlankHeight, PlankThickness);
 222                 glEnd();
 223                 glEndList();
 224                 cp->AreObjectsDefined[ObjWoodPlank] = 1;
 225 #ifdef DEBUG_LISTS
 226                 (void) printf("WoodPlank drawn SLOWLY\n");
 227 #endif
 228         } else {
 229                 glCallList(objects + ObjWoodPlank);
 230 #ifdef DEBUG_LISTS
 231                 (void) printf("WoodPlank drawn quickly\n");
 232 #endif
 233         }
 234 }
 235
 236 static void
 237 draw_impossiblecage(cagestruct * cp)
 238 {
 239         glPushMatrix();
 240         glRotatef(90, 0, 1, 0);
 241         glTranslatef(0.0, PlankHeight - PlankWidth, -PlankThickness - PlankWidth);
 242         draw_woodplank(cp);
 243         glPopMatrix();
 244         glPushMatrix();
 245         glRotatef(90, 0, 0, 1);
 246         glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth - PlankThickness);
 247         draw_woodplank(cp);
 248         glPopMatrix();
 249         glPushMatrix();
 250         glRotatef(90, 0, 1, 0);
 251         glTranslatef(0.0, PlankWidth - PlankHeight, -PlankThickness - PlankWidth);
 252         draw_woodplank(cp);
 253         glPopMatrix();
 254         glPushMatrix();
 255         glTranslatef(0.0, PlankWidth - PlankHeight, 3 * PlankThickness - PlankWidth);
 256         draw_woodplank(cp);
 257         glPopMatrix();
 258         glPushMatrix();
 259         glRotatef(90, 0, 0, 1);
 260         glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth - PlankThickness);
 261         draw_woodplank(cp);
 262         glPopMatrix();
 263         glPushMatrix();
 264         glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth - 3 * PlankThickness);
 265         draw_woodplank(cp);
 266         glPopMatrix();
 267         glPushMatrix();
 268         glTranslatef(0.0, PlankHeight - PlankWidth, 3 * PlankThickness - PlankWidth);
 269         draw_woodplank(cp);
 270         glPopMatrix();
 271         glPushMatrix();
 272         glRotatef(90, 0, 0, 1);
 273         glTranslatef(0.0, PlankHeight - PlankWidth, PlankThickness - PlankWidth);
 274         draw_woodplank(cp);
 275         glPopMatrix();
 276         glPushMatrix();
 277         glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth - 3 * PlankThickness);
 278         draw_woodplank(cp);
 279         glPopMatrix();
 280         glPushMatrix();
 281         glRotatef(90, 0, 1, 0);
 282         glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth + PlankThickness);
 283         draw_woodplank(cp);
 284         glPopMatrix();
 285         glPushMatrix();
 286         glRotatef(90, 0, 0, 1);
 287         glTranslatef(0.0, PlankWidth - PlankHeight, PlankThickness - PlankWidth);
 288         draw_woodplank(cp);
 289         glPopMatrix();
 290         glPushMatrix();
 291         glRotatef(90, 0, 1, 0);
 292         glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth + PlankThickness);
 293         draw_woodplank(cp);
 294         glPopMatrix();
 295 }
 296
 297 void
 298 reshape_cage(ModeInfo * mi, int width, int height)
 299 {
 300         cagestruct *cp = &cage[MI_SCREEN(mi)];
 301
 302         glViewport(0, 0, cp->WindW = (GLint) width, cp->WindH = (GLint) height);
 303         glMatrixMode(GL_PROJECTION);
 304         glLoadIdentity();
 305         glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 15.0);
 306         glMatrixMode(GL_MODELVIEW);
 307         if (width >= 1024) {
 308                 glLineWidth(3);
 309                 glPointSize(3);
 310         } else if (width >= 512) {
 311                 glLineWidth(2);
 312                 glPointSize(2);
 313         } else {
 314                 glLineWidth(1);
 315                 glPointSize(1);
 316         }
 317         cp->AreObjectsDefined[ObjWoodPlank] = 0;
 318 }
 319
 320 static void
 321 pinit(void)
 322 {
 323         glClearDepth(1.0);
 324         glClearColor(0.0, 0.0, 0.0, 1.0);
 325
 326         glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);
 327         glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse);
 328         glLightfv(GL_LIGHT0, GL_POSITION, position0);
 329         glLightfv(GL_LIGHT1, GL_AMBIENT, ambient);
