/* projectiveplane --- Shows a 4d embedding of the real projective plane
that rotates in 4d or on which you can walk */
#if 0
static const char sccsid[] = "@(#)projectiveplane.c 1.1 03/01/14 xlockmore";
#endif
/* Copyright (c) 2013-2020 Carsten Steger <carsten@mirsanmir.org>. */
/*
* 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.
*
* REVISION HISTORY:
* C. Steger - 03/01/14: Initial version
* C. Steger - 03/10/14: Moved the curlicue texture to curlicue.h
* C. Steger - 06/01/20: Added the changing colors mode.
*/
/*
* This program shows a 4d embedding of the real projective plane.
* You can walk on the projective plane, see it turn in 4d, or walk on
* it while it turns in 4d. The fact that the surface is an embedding
* of the real projective plane in 4d can be seen in the depth colors
* mode (using static colors): set all rotation speeds to 0 and the
* projection mode to 4d orthographic projection. In its default
* orientation, the embedding of the real projective plane will then
* project to the Roman surface, which has three lines of
* self-intersection. However, at the three lines of
* self-intersection the parts of the surface that intersect have
* different colors, i.e., different 4d depths.
*
* The real projective plane is a non-orientable surface. To make
* this apparent, the two-sided color mode can be used.
* Alternatively, orientation markers (curling arrows) can be drawn as
* a texture map on the surface of the projective plane. While
* walking on the projective plane, you will notice that the
* orientation of the curling arrows changes (which it must because
* the projective plane is non-orientable).
*
* The real projective plane is a model for the projective geometry in
* 2d space. One point can be singled out as the origin. A line can
* be singled out as the line at infinity, i.e., a line that lies at
* an infinite distance to the origin. The line at infinity, like all
* lines in the projective plane, is topologically a circle. Points
* on the line at infinity are also used to model directions in
* projective geometry. The origin can be visualized in different
* manners. When using distance colors (and using static colors), the
* origin is the point that is displayed as fully saturated red, which
* is easier to see as the center of the reddish area on the
* projective plane. Alternatively, when using distance bands, the
* origin is the center of the only band that projects to a disk.
* When using direction bands, the origin is the point where all
* direction bands collapse to a point. Finally, when orientation
* markers are being displayed, the origin the the point where all
* orientation markers are compressed to a point. The line at
* infinity can also be visualized in different ways. When using
* distance colors (and using static colors), the line at infinity is
* the line that is displayed as fully saturated magenta. When
* two-sided (and static) colors are used, the line at infinity lies
* at the points where the red and green "sides" of the projective
* plane meet (of course, the real projective plane only has one side,
* so this is a design choice of the visualization). Alternatively,
* when orientation markers are being displayed, the line at infinity
* is the place where the orientation markers change their
* orientation.
*
* Note that when the projective plane is displayed with bands, the
* orientation markers are placed in the middle of the bands. For
* distance bands, the bands are chosen in such a way that the band at
* the origin is only half as wide as the remaining bands, which
* results in a disk being displayed at the origin that has the same
* diameter as the remaining bands. This choice, however, also
* implies that the band at infinity is half as wide as the other
* bands. Since the projective plane is attached to itself (in a
* complicated fashion) at the line at infinity, effectively the band
* at infinity is again as wide as the remaining bands. However,
* since the orientation markers are displayed in the middle of the
* bands, this means that only one half of the orientation markers
* will be displayed twice at the line at infinity if distance bands
* are used. If direction bands are used or if the projective plane
* is displayed as a solid surface, the orientation markers are
* displayed fully at the respective sides of the line at infinity.
*
* The program projects the 4d projective plane to 3d using either a
* perspective or an orthographic projection. Which of the two
* alternatives looks more appealing is up to you. However, two
* famous surfaces are obtained if orthographic 4d projection is used:
* The Roman surface and the cross cap. If the projective plane is
* rotated in 4d, the result of the projection for certain rotations
* is a Roman surface and for certain rotations it is a cross cap.
* The easiest way to see this is to set all rotation speeds to 0 and
* the rotation speed around the yz plane to a value different from 0.
* However, for any 4d rotation speeds, the projections will generally
* cycle between the Roman surface and the cross cap. The difference
* is where the origin and the line at infinity will lie with respect
* to the self-intersections in the projections to 3d.
*
* The projected projective plane can then be projected to the screen
* either perspectively or orthographically. When using the walking
* modes, perspective projection to the screen will be used.
*
* There are three display modes for the projective plane: mesh
* (wireframe), solid, or transparent. Furthermore, the appearance of
* the projective plane can be as a solid object or as a set of
* see-through bands. The bands can be distance bands, i.e., bands
* that lie at increasing distances from the origin, or direction
* bands, i.e., bands that lie at increasing angles with respect to
* the origin.
*
* When the projective plane is displayed with direction bands, you
* will be able to see that each direction band (modulo the "pinching"
* at the origin) is a Moebius strip, which also shows that the
* projective plane is non-orientable.
*
* Finally, the colors with with the projective plane is drawn can be
* set to one-sided, two-sided, distance, direction, or depth. In
* one-sided mode, the projective plane is drawn with the same color
* on both "sides." In two-sided mode (using static colors), the
* projective plane is drawn with red on one "side" and green on the
* "other side." As described above, the projective plane only has
* one side, so the color jumps from red to green along the line at
* infinity. This mode enables you to see that the projective plane
* is non-orientable. If changing colors are used in two-sided mode,
* changing complementary colors are used on the respective "sides."
* In distance mode, the projective plane is displayed with fully
* saturated colors that depend on the distance of the points on the
* projective plane to the origin. If static colors are used, the
* origin is displayed in red, while the line at infinity is displayed
* in magenta. If the projective plane is displayed as distance
* bands, each band will be displayed with a different color. In
* direction mode, the projective plane is displayed with fully
* saturated colors that depend on the angle of the points on the
* projective plane with respect to the origin. Angles in opposite
* directions to the origin (e.g., 15 and 205 degrees) are displayed
* in the same color since they are projectively equivalent. If the
* projective plane is displayed as direction bands, each band will be
* displayed with a different color. Finally, in depth mode the
* projective plane is displayed with colors chosen depending on the
* 4d "depth" (i.e., the w coordinate) of the points on the projective
* plane at its default orientation in 4d. As discussed above, this
* mode enables you to see that the projective plane does not
* intersect itself in 4d.
*
* The rotation speed for each of the six planes around which the
* projective plane rotates can be chosen. For the walk-and-turn
* mode, only the rotation speeds around the true 4d planes are used
* (the xy, xz, and yz planes).
*
* Furthermore, in the walking modes the walking direction in the 2d
* base square of the projective plane and the walking speed can be
* chosen. The walking direction is measured as an angle in degrees
* in the 2d square that forms the coordinate system of the surface of
* the projective plane. A value of 0 or 180 means that the walk is
* along a circle at a randomly chosen distance from the origin
* (parallel to a distance band). A value of 90 or 270 means that the
* walk is directly from the origin to the line at infinity and back
* (analogous to a direction band). Any other value results in a
* curved path from the origin to the line at infinity and back.
*
* This program is somewhat inspired by Thomas Banchoff's book "Beyond
* the Third Dimension: Geometry, Computer Graphics, and Higher
* Dimensions", Scientific American Library, 1990.
