/* -*- 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 (glIsList(sp->objects)) {
glDeleteLists(sp->objects, 1);
}
}
XSCREENSAVER_MODULE ("Stairs", stairs)
#endif