/* -*- Mode: C; tab-width: 4 -*- */
/* cage --- the Impossible Cage, an Escher like scene. */
#if 0
static const char sccsid[] = "@(#)cage.c 5.01 2001/03/01 xlockmore";
#endif
/*-
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose and without fee is hereby granted,
* provided that the above copyright notice appear in all copies and that
* both that copyright notice and this permission notice appear in
* supporting documentation.
*
* This file is provided AS IS with no warranties of any kind. The author
* shall have no liability with respect to the infringement of copyrights,
* trade secrets or any patents by this file or any part thereof. In no
* event will the author be liable for any lost revenue or profits or
* other special, indirect and consequential damages.
*
* The RotateAroundU() routine was adapted from the book
* "Computer Graphics Principles and Practice
* Foley - vanDam - Feiner - Hughes
* Second Edition" Pag. 227, exercise 5.15.
*
* This mode shows some interesting scenes that are impossible OR very
* wierd to build in the real universe. Much of the scenes are inspirated
* on Mauritz Cornelis Escher's works which derivated the mode's name.
* M.C. Escher (1898-1972) was a dutch artist and many people prefer to
* say he was a mathematician.
*
* Thanks goes to Brian Paul for making it possible and inexpensive to use
* OpenGL at home.
*
* Since I'm not a native English speaker, my apologies for any grammatical
* mistakes.
*
* My e-mail address is
* mfvianna@centroin.com.br
*
* Marcelo F. Vianna (Jun-01-1997)
*
* Revision History:
* 05-Apr-2002: Removed all gllist uses (fix some bug with nvidia driver)
* 01-Mar-2001: Added FPS stuff E.Lassauge <lassauge@mail.dotcom.fr>
* 01-Nov-2000: Allocation checks
* 01-Jan-1998: Mode separated from escher and renamed
* 08-Jun-1997: New scene implemented: "Impossible Cage" based in a M.C.
* Escher's painting with the same name (quite similar). The
* first GL mode to use texture mapping.
* The "Impossible Cage" scene doesn't use DEPTH BUFFER, the
* wood planks are drawn consistently using GL_CULL_FACE, and
* the painter's algorithm is used to sort the planks.
* Marcelo F. Vianna.
* 07-Jun-1997: Speed ups in Moebius Strip using GL_CULL_FACE.
* Marcelo F. Vianna.
* 03-Jun-1997: Initial Release (Only one scene: "Moebius Strip")
* The Moebius Strip scene was inspirated in a M.C. Escher's
* painting named Moebius Strip II in wich ants walk across a
* Moebius Strip path, sometimes meeting each other and sometimes
* being in "opposite faces" (note that the moebius strip has
* only one face and one edge).
* Marcelo F. Vianna.
*/
/*-
* Texture mapping is only available on RGBA contexts, Mono and color index
* visuals DO NOT support texture mapping in OpenGL.
*
* BUT Mesa do implements RGBA contexts in pseudo color visuals, so texture
* mapping shuld work on PseudoColor, DirectColor, TrueColor using Mesa. Mono
* is not officially supported for both OpenGL and Mesa, but seems to not crash
* Mesa.
*
* In real OpenGL, PseudoColor DO NOT support texture map (as far as I know).