*/
#include "curlicue.h"
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
#define DISP_WIREFRAME 0
#define DISP_SURFACE 1
#define DISP_TRANSPARENT 2
#define NUM_DISPLAY_MODES 3
#define APPEARANCE_SOLID 0
#define APPEARANCE_DISTANCE_BANDS 1
#define APPEARANCE_DIRECTION_BANDS 2
#define NUM_APPEARANCES 3
#define COLORS_ONESIDED 0
#define COLORS_TWOSIDED 1
#define COLORS_DISTANCE 2
#define COLORS_DIRECTION 3
#define COLORS_DEPTH 4
#define NUM_COLORS 5
#define VIEW_WALK 0
#define VIEW_TURN 1
#define VIEW_WALKTURN 2
#define NUM_VIEW_MODES 3
#define DISP_3D_PERSPECTIVE 0
#define DISP_3D_ORTHOGRAPHIC 1
#define NUM_DISP_3D_MODES 2
#define DISP_4D_PERSPECTIVE 0
#define DISP_4D_ORTHOGRAPHIC 1
#define NUM_DISP_4D_MODES 2
#define DEF_DISPLAY_MODE "random"
#define DEF_APPEARANCE "random"
#define DEF_COLORS "random"
#define DEF_VIEW_MODE "random"
#define DEF_MARKS "False"
#define DEF_CHANGE_COLORS "False"
#define DEF_PROJECTION_3D "random"
#define DEF_PROJECTION_4D "random"
#define DEF_SPEEDWX "1.1"
#define DEF_SPEEDWY "1.3"
#define DEF_SPEEDWZ "1.5"
#define DEF_SPEEDXY "1.7"
#define DEF_SPEEDXZ "1.9"
#define DEF_SPEEDYZ "2.1"
#define DEF_WALK_DIRECTION "83.0"
#define DEF_WALK_SPEED "20.0"
#ifdef STANDALONE
# define DEFAULTS "*delay: 10000 \n" \
"*showFPS: False \n" \
# define release_projectiveplane 0
# include "xlockmore.h" /* from the xscreensaver distribution */
#else /* !STANDALONE */
# include "xlock.h" /* from the xlockmore distribution */
#endif /* !STANDALONE */
#ifdef USE_GL
#ifndef HAVE_JWXYZ
# include <X11/keysym.h>
#endif
#include "gltrackball.h"
#include <float.h>
#ifdef USE_MODULES
ModStruct projectiveplane_description =
{"projectiveplane", "init_projectiveplane", "draw_projectiveplane",
NULL, "draw_projectiveplane", "change_projectiveplane",
NULL, &projectiveplane_opts, 25000, 1, 1, 1, 1.0, 4, "",
"Rotate a 4d embedding of the real projective plane in 4d or walk on it",
0, NULL};
#endif
static char *mode;
static char *appear;
static char *color_mode;
static char *view_mode;
static Bool marks;
static Bool change_colors;
static char *proj_3d;
static char *proj_4d;
static float speed_wx;
static float speed_wy;
static float speed_wz;
static float speed_xy;
static float speed_xz;
static float speed_yz;
static float walk_direction;
static float walk_speed;
static XrmOptionDescRec opts[] =
{
{"-mode", ".displayMode", XrmoptionSepArg, 0 },
{"-wireframe", ".displayMode", XrmoptionNoArg, "wireframe" },
{"-surface", ".displayMode", XrmoptionNoArg, "surface" },
{"-transparent", ".displayMode", XrmoptionNoArg, "transparent" },
{"-appearance", ".appearance", XrmoptionSepArg, 0 },
{"-solid", ".appearance", XrmoptionNoArg, "solid" },
{"-distance-bands", ".appearance", XrmoptionNoArg, "distance-bands" },
{"-direction-bands", ".appearance", XrmoptionNoArg, "direction-bands" },
{"-colors", ".colors", XrmoptionSepArg, 0 },
{"-onesided-colors", ".colors", XrmoptionNoArg, "one-sided" },
{"-twosided-colors", ".colors", XrmoptionNoArg, "two-sided" },
{"-distance-colors", ".colors", XrmoptionNoArg, "distance" },
{"-direction-colors", ".colors", XrmoptionNoArg, "direction" },
{"-depth-colors", ".colors", XrmoptionNoArg, "depth" },
{"-change-colors", ".changeColors", XrmoptionNoArg, "on"},
{"+change-colors", ".changeColors", XrmoptionNoArg, "off"},
{"-view-mode", ".viewMode", XrmoptionSepArg, 0 },
{"-walk", ".viewMode", XrmoptionNoArg, "walk" },
{"-turn", ".viewMode", XrmoptionNoArg, "turn" },
{"-walk-turn", ".viewMode", XrmoptionNoArg, "walk-turn" },
{"-orientation-marks", ".marks", XrmoptionNoArg, "on"},
{"+orientation-marks", ".marks", XrmoptionNoArg, "off"},
{"-projection-3d", ".projection3d", XrmoptionSepArg, 0 },
{"-perspective-3d", ".projection3d", XrmoptionNoArg, "perspective" },
{"-orthographic-3d", ".projection3d", XrmoptionNoArg, "orthographic" },
{"-projection-4d", ".projection4d", XrmoptionSepArg, 0 },
{"-perspective-4d", ".projection4d", XrmoptionNoArg, "perspective" },
{"-orthographic-4d", ".projection4d", XrmoptionNoArg, "orthographic" },
{"-speed-wx", ".speedwx", XrmoptionSepArg, 0 },
{"-speed-wy", ".speedwy", XrmoptionSepArg, 0 },
{"-speed-wz", ".speedwz", XrmoptionSepArg, 0 },
{"-speed-xy", ".speedxy", XrmoptionSepArg, 0 },
{"-speed-xz", ".speedxz", XrmoptionSepArg, 0 },
{"-speed-yz", ".speedyz", XrmoptionSepArg, 0 },
{"-walk-direction", ".walkDirection", XrmoptionSepArg, 0 },
{"-walk-speed", ".walkSpeed", XrmoptionSepArg, 0 }
};
static argtype vars[] =
{
{ &mode, "displayMode", "DisplayMode", DEF_DISPLAY_MODE, t_String },
{ &appear, "appearance", "Appearance", DEF_APPEARANCE, t_String },
{ &color_mode, "colors", "Colors", DEF_COLORS, t_String },
{ &change_colors, "changeColors", "ChangeColors", DEF_CHANGE_COLORS, t_Bool },
{ &view_mode, "viewMode", "ViewMode", DEF_VIEW_MODE, t_String },
{ &marks, "marks", "Marks", DEF_MARKS, t_Bool },
{ &proj_3d, "projection3d", "Projection3d", DEF_PROJECTION_3D, t_String },
{ &proj_4d, "projection4d", "Projection4d", DEF_PROJECTION_4D, t_String },
{ &speed_wx, "speedwx", "Speedwx", DEF_SPEEDWX, t_Float},
{ &speed_wy, "speedwy", "Speedwy", DEF_SPEEDWY, t_Float},
{ &speed_wz, "speedwz", "Speedwz", DEF_SPEEDWZ, t_Float},
{ &speed_xy, "speedxy", "Speedxy", DEF_SPEEDXY, t_Float},
