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+/* -*- Mode: C; tab-width: 4 -*- */
+/* moebius --- Moebius Strip II, an Escher-like GL scene with ants. */
+
+#if 0
+static const char sccsid[] = "@(#)moebius.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: backported from xscreensaver by lassauge@mail.dotcom.fr
+ * Feb-2001: Made motion and rotation be smoother Jamie Zawinski
+ * <jwz@jwz.org>
+ * 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 STANDALONE
+# define MODE_moebius
+# define free_moebius 0
+# define release_moebius 0
+# define DEFAULTS "*delay: 20000 \n" \
+ "*showFPS: False \n" \
+ "*suppressRotationAnimation: True\n" \
+
+# include "xlockmore.h" /* from the xscreensaver distribution */
+#else /* !STANDALONE */
+# include "xlock.h" /* from the xlockmore distribution */
+#endif /* !STANDALONE */
+
+#ifdef HAVE_JWXYZ
+# include "jwxyz.h"
+#else
+# include <X11/Xlib.h>
+# include <GL/gl.h>
+# include <GL/glu.h>
+#endif
+
+#ifdef HAVE_JWZGLES
+# include "jwzgles.h"
+#endif /* HAVE_JWZGLES */
+
+#ifdef MODE_moebius
+
+#if 0 /* Hey, this never actually used the texture at all! */
+#if 0
+#include "e_textures.h"
+#else
+#include "ximage-loader.h"
+#include "images/gen/wood_png.h"
+#endif
+#endif /* 0 */
+
+#include "sphere.h"
+#include "tube.h"
+
+#include "rotator.h"
+#include "gltrackball.h"
+
+#define DEF_SOLIDMOEBIUS "False"
+#define DEF_DRAWANTS "True"
+
+static int solidmoebius;
+static int drawants;
+
+static XrmOptionDescRec opts[] =
+{
+ {"-solidmoebius", ".moebius.solidmoebius", XrmoptionNoArg, "on"},
+ {"+solidmoebius", ".moebius.solidmoebius", XrmoptionNoArg, "off"},
+ {"-ants", ".moebius.drawants", XrmoptionNoArg, "on"},
+ {"+ants", ".moebius.drawants", XrmoptionNoArg, "off"}
+};
+static argtype vars[] =
+{
+ {&solidmoebius, "solidmoebius", "Solidmoebius", DEF_SOLIDMOEBIUS, t_Bool},
+ {&drawants, "drawants", "Drawants", DEF_DRAWANTS, t_Bool}
+
+};
+static OptionStruct desc[] =
+{
+ {"-/+solidmoebius", "select between a SOLID or a NET Moebius Strip"},
+ {"-/+drawants", "turn on/off walking ants"}
+};
+
+ENTRYPOINT ModeSpecOpt moebius_opts =
+{sizeof opts / sizeof opts[0], opts, sizeof vars / sizeof vars[0], vars, desc};
+
+#ifdef USE_MODULES
+ModStruct moebius_description =
+{"moebius", "init_moebius", "draw_moebius", (char *) NULL,
+ "draw_moebius", "change_moebius", (char *) NULL, &moebius_opts,
+ 1000, 1, 1, 1, 4, 1.0, "",
+ "Shows Moebius Strip II, an Escher-like GL scene with ants", 0, NULL};
+
+#endif
+
+#define Scale4Window 0.3
+#define Scale4Iconic 0.4
+
+#define sqr(A) ((A)*(A))
+
+#ifndef Pi
+#define Pi M_PI
+#endif
+
+#define ObjMoebiusStrip 0
+#define ObjAntBody 1
+#define MaxObj 2
+
+/*************************************************************************/
+