*/
#ifdef STANDALONE
# define MODE_cage
# define DEFAULTS "*delay: 25000 \n" \
"*showFPS: False \n" \
"*wireframe: False \n" \
"*suppressRotationAnimation: True\n" \
# define release_cage 0
# define cage_handle_event xlockmore_no_events
# include "xlockmore.h" /* from the xscreensaver distribution */
#else /* !STANDALONE */
# include "xlock.h" /* from the xlockmore distribution */
#endif /* !STANDALONE */
#ifdef MODE_cage
#if 0
#include "e_textures.h"
#else
#include "ximage-loader.h"
#include "images/gen/wood_png.h"
#endif
ENTRYPOINT ModeSpecOpt cage_opts =
{0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL};
#ifdef USE_MODULES
ModStruct cage_description =
{"cage", "init_cage", "draw_cage", NULL,
"draw_cage", "change_cage", (char *) NULL, &cage_opts,
25000, 1, 1, 1, 1.0, 4, "",
"Shows the Impossible Cage, an Escher-like GL scene", 0, NULL};
#endif
#define Scale4Window 0.3
#define Scale4Iconic 0.4
#define sqr(A) ((A)*(A))
#ifndef Pi
#define Pi M_PI
#endif
#define ObjWoodPlank 0
#define MaxObj 1
/*************************************************************************/
typedef struct {
GLint WindH, WindW;
GLfloat step;
GLXContext *glx_context;
} cagestruct;
static const float front_shininess[] = {60.0};
static const float front_specular[] = {0.7, 0.7, 0.7, 1.0};
static const float ambient[] = {0.0, 0.0, 0.0, 1.0};
static const float diffuse[] = {1.0, 1.0, 1.0, 1.0};
static const float position0[] = {1.0, 1.0, 1.0, 0.0};
static const float position1[] = {-1.0, -1.0, 1.0, 0.0};
static const float lmodel_ambient[] = {0.5, 0.5, 0.5, 1.0};
static const float lmodel_twoside[] = {GL_TRUE};
static const float MaterialWhite[] = {0.7, 0.7, 0.7, 1.0};
static cagestruct *cage = (cagestruct *) NULL;
#define PlankWidth 3.0
#define PlankHeight 0.35
#define PlankThickness 0.15
static Bool
draw_woodplank(ModeInfo *mi, cagestruct * cp, int wire)
{
glBegin(wire ? GL_LINES : GL_QUADS);
glNormal3f(0, 0, 1);
glTexCoord2f(0, 0);
glVertex3f(-PlankWidth, -PlankHeight, PlankThickness);
glTexCoord2f(1, 0);
glVertex3f(PlankWidth, -PlankHeight, PlankThickness);
glTexCoord2f(1, 1);
glVertex3f(PlankWidth, PlankHeight, PlankThickness);
glTexCoord2f(0, 1);
glVertex3f(-PlankWidth, PlankHeight, PlankThickness);
mi->polygon_count++;
glNormal3f(0, 0, -1);
glTexCoord2f(0, 0);
glVertex3f(-PlankWidth, PlankHeight, -PlankThickness);
glTexCoord2f(1, 0);
glVertex3f(PlankWidth, PlankHeight, -PlankThickness);
glTexCoord2f(1, 1);
glVertex3f(PlankWidth, -PlankHeight, -PlankThickness);
glTexCoord2f(0, 1);
glVertex3f(-PlankWidth, -PlankHeight, -PlankThickness);
mi->polygon_count++;
glNormal3f(0, 1, 0);
glTexCoord2f(0, 0);
glVertex3f(-PlankWidth, PlankHeight, PlankThickness);
glTexCoord2f(1, 0);
glVertex3f(PlankWidth, PlankHeight, PlankThickness);
glTexCoord2f(1, 1);
glVertex3f(PlankWidth, PlankHeight, -PlankThickness);
glTexCoord2f(0, 1);
glVertex3f(-PlankWidth, PlankHeight, -PlankThickness);
mi->polygon_count++;
glNormal3f(0, -1, 0);
glTexCoord2f(0, 0);
glVertex3f(-PlankWidth, -PlankHeight, -PlankThickness);
glTexCoord2f(1, 0);
glVertex3f(PlankWidth, -PlankHeight, -PlankThickness);
glTexCoord2f(1, 1);
glVertex3f(PlankWidth, -PlankHeight, PlankThickness);
glTexCoord2f(0, 1);
glVertex3f(-PlankWidth, -PlankHeight, PlankThickness);
mi->polygon_count++;
glNormal3f(1, 0, 0);
glTexCoord2f(0, 0);
glVertex3f(PlankWidth, -PlankHeight, PlankThickness);