{ &speed_xz, "speedxz", "Speedxz", DEF_SPEEDXZ, t_Float},
{ &speed_yz, "speedyz", "Speedyz", DEF_SPEEDYZ, t_Float},
{ &walk_direction, "walkDirection", "WalkDirection", DEF_WALK_DIRECTION, t_Float},
{ &walk_speed, "walkSpeed", "WalkSpeed", DEF_WALK_SPEED, t_Float}
};
ENTRYPOINT ModeSpecOpt projectiveplane_opts =
{sizeof opts / sizeof opts[0], opts, sizeof vars / sizeof vars[0], vars, NULL};
/* Offset by which we walk above the projective plane */
#define DELTAY 0.01
/* Color change speeds */
#define DRHO 0.7
#define DSIGMA 1.1
#define DTAU 1.7
/* Number of subdivisions of the projective plane */
#define NUMU 128
#define NUMV 128
/* Number of subdivisions per band */
#define NUMB 8
typedef struct {
GLint WindH, WindW;
GLXContext *glx_context;
/* Options */
int display_mode;
int appearance;
int colors;
Bool change_colors;
int view;
Bool marks;
int projection_3d;
int projection_4d;
/* 4D rotation angles */
float alpha, beta, delta, zeta, eta, theta;
/* Color rotation angles */
float rho, sigma, tau;
/* Movement parameters */
float umove, vmove, dumove, dvmove;
int side, dir;
/* The viewing offset in 4d */
float offset4d[4];
/* The viewing offset in 3d */
float offset3d[4];
/* The 4d coordinates of the projective plane and their derivatives */
float x[(NUMU+1)*(NUMV+1)][4];
float xu[(NUMU+1)*(NUMV+1)][4];
float xv[(NUMU+1)*(NUMV+1)][4];
float pp[(NUMU+1)*(NUMV+1)][3];
float pn[(NUMU+1)*(NUMV+1)][3];
/* The precomputed colors of the projective plane */
float col[(NUMU+1)*(NUMV+1)][4];
/* The precomputed texture coordinates of the projective plane */
float tex[(NUMU+1)*(NUMV+1)][2];
/* The "curlicue" texture */
GLuint tex_name;
/* Aspect ratio of the current window */
float aspect;
/* Trackball states */
trackball_state *trackballs[2];
int current_trackball;
Bool button_pressed;
/* A random factor to modify the rotation speeds */
float speed_scale;
} projectiveplanestruct;
static projectiveplanestruct *projectiveplane = (projectiveplanestruct *) NULL;
/* Add a rotation around the wx-plane to the matrix m. */
static void rotatewx(float m[4][4], float phi)
{
float c, s, u, v;
int i;
phi *= M_PI/180.0;
c = cos(phi);
s = sin(phi);
for (i=0; i<4; i++)
{
u = m[i][1];
v = m[i][2];
m[i][1] = c*u+s*v;
m[i][2] = -s*u+c*v;
}
}
/* Add a rotation around the wy-plane to the matrix m. */
static void rotatewy(float m[4][4], float phi)
{
float c, s, u, v;
int i;
phi *= M_PI/180.0;
c = cos(phi);
s = sin(phi);
for (i=0; i<4; i++)
{
u = m[i][0];
v = m[i][2];
m[i][0] = c*u-s*v;
m[i][2] = s*u+c*v;
}
}
/* Add a rotation around the wz-plane to the matrix m. */
static void rotatewz(float m[4][4], float phi)
{
float c, s, u, v;
int i;
phi *= M_PI/180.0;
c = cos(phi);
s = sin(phi);
for (i=0; i<4; i++)
{
u = m[i][0];
v = m[i][1];
m[i][0] = c*u+s*v;
m[i][1] = -s*u+c*v;
}
}
/* Add a rotation around the xy-plane to the matrix m. */
static void rotatexy(float m[4][4], float phi)
{
float c, s, u, v;
int i;
phi *= M_PI/180.0;
c = cos(phi);
s = sin(phi);
for (i=0; i<4; i++)
{
u = m[i][2];
v = m[i][3];
m[i][2] = c*u+s*v;
m[i][3] = -s*u+c*v;
}
}
/* Add a rotation around the xz-plane to the matrix m. */
static void rotatexz(float m[4][4], float phi)
{
float c, s, u, v;
int i;
phi *= M_PI/180.0;
c = cos(phi);
s = sin(phi);
for (i=0; i<4; i++)
{
u = m[i][1];
v = m[i][3];
m[i][1] = c*u-s*v;
m[i][3] = s*u+c*v;
}
}
/* Add a rotation around the yz-plane to the matrix m. */
static void rotateyz(float m[4][4], float phi)
{
float c, s, u, v;
int i;
phi *= M_PI/180.0;
c = cos(phi);
s = sin(phi);
for (i=0; i<4; i++)
{
u = m[i][0];
v = m[i][3];
m[i][0] = c*u-s*v;
m[i][3] = s*u+c*v;
}
}
/* Compute the rotation matrix m from the rotation angles. */
static void rotateall(float al, float be, float de, float ze, float et,
float th, float m[4][4])
{
int i, j;
for (i=0; i<4; i++)
for (j=0; j<4; j++)
m[i][j] = (i==j);
rotatewx(m,al);
rotatewy(m,be);
rotatewz(m,de);
rotatexy(m,ze);
rotatexz(m,et);
rotateyz(m,th);
}
/* Compute the rotation matrix m from the 4d rotation angles. */
static void rotateall4d(float ze, float et, float th, float m[4][4])
{
int i, j;
for (i=0; i<4; i++)
for (j=0; j<4; j++)
m[i][j] = (i==j);
rotatexy(m,ze);
rotatexz(m,et);
rotateyz(m,th);
}
/* Add a rotation around the x-axis to the matrix m. */
static void rotatex(float m[3][3], float phi)
{
float c, s, u, v;
int i;
phi *= M_PI/180.0;
c = cos(phi);
s = sin(phi);
for (i=0; i<3; i++)
{
u = m[i][1];
v = m[i][2];
m[i][1] = c*u+s*v;
m[i][2] = -s*u+c*v;
}
}
/* Add a rotation around the y-axis to the matrix m. */
static void rotatey(float m[3][3], float phi)
{
float c, s, u, v;
int i;
phi *= M_PI/180.0;
c = cos(phi);
s = sin(phi);
for (i=0; i<3; i++)
{
u = m[i][0];
v = m[i][2];
m[i][0] = c*u-s*v;
m[i][2] = s*u+c*v;
}
}
/* Add a rotation around the z-axis to the matrix m. */
static void rotatez(float m[3][3], float phi)
{
float c, s, u, v;
int i;
phi *= M_PI/180.0;
c = cos(phi);
s = sin(phi);
for (i=0; i<3; i++)
{
u = m[i][0];
v = m[i][1];
m[i][0] = c*u+s*v;
m[i][1] = -s*u+c*v;
}
}
/* Compute the 3d rotation matrix m from the 3d rotation angles. */
static void rotateall3d(float al, float be, float de, float m[3][3])
{
int i, j;
for (i=0; i<3; i++)
for (j=0; j<3; j++)
m[i][j] = (i==j);
rotatex(m,al);
rotatey(m,be);
rotatez(m,de);
}