+typedef struct {
+ GLint WindH, WindW;
+ GLfloat step;
+ GLfloat ant_position;
+ float ant_step;
+ GLXContext *glx_context;
+ rotator *rot;
+ trackball_state *trackball;
+ Bool button_down_p;
+} moebiusstruct;
+
+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 MaterialRed[] = {0.7, 0.0, 0.0, 1.0};
+static const float MaterialGreen[] = {0.1, 0.5, 0.2, 1.0};
+static const float MaterialBlue[] = {0.0, 0.0, 0.7, 1.0};
+static const float MaterialCyan[] = {0.2, 0.5, 0.7, 1.0};
+static const float MaterialYellow[] = {0.7, 0.7, 0.0, 1.0};
+static const float MaterialMagenta[] = {0.6, 0.2, 0.5, 1.0};
+static const float MaterialWhite[] = {0.7, 0.7, 0.7, 1.0};
+static const float MaterialGray[] = {0.2, 0.2, 0.2, 1.0};
+static const float MaterialGray5[] = {0.5, 0.5, 0.5, 1.0};
+static const float MaterialGray6[] = {0.6, 0.6, 0.6, 1.0};
+static const float MaterialGray8[] = {0.8, 0.8, 0.8, 1.0};
+
+static moebiusstruct *moebius = (moebiusstruct *) NULL;
+
+#define NUM_SCENES 2
+
+static Bool
+mySphere(float radius)
+{
+#if 0
+ GLUquadricObj *quadObj;
+
+ if ((quadObj = gluNewQuadric()) == 0)
+ return False;
+ gluQuadricDrawStyle(quadObj, (GLenum) GLU_FILL);
+ gluSphere(quadObj, radius, 16, 16);
+ gluDeleteQuadric(quadObj);
+#else
+ glPushMatrix();
+ glScalef (radius, radius, radius);
+ unit_sphere (16, 16, False);
+ glPopMatrix();
+#endif
+ return True;
+}
+
+static Bool
+myCone(float radius)
+{
+#if 0
+ GLUquadricObj *quadObj;
+
+ if ((quadObj = gluNewQuadric()) == 0)
+ return False;
+ gluQuadricDrawStyle(quadObj, (GLenum) GLU_FILL);
+ gluCylinder(quadObj, radius, 0, radius * 3, 8, 1);
+ gluDeleteQuadric(quadObj);
+#else
+ cone (0, 0, 0,
+ 0, 0, radius * 3,
+ radius, 0,
+ 8, True, True, False);
+#endif
+ return True;
+}
+
+static Bool
+draw_moebius_ant(moebiusstruct * mp, const float *Material, int mono)
+{
+ float cos1 = cos(mp->ant_step);
+ float cos2 = cos(mp->ant_step + 2 * Pi / 3);
+ float cos3 = cos(mp->ant_step + 4 * Pi / 3);
+ float sin1 = sin(mp->ant_step);
+ float sin2 = sin(mp->ant_step + 2 * Pi / 3);
+ float sin3 = sin(mp->ant_step + 4 * Pi / 3);
+
+ if (mono)
+ glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialGray5);
+ else
+ glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, Material);
+ glEnable(GL_CULL_FACE);
+ glPushMatrix();
+ glScalef(1, 1.3, 1);
+ if (!mySphere(0.18))
+ return False;
+ glScalef(1, 1 / 1.3, 1);
+ glTranslatef(0.00, 0.30, 0.00);
+ if (!mySphere(0.2))
+ return False;
+
+ glTranslatef(-0.05, 0.17, 0.05);
+ glRotatef(-90, 1, 0, 0);
+ glRotatef(-25, 0, 1, 0);
+ if (!myCone(0.05))
+ return False;
+ glTranslatef(0.00, 0.10, 0.00);
+ if (!myCone(0.05))
+ return False;
+ glRotatef(25, 0, 1, 0);
+ glRotatef(90, 1, 0, 0);
+
+ glScalef(1, 1.3, 1);
+ glTranslatef(0.15, -0.65, 0.05);
