--- /dev/null
+/* -*- Mode: C; tab-width: 4 -*- */
+/* cage --- the Impossible Cage, an Escher like scene. */
+
+#if !defined( lint ) && !defined( SABER )
+static const char sccsid[] = "@(#)cage.c 4.07 98/01/04 xlockmore";
+
+#endif
+
+#undef DEBUG_LISTS
+
+/*-
+ * 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
+ * mistake.
+ *
+ * My e-mail address is
+ * m-vianna@usa.net
+ *
+ * Marcelo F. Vianna (Jun-01-1997)
+ *
+ * Revision History:
+ * 01-Jan-98: Mode separated from escher and renamed
+ * 08-Jun-97: 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-97: Speed ups in Moebius Strip using GL_CULL_FACE.
+ * Marcelo F. Vianna.
+ * 03-Jun-97: 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).
+ */
+
+#include <X11/Intrinsic.h>
+
+#ifdef STANDALONE
+# define PROGCLASS "Cage"
+# define HACK_INIT init_cage
+# define HACK_DRAW draw_cage
+# define cage_opts xlockmore_opts
+# define DEFAULTS "*cycles: 1 \n" \
+ "*delay: 1000 \n" \
+ "*wireframe: False \n"
+# include "xlockmore.h" /* from the xscreensaver distribution */
+#else /* !STANDALONE */
+# include "xlock.h" /* from the xlockmore distribution */
+
+#endif /* !STANDALONE */
+
+#ifdef USE_GL
+
+
+#include <GL/glu.h>
+#include "e_textures.h"
+
+ModeSpecOpt cage_opts =
+{0, NULL, 0, NULL, NULL};
+
+#ifdef USE_MODULES
+ModStruct cage_description =
+{"cage", "init_cage", "draw_cage", "release_cage",
+ "draw_cage", "change_cage", NULL, &cage_opts,
+ 1000, 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
+
+/*************************************************************************/
+
+typedef struct {
+ GLint WindH, WindW;
+ GLfloat step;
+ int AreObjectsDefined[1];
+ GLXContext *glx_context;
+} cagestruct;
+
+static float front_shininess[] =
+{60.0};
+static float front_specular[] =
+{0.7, 0.7, 0.7, 1.0};
+static float ambient[] =
+{0.0, 0.0, 0.0, 1.0};
+static float diffuse[] =
+{1.0, 1.0, 1.0, 1.0};
+static float position0[] =
+{1.0, 1.0, 1.0, 0.0};
+static float position1[] =
+{-1.0, -1.0, 1.0, 0.0};
+static float lmodel_ambient[] =
+{0.5, 0.5, 0.5, 1.0};
+static float lmodel_twoside[] =
+{GL_TRUE};
+
+static float MaterialWhite[] =
+{0.7, 0.7, 0.7, 1.0};
+
+static cagestruct *cage = NULL;
+static GLuint objects;
+
+#define ObjWoodPlank 0
+
+#define PlankWidth 3.0
+#define PlankHeight 0.35
+#define PlankThickness 0.15
+
+static void
+draw_woodplank(cagestruct * cp)
+{
+ if (!cp->AreObjectsDefined[ObjWoodPlank]) {
+ glNewList(objects + ObjWoodPlank, GL_COMPILE_AND_EXECUTE);
+ glBegin(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);
+ 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);
+ 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);
+ 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);
+ 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);
+ 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);
+ glEnd();
+ glEndList();
+ cp->AreObjectsDefined[ObjWoodPlank] = 1;
+#ifdef DEBUG_LISTS
+ (void) printf("WoodPlank drawn SLOWLY\n");
+#endif
+ } else {
+ glCallList(objects + ObjWoodPlank);
+#ifdef DEBUG_LISTS
+ (void) printf("WoodPlank drawn quickly\n");
+#endif
+ }
+}
+
+static void
+draw_impossiblecage(cagestruct * cp)
+{
+ glPushMatrix();
+ glRotatef(90, 0, 1, 0);
+ glTranslatef(0.0, PlankHeight - PlankWidth, -PlankThickness - PlankWidth);
+ draw_woodplank(cp);
+ glPopMatrix();
+ glPushMatrix();
+ glRotatef(90, 0, 0, 1);
+ glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth - PlankThickness);
+ draw_woodplank(cp);
+ glPopMatrix();