/* Multiply two rotation matrices: o=m*n. */
static void mult_rotmat(float m[4][4], float n[4][4], float o[4][4])
{
int i, j, k;
for (i=0; i<4; i++)
{
for (j=0; j<4; j++)
{
o[i][j] = 0.0;
for (k=0; k<4; k++)
o[i][j] += m[i][k]*n[k][j];
}
}
}
/* Compute a 4D rotation matrix from two unit quaternions. */
static void quats_to_rotmat(float p[4], float q[4], float m[4][4])
{
double al, be, de, ze, et, th;
double r00, r01, r02, r12, r22;
r00 = 1.0-2.0*(p[1]*p[1]+p[2]*p[2]);
r01 = 2.0*(p[0]*p[1]+p[2]*p[3]);
r02 = 2.0*(p[2]*p[0]-p[1]*p[3]);
r12 = 2.0*(p[1]*p[2]+p[0]*p[3]);
r22 = 1.0-2.0*(p[1]*p[1]+p[0]*p[0]);
al = atan2(-r12,r22)*180.0/M_PI;
be = atan2(r02,sqrt(r00*r00+r01*r01))*180.0/M_PI;
de = atan2(-r01,r00)*180.0/M_PI;
r00 = 1.0-2.0*(q[1]*q[1]+q[2]*q[2]);
r01 = 2.0*(q[0]*q[1]+q[2]*q[3]);
r02 = 2.0*(q[2]*q[0]-q[1]*q[3]);
r12 = 2.0*(q[1]*q[2]+q[0]*q[3]);
r22 = 1.0-2.0*(q[1]*q[1]+q[0]*q[0]);
et = atan2(-r12,r22)*180.0/M_PI;
th = atan2(r02,sqrt(r00*r00+r01*r01))*180.0/M_PI;
ze = atan2(-r01,r00)*180.0/M_PI;
rotateall(al,be,de,ze,et,-th,m);
}
/* Compute a fully saturated and bright color based on an angle. */
static void color(projectiveplanestruct *pp, double angle, float mat[3][3],
float col[4])
{
int s;
double t, ca, sa;
float m;
if (!pp->change_colors)
{
if (pp->colors == COLORS_ONESIDED || pp->colors == COLORS_TWOSIDED)
return;
if (angle >= 0.0)
angle = fmod(angle,2.0*M_PI);
else
angle = fmod(angle,-2.0*M_PI);
s = floor(angle/(M_PI/3));
t = angle/(M_PI/3)-s;
if (s >= 6)
s = 0;
switch (s)
{
case 0:
col[0] = 1.0;
col[1] = t;
col[2] = 0.0;
break;
case 1:
col[0] = 1.0-t;
col[1] = 1.0;
col[2] = 0.0;
break;
case 2:
col[0] = 0.0;
col[1] = 1.0;
col[2] = t;
break;
case 3:
col[0] = 0.0;
col[1] = 1.0-t;
col[2] = 1.0;
break;
case 4:
col[0] = t;
col[1] = 0.0;
col[2] = 1.0;
break;
case 5:
col[0] = 1.0;
col[1] = 0.0;
col[2] = 1.0-t;
break;
}
}
else /* pp->change_colors */
{
if (pp->colors == COLORS_ONESIDED || pp->colors == COLORS_TWOSIDED)
{
col[0] = mat[0][2];
col[1] = mat[1][2];
col[2] = mat[2][2];
}
else
{
ca = cos(angle);
sa = sin(angle);
col[0] = ca*mat[0][0]+sa*mat[0][1];
col[1] = ca*mat[1][0]+sa*mat[1][1];
col[2] = ca*mat[2][0]+sa*mat[2][1];
}
m = 0.5f/fmaxf(fmaxf(fabsf(col[0]),fabsf(col[1])),fabsf(col[2]));
col[0] = m*col[0]+0.5f;
col[1] = m*col[1]+0.5f;
col[2] = m*col[2]+0.5f;
}
if (pp->display_mode == DISP_TRANSPARENT)
col[3] = 0.7;
else
col[3] = 1.0;
}
/* Set up the projective plane coordinates, colors, and texture. */
static void setup_projective_plane(ModeInfo *mi, double umin, double umax,
double vmin, double vmax)
{
int i, j, k;
double u, v, w, ur, vr;
double cu, su, cv2, sv2, cv4, sv4, c2u, s2u;
projectiveplanestruct *pp = &projectiveplane[MI_SCREEN(mi)];
ur = umax-umin;
vr = vmax-vmin;
for (i=0; i<=NUMV; i++)
{
for (j=0; j<=NUMU; j++)
{
k = i*(NUMU+1)+j;
if (pp->appearance != APPEARANCE_DIRECTION_BANDS)
u = -ur*j/NUMU+umin;
else
u = ur*j/NUMU+umin;
v = vr*i/NUMV+vmin;
cu = cos(u);
su = sin(u);
c2u = cos(2.0*u);
s2u = sin(2.0*u);
sv2 = sin(0.5*v);
cv4 = cos(0.25*v);
sv4 = sin(0.25*v);
w = 0.5*(su*su*sv4*sv4-cv4*cv4);
if (!pp->change_colors)
{
if (pp->colors == COLORS_DEPTH)
color(pp,(2.0*w+1.0)*M_PI*2.0/3.0,NULL,pp->col[k]);
else if (pp->colors == COLORS_DIRECTION)
color(pp,2.0*M_PI+fmod(2.0*u,2.0*M_PI),NULL,pp->col[k]);
else /* pp->colors == COLORS_DISTANCE */
color(pp,v*(5.0/6.0),NULL,pp->col[k]);
}
pp->tex[k][0] = -32*u/(2.0*M_PI);
if (pp->appearance != APPEARANCE_DISTANCE_BANDS)
pp->tex[k][1] = 32*v/(2.0*M_PI);
else
pp->tex[k][1] = 32*v/(2.0*M_PI)-0.5;
pp->x[k][0] = 0.5*s2u*sv4*sv4;
pp->x[k][1] = 0.5*su*sv2;
pp->x[k][2] = 0.5*cu*sv2;
pp->x[k][3] = w;
/* Avoid degenerate tangential plane basis vectors. */
if (v < FLT_EPSILON)
v = FLT_EPSILON;
cv2 = cos(0.5*v);
sv2 = sin(0.5*v);
sv4 = sin(0.25*v);
pp->xu[k][0] = c2u*sv4*sv4;
pp->xu[k][1] = 0.5*cu*sv2;
pp->xu[k][2] = -0.5*su*sv2;
pp->xu[k][3] = 0.5*s2u*sv4*sv4;
pp->xv[k][0] = 0.125*s2u*sv2;
pp->xv[k][1] = 0.25*su*cv2;
pp->xv[k][2] = 0.25*cu*cv2;
pp->xv[k][3] = 0.125*(su*su+1.0)*sv2;
}
}
}
/* Draw a 4d embedding of the projective plane projected into 3D. */
static int projective_plane(ModeInfo *mi, double umin, double umax,
double vmin, double vmax)
{
int polys = 0;
static const GLfloat mat_diff_red[] = { 1.0, 0.0, 0.0, 1.0 };
static const GLfloat mat_diff_green[] = { 0.0, 1.0, 0.0, 1.0 };
static const GLfloat mat_diff_oneside[] = { 0.9, 0.4, 0.3, 1.0 };
static const GLfloat mat_diff_trans_red[] = { 1.0, 0.0, 0.0, 0.7 };
static const GLfloat mat_diff_trans_green[] = { 0.0, 1.0, 0.0, 0.7 };
static const GLfloat mat_diff_trans_oneside[] = { 0.9, 0.4, 0.3, 0.7 };
float mat_diff_dyn[4], mat_diff_dyn_compl[4];
float p[3], pu[3], pv[3], pm[3], n[3], b[3], mat[4][4], matc[3][3];
int i, j, k, l, m, o;
double u, v, ur, vr;
double xx[4], xxu[4], xxv[4], y[4], yu[4], yv[4];
double q, r, s, t;
double cu, su, cv2, sv2, cv4, sv4, c2u, s2u;
float q1[4], q2[4], r1[4][4], r2[4][4];
projectiveplanestruct *pp = &projectiveplane[MI_SCREEN(mi)];
if (pp->change_colors)
rotateall3d(pp->rho,pp->sigma,pp->tau,matc);
if (pp->view == VIEW_WALK || pp->view == VIEW_WALKTURN)
{
/* Compute the rotation that rotates the projective plane in 4D without
the trackball rotations. */
rotateall4d(pp->zeta,pp->eta,pp->theta,mat);