+ if (!mySphere(0.25))
+ return False;
+ glScalef(1, 1 / 1.3, 1);
+ glPopMatrix();
+ glDisable(GL_CULL_FACE);
+
+ glDisable(GL_LIGHTING);
+ /* ANTENNAS */
+ glBegin(GL_LINES);
+ if (mono)
+ glColor3fv(MaterialGray5);
+ else
+ glColor3fv(Material);
+ glVertex3f(0.00, 0.30, 0.00);
+ glColor3fv(MaterialGray);
+ glVertex3f(0.40, 0.70, 0.40);
+ if (mono)
+ glColor3fv(MaterialGray5);
+ else
+ glColor3fv(Material);
+ glVertex3f(0.00, 0.30, 0.00);
+ glColor3fv(MaterialGray);
+ glVertex3f(0.40, 0.70, -0.40);
+ glEnd();
+ glBegin(GL_POINTS);
+ if (mono)
+ glColor3fv(MaterialGray6);
+ else
+ glColor3fv(MaterialRed);
+ glVertex3f(0.40, 0.70, 0.40);
+ glVertex3f(0.40, 0.70, -0.40);
+ glEnd();
+
+ /* LEFT-FRONT ARM */
+ glBegin(GL_LINE_STRIP);
+ if (mono)
+ glColor3fv(MaterialGray5);
+ else
+ glColor3fv(Material);
+ glVertex3f(0.00, 0.05, 0.18);
+ glVertex3f(0.35 + 0.05 * cos1, 0.15, 0.25);
+ glColor3fv(MaterialGray);
+ glVertex3f(-0.20 + 0.05 * cos1, 0.25 + 0.1 * sin1, 0.45);
+ glEnd();
+
+ /* LEFT-CENTER ARM */
+ glBegin(GL_LINE_STRIP);
+ if (mono)
+ glColor3fv(MaterialGray5);
+ else
+ glColor3fv(Material);
+ glVertex3f(0.00, 0.00, 0.18);
+ glVertex3f(0.35 + 0.05 * cos2, 0.00, 0.25);
+ glColor3fv(MaterialGray);
+ glVertex3f(-0.20 + 0.05 * cos2, 0.00 + 0.1 * sin2, 0.45);
+ glEnd();
+
+ /* LEFT-BACK ARM */
+ glBegin(GL_LINE_STRIP);
+ if (mono)
+ glColor3fv(MaterialGray5);
+ else
+ glColor3fv(Material);
+ glVertex3f(0.00, -0.05, 0.18);
+ glVertex3f(0.35 + 0.05 * cos3, -0.15, 0.25);
+ glColor3fv(MaterialGray);
+ glVertex3f(-0.20 + 0.05 * cos3, -0.25 + 0.1 * sin3, 0.45);
+ glEnd();
+
+ /* RIGHT-FRONT ARM */
+ glBegin(GL_LINE_STRIP);
+ if (mono)
+ glColor3fv(MaterialGray5);
+ else
+ glColor3fv(Material);
+ glVertex3f(0.00, 0.05, -0.18);
+ glVertex3f(0.35 - 0.05 * sin1, 0.15, -0.25);
+ glColor3fv(MaterialGray);
+ glVertex3f(-0.20 - 0.05 * sin1, 0.25 + 0.1 * cos1, -0.45);
+ glEnd();
+
+ /* RIGHT-CENTER ARM */
+ glBegin(GL_LINE_STRIP);
+ if (mono)
+ glColor3fv(MaterialGray5);
+ else
+ glColor3fv(Material);
+ glVertex3f(0.00, 0.00, -0.18);
+ glVertex3f(0.35 - 0.05 * sin2, 0.00, -0.25);
+ glColor3fv(MaterialGray);
+ glVertex3f(-0.20 - 0.05 * sin2, 0.00 + 0.1 * cos2, -0.45);
+ glEnd();
+
+ /* RIGHT-BACK ARM */
+ glBegin(GL_LINE_STRIP);
+ if (mono)
+ glColor3fv(MaterialGray5);
+ else
+ glColor3fv(Material);
+ glVertex3f(0.00, -0.05, -0.18);
+ glVertex3f(0.35 - 0.05 * sin3, -0.15, -0.25);
+ glColor3fv(MaterialGray);
+ glVertex3f(-0.20 - 0.05 * sin3, -0.25 + 0.1 * cos3, -0.45);
+ glEnd();
+
+ glBegin(GL_POINTS);
+ if (mono)
+ glColor3fv(MaterialGray8);
+ else
+ glColor3fv(MaterialMagenta);
+ glVertex3f(-0.20 + 0.05 * cos1, 0.25 + 0.1 * sin1, 0.45);
+ glVertex3f(-0.20 + 0.05 * cos2, 0.00 + 0.1 * sin2, 0.45);