 330         glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuse);
 331         glLightfv(GL_LIGHT1, GL_POSITION, position1);
 332         glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);
 333         glLightModelfv(GL_LIGHT_MODEL_TWO_SIDE, lmodel_twoside);
 334         glEnable(GL_LIGHTING);
 335         glEnable(GL_LIGHT0);
 336         glEnable(GL_LIGHT1);
 337         glEnable(GL_NORMALIZE);
 338         glFrontFace(GL_CCW);
 339         glCullFace(GL_BACK);
 340
 341         /* cage */
 342         glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialWhite);
 343         glShadeModel(GL_FLAT);
 344         glDisable(GL_DEPTH_TEST);
 345         glEnable(GL_TEXTURE_2D);
 346         glEnable(GL_CULL_FACE);
 347
 348         glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 349         gluBuild2DMipmaps(GL_TEXTURE_2D, 3, WoodTextureWidth, WoodTextureHeight,
 350                           GL_RGB, GL_UNSIGNED_BYTE, WoodTextureData);
 351         glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 352         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
 353         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 354         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 355         glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 356
 357         glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, front_shininess);
 358         glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, front_specular);
 359 }
 360
 361 void
 362 init_cage(ModeInfo * mi)
 363 {
 364         int         screen = MI_SCREEN(mi);
 365         cagestruct *cp;
 366
 367         if (cage == NULL) {
 368                 if ((cage = (cagestruct *) calloc(MI_NUM_SCREENS(mi),
 369                                                sizeof (cagestruct))) == NULL)
 370                         return;
 371         }
 372         cp = &cage[screen];
 373         cp->step = NRAND(90);
 374
 375         if ((cp->glx_context = init_GL(mi)) != NULL) {
 376
 377                 reshape_cage(mi, MI_WIDTH(mi), MI_HEIGHT(mi));
 378                 glDrawBuffer(GL_BACK);
 379                 if (!glIsList(objects))
 380                         objects = glGenLists(1);
 381                 pinit();
 382         } else {
 383                 MI_CLEARWINDOW(mi);
 384         }
 385 }
 386
 387 void
 388 draw_cage(ModeInfo * mi)
 389 {
 390         cagestruct *cp = &cage[MI_SCREEN(mi)];
 391
 392         Display    *display = MI_DISPLAY(mi);
 393         Window      window = MI_WINDOW(mi);
 394
 395         MI_IS_DRAWN(mi) = True;
 396
 397         if (!cp->glx_context)
 398                 return;
 399
 400         glXMakeCurrent(display, window, *(cp->glx_context));
 401
 402         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 403
 404         glPushMatrix();
 405
 406         glTranslatef(0.0, 0.0, -10.0);
 407
 408         if (!MI_IS_ICONIC(mi)) {
 409                 glScalef(Scale4Window * cp->WindH / cp->WindW, Scale4Window, Scale4Window);
 410         } else {
 411                 glScalef(Scale4Iconic * cp->WindH / cp->WindW, Scale4Iconic, Scale4Iconic);
 412         }
 413
 414         /* cage */
 415         glRotatef(cp->step * 100, 0, 0, 1);
 416         glRotatef(25 + cos(cp->step * 5) * 6, 1, 0, 0);
 417         glRotatef(204.5 - sin(cp->step * 5) * 8, 0, 1, 0);
 418         draw_impossiblecage(cp);
 419
 420         glPopMatrix();
 421
 422     if (mi->fps_p) do_fps (mi);
 423         glFlush();
 424
 425         glXSwapBuffers(display, window);
 426
 427         cp->step += 0.025;
 428 }
 429
 430 void
 431 change_cage(ModeInfo * mi)
 432 {
 433         cagestruct *cp = &cage[MI_SCREEN(mi)];
 434
 435         if (!cp->glx_context)
 436                 return;
 437
 438         glXMakeCurrent(MI_DISPLAY(mi), MI_WINDOW(mi), *(cp->glx_context));
 439         pinit();
 440 }
 441
 442 void
 443 release_cage(ModeInfo * mi)
 444 {
 445         if (cage != NULL) {
 446                 (void) free((void *) cage);
 447                 cage = NULL;
 448         }
 449         if (glIsList(objects)) {
 450                 glDeleteLists(objects, 1);
 451         }
 452         FreeAllGL(mi);
 453 }
 454
 455 #endif