u = pp->umove;
v = pp->vmove;
cu = cos(u);
su = sin(u);
c2u = cos(2.0*u);
s2u = sin(2.0*u);
sv2 = sin(0.5*v);
cv4 = cos(0.25*v);
sv4 = sin(0.25*v);
xx[0] = 0.5*s2u*sv4*sv4;
xx[1] = 0.5*su*sv2;
xx[2] = 0.5*cu*sv2;
xx[3] = 0.5*(su*su*sv4*sv4-cv4*cv4);
/* Avoid degenerate tangential plane basis vectors. */
if (v < FLT_EPSILON)
v = FLT_EPSILON;
cv2 = cos(0.5*v);
sv2 = sin(0.5*v);
sv4 = sin(0.25*v);
xxu[0] = c2u*sv4*sv4;
xxu[1] = 0.5*cu*sv2;
xxu[2] = -0.5*su*sv2;
xxu[3] = 0.5*s2u*sv4*sv4;
xxv[0] = 0.125*s2u*sv2;
xxv[1] = 0.25*su*cv2;
xxv[2] = 0.25*cu*cv2;
xxv[3] = 0.125*(su*su+1.0)*sv2;
for (l=0; l<4; l++)
{
y[l] = (mat[l][0]*xx[0]+mat[l][1]*xx[1]+
mat[l][2]*xx[2]+mat[l][3]*xx[3]);
yu[l] = (mat[l][0]*xxu[0]+mat[l][1]*xxu[1]+
mat[l][2]*xxu[2]+mat[l][3]*xxu[3]);
yv[l] = (mat[l][0]*xxv[0]+mat[l][1]*xxv[1]+
mat[l][2]*xxv[2]+mat[l][3]*xxv[3]);
}
if (pp->projection_4d == DISP_4D_ORTHOGRAPHIC)
{
for (l=0; l<3; l++)
{
p[l] = y[l]+pp->offset4d[l];
pu[l] = yu[l];
pv[l] = yv[l];
}
}
else
{
s = y[3]+pp->offset4d[3];
q = 1.0/s;
t = q*q;
for (l=0; l<3; l++)
{
r = y[l]+pp->offset4d[l];
p[l] = r*q;
pu[l] = (yu[l]*s-r*yu[3])*t;
pv[l] = (yv[l]*s-r*yv[3])*t;
}
}
n[0] = pu[1]*pv[2]-pu[2]*pv[1];
n[1] = pu[2]*pv[0]-pu[0]*pv[2];
n[2] = pu[0]*pv[1]-pu[1]*pv[0];
t = 1.0/(pp->side*4.0*sqrt(n[0]*n[0]+n[1]*n[1]+n[2]*n[2]));
n[0] *= t;
n[1] *= t;
n[2] *= t;
pm[0] = pu[0]*pp->dumove+pv[0]*pp->dvmove;
pm[1] = pu[1]*pp->dumove+pv[1]*pp->dvmove;
pm[2] = pu[2]*pp->dumove+pv[2]*pp->dvmove;
t = 1.0/(4.0*sqrt(pm[0]*pm[0]+pm[1]*pm[1]+pm[2]*pm[2]));
pm[0] *= t;
pm[1] *= t;
pm[2] *= t;
b[0] = n[1]*pm[2]-n[2]*pm[1];
b[1] = n[2]*pm[0]-n[0]*pm[2];
b[2] = n[0]*pm[1]-n[1]*pm[0];
t = 1.0/(4.0*sqrt(b[0]*b[0]+b[1]*b[1]+b[2]*b[2]));
b[0] *= t;
b[1] *= t;
b[2] *= t;
/* Compute alpha, beta, delta from the three basis vectors.
| -b[0] -b[1] -b[2] |
m = | n[0] n[1] n[2] |
| -pm[0] -pm[1] -pm[2] |
*/
pp->alpha = atan2(-n[2],-pm[2])*180/M_PI;
pp->beta = atan2(-b[2],sqrt(b[0]*b[0]+b[1]*b[1]))*180/M_PI;
pp->delta = atan2(b[1],-b[0])*180/M_PI;
/* Compute the rotation that rotates the projective plane in 4D. */
rotateall(pp->alpha,pp->beta,pp->delta,pp->zeta,pp->eta,pp->theta,mat);
u = pp->umove;
v = pp->vmove;
cu = cos(u);
su = sin(u);
s2u = sin(2.0*u);
sv2 = sin(0.5*v);
cv4 = cos(0.25*v);
sv4 = sin(0.25*v);
xx[0] = 0.5*s2u*sv4*sv4;
xx[1] = 0.5*su*sv2;
xx[2] = 0.5*cu*sv2;
xx[3] = 0.5*(su*su*sv4*sv4-cv4*cv4);
for (l=0; l<4; l++)
{
r = 0.0;
for (m=0; m<4; m++)
r += mat[l][m]*xx[m];
y[l] = r;
}
if (pp->projection_4d == DISP_4D_ORTHOGRAPHIC)
{
for (l=0; l<3; l++)
p[l] = y[l]+pp->offset4d[l];
}
else
{
s = y[3]+pp->offset4d[3];
for (l=0; l<3; l++)
p[l] = (y[l]+pp->offset4d[l])/s;
}
pp->offset3d[0] = -p[0];
pp->offset3d[1] = -p[1]-DELTAY;
pp->offset3d[2] = -p[2];
}
else
{
/* Compute the rotation that rotates the projective plane in 4D,
including the trackball rotations. */
rotateall(pp->alpha,pp->beta,pp->delta,pp->zeta,pp->eta,pp->theta,r1);
gltrackball_get_quaternion(pp->trackballs[0],q1);
gltrackball_get_quaternion(pp->trackballs[1],q2);
quats_to_rotmat(q1,q2,r2);
mult_rotmat(r2,r1,mat);
}
/* Project the points from 4D to 3D. */
for (i=0; i<=NUMV; i++)
{
for (j=0; j<=NUMU; j++)
{
o = i*(NUMU+1)+j;
for (l=0; l<4; l++)
{
y[l] = (mat[l][0]*pp->x[o][0]+mat[l][1]*pp->x[o][1]+
mat[l][2]*pp->x[o][2]+mat[l][3]*pp->x[o][3]);
yu[l] = (mat[l][0]*pp->xu[o][0]+mat[l][1]*pp->xu[o][1]+
mat[l][2]*pp->xu[o][2]+mat[l][3]*pp->xu[o][3]);
yv[l] = (mat[l][0]*pp->xv[o][0]+mat[l][1]*pp->xv[o][1]+
mat[l][2]*pp->xv[o][2]+mat[l][3]*pp->xv[o][3]);
}
if (pp->projection_4d == DISP_4D_ORTHOGRAPHIC)
{
for (l=0; l<3; l++)
{
pp->pp[o][l] = (y[l]+pp->offset4d[l])+pp->offset3d[l];
pu[l] = yu[l];
pv[l] = yv[l];
}
}
else
{
s = y[3]+pp->offset4d[3];
q = 1.0/s;
t = q*q;
for (l=0; l<3; l++)
{
r = y[l]+pp->offset4d[l];
pp->pp[o][l] = r*q+pp->offset3d[l];
pu[l] = (yu[l]*s-r*yu[3])*t;
pv[l] = (yv[l]*s-r*yv[3])*t;
}
}
pp->pn[o][0] = pu[1]*pv[2]-pu[2]*pv[1];
pp->pn[o][1] = pu[2]*pv[0]-pu[0]*pv[2];
pp->pn[o][2] = pu[0]*pv[1]-pu[1]*pv[0];
t = 1.0/sqrt(pp->pn[o][0]*pp->pn[o][0]+pp->pn[o][1]*pp->pn[o][1]+
pp->pn[o][2]*pp->pn[o][2]);
pp->pn[o][0] *= t;
pp->pn[o][1] *= t;
pp->pn[o][2] *= t;
}
}
if (!pp->change_colors)
{
if (pp->colors == COLORS_ONESIDED)
{
glColor3fv(mat_diff_oneside);
if (pp->display_mode == DISP_TRANSPARENT)
{
glMaterialfv(GL_FRONT_AND_BACK,GL_AMBIENT_AND_DIFFUSE,
mat_diff_trans_oneside);
}
else
{
glMaterialfv(GL_FRONT_AND_BACK,GL_AMBIENT_AND_DIFFUSE,
mat_diff_oneside);
}
}
else if (pp->colors == COLORS_TWOSIDED)
{
glColor3fv(mat_diff_red);
if (pp->display_mode == DISP_TRANSPARENT)
{
glMaterialfv(GL_FRONT,GL_AMBIENT_AND_DIFFUSE,mat_diff_trans_red);
glMaterialfv(GL_BACK,GL_AMBIENT_AND_DIFFUSE,mat_diff_trans_green);
}
else
{
glMaterialfv(GL_FRONT,GL_AMBIENT_AND_DIFFUSE,mat_diff_red);
glMaterialfv(GL_BACK,GL_AMBIENT_AND_DIFFUSE,mat_diff_green);
}
}
}
else /* pp->change_colors */
{
color(pp,0.0,matc,mat_diff_dyn);
if (pp->colors == COLORS_ONESIDED)
{
glColor3fv(mat_diff_dyn);
glMaterialfv(GL_FRONT_AND_BACK,GL_AMBIENT_AND_DIFFUSE,mat_diff_dyn);
}
else if (pp->colors == COLORS_TWOSIDED)
{
mat_diff_dyn_compl[0] = 1.0f-mat_diff_dyn[0];
mat_diff_dyn_compl[1] = 1.0f-mat_diff_dyn[1];
mat_diff_dyn_compl[2] = 1.0f-mat_diff_dyn[2];
