464 lines
13 KiB
C
464 lines
13 KiB
C
/* -*- Mode: C; tab-width: 4 -*- */
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/* cage --- the Impossible Cage, an Escher like scene. */
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#if !defined( lint ) && !defined( SABER )
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static const char sccsid[] = "@(#)cage.c 5.01 2001/03/01 xlockmore";
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#endif
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/*-
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* Permission to use, copy, modify, and distribute this software and its
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* documentation for any purpose and without fee is hereby granted,
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* provided that the above copyright notice appear in all copies and that
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* both that copyright notice and this permission notice appear in
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* supporting documentation.
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*
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* This file is provided AS IS with no warranties of any kind. The author
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* shall have no liability with respect to the infringement of copyrights,
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* trade secrets or any patents by this file or any part thereof. In no
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* event will the author be liable for any lost revenue or profits or
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* other special, indirect and consequential damages.
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*
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* The RotateAroundU() routine was adapted from the book
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* "Computer Graphics Principles and Practice
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* Foley - vanDam - Feiner - Hughes
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* Second Edition" Pag. 227, exercise 5.15.
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*
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* This mode shows some interesting scenes that are impossible OR very
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* wierd to build in the real universe. Much of the scenes are inspirated
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* on Mauritz Cornelis Escher's works which derivated the mode's name.
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* M.C. Escher (1898-1972) was a dutch artist and many people prefer to
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* say he was a mathematician.
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*
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* Thanks goes to Brian Paul for making it possible and inexpensive to use
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* OpenGL at home.
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*
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* Since I'm not a native English speaker, my apologies for any grammatical
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* mistakes.
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*
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* My e-mail address is
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* mfvianna@centroin.com.br
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*
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* Marcelo F. Vianna (Jun-01-1997)
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*
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* Revision History:
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* 05-Apr-2002: Removed all gllist uses (fix some bug with nvidia driver)
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* 01-Mar-2001: Added FPS stuff E.Lassauge <lassauge AT users.sourceforge.net>
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* 01-Nov-2000: Allocation checks
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* 01-Jan-1998: Mode separated from escher and renamed
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* 08-Jun-1997: New scene implemented: "Impossible Cage" based in a M.C.
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* Escher's painting with the same name (quite similar). The
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* first GL mode to use texture mapping.
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* The "Impossible Cage" scene doesn't use DEPTH BUFFER, the
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* wood planks are drawn consistently using GL_CULL_FACE, and
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* the painter's algorithm is used to sort the planks.
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* Marcelo F. Vianna.
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* 07-Jun-1997: Speed ups in Moebius Strip using GL_CULL_FACE.
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* Marcelo F. Vianna.
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* 03-Jun-1997: Initial Release (Only one scene: "Moebius Strip")
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* The Moebius Strip scene was inspirated in a M.C. Escher's
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* painting named Moebius Strip II in wich ants walk across a
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* Moebius Strip path, sometimes meeting each other and sometimes
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* being in "opposite faces" (note that the moebius strip has
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* only one face and one edge).
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* Marcelo F. Vianna.
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*/
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/*-
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* Texture mapping is only available on RGBA contexts, Mono and color index
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* visuals DO NOT support texture mapping in OpenGL.
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*
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* BUT Mesa do implements RGBA contexts in pseudo color visuals, so texture
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* mapping shuld work on PseudoColor, DirectColor, TrueColor using Mesa. Mono
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* is not officially supported for both OpenGL and Mesa, but seems to not crash
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* Mesa.
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*
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* In real OpenGL, PseudoColor DO NOT support texture map (as far as I know).
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*/
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#ifdef VMS
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/*-
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* due to a Bug/feature in VMS X11/Intrinsic.h has to be placed before xlock.
