/* -*- Mode: C; tab-width: 4 -*- */
/* invert --- shere inversion */
#if !defined( lint ) && !defined( SABER )
static const char sccsid[] = "@(#)invert.c 5.01 2001/03/01 xlockmore";
#endif
/*-
* invert.c - Sphere inversion
*
* See xlock.c for copying information.
*
* Revision History:
* 01-Nov-2000: Allocation checks
* 199?: Written
*
* Tim Rowley (code from the Geometry Center
*
* This is a sphere eversion of William P. Thurston which was the subject
* of the Geometry Center film "Outside In". The code is based on the
* software which was used to create the RIB files for the film.
* Trying to figure it out from the full eversion is difficult. If you get
* a chance to look at the original film, it leads up the eversion nicely.
* There is more information about the eversion, including the script from
* the film, at: http://www.geom.umn.edu/docs/outreach/oi/
*
* Demonstration of turning a sphere inside out without creating
* any kinks (two surfaces can occupy the same space at the same time).
*
* Revision History:
* 01-Mar-2001: Added FPS stuff E.Lassauge
*/
#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
#include "xlock.h"
#include "visgl.h"
#ifdef MODE_invert
#include "i_linkage.h"
#define STEPS 75
ModeSpecOpt invert_opts =
{0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL};
#ifdef USE_MODULES
ModStruct invert_description =
{(char *) "invert", (char *) "init_invert",
(char *) "draw_invert", (char *) "release_invert",
(char *) "draw_invert", (char *) "init_invert",
(char *) NULL, &invert_opts,
80000, 1, 1, 1, 64, 1.0, (char *) "",
(char *) "Shows a sphere inverted without wrinkles", 0, NULL};
#endif
static spherestruct *spheres = (spherestruct *) NULL;
/* new window size or exposure */
static void
reshape(int width, int height)
{
GLfloat h = (GLfloat) height / (GLfloat) width;
glViewport(0, 0, (GLint) width, (GLint) height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-1.0, 1.0, -h, h, 5.0, 60.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.0, 0.0, -10.0);
/* The depth buffer will be cleared, if needed, before the
* next frame. Right now we just want to black the screen.
*/
glClear(GL_COLOR_BUFFER_BIT);
}
static void
pinit(void)
{
/*
GLfloat front_mat[] = {.8, .7, .4, 1.0};
GLfloat back_mat[] = {.508, .333, .774, 1.0};
*/
GLfloat front_ambient[] = {.16, .14, .08, 1.0};
GLfloat front_diffuse[] = {.56, .49, .28, 1.0};
GLfloat front_specular[] = {1, 1, 0.8, 1.0};
GLfloat back_ambient[] = {.1016, .0666, .1548, 1.0};
GLfloat back_diffuse[] = {.254, .166, .387, 1.0};
GLfloat back_specular[] = {.4, .2, .5, 1.0};
/* spherestruct *gp = &spheres[MI_SCREEN(mi)]; */
static GLfloat pos[4] =
{5.0, 5.0, 10.0, 0.0};
glLightfv(GL_LIGHT0, GL_POSITION, pos);
glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_TRUE);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_DEPTH_TEST);
glShadeModel(GL_SMOOTH);
glMaterialfv(GL_FRONT, GL_AMBIENT, front_ambient);
glMaterialfv(GL_FRONT, GL_DIFFUSE, front_diffuse);
glMaterialfv(GL_FRONT, GL_SPECULAR, front_specular);
glMaterialf(GL_FRONT, GL_SHININESS, 32.0);
glMaterialfv(GL_BACK, GL_AMBIENT, back_ambient);
glMaterialfv(GL_BACK, GL_DIFFUSE, back_diffuse);
glMaterialfv(GL_BACK, GL_SPECULAR, back_specular);
glMaterialf(GL_BACK, GL_SHININESS, 38.0);
}
static void
free_invert(Display *display, spherestruct *gp)
{
if (gp->glx_context) {
/* Display lists MUST be freed while their glXContext is current. */
glXMakeCurrent(display, gp->window, *(gp->glx_context));
if (glIsList(gp->frames)) {
glDeleteLists(gp->frames, STEPS);
gp->frames = 0;
/* Don't destroy the glXContext. init_GL does that. */
}
}
if (gp->partlist != NULL) {
free(gp->partlist);
gp->partlist = (char *) NULL;
}
}
void
init_invert(ModeInfo * mi)
{
spherestruct *gp;
if (spheres == NULL) {
if ((spheres = (spherestruct *) calloc(MI_NUM_SCREENS(mi),
sizeof (spherestruct))) == NULL)
return;
}
gp = &spheres[MI_SCREEN(mi)];
gp->window = MI_WINDOW(mi);
gp->time = 0;
gp->construction = 1;
gp->partlist = (char *) NULL;
gp->numsteps = STEPS;
gp->view_rotx = NRAND(360);
gp->view_roty = NRAND(360);
gp->view_rotz = NRAND(360);
if ((gp->glx_context = init_GL(mi)) != NULL) {
if ((gp->frames = glGenLists(STEPS)) == 0) {
free_invert(MI_DISPLAY(mi), gp);
return;
}
reshape(MI_WIDTH(mi), MI_HEIGHT(mi));
pinit();
} else {
MI_CLEARWINDOW(mi);
}
}
void
draw_invert(ModeInfo * mi)
{
Display *display = MI_DISPLAY(mi);
Window window = MI_WINDOW(mi);
/* int angle_incr = MI_CYCLES(mi) ? MI_CYCLES(mi) : 2; */
int rot_incr = MI_COUNT(mi) ? MI_COUNT(mi) : 1;
spherestruct *gp;
if (spheres == NULL)
return;
gp = &spheres[MI_SCREEN(mi)];
if (!gp->glx_context)
return;
MI_IS_DRAWN(mi) = True;
glDrawBuffer(GL_BACK);
glXMakeCurrent(display, window, *(gp->glx_context));
if (!invert_draw(gp)) {
free_invert(display, gp);
return;
}
/* let's do something so we don't get bored */
if (gp->time == STEPS-1)
gp->construction = 0;
if (gp->time == STEPS-1)
gp->forwards = 0;
if (gp->time == 0)
gp->forwards = 1;
if (gp->forwards)
gp->time++;
else
gp->time--;
gp->view_rotx = (int) (gp->view_rotx + rot_incr) % 360;
gp->view_roty = (int) (gp->view_roty + rot_incr) % 360;
gp->view_rotz = (int) (gp->view_rotz + rot_incr) % 360;
glFinish();
if (MI_IS_FPS(mi)) do_fps (mi);
glXSwapBuffers(display, window);
}
void
release_invert(ModeInfo * mi)
{
if (spheres != NULL) {
int screen;
for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++)
free_invert(MI_DISPLAY(mi), &spheres[screen]);
free(spheres);
spheres = (spherestruct *) NULL;
}
FreeAllGL(mi);
}
/*********************************************************/
#endif /* MODE_invert */