mat_diff_dyn_compl[3] = mat_diff_dyn[3];
glColor3fv(mat_diff_dyn);
glMaterialfv(GL_FRONT,GL_AMBIENT_AND_DIFFUSE,mat_diff_dyn);
glMaterialfv(GL_BACK,GL_AMBIENT_AND_DIFFUSE,mat_diff_dyn_compl);
}
}
glBindTexture(GL_TEXTURE_2D,pp->tex_name);
ur = umax-umin;
vr = vmax-vmin;
if (pp->appearance != APPEARANCE_DIRECTION_BANDS)
{
for (i=0; i<NUMV; i++)
{
if (pp->appearance == APPEARANCE_DISTANCE_BANDS &&
((i & (NUMB-1)) >= NUMB/4) && ((i & (NUMB-1)) < 3*NUMB/4))
continue;
if (pp->display_mode == DISP_WIREFRAME)
glBegin(GL_QUAD_STRIP);
else
glBegin(GL_TRIANGLE_STRIP);
for (j=0; j<=NUMU; j++)
{
for (k=0; k<=1; k++)
{
l = (i+k);
m = j;
o = l*(NUMU+1)+m;
glNormal3fv(pp->pn[o]);
glTexCoord2fv(pp->tex[o]);
if (pp->change_colors)
{
if (pp->colors == COLORS_DEPTH)
{
color(pp,(2.0*pp->x[o][3]+1.0)*M_PI*2.0/3.0,matc,pp->col[o]);
}
else if (pp->colors == COLORS_DIRECTION)
{
u = -ur*m/NUMU+umin;
color(pp,2.0*M_PI+fmod(2.0*u,2.0*M_PI),matc,pp->col[o]);
}
else if (pp->colors == COLORS_DISTANCE)
{
v = vr*l/NUMV+vmin;
color(pp,v*(5.0/6.0),matc,pp->col[o]);
}
}
if (pp->colors != COLORS_ONESIDED && pp->colors != COLORS_TWOSIDED)
{
glColor3fv(pp->col[o]);
glMaterialfv(GL_FRONT_AND_BACK,GL_AMBIENT_AND_DIFFUSE,pp->col[o]);
}
glVertex3fv(pp->pp[o]);
polys++;
}
}
glEnd();
}
}
else /* pp->appearance == APPEARANCE_DIRECTION_BANDS */
{
for (j=0; j<NUMU; j++)
{
if ((j & (NUMB-1)) >= NUMB/2)
continue;
if (pp->display_mode == DISP_WIREFRAME)
glBegin(GL_QUAD_STRIP);
else
glBegin(GL_TRIANGLE_STRIP);
for (i=0; i<=NUMV; i++)
{
for (k=0; k<=1; k++)
{
l = i;
m = (j+k);
o = l*(NUMU+1)+m;
glNormal3fv(pp->pn[o]);
glTexCoord2fv(pp->tex[o]);
if (pp->change_colors)
{
if (pp->colors == COLORS_DEPTH)
{
color(pp,(2.0*pp->x[o][3]+1.0)*M_PI*2.0/3.0,matc,pp->col[o]);
}
else if (pp->colors == COLORS_DIRECTION)
{
u = ur*m/NUMU+umin;
color(pp,2.0*M_PI+fmod(2.0*u,2.0*M_PI),matc,pp->col[o]);
}
else if (pp->colors == COLORS_DISTANCE)
{
v = vr*l/NUMV+vmin;
color(pp,v*(5.0/6.0),matc,pp->col[o]);
}
}
if (pp->colors != COLORS_ONESIDED && pp->colors != COLORS_TWOSIDED)
{
glColor3fv(pp->col[o]);
glMaterialfv(GL_FRONT_AND_BACK,GL_AMBIENT_AND_DIFFUSE,pp->col[o]);
}
glVertex3fv(pp->pp[o]);
polys++;
}
}
glEnd();
}
}
polys /= 2;
return polys;
}
/* Generate a texture image that shows the orientation reversal. */
static void gen_texture(ModeInfo *mi)
{
projectiveplanestruct *pp = &projectiveplane[MI_SCREEN(mi)];
glGenTextures(1,&pp->tex_name);
glBindTexture(GL_TEXTURE_2D,pp->tex_name);
glPixelStorei(GL_UNPACK_ALIGNMENT,1);
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_LINEAR);
glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_MODULATE);
glTexImage2D(GL_TEXTURE_2D,0,GL_LUMINANCE,TEX_DIMENSION,TEX_DIMENSION,0,
GL_LUMINANCE,GL_UNSIGNED_BYTE,texture);
}
static void init(ModeInfo *mi)
{
static const GLfloat light_ambient[] = { 0.0, 0.0, 0.0, 1.0 };
static const GLfloat light_diffuse[] = { 1.0, 1.0, 1.0, 1.0 };
static const GLfloat light_specular[] = { 1.0, 1.0, 1.0, 1.0 };
static const GLfloat light_position[] = { 1.0, 1.0, 1.0, 0.0 };
static const GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 };
projectiveplanestruct *pp = &projectiveplane[MI_SCREEN(mi)];
if (walk_speed == 0.0)
walk_speed = 20.0;
if (pp->view == VIEW_TURN)
{
pp->alpha = frand(360.0);
pp->beta = frand(360.0);
pp->delta = frand(360.0);
pp->zeta = 0.0;
pp->eta = 0.0;
pp->theta = 0.0;
}
else
{
pp->alpha = 0.0;
pp->beta = 0.0;
pp->delta = 0.0;
pp->zeta = 120.0;
pp->eta = 180.0;
pp->theta = 90.0;
}
pp->umove = frand(2.0*M_PI);
pp->vmove = frand(2.0*M_PI);
pp->dumove = 0.0;
pp->dvmove = 0.0;
pp->side = 1;
if (sin(walk_direction*M_PI/180.0) >= 0.0)
pp->dir = 1;
else
pp->dir = -1;
pp->rho = frand(360.0);
pp->sigma = frand(360.0);
pp->tau = frand(360.0);
pp->offset4d[0] = 0.0;
pp->offset4d[1] = 0.0;
pp->offset4d[2] = 0.0;
pp->offset4d[3] = 1.2;
pp->offset3d[0] = 0.0;
pp->offset3d[1] = 0.0;
pp->offset3d[2] = -1.2;
pp->offset3d[3] = 0.0;
gen_texture(mi);
setup_projective_plane(mi,0.0,2.0*M_PI,0.0,2.0*M_PI);
if (pp->marks)
glEnable(GL_TEXTURE_2D);
else
glDisable(GL_TEXTURE_2D);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (pp->projection_3d == DISP_3D_PERSPECTIVE ||
pp->view == VIEW_WALK || pp->view == VIEW_WALKTURN)
{
if (pp->view == VIEW_WALK || pp->view == VIEW_WALKTURN)
gluPerspective(60.0,1.0,0.01,10.0);
else
gluPerspective(60.0,1.0,0.1,10.0);
}
else
{
glOrtho(-0.6,0.6,-0.6,0.6,0.1,10.0);
}
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
# ifdef HAVE_JWZGLES /* #### glPolygonMode other than GL_FILL unimplemented */
if (pp->display_mode == DISP_WIREFRAME)
pp->display_mode = DISP_SURFACE;
# endif
if (pp->display_mode == DISP_SURFACE)
{
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
glShadeModel(GL_SMOOTH);
glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
glLightModeli(GL_LIGHT_MODEL_TWO_SIDE,GL_TRUE);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glLightfv(GL_LIGHT0,GL_AMBIENT,light_ambient);
glLightfv(GL_LIGHT0,GL_DIFFUSE,light_diffuse);
glLightfv(GL_LIGHT0,GL_SPECULAR,light_specular);
glLightfv(GL_LIGHT0,GL_POSITION,light_position);
glMaterialfv(GL_FRONT_AND_BACK,GL_SPECULAR,mat_specular);
glMaterialf(GL_FRONT_AND_BACK,GL_SHININESS,50.0);
glDepthMask(GL_TRUE);
glDisable(GL_BLEND);