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* otherwise caddr_t is not defined correctly
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*/
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#include <X11/Intrinsic.h>
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#endif
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#ifdef STANDALONE
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#define MODE_cage
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#define PROGCLASS "Cage"
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#define HACK_INIT init_cage
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#define HACK_DRAW draw_cage
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#define cage_opts xlockmore_opts
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#define DEFAULTS "*delay: 80000 \n" \
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"*showFps : False \n" \
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"*wireframe: False \n"
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#include "xlockmore.h" /* from the xscreensaver distribution */
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#else /* !STANDALONE */
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#include "xlock.h" /* from the xlockmore distribution */
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#include "visgl.h"
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#endif /* !STANDALONE */
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#ifdef MODE_cage
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#include <GL/glu.h>
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#include "e_textures.h"
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ModeSpecOpt cage_opts =
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{0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL};
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#ifdef USE_MODULES
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ModStruct cage_description =
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{"cage", "init_cage", "draw_cage", "release_cage",
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"draw_cage", "change_cage", (char *) NULL, &cage_opts,
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80000, 1, 1, 1, 1.0, 4, "",
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"Shows the Impossible Cage, an Escher-like GL scene", 0, NULL};
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#endif
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#define Scale4Window 0.3
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#define Scale4Iconic 0.4
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#define sqr(A) ((A)*(A))
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#ifndef Pi
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#define Pi M_PI
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#endif
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#define ObjWoodPlank 0
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#define MaxObj 1
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/*************************************************************************/
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typedef struct {
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GLint WindH, WindW;
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GLfloat step;
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GLXContext *glx_context;
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} cagestruct;
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static float front_shininess[] =
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{60.0};
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static float front_specular[] =
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{0.7, 0.7, 0.7, 1.0};
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static float ambient[] =
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{0.0, 0.0, 0.0, 1.0};
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static float diffuse[] =
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{1.0, 1.0, 1.0, 1.0};
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static float position0[] =
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{1.0, 1.0, 1.0, 0.0};
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static float position1[] =
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{-1.0, -1.0, 1.0, 0.0};
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static float lmodel_ambient[] =
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{0.5, 0.5, 0.5, 1.0};
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static float lmodel_twoside[] =
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{GL_TRUE};
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static float MaterialWhite[] =
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{0.7, 0.7, 0.7, 1.0};
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static cagestruct *cage = (cagestruct *) NULL;
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#define PlankWidth 3.0
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#define PlankHeight 0.35
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#define PlankThickness 0.15
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static Bool
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draw_woodplank()
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{
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glBegin(GL_QUADS);
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glNormal3f(0, 0, 1);
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glTexCoord2f(0, 0);
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glVertex3f(-PlankWidth, -PlankHeight, PlankThickness);
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glTexCoord2f(1, 0);
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glVertex3f(PlankWidth, -PlankHeight, PlankThickness);
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glTexCoord2f(1, 1);
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glVertex3f(PlankWidth, PlankHeight, PlankThickness);
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glTexCoord2f(0, 1);
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glVertex3f(-PlankWidth, PlankHeight, PlankThickness);
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glNormal3f(0, 0, -1);
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glTexCoord2f(0, 0);
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glVertex3f(-PlankWidth, PlankHeight, -PlankThickness);
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glTexCoord2f(1, 0);
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glVertex3f(PlankWidth, PlankHeight, -PlankThickness);
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glTexCoord2f(1, 1);
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glVertex3f(PlankWidth, -PlankHeight, -PlankThickness);
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glTexCoord2f(0, 1);
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glVertex3f(-PlankWidth, -PlankHeight, -PlankThickness);
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glNormal3f(0, 1, 0);
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glTexCoord2f(0, 0);
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glVertex3f(-PlankWidth, PlankHeight, PlankThickness);
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glTexCoord2f(1, 0);
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glVertex3f(PlankWidth, PlankHeight, PlankThickness);
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glTexCoord2f(1, 1);
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glVertex3f(PlankWidth, PlankHeight, -PlankThickness);
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glTexCoord2f(0, 1);
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glVertex3f(-PlankWidth, PlankHeight, -PlankThickness);
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glNormal3f(0, -1, 0);
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glTexCoord2f(0, 0);
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glVertex3f(-PlankWidth, -PlankHeight, -PlankThickness);
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glTexCoord2f(1, 0);
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glVertex3f(PlankWidth, -PlankHeight, -PlankThickness);
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glTexCoord2f(1, 1);
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glVertex3f(PlankWidth, -PlankHeight, PlankThickness);
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glTexCoord2f(0, 1);
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glVertex3f(-PlankWidth, -PlankHeight, PlankThickness);
