/* -*- Mode: C; tab-width: 4 -*- */ /* stairs --- Infinite Stairs, and Escher-like scene. */ #if 0 static const char sccsid[] = "@(#)stairs.c 4.07 97/11/24 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. * * This mode shows some interesting scenes that are impossible OR very * weird to build in the real universe. Much of the scenes are inspirated * on Mauritz Cornelis stairs'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: * 07-Jan-98: This would be a scene for the escher mode, but now escher mode * was splitted in different modes for each scene. This is the * initial release and is not working yet. * 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 DEFAULTS "*delay: 20000 \n" \ "*showFPS: False \n" # define release_stairs 0 # include "xlockmore.h" /* from the xscreensaver distribution */ #else /* !STANDALONE */ # include "xlock.h" /* from the xlockmore distribution */ #endif /* !STANDALONE */ #ifdef USE_GL #if 0 #include "e_textures.h" #else #include "ximage-loader.h" #include "images/gen/wood_png.h" #endif #include "sphere.h" #include "gltrackball.h" ENTRYPOINT ModeSpecOpt stairs_opts = {0, NULL, 0, NULL, NULL}; #ifdef USE_MODULES ModStruct stairs_description = {"stairs", "init_stairs", "draw_stairs", NULL, "draw_stairs", "change_stairs", "free_stairs", &stairs_opts, 1000, 1, 1, 1, 4, 1.0, "", "Shows Infinite Stairs, an Escher-like 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 rotating; int AreObjectsDefined[1]; int sphere_position; int sphere_tick; GLXContext *glx_context; trackball_state *trackball; Bool button_down_p; GLuint objects; } stairsstruct; 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 MaterialYellow[] = {0.7, 0.7, 0.0, 1.0}; static const float MaterialWhite[] = {0.7, 0.7, 0.7, 1.0}; static const float ball_positions[] = { -3.0, 3.0, 1.0, -3.0, 2.8, 2.0, -3.0, 2.6, 3.0, -2.0, 2.4, 3.0, -1.0, 2.2, 3.0, 0.0, 2.0, 3.0, 1.0, 1.8, 3.0, 2.0, 1.6, 3.0, 2.0, 1.5, 2.0, 2.0, 1.4, 1.0, 2.0, 1.3, 0.0, 2.0, 1.2, -1.0, 2.0, 1.1, -2.0, 1.0, 0.9, -2.0, 0.0, 0.7, -2.0, -1.0, 0.5, -2.0, }; #define NPOSITIONS ((sizeof ball_positions) / (sizeof ball_positions[0]) / 3) #define SPHERE_TICKS 32 static stairsstruct *stairs = NULL; static int draw_block(GLfloat width, GLfloat height, GLfloat thickness) { int polys = 0; glFrontFace(GL_CCW); glBegin(GL_QUADS); glNormal3f(0, 0, 1); glTexCoord2f(0, 0); glVertex3f(-width, -height, thickness); glTexCoord2f(1, 0); glVertex3f(width, -height, thickness); glTexCoord2f(1, 1); glVertex3f(width, height, thickness); glTexCoord2f(0, 1); glVertex3f(-width, height, thickness); polys++; glNormal3f(0, 0, -1); glTexCoord2f(0, 0); glVertex3f(-width, height, -thickness); glTexCoord2f(1, 0); glVertex3f(width, height, -thickness); glTexCoord2f(1, 1); glVertex3f(width, -height, -thickness); glTexCoord2f(0, 1); glVertex3f(-width, -height, -thickness); polys++; glNormal3f(0, 1, 0); glTexCoord2f(0, 0); glVertex3f(-width, height, thickness); glTexCoord2f(1, 0); glVertex3f(width, height, thickness); glTexCoord2f(1, 1); glVertex3f(width, height, -thickness); glTexCoord2f(0, 1); glVertex3f(-width, height, -thickness); polys++; glNormal3f(0, -1, 0); glTexCoord2f(0, 0); glVertex3f(-width, -height, -thickness); glTexCoord2f(1, 0); glVertex3f(width, -height, -thickness); glTexCoord2f(1, 1); glVertex3f(width, -height, thickness); glTexCoord2f(0, 1); glVertex3f(-width, -height, thickness); polys++; glNormal3f(1, 0, 0); glTexCoord2f(0, 