}
else if (pp->display_mode == DISP_TRANSPARENT)
{
glDisable(GL_DEPTH_TEST);
glShadeModel(GL_SMOOTH);
glPolygonMode(GL_FRONT_AND_BACK,GL_FILL);
glLightModeli(GL_LIGHT_MODEL_TWO_SIDE,GL_TRUE);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glLightfv(GL_LIGHT0,GL_AMBIENT,light_ambient);
glLightfv(GL_LIGHT0,GL_DIFFUSE,light_diffuse);
glLightfv(GL_LIGHT0,GL_SPECULAR,light_specular);
glLightfv(GL_LIGHT0,GL_POSITION,light_position);
glMaterialfv(GL_FRONT_AND_BACK,GL_SPECULAR,mat_specular);
glMaterialf(GL_FRONT_AND_BACK,GL_SHININESS,50.0);
glDepthMask(GL_FALSE);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA,GL_ONE);
}
else /* pp->display_mode == DISP_WIREFRAME */
{
glDisable(GL_DEPTH_TEST);
glShadeModel(GL_FLAT);
glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);
glDisable(GL_LIGHTING);
glDisable(GL_LIGHT0);
glDisable(GL_BLEND);
}
}
/* Redisplay the Klein bottle. */
static void display_projectiveplane(ModeInfo *mi)
{
projectiveplanestruct *pp = &projectiveplane[MI_SCREEN(mi)];
if (!pp->button_pressed)
{
if (pp->view == VIEW_TURN)
{
pp->alpha += speed_wx * pp->speed_scale;
if (pp->alpha >= 360.0)
pp->alpha -= 360.0;
pp->beta += speed_wy * pp->speed_scale;
if (pp->beta >= 360.0)
pp->beta -= 360.0;
pp->delta += speed_wz * pp->speed_scale;
if (pp->delta >= 360.0)
pp->delta -= 360.0;
pp->zeta += speed_xy * pp->speed_scale;
if (pp->zeta >= 360.0)
pp->zeta -= 360.0;
pp->eta += speed_xz * pp->speed_scale;
if (pp->eta >= 360.0)
pp->eta -= 360.0;
pp->theta += speed_yz * pp->speed_scale;
if (pp->theta >= 360.0)
pp->theta -= 360.0;
}
if (pp->view == VIEW_WALKTURN)
{
pp->zeta += speed_xy * pp->speed_scale;
if (pp->zeta >= 360.0)
pp->zeta -= 360.0;
pp->eta += speed_xz * pp->speed_scale;
if (pp->eta >= 360.0)
pp->eta -= 360.0;
pp->theta += speed_yz * pp->speed_scale;
if (pp->theta >= 360.0)
pp->theta -= 360.0;
}
if (pp->view == VIEW_WALK || pp->view == VIEW_WALKTURN)
{
pp->dvmove = (pp->dir*sin(walk_direction*M_PI/180.0)*
walk_speed*M_PI/4096.0);
pp->vmove += pp->dvmove;
if (pp->vmove > 2.0*M_PI)
{
pp->vmove = 4.0*M_PI-pp->vmove;
pp->umove = pp->umove-M_PI;
if (pp->umove < 0.0)
pp->umove += 2.0*M_PI;
pp->side = -pp->side;
pp->dir = -pp->dir;
pp->dvmove = -pp->dvmove;
}
if (pp->vmove < 0.0)
{
pp->vmove = -pp->vmove;
pp->umove = pp->umove-M_PI;
if (pp->umove < 0.0)
pp->umove += 2.0*M_PI;
pp->dir = -pp->dir;
pp->dvmove = -pp->dvmove;
}
pp->dumove = cos(walk_direction*M_PI/180.0)*walk_speed*M_PI/4096.0;
pp->umove += pp->dumove;
if (pp->umove >= 2.0*M_PI)
pp->umove -= 2.0*M_PI;
if (pp->umove < 0.0)
pp->umove += 2.0*M_PI;
}
if (pp->change_colors)
{
pp->rho += DRHO;
if (pp->rho >= 360.0)
pp->rho -= 360.0;
pp->sigma += DSIGMA;
if (pp->sigma >= 360.0)
pp->sigma -= 360.0;
pp->tau += DTAU;
if (pp->tau >= 360.0)
pp->tau -= 360.0;
}
}
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (pp->projection_3d == DISP_3D_PERSPECTIVE ||
pp->view == VIEW_WALK || pp->view == VIEW_WALKTURN)
{
if (pp->view == VIEW_WALK || pp->view == VIEW_WALKTURN)
gluPerspective(60.0,pp->aspect,0.01,10.0);
else
gluPerspective(60.0,pp->aspect,0.1,10.0);
}
else
{
if (pp->aspect >= 1.0)
glOrtho(-0.6*pp->aspect,0.6*pp->aspect,-0.6,0.6,0.1,10.0);
else
glOrtho(-0.6,0.6,-0.6/pp->aspect,0.6/pp->aspect,0.1,10.0);
}
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
mi->polygon_count = projective_plane(mi,0.0,2.0*M_PI,0.0,2.0*M_PI);
}
ENTRYPOINT void reshape_projectiveplane(ModeInfo *mi, int width, int height)
{
projectiveplanestruct *pp = &projectiveplane[MI_SCREEN(mi)];
pp->WindW = (GLint)width;
pp->WindH = (GLint)height;
glViewport(0,0,width,height);
pp->aspect = (GLfloat)width/(GLfloat)height;
}
ENTRYPOINT Bool projectiveplane_handle_event(ModeInfo *mi, XEvent *event)
{
projectiveplanestruct *pp = &projectiveplane[MI_SCREEN(mi)];
KeySym sym = 0;
char c = 0;
if (event->xany.type == KeyPress || event->xany.type == KeyRelease)
XLookupString (&event->xkey, &c, 1, &sym, 0);
if (event->xany.type == ButtonPress &&
event->xbutton.button == Button1)
{
pp->button_pressed = True;
gltrackball_start(pp->trackballs[pp->current_trackball],
event->xbutton.x, event->xbutton.y,
MI_WIDTH(mi), MI_HEIGHT(mi));
return True;
}
else if (event->xany.type == ButtonRelease &&
event->xbutton.button == Button1)
{
pp->button_pressed = False;
return True;
}
else if (event->xany.type == KeyPress)
{
if (sym == XK_Shift_L || sym == XK_Shift_R)
{
pp->current_trackball = 1;
if (pp->button_pressed)
gltrackball_start(pp->trackballs[pp->current_trackball],
event->xbutton.x, event->xbutton.y,
MI_WIDTH(mi), MI_HEIGHT(mi));
return True;
}
}
else if (event->xany.type == KeyRelease)
{
if (sym == XK_Shift_L || sym == XK_Shift_R)
{
pp->current_trackball = 0;
if (pp->button_pressed)
gltrackball_start(pp->trackballs[pp->current_trackball],
event->xbutton.x, event->xbutton.y,
MI_WIDTH(mi), MI_HEIGHT(mi));
return True;
}
}
else if (event->xany.type == MotionNotify && pp->button_pressed)
{
gltrackball_track(pp->trackballs[pp->current_trackball],
event->xmotion.x, event->xmotion.y,
MI_WIDTH(mi), MI_HEIGHT(mi));
return True;
}
return False;
}
/*
*-----------------------------------------------------------------------------
*-----------------------------------------------------------------------------
* Xlock hooks.
