/* -*- Mode: C; tab-width: 4 -*- */ /* cage --- the Impossible Cage, an Escher like scene. */ #if !defined( lint ) && !defined( SABER ) 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 * 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 VMS /*- * due to a Bug/feature in VMS X11/Intrinsic.h has to be placed before xlock. * otherwise caddr_t is not defined correctly */ #include #endif #ifdef STANDALONE #define MODE_cage #define PROGCLASS "Cage" #define HACK_INIT init_cage #define HACK_DRAW draw_cage #define cage_opts xlockmore_opts #define DEFAULTS "*delay: 80000 \n" \ "*showFps : False \n" \ "*wireframe: False \n" #include "xlockmore.h" /* from the xscreensaver distribution */ #else /* !STANDALONE */ #include "xlock.h" /* from the xlockmore distribution */ #include "visgl.h" #endif /* !STANDALONE */ #ifdef MODE_cage #include #include "e_textures.h" ModeSpecOpt cage_opts = {0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL}; #ifdef USE_MODULES ModStruct cage_description = {"cage", "init_cage", "draw_cage", "release_cage", "draw_cage", "change_cage", (char *) NULL, &cage_opts, 80000, 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 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 = (cagestruct *) NULL; #define PlankWidth 3.0 #define PlankHeight 0.35 #define PlankThickness 0.15 static Bool draw_woodplank() { 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(); return True; } static Bool draw_impossiblecage() { glPushMatrix(); glRotatef(90, 0, 1, 0); glTranslatef(0.0, PlankHeight - PlankWidth, -PlankThickness - PlankWidth); if (!draw_woodplank()) return False; glPopMatrix(); glPushMatrix(); glRotatef(90, 0, 0, 1); glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth - PlankThickness); if (!draw_woodplank()) return False; glPopMatrix(); glPushMatrix(); glRotatef(90, 0, 1, 0); glTranslatef(0.0, PlankWidth - PlankHeight, -PlankThickness - PlankWidth); if (!draw_woodplank()) return False; glPopMatrix(); glPushMatrix(); glTranslatef(0.0, PlankWidth - PlankHeight, 3 * PlankThickness - PlankWidth); if (!draw_woodplank()) return False; glPopMatrix(); glPushMatrix(); glRotatef(90, 0, 0, 1); glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth - PlankThickness); if (!draw_woodplank()) return False; glPopMatrix(); glPushMatrix(); glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth - 3 * PlankThickness); if (!draw_woodplank()) return False; glPopMatrix(); glPushMatrix(); glTranslatef(0.0, PlankHeight - PlankWidth, 3 * PlankThickness - PlankWidth); if (!draw_woodplank()) return False; glPopMatrix(); glPushMatrix(); glRotatef(90, 0, 0, 1); glTranslatef(0.0, PlankHeight - PlankWidth, PlankThickness - PlankWidth); if (!draw_woodplank()) return False; glPopMatrix(); glPushMatrix(); glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth - 3 * PlankThickness); if (!draw_woodplank()) return False; glPopMatrix(); glPushMatrix(); glRotatef(90, 0, 1, 0); glTranslatef(0.0, PlankHeight - PlankWidth, PlankWidth + PlankThickness); if (!draw_woodplank()) return False; glPopMatrix(); glPushMatrix(); glRotatef(90, 0, 0, 1); glTranslatef(0.0, PlankWidth - PlankHeight, PlankThickness - PlankWidth); if (!draw_woodplank()) return False; glPopMatrix(); glPushMatrix(); glRotatef(90, 0, 1, 0); glTranslatef(0.0, PlankWidth - PlankHeight, PlankWidth + PlankThickness); if (!draw_woodplank()) return False; glPopMatrix(); return True; } static void reshape(ModeInfo * mi, int width, int height) { cagestruct *cp = &cage[MI_SCREEN(mi)]; int i; 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); i = width / 512 + 1; glLineWidth(i); glPointSize(i); } static void pinit(ModeInfo *mi) { 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); if (!MI_IS_MONO(mi)) 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 release_cage(ModeInfo * mi) { if (cage != NULL) { int screen; for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++) { cagestruct *cp = &cage[screen]; if (cp->glx_context) { cp->glx_context = (GLXContext *) NULL; } } free(cage); cage = (cagestruct *) NULL; } FreeAllGL(mi); } void init_cage(ModeInfo * mi) { cagestruct *cp; if (cage == NULL) { if ((cage = (cagestruct *) calloc(MI_NUM_SCREENS(mi), sizeof (cagestruct))) == NULL) return; } cp = &cage[MI_SCREEN(mi)]; cp->step = NRAND(90); if ((cp->glx_context = init_GL(mi)) != NULL) { reshape(mi, MI_WIDTH(mi), MI_HEIGHT(mi)); glDrawBuffer(GL_BACK); pinit(mi); } else { MI_CLEARWINDOW(mi); } } 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; 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); if (!draw_impossiblecage()) { release_cage(mi); return; } glPopMatrix(); if (MI_IS_FPS(mi)) do_fps (mi); 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(mi); } #endif