+ glPushMatrix();
+ glRotatef(90, 0, 1, 0);
+ glTranslatef(0.0, PlankWidth - PlankHeight, -PlankThickness - PlankWidth);
+ draw_woodplank(cp);
+ glPopMatrix();
+ glPushMatrix();
+ glTranslatef(0.0, PlankWidth - PlankHeight, 3 * PlankThickness - PlankWidth);
+ draw_woodplank(cp);
+ glPopMatrix();
+ glPushMatrix();
+ glRotatef(90, 0, 0, 1);
+ glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth - PlankThickness);
+ draw_woodplank(cp);
+ glPopMatrix();
+ glPushMatrix();
+ glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth - 3 * PlankThickness);
+ draw_woodplank(cp);
+ glPopMatrix();
+ glPushMatrix();
+ glTranslatef(0.0, PlankHeight - PlankWidth, 3 * PlankThickness - PlankWidth);
+ draw_woodplank(cp);
+ glPopMatrix();
+ glPushMatrix();
+ glRotatef(90, 0, 0, 1);
+ glTranslatef(0.0, PlankHeight - PlankWidth, PlankThickness - PlankWidth);
+ draw_woodplank(cp);
+ glPopMatrix();
+ glPushMatrix();
+ glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth - 3 * PlankThickness);
+ draw_woodplank(cp);
+ glPopMatrix();
+ glPushMatrix();
+ glRotatef(90, 0, 1, 0);
+ glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth + PlankThickness);
+ draw_woodplank(cp);
+ glPopMatrix();
+ glPushMatrix();
+ glRotatef(90, 0, 0, 1);
+ glTranslatef(0.0, PlankWidth - PlankHeight, PlankThickness - PlankWidth);
+ draw_woodplank(cp);
+ glPopMatrix();
+ glPushMatrix();
+ glRotatef(90, 0, 1, 0);
+ glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth + PlankThickness);
+ draw_woodplank(cp);
+ glPopMatrix();
+}
+
+static void
+reshape(ModeInfo * mi, int width, int height)
+{
+ cagestruct *cp = &cage[MI_SCREEN(mi)];
+
+ glViewport(0, 0, 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);
+ if (width >= 1024) {
+ glLineWidth(3);
+ glPointSize(3);
+ } else if (width >= 512) {
+ glLineWidth(2);
+ glPointSize(2);
+ } else {
+ glLineWidth(1);
+ glPointSize(1);
+ }
+ cp->AreObjectsDefined[ObjWoodPlank] = 0;
+}
+
+static void
+pinit(void)
+{
+ glClearDepth(1.0);
+ glClearColor(0.0, 0.0, 0.0, 1.0);
+
+ 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);
+ gluBuild2DMipmaps(GL_TEXTURE_2D, 3, WoodTextureWidth, WoodTextureHeight,
+ GL_RGB, GL_UNSIGNED_BYTE, WoodTextureData);
+ 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);
+}
+
+void
+init_cage(ModeInfo * mi)
+{
+ int screen = MI_SCREEN(mi);
+ cagestruct *cp;
+
+ if (cage == NULL) {
+ if ((cage = (cagestruct *) calloc(MI_NUM_SCREENS(mi),
+ sizeof (cagestruct))) == NULL)
+ return;
+ }
+ cp = &cage[screen];
+ cp->step = NRAND(90);
+
+ if ((cp->glx_context = init_GL(mi)) != NULL) {
+
+ reshape(mi, MI_WIDTH(mi), MI_HEIGHT(mi));
+ glDrawBuffer(GL_BACK);
+ if (!glIsList(objects))
+ objects = glGenLists(1);
+ pinit();
+ } else {
+ MI_CLEARWINDOW(mi);
+ }
+}
+
+void
+draw_cage(ModeInfo * mi)
+{
+ cagestruct *cp = &cage[MI_SCREEN(mi)];
+
+ Display *display = MI_DISPLAY(mi);
+ Window window = MI_WINDOW(mi);
+
+ MI_IS_DRAWN(mi) = True;
+
+ if (!cp->glx_context)
+ return;
+
+ 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);
+ }
+
+ /* 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);
+ draw_impossiblecage(cp);
+
+ glPopMatrix();
+
+ glFlush();
+
+ glXSwapBuffers(display, window);
+
+ cp->step += 0.025;
+}
+
+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();
+}
+
+void
+release_cage(ModeInfo * mi)
+{
+ if (cage != NULL) {
+ (void) free((void *) cage);
+ cage = NULL;
+ }
+ if (glIsList(objects)) {
+ glDeleteLists(objects, 1);
+ }
+ FreeAllGL(mi);
+}
+
+#endif
projects / xscreensaver / blobdiff