*-----------------------------------------------------------------------------
*-----------------------------------------------------------------------------
*/
/*
*-----------------------------------------------------------------------------
* Initialize projectiveplane. Called each time the window changes.
*-----------------------------------------------------------------------------
*/
ENTRYPOINT void init_projectiveplane(ModeInfo *mi)
{
projectiveplanestruct *pp;
MI_INIT(mi, projectiveplane);
pp = &projectiveplane[MI_SCREEN(mi)];
pp->trackballs[0] = gltrackball_init(True);
pp->trackballs[1] = gltrackball_init(True);
pp->current_trackball = 0;
pp->button_pressed = False;
/* Set the display mode. */
if (!strcasecmp(mode,"random"))
{
pp->display_mode = random() % NUM_DISPLAY_MODES;
}
else if (!strcasecmp(mode,"wireframe"))
{
pp->display_mode = DISP_WIREFRAME;
}
else if (!strcasecmp(mode,"surface"))
{
pp->display_mode = DISP_SURFACE;
}
else if (!strcasecmp(mode,"transparent"))
{
pp->display_mode = DISP_TRANSPARENT;
}
else
{
pp->display_mode = random() % NUM_DISPLAY_MODES;
}
/* Orientation marks don't make sense in wireframe mode. */
pp->marks = marks;
if (pp->display_mode == DISP_WIREFRAME)
pp->marks = False;
/* Set the appearance. */
if (!strcasecmp(appear,"random"))
{
pp->appearance = random() % NUM_APPEARANCES;
}
else if (!strcasecmp(appear,"solid"))
{
pp->appearance = APPEARANCE_SOLID;
}
else if (!strcasecmp(appear,"distance-bands"))
{
pp->appearance = APPEARANCE_DISTANCE_BANDS;
}
else if (!strcasecmp(appear,"direction-bands"))
{
pp->appearance = APPEARANCE_DIRECTION_BANDS;
}
else
{
pp->appearance = random() % NUM_APPEARANCES;
}
/* Set the color mode. */
if (!strcasecmp(color_mode,"random"))
{
pp->colors = random() % NUM_COLORS;
}
else if (!strcasecmp(color_mode,"one-sided"))
{
pp->colors = COLORS_ONESIDED;
}
else if (!strcasecmp(color_mode,"two-sided"))
{
pp->colors = COLORS_TWOSIDED;
}
else if (!strcasecmp(color_mode,"distance"))
{
pp->colors = COLORS_DISTANCE;
}
else if (!strcasecmp(color_mode,"direction"))
{
pp->colors = COLORS_DIRECTION;
}
else if (!strcasecmp(color_mode,"depth"))
{
pp->colors = COLORS_DEPTH;
}
else
{
pp->colors = random() % NUM_COLORS;
}
pp->change_colors = change_colors;
/* Set the view mode. */
if (!strcasecmp(view_mode,"random"))
{
pp->view = random() % NUM_VIEW_MODES;
}
else if (!strcasecmp(view_mode,"walk"))
{
pp->view = VIEW_WALK;
}
else if (!strcasecmp(view_mode,"turn"))
{
pp->view = VIEW_TURN;
}
else if (!strcasecmp(view_mode,"walk-turn"))
{
pp->view = VIEW_WALKTURN;
}
else
{
pp->view = random() % NUM_VIEW_MODES;
}
/* Set the 3d projection mode. */
if (!strcasecmp(proj_3d,"random"))
{
/* Orthographic projection only makes sense in turn mode. */
if (pp->view == VIEW_TURN)
pp->projection_3d = random() % NUM_DISP_3D_MODES;
else
pp->projection_3d = DISP_3D_PERSPECTIVE;
}
else if (!strcasecmp(proj_3d,"perspective"))
{
pp->projection_3d = DISP_3D_PERSPECTIVE;
}
else if (!strcasecmp(proj_3d,"orthographic"))
{
pp->projection_3d = DISP_3D_ORTHOGRAPHIC;
}
else
{
/* Orthographic projection only makes sense in turn mode. */
if (pp->view == VIEW_TURN)
pp->projection_3d = random() % NUM_DISP_3D_MODES;
else
pp->projection_3d = DISP_3D_PERSPECTIVE;
}
/* Set the 4d projection mode. */
if (!strcasecmp(proj_4d,"random"))
{
pp->projection_4d = random() % NUM_DISP_4D_MODES;
}
else if (!strcasecmp(proj_4d,"perspective"))
{
pp->projection_4d = DISP_4D_PERSPECTIVE;
}
else if (!strcasecmp(proj_4d,"orthographic"))
{
pp->projection_4d = DISP_4D_ORTHOGRAPHIC;
}
else
{
pp->projection_4d = random() % NUM_DISP_4D_MODES;
}
/* Modify the speeds to a useful range in walk-and-turn mode. */
if (pp->view == VIEW_WALKTURN)
{
speed_wx *= 0.2;
speed_wy *= 0.2;
speed_wz *= 0.2;
speed_xy *= 0.2;
speed_xz *= 0.2;
speed_yz *= 0.2;
}
/* make multiple screens rotate at slightly different rates. */
pp->speed_scale = 0.9 + frand(0.3);
if ((pp->glx_context = init_GL(mi)) != NULL)
{
reshape_projectiveplane(mi,MI_WIDTH(mi),MI_HEIGHT(mi));
glDrawBuffer(GL_BACK);
init(mi);
}
else
{
MI_CLEARWINDOW(mi);
}
}
/*
*-----------------------------------------------------------------------------
* Called by the mainline code periodically to update the display.
*-----------------------------------------------------------------------------
*/
ENTRYPOINT void draw_projectiveplane(ModeInfo *mi)
{
Display *display = MI_DISPLAY(mi);
Window window = MI_WINDOW(mi);
projectiveplanestruct *pp;
if (projectiveplane == NULL)
return;
pp = &projectiveplane[MI_SCREEN(mi)];
MI_IS_DRAWN(mi) = True;
if (!pp->glx_context)
return;
glXMakeCurrent(display, window, *pp->glx_context);
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
display_projectiveplane(mi);
if (MI_IS_FPS(mi))
do_fps (mi);
glFlush();
glXSwapBuffers(display,window);
}
#ifndef STANDALONE
ENTRYPOINT void change_projectiveplane(ModeInfo *mi)
{
projectiveplanestruct *pp = &projectiveplane[MI_SCREEN(mi)];
if (!pp->glx_context)
return;
glXMakeCurrent(MI_DISPLAY(mi), MI_WINDOW(mi), *pp->glx_context);
init(mi);
}
#endif /* !STANDALONE */
ENTRYPOINT void free_projectiveplane(ModeInfo *mi)
{
projectiveplanestruct *pp = &projectiveplane[MI_SCREEN(mi)];
if (!pp->glx_context) return;
glXMakeCurrent (MI_DISPLAY(mi), MI_WINDOW(mi), *pp->glx_context);
gltrackball_free (pp->trackballs[0]);
gltrackball_free (pp->trackballs[1]);
if (pp->tex_name) glDeleteTextures (1, &pp->tex_name);
}
XSCREENSAVER_MODULE ("ProjectivePlane", projectiveplane)
#endif /* USE_GL */