glTexCoord2f(1, 0);
glVertex3f(PlankWidth, -PlankHeight, -PlankThickness);
glTexCoord2f(1, 1);
glVertex3f(PlankWidth, PlankHeight, -PlankThickness);
glTexCoord2f(0, 1);
glVertex3f(PlankWidth, PlankHeight, PlankThickness);
mi->polygon_count++;
glNormal3f(-1, 0, 0);
glTexCoord2f(0, 0);
glVertex3f(-PlankWidth, PlankHeight, PlankThickness);
glTexCoord2f(1, 0);
glVertex3f(-PlankWidth, PlankHeight, -PlankThickness);
glTexCoord2f(1, 1);
glVertex3f(-PlankWidth, -PlankHeight, -PlankThickness);
glTexCoord2f(0, 1);
glVertex3f(-PlankWidth, -PlankHeight, PlankThickness);
mi->polygon_count++;
glEnd();
return True;
}
static Bool
draw_impossiblecage(ModeInfo *mi, cagestruct * cp, int wire)
{
glPushMatrix();
glRotatef(90, 0, 1, 0);
glTranslatef(0.0, PlankHeight - PlankWidth, -PlankThickness - PlankWidth);
if (!draw_woodplank(mi, cp, wire))
return False;
glPopMatrix();
glPushMatrix();
glRotatef(90, 0, 0, 1);
glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth - PlankThickness);
if (!draw_woodplank(mi, cp, wire))
return False;
glPopMatrix();
glPushMatrix();
glRotatef(90, 0, 1, 0);
glTranslatef(0.0, PlankWidth - PlankHeight, -PlankThickness - PlankWidth);
if (!draw_woodplank(mi, cp, wire))
return False;
glPopMatrix();
glPushMatrix();
glTranslatef(0.0, PlankWidth - PlankHeight, 3 * PlankThickness - PlankWidth);
if (!draw_woodplank(mi, cp, wire))
return False;
glPopMatrix();
glPushMatrix();
glRotatef(90, 0, 0, 1);
glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth - PlankThickness);
if (!draw_woodplank(mi, cp, wire))
return False;
glPopMatrix();
glPushMatrix();
glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth - 3 * PlankThickness);
if (!draw_woodplank(mi, cp, wire))
return False;
glPopMatrix();
glPushMatrix();
glTranslatef(0.0, PlankHeight - PlankWidth, 3 * PlankThickness - PlankWidth);
if (!draw_woodplank(mi, cp, wire))
return False;
glPopMatrix();
glPushMatrix();
glRotatef(90, 0, 0, 1);
glTranslatef(0.0, PlankHeight - PlankWidth, PlankThickness - PlankWidth);
if (!draw_woodplank(mi, cp, wire))
return False;
glPopMatrix();
glPushMatrix();
glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth - 3 * PlankThickness);
if (!draw_woodplank(mi, cp, wire))
return False;
glPopMatrix();
glPushMatrix();
glRotatef(90, 0, 1, 0);
glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth + PlankThickness);
if (!draw_woodplank(mi, cp, wire))
return False;
glPopMatrix();
glPushMatrix();
glRotatef(90, 0, 0, 1);
glTranslatef(0.0, PlankWidth - PlankHeight, PlankThickness - PlankWidth);
if (!draw_woodplank(mi, cp, wire))
return False;
glPopMatrix();
glPushMatrix();
glRotatef(90, 0, 1, 0);
glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth + PlankThickness);
if (!draw_woodplank(mi, cp, wire))
return False;
glPopMatrix();
return True;
}
static void
reshape_cage(ModeInfo * mi, int width, int height)
{
cagestruct *cp = &cage[MI_SCREEN(mi)];
int i;
int y = 0;
if (width > height * 5) { /* tiny window: show middle */
height = width * 9/16;
y = -height/2;
}
glViewport(0, y, cp->WindW = (GLint) width, cp->WindH = (GLint) height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 15.0);
glMatrixMode(GL_MODELVIEW);
i = width / 512 + 1;
glLineWidth(i);
glPointSize(i);
}
static void
pinit(ModeInfo *mi)
{
/* int status; */
if (MI_IS_WIREFRAME(mi))
return;
glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse);