0); glVertex3f(width, -height, thickness); glTexCoord2f(1, 0); glVertex3f(width, -height, -thickness); glTexCoord2f(1, 1); glVertex3f(width, height, -thickness); glTexCoord2f(0, 1); glVertex3f(width, height, thickness); polys++; glNormal3f(-1, 0, 0); glTexCoord2f(0, 0); glVertex3f(-width, height, thickness); glTexCoord2f(1, 0); glVertex3f(-width, height, -thickness); glTexCoord2f(1, 1); glVertex3f(-width, -height, -thickness); glTexCoord2f(0, 1); glVertex3f(-width, -height, thickness); polys++; glEnd(); return polys; } static void draw_stairs_internal(ModeInfo * mi) { GLfloat X; mi->polygon_count = 0; glPushMatrix(); glPushMatrix(); glTranslatef(-3.0, 0.1, 2.0); for (X = 0; X < 2; X++) { mi->polygon_count += draw_block(0.5, 2.7 + 0.1 * X, 0.5); glTranslatef(0.0, 0.1, -1.0); } glPopMatrix(); glTranslatef(-3.0, 0.0, 3.0); glPushMatrix(); for (X = 0; X < 6; X++) { mi->polygon_count += draw_block(0.5, 2.6 - 0.1 * X, 0.5); glTranslatef(1.0, -0.1, 0.0); } glTranslatef(-1.0, -0.9, -1.0); for (X = 0; X < 5; X++) { mi->polygon_count += draw_block(0.5, 3.0 - 0.1 * X, 0.5); glTranslatef(0.0, 0.0, -1.0); } glTranslatef(-1.0, -1.1, 1.0); for (X = 0; X < 3; X++) { mi->polygon_count += draw_block(0.5, 3.5 - 0.1 * X, 0.5); glTranslatef(-1.0, -0.1, 0.0); } glPopMatrix(); glPopMatrix(); } /*#define DEBUG*/ /*#define DEBUG_PATH*/ static int draw_sphere(int pos, int tick) { int pos2 = (pos+1) % NPOSITIONS; GLfloat x1 = ball_positions[pos*3]; GLfloat y1 = ball_positions[pos*3+1]; GLfloat z1 = ball_positions[pos*3+2]; GLfloat x2 = ball_positions[pos2*3]; GLfloat y2 = ball_positions[pos2*3+1]; GLfloat z2 = ball_positions[pos2*3+2]; GLfloat frac = tick / (GLfloat) SPHERE_TICKS; GLfloat x = x1 + (x2 - x1) * frac; GLfloat y = y1 + (y2 - y1) * frac + (2 * sin (M_PI * frac)); GLfloat z = z1 + (z2 - z1) * frac; int polys = 0; glPushMatrix(); # ifdef DEBUG_PATH glVertex3f(x, y, z); if (tick == 0) { glVertex3f(x, y-7.5, z); glVertex3f(x, y, z); glVertex3f(x, y, z-0.6); glVertex3f(x, y, z); glVertex3f(x, y, z+0.6); glVertex3f(x, y, z); glVertex3f(x+0.6, y, z); glVertex3f(x, y, z); glVertex3f(x-0.6, y, z); glVertex3f(x, y, z); } # else /* !DEBUG_PATH */ y += 0.5; glTranslatef(x, y, z); glScalef (0.5, 0.5, 0.5); /* make ball a little smaller on the gap to obscure distance */ if (pos == NPOSITIONS-1) glScalef (0.95, 0.95, 0.95); glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialYellow); glDisable (GL_TEXTURE_2D); glShadeModel(GL_SMOOTH); glFrontFace(GL_CCW); polys += unit_sphere (32, 32, False); glShadeModel(GL_FLAT); glEnable (GL_TEXTURE_2D); #endif /* !DEBUG_PATH */ glPopMatrix(); return polys; } ENTRYPOINT void reshape_stairs (ModeInfo * mi, int width, int height) { stairsstruct *sp = &stairs[MI_SCREEN(mi)]; int y = 0; if (width > height * 5) { /* tiny window: show middle */ height = width; y = -height/2; } glViewport(0, y, sp->WindW = (GLint) width, sp->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); } } ENTRYPOINT Bool stairs_handle_event (ModeInfo *mi, XEvent *event) { stairsstruct *sp = &stairs[MI_SCREEN(mi)]; if (gltrackball_event_handler (event, sp->trackball, MI_WIDTH (mi), MI_HEIGHT (mi), &sp->button_down_p)) return True; else if (event->xany.type == KeyPress) { KeySym keysym; char c = 0; XLookupString (&event->xkey, &c, 1, &keysym, 0); if (c == ' ' || c == '\t') { gltrackball_reset (sp->trackball, 0, 0); return True; } } return False; } static void pinit(ModeInfo *mi) { /* int status; */ glClearDepth(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); glCullFace(GL_BACK); glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialWhite); glShadeModel(GL_FLAT); glEnable(GL_DEPTH_TEST); glEnable(GL_TEXTURE_2D); glEnable(GL_CULL_FACE); glPixelStorei(GL_UNPACK_ALIGNMENT, 1); #if 0 clear_gl_error(); 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 %dx%d texture: %s\n", progname, WoodTextureWidth, WoodTextureHeight, (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_stairs (ModeInfo * mi) { int screen = MI_SCREEN(mi); stairsstruct *sp; MI_INIT (mi, stairs); sp = &stairs[screen]; sp->step = 0.0; sp->rotating = 0; sp->sphere_position = NRAND(NPOSITIONS); sp->sphere_tick = 0; if ((sp->glx_context = init_GL(mi)) != NULL) { reshape_stairs(mi, MI_WIDTH(mi), MI_HEIGHT(mi)); glDrawBuffer(GL_BACK); if (!glIsList(sp->objects)) sp->objects = glGenLists(1); pinit(mi); } else { MI_CLEARWINDOW(mi); } sp->trackball = gltrackball_init (False); } ENTRYPOINT void draw_stairs (ModeInfo * mi) { stairsstruct *sp = &stairs[MI_SCREEN(mi)]; GLfloat rot = current_device_rotation(); Display *display = MI_DISPLAY(mi); Window window = MI_WINDOW(mi); if (!sp->glx_context) return; glXMakeCurrent(display, window, *sp->glx_context); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glPushMatrix(); glRotatef(rot, 0, 0, 1); glTranslatef(0.0, 0.0, -10.0); if (!MI_IS_ICONIC(mi)) { glScalef(Scale4Window * sp->WindH / sp->WindW, Scale4Window, Scale4Window); } else { glScalef(Scale4Iconic * sp->WindH / sp->WindW, Scale4Iconic, Scale4Iconic); } # ifdef HAVE_MOBILE /* Keep it the same relative size when rotated. */ { GLfloat h = MI_HEIGHT(mi) / (GLfloat) MI_WIDTH(mi); if (rot != 0 && rot != 180 && rot != -180) glScalef (1/h, 1/h, 1/h); } # endif gltrackball_rotate (sp->trackball); glTranslatef(0, 0.5, 0); glRotatef(44.5, 1, 0, 0); glRotatef(50, 0, 1, 0); if (!sp->rotating) { if ((LRAND() % 500) == 0) sp->rotating = (LRAND() & 1) ? 1 : -1; } if (sp->rotating) { glRotatef(sp->rotating * sp->step, 0, 1, 0); if (sp->step >= 360) { sp->rotating = 0; sp->step = 0; } # ifndef DEBUG if (!sp->button_down_p) sp->step += 2; # endif /* DEBUG */ } draw_stairs_internal(mi); # ifdef DEBUG { int i, j; # ifdef DEBUG_PATH glDisable(GL_LIGHTING); glDisable(GL_TEXTURE_2D); glBegin (GL_LINE_LOOP); # endif /* DEBUG_PATH */ for (i = 0; i < NPOSITIONS; i ++) for (j = 0; j < SPHERE_TICKS; j++) mi->polygon_count += draw_sphere(i, j); # ifdef DEBUG_PATH glEnd(); glEnable(GL_LIGHTING); glEnable(GL_TEXTURE_2D); # endif /* DEBUG_PATH */ } #else /* !DEBUG */ mi->polygon_count += draw_sphere(sp->sphere_position, sp->sphere_tick); #endif /* !DEBUG */ if (sp->button_down_p) ; else if (++sp->sphere_tick >= SPHERE_TICKS) { sp->sphere_tick = 0; if (++sp->sphere_position >= NPOSITIONS) sp->sphere_position = 0; } glPopMatrix(); if (mi->fps_p) do_fps (mi); glFlush(); glXSwapBuffers(display, window); } #ifndef STANDALONE ENTRYPOINT void change_stairs (ModeInfo * mi) { stairsstruct *sp = &stairs[MI_SCREEN(mi)]; if (!sp->glx_context) return; glXMakeCurrent(MI_DISPLAY(mi), MI_WINDOW(mi), *sp->glx_context); pinit(); } #endif /* !STANDALONE */ ENTRYPOINT void free_stairs (ModeInfo * mi) { stairsstruct *sp = &stairs[MI_SCREEN(mi)]; if (!sp->glx_context) return; glXMakeCurrent (MI_DISPLAY(mi), MI_WINDOW(mi), *sp->glx_context); if (glIsList(sp->objects)) glDeleteLists(sp->objects, 1); if (sp->trackball) gltrackball_free (sp->trackball); } XSCREENSAVER_MODULE ("Stairs", stairs) #endif