+ glVertex3f(-0.20 + 0.05 * cos3, -0.25 + 0.1 * sin3, 0.45);
+ glVertex3f(-0.20 - 0.05 * sin1, 0.25 + 0.1 * cos1, -0.45);
+ glVertex3f(-0.20 - 0.05 * sin2, 0.00 + 0.1 * cos2, -0.45);
+ glVertex3f(-0.20 - 0.05 * sin3, -0.25 + 0.1 * cos3, -0.45);
+ glEnd();
+
+ glEnable(GL_LIGHTING);
+
+ mp->ant_step += 0.3;
+ return True;
+}
+
+static void
+RotateAaroundU(float Ax, float Ay, float Az,
+ float Ux, float Uy, float Uz,
+ float *Cx, float *Cy, float *Cz,
+ float Theta)
+{
+ float cosO = cos(Theta);
+ float sinO = sin(Theta);
+ float one_cosO = 1 - cosO;
+ float Ux2 = sqr(Ux);
+ float Uy2 = sqr(Uy);
+ float Uz2 = sqr(Uz);
+ float UxUy = Ux * Uy;
+ float UxUz = Ux * Uz;
+ float UyUz = Uy * Uz;
+
+ *Cx = (Ux2 + cosO * (1 - Ux2)) * Ax + (UxUy * one_cosO - Uz * sinO) * Ay + (UxUz * one_cosO + Uy * sinO) * Az;
+ *Cy = (UxUy * one_cosO + Uz * sinO) * Ax + (Uy2 + cosO * (1 - Uy2)) * Ay + (UyUz * one_cosO - Ux * sinO) * Az;
+ *Cz = (UxUz * one_cosO - Uy * sinO) * Ax + (UyUz * one_cosO + Ux * sinO) * Ay + (Uz2 + cosO * (1 - Uz2)) * Az;
+}
+
+#define MoebiusDivisions 40
+#define MoebiusTransversals 4
+static Bool
+draw_moebius_strip(ModeInfo * mi)
+{
+ GLfloat Phi, Theta;
+ GLfloat cPhi, sPhi;
+ moebiusstruct *mp = &moebius[MI_SCREEN(mi)];
+ int i, j;
+ int mono = MI_IS_MONO(mi);
+
+ float Cx, Cy, Cz;
+
+#ifdef HAVE_JWZGLES /* #### glPolygonMode other than GL_FILL unimplemented */
+ solidmoebius = True;
+#endif
+
+ if (solidmoebius) {
+ glBegin(GL_QUAD_STRIP);
+ Phi = 0;
+ i = 0;
+ while (i < (MoebiusDivisions * 2 + 1)) {
+ Theta = Phi / 2;
+ cPhi = cos(Phi);
+ sPhi = sin(Phi);
+
+ i++;
+ if (mono)
+ glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialWhite);
+ else if (i % 2)
+ glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialRed);
+ else
+ glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialGray);
+
+ RotateAaroundU(cPhi, sPhi, 0, -sPhi, cPhi, 0, &Cx, &Cy, &Cz, Theta);
+ glNormal3f(Cx, Cy, Cz);
+ RotateAaroundU(0, 0, 1, -sPhi, cPhi, 0, &Cx, &Cy, &Cz, Theta);
+ glVertex3f(cPhi * 3 + Cx, sPhi * 3 + Cy, +Cz);
+ glVertex3f(cPhi * 3 - Cx, sPhi * 3 - Cy, -Cz);
+
+ Phi += Pi / MoebiusDivisions;
+ }
+ glEnd();
+ } else {
+ for (j = -MoebiusTransversals; j < MoebiusTransversals; j++) {
+ glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+ glBegin(GL_QUAD_STRIP);
+ Phi = 0;
+ i = 0;
+ while (i < (MoebiusDivisions * 2 + 1)) {
+ Theta = Phi / 2;
+ cPhi = cos(Phi);
+ sPhi = sin(Phi);
+
+ RotateAaroundU(cPhi, sPhi, 0, -sPhi, cPhi, 0, &Cx, &Cy, &Cz, Theta);
+ glNormal3f(Cx, Cy, Cz);
+ RotateAaroundU(0, 0, 1, -sPhi, cPhi, 0, &Cx, &Cy, &Cz, Theta);
+ j++;
+ if (j == MoebiusTransversals || mono)
+ glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialWhite);
+ else if (i % 2)
+ glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialRed);