glLightfv(GL_LIGHT0, GL_POSITION, position0);
glLightfv(GL_LIGHT1, GL_AMBIENT, ambient);
glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuse);
glLightfv(GL_LIGHT1, GL_POSITION, position1);
glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);
glLightModelfv(GL_LIGHT_MODEL_TWO_SIDE, lmodel_twoside);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_LIGHT1);
glEnable(GL_NORMALIZE);
glFrontFace(GL_CCW);
glCullFace(GL_BACK);
/* cage */
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialWhite);
glShadeModel(GL_FLAT);
glDisable(GL_DEPTH_TEST);
glEnable(GL_TEXTURE_2D);
glEnable(GL_CULL_FACE);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
#if 0
clear_gl_error();
if (MI_IS_MONO(mi))
status = 0;
else
status = gluBuild2DMipmaps(GL_TEXTURE_2D, 3,
WoodTextureWidth, WoodTextureHeight,
GL_RGB, GL_UNSIGNED_BYTE, WoodTextureData);
if (status)
{
const char *s = (char *) gluErrorString (status);
fprintf (stderr, "%s: error mipmapping texture: %s\n",
progname, (s ? s : "(unknown)"));
exit (1);
}
check_gl_error("mipmapping");
#else
{
XImage *img = image_data_to_ximage (mi->dpy, mi->xgwa.visual,
wood_png, sizeof(wood_png));
glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA,
img->width, img->height, 0,
GL_RGBA, GL_UNSIGNED_BYTE, img->data);
check_gl_error("texture");
XDestroyImage (img);
}
#endif
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, front_shininess);
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, front_specular);
}
ENTRYPOINT void
init_cage (ModeInfo * mi)
{
cagestruct *cp;
MI_INIT (mi, cage);
cp = &cage[MI_SCREEN(mi)];
cp->step = NRAND(90);
if ((cp->glx_context = init_GL(mi)) != NULL) {
reshape_cage(mi, MI_WIDTH(mi), MI_HEIGHT(mi));
glDrawBuffer(GL_BACK);
pinit(mi);
} else {
MI_CLEARWINDOW(mi);
}
}
ENTRYPOINT void
draw_cage (ModeInfo * mi)
{
Display *display = MI_DISPLAY(mi);
Window window = MI_WINDOW(mi);
cagestruct *cp;
if (cage == NULL)
return;
cp = &cage[MI_SCREEN(mi)];
MI_IS_DRAWN(mi) = True;
if (!cp->glx_context)
return;
mi->polygon_count = 0;
glXMakeCurrent(display, window, *cp->glx_context);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glTranslatef(0.0, 0.0, -10.0);
if (!MI_IS_ICONIC(mi)) {
glScalef(Scale4Window * cp->WindH / cp->WindW, Scale4Window, Scale4Window);
} else {
glScalef(Scale4Iconic * cp->WindH / cp->WindW, Scale4Iconic, Scale4Iconic);
}
# ifdef HAVE_MOBILE /* Keep it the same relative size when rotated. */
{
int o = (int) current_device_rotation();
GLfloat h = MI_HEIGHT(mi) / (GLfloat) MI_WIDTH(mi);
if (o != 0 && o != 180 && o != -180) {
glScalef (1/h, h, 1/h); /* #### not quite right */
h = 1.7;
glScalef (h, h, h);
}
}
# endif
/* cage */
glRotatef(cp->step * 100, 0, 0, 1);
glRotatef(25 + cos(cp->step * 5) * 6, 1, 0, 0);
glRotatef(204.5 - sin(cp->step * 5) * 8, 0, 1, 0);
if (!draw_impossiblecage(mi, cp, MI_IS_WIREFRAME(mi))) {
MI_ABORT(mi);
return;
}
glPopMatrix();
if (MI_IS_FPS(mi)) do_fps (mi);
glFlush();
glXSwapBuffers(display, window);
cp->step += 0.025;
}
#ifndef STANDALONE
ENTRYPOINT void
change_cage (ModeInfo * mi)
{
cagestruct *cp = &cage[MI_SCREEN(mi)];
if (!cp->glx_context)
return;
glXMakeCurrent(MI_DISPLAY(mi), MI_WINDOW(mi), *cp->glx_context);
pinit(mi);
}
#endif /* !STANDALONE */
ENTRYPOINT void
free_cage (ModeInfo * mi)
{
/* nothing to do */
}
XSCREENSAVER_MODULE ("Cage", cage)
#endif