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glNormal3f(1, 0, 0);
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glTexCoord2f(0, 0);
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glVertex3f(PlankWidth, -PlankHeight, PlankThickness);
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glTexCoord2f(1, 0);
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glVertex3f(PlankWidth, -PlankHeight, -PlankThickness);
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glTexCoord2f(1, 1);
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glVertex3f(PlankWidth, PlankHeight, -PlankThickness);
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glTexCoord2f(0, 1);
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glVertex3f(PlankWidth, PlankHeight, PlankThickness);
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glNormal3f(-1, 0, 0);
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glTexCoord2f(0, 0);
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glVertex3f(-PlankWidth, PlankHeight, PlankThickness);
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glTexCoord2f(1, 0);
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glVertex3f(-PlankWidth, PlankHeight, -PlankThickness);
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glTexCoord2f(1, 1);
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glVertex3f(-PlankWidth, -PlankHeight, -PlankThickness);
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glTexCoord2f(0, 1);
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glVertex3f(-PlankWidth, -PlankHeight, PlankThickness);
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glEnd();
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return True;
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}
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static Bool
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draw_impossiblecage()
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{
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glPushMatrix();
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glRotatef(90, 0, 1, 0);
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glTranslatef(0.0, PlankHeight - PlankWidth, -PlankThickness - PlankWidth);
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if (!draw_woodplank())
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return False;
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glPopMatrix();
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glPushMatrix();
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glRotatef(90, 0, 0, 1);
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glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth - PlankThickness);
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if (!draw_woodplank())
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return False;
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glPopMatrix();
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glPushMatrix();
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glRotatef(90, 0, 1, 0);
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glTranslatef(0.0, PlankWidth - PlankHeight, -PlankThickness - PlankWidth);
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if (!draw_woodplank())
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return False;
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glPopMatrix();
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glPushMatrix();
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glTranslatef(0.0, PlankWidth - PlankHeight, 3 * PlankThickness - PlankWidth);
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if (!draw_woodplank())
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return False;
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glPopMatrix();
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glPushMatrix();
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glRotatef(90, 0, 0, 1);
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glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth - PlankThickness);
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if (!draw_woodplank())
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return False;
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glPopMatrix();
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glPushMatrix();
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glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth - 3 * PlankThickness);
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if (!draw_woodplank())
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return False;
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glPopMatrix();
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glPushMatrix();
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glTranslatef(0.0, PlankHeight - PlankWidth, 3 * PlankThickness - PlankWidth);
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if (!draw_woodplank())
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return False;
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glPopMatrix();
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glPushMatrix();
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glRotatef(90, 0, 0, 1);
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glTranslatef(0.0, PlankHeight - PlankWidth, PlankThickness - PlankWidth);
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if (!draw_woodplank())
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return False;
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glPopMatrix();
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glPushMatrix();
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glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth - 3 * PlankThickness);
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if (!draw_woodplank())
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return False;
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glPopMatrix();
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glPushMatrix();
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glRotatef(90, 0, 1, 0);
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glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth + PlankThickness);
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if (!draw_woodplank())
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return False;
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glPopMatrix();
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glPushMatrix();
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glRotatef(90, 0, 0, 1);
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glTranslatef(0.0, PlankWidth - PlankHeight, PlankThickness - PlankWidth);
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if (!draw_woodplank())
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return False;
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glPopMatrix();
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glPushMatrix();
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glRotatef(90, 0, 1, 0);
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glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth + PlankThickness);
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if (!draw_woodplank())
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return False;
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glPopMatrix();
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return True;
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}
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static void
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reshape(ModeInfo * mi, int width, int height)
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{
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cagestruct *cp = &cage[MI_SCREEN(mi)];
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int i;
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glViewport(0, 0, cp->WindW = (GLint) width, cp->WindH = (GLint) height);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 15.0);
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glMatrixMode(GL_MODELVIEW);
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i = width / 512 + 1;
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glLineWidth(i);
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glPointSize(i);
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}
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static void
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pinit(ModeInfo *mi)
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{