+ else
+ glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialGray);
+ glVertex3f(cPhi * 3 + Cx / MoebiusTransversals * j, sPhi * 3 + Cy / MoebiusTransversals * j, +Cz / MoebiusTransversals * j);
+ j--;
+ if (j == -MoebiusTransversals || mono)
+ glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialWhite);
+ else if (i % 2)
+ glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialRed);
+ else
+ glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, MaterialGray);
+ glVertex3f(cPhi * 3 + Cx / MoebiusTransversals * j, sPhi * 3 + Cy / MoebiusTransversals * j, +Cz / MoebiusTransversals * j);
+
+ Phi += Pi / MoebiusDivisions;
+ i++;
+ }
+ glEnd();
+ }
+ glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+ }
+
+ if (drawants) {
+ /* DRAW BLUE ANT */
+ glPushMatrix();
+ glRotatef(mp->ant_position + 180, 0, 0, 1);
+ glTranslatef(3, 0, 0);
+ glRotatef(mp->ant_position / 2 + 90, 0, 1, 0);
+ glTranslatef(0.28, 0, -0.45);
+ if (!draw_moebius_ant(mp, MaterialYellow, mono))
+ return False;
+ glPopMatrix();
+
+ /* DRAW YELLOW ANT */
+ glPushMatrix();
+ glRotatef(mp->ant_position, 0, 0, 1);
+ glTranslatef(3, 0, 0);
+ glRotatef(mp->ant_position / 2, 0, 1, 0);
+ glTranslatef(0.28, 0, -0.45);
+ if (!draw_moebius_ant(mp, MaterialBlue, mono))
+ return False;
+ glPopMatrix();
+
+ /* DRAW GREEN ANT */
+ glPushMatrix();
+ glRotatef(-mp->ant_position, 0, 0, 1);
+ glTranslatef(3, 0, 0);
+ glRotatef(-mp->ant_position / 2, 0, 1, 0);
+ glTranslatef(0.28, 0, 0.45);
+ glRotatef(180, 1, 0, 0);
+ if (!draw_moebius_ant(mp, MaterialGreen, mono))
+ return False;
+ glPopMatrix();
+
+ /* DRAW CYAN ANT */
+ glPushMatrix();
+ glRotatef(-mp->ant_position + 180, 0, 0, 1);
+ glTranslatef(3, 0, 0);
+ glRotatef(-mp->ant_position / 2 + 90, 0, 1, 0);
+ glTranslatef(0.28, 0, 0.45);
+ glRotatef(180, 1, 0, 0);
+ if (!draw_moebius_ant(mp, MaterialCyan, mono))
+ return False;
+ glPopMatrix();
+ }
+ mp->ant_position += 1;
+ return True;
+}
+#undef MoebiusDivisions
+#undef MoebiusTransversals
+
+ENTRYPOINT void
+reshape_moebius (ModeInfo * mi, int width, int height)
+{
+ moebiusstruct *mp = &moebius[MI_SCREEN(mi)];
+ int y = 0;
+
+ if (width > height * 5) { /* tiny window: show middle */
+ height = width;
+ y = -height/2;
+ }
+
+ glViewport(0, y, mp->WindW = (GLint) width, mp->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);
+ }
+}
+
+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);
+ glFrontFace(GL_CCW);
+ glCullFace(GL_BACK);
+
+ /* moebius */
+ glShadeModel(GL_SMOOTH);
+ glEnable(GL_DEPTH_TEST);
+ glDisable(GL_CULL_FACE);
+
+#if 0
+ glEnable(GL_TEXTURE_2D);
+ 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, */
+ GL_UNSIGNED_INT_8_8_8_8_REV,
+ 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);
+#endif
+
+ glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, front_shininess);
+ glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, front_specular);
+}
+
+
+ENTRYPOINT Bool
+moebius_handle_event (ModeInfo *mi, XEvent *event)
+{
+ moebiusstruct *mp = &moebius[MI_SCREEN(mi)];
+
+ if (gltrackball_event_handler (event, mp->trackball,
+ MI_WIDTH (mi), MI_HEIGHT (mi),
+ &mp->button_down_p))
+ return True;
+
+ return False;
+}
+
+
+ENTRYPOINT void
+init_moebius (ModeInfo * mi)
+{
+ moebiusstruct *mp;
+
+ MI_INIT (mi, moebius);
+ mp = &moebius[MI_SCREEN(mi)];
+ mp->step = NRAND(90);
+ mp->ant_position = NRAND(90);
+
+ {
+ double rot_speed = 0.3;
+ mp->rot = make_rotator (rot_speed, rot_speed, rot_speed, 1, 0, True);
+ mp->trackball = gltrackball_init (True);
+ }
+
+ if ((mp->glx_context = init_GL(mi)) != NULL) {
+
+ reshape_moebius(mi, MI_WIDTH(mi), MI_HEIGHT(mi));
+ glDrawBuffer(GL_BACK);
+ pinit(mi);
+ } else {
+ MI_CLEARWINDOW(mi);
+ }
+}
+
+ENTRYPOINT void
+draw_moebius (ModeInfo * mi)
+{
+ moebiusstruct *mp;
+
+ Display *display = MI_DISPLAY(mi);
+ Window window = MI_WINDOW(mi);
+
+ if (moebius == NULL)
+ return;
+ mp = &moebius[MI_SCREEN(mi)];
+
+ MI_IS_DRAWN(mi) = True;
+
+ if (!mp->glx_context)
+ return;
+
+ glXMakeCurrent(display, window, *(mp->glx_context));
+
+ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+ glPushMatrix();
+
+
+ glTranslatef(0.0, 0.0, -10.0);
+
+ gltrackball_rotate (mp->trackball);
+
+ if (!MI_IS_ICONIC(mi)) {
+ glScalef(Scale4Window * mp->WindH / mp->WindW, Scale4Window, Scale4Window);
+ } else {
+ glScalef(Scale4Iconic * mp->WindH / mp->WindW, Scale4Iconic, Scale4Iconic);
+ }
+
+# ifdef HAVE_MOBILE /* Keep it the same relative size when rotated. */
+ {
+ GLfloat h = MI_HEIGHT(mi) / (GLfloat) MI_WIDTH(mi);
+ int o = (int) current_device_rotation();
+ if (o != 0 && o != 180 && o != -180) {
+ glScalef (1/h, h, 1); /* #### not quite right */
+ h = 1.7;
+ glScalef (h, h, h);
+ }
+ }
+# endif
+
+ {
+ double x, y, z;
+ get_rotation (mp->rot, &x, &y, &z, !mp->button_down_p);
+ glRotatef (x * 360, 1.0, 0.0, 0.0);
+ glRotatef (y * 360, 0.0, 1.0, 0.0);
+ glRotatef (z * 360, 0.0, 0.0, 1.0);
+ }
+
+ /* moebius */
+ if (!draw_moebius_strip(mi)) {
+ MI_ABORT(mi);
+ return;
+ }
+
+ glPopMatrix();
+
+ if (MI_IS_FPS(mi)) do_fps (mi);
+ glFlush();
+
+ glXSwapBuffers(display, window);
+
+ mp->step += 0.025;
+}
+
+#ifndef STANDALONE
+ENTRYPOINT void
+change_moebius (ModeInfo * mi)
+{
+ moebiusstruct *mp = &moebius[MI_SCREEN(mi)];
+
+ if (!mp->glx_context)
+ return;
+
+ glXMakeCurrent(MI_DISPLAY(mi), MI_WINDOW(mi), *(mp->glx_context));
+ pinit();
+}
+#endif /* !STANDALONE */
+
+
+XSCREENSAVER_MODULE ("Moebius", moebius)
+
+#endif
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-06-04 12:29:42 +0200