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glClearDepth(1.0);
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glClearColor(0.0, 0.0, 0.0, 1.0);
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glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);
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glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse);
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glLightfv(GL_LIGHT0, GL_POSITION, position0);
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glLightfv(GL_LIGHT1, GL_AMBIENT, ambient);
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glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuse);
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glLightfv(GL_LIGHT1, GL_POSITION, position1);
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glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);
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glLightModelfv(GL_LIGHT_MODEL_TWO_SIDE, lmodel_twoside);
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glEnable(GL_LIGHTING);
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glEnable(GL_LIGHT0);
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glEnable(GL_LIGHT1);
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glEnable(GL_NORMALIZE);
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glFrontFace(GL_CCW);
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glCullFace(GL_BACK);
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/* cage */
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glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialWhite);
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glShadeModel(GL_FLAT);
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glDisable(GL_DEPTH_TEST);
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glEnable(GL_TEXTURE_2D);
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glEnable(GL_CULL_FACE);
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glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
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if (!MI_IS_MONO(mi))
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gluBuild2DMipmaps(GL_TEXTURE_2D, 3,
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WoodTextureWidth, WoodTextureHeight,
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GL_RGB, GL_UNSIGNED_BYTE, WoodTextureData);
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glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, front_shininess);
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glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, front_specular);
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}
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void
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release_cage(ModeInfo * mi)
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{
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if (cage != NULL) {
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int screen;
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for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++) {
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cagestruct *cp = &cage[screen];
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if (cp->glx_context) {
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cp->glx_context = (GLXContext *) NULL;
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}
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}
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free(cage);
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cage = (cagestruct *) NULL;
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}
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FreeAllGL(mi);
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}
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void
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init_cage(ModeInfo * mi)
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{
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cagestruct *cp;
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if (cage == NULL) {
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if ((cage = (cagestruct *) calloc(MI_NUM_SCREENS(mi),
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sizeof (cagestruct))) == NULL)
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return;
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}
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cp = &cage[MI_SCREEN(mi)];
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cp->step = NRAND(90);
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if ((cp->glx_context = init_GL(mi)) != NULL) {
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reshape(mi, MI_WIDTH(mi), MI_HEIGHT(mi));
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glDrawBuffer(GL_BACK);
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pinit(mi);
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} else {
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MI_CLEARWINDOW(mi);
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}
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}
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void
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draw_cage(ModeInfo * mi)
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{
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Display *display = MI_DISPLAY(mi);
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Window window = MI_WINDOW(mi);
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cagestruct *cp;
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if (cage == NULL)
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return;
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cp = &cage[MI_SCREEN(mi)];
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MI_IS_DRAWN(mi) = True;
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if (!cp->glx_context)
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return;
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glXMakeCurrent(display, window, *(cp->glx_context));
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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glPushMatrix();
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glTranslatef(0.0, 0.0, -10.0);
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if (!MI_IS_ICONIC(mi)) {
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glScalef(Scale4Window * cp->WindH / cp->WindW, Scale4Window, Scale4Window);
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} else {
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glScalef(Scale4Iconic * cp->WindH / cp->WindW, Scale4Iconic, Scale4Iconic);
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}
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/* cage */
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glRotatef(cp->step * 100, 0, 0, 1);
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glRotatef(25 + cos(cp->step * 5) * 6, 1, 0, 0);
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glRotatef(204.5 - sin(cp->step * 5) * 8, 0, 1, 0);
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if (!draw_impossiblecage()) {
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release_cage(mi);
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return;
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}
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glPopMatrix();
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if (MI_IS_FPS(mi)) do_fps (mi);
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glFlush();
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glXSwapBuffers(display, window);
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cp->step += 0.025;
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}
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void
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change_cage(ModeInfo * mi)
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{
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cagestruct *cp = &cage[MI_SCREEN(mi)];
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if (!cp->glx_context)
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return;
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glXMakeCurrent(MI_DISPLAY(mi), MI_WINDOW(mi), *(cp->glx_context));
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pinit(mi);
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}
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#endif
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