/* geodesic, Copyright (c) 2013-2014 Jamie Zawinski * * Permission to use, copy, modify, distribute, and sell this software and its * documentation for any purpose is hereby granted without fee, provided that * the above copyright notice appear in all copies and that both that * copyright notice and this permission notice appear in supporting * documentation. No representations are made about the suitability of this * software for any purpose. It is provided "as is" without express or * implied warranty. */ #define DEFAULTS "*delay: 30000 \n" \ "*count: 4 \n" \ "*showFPS: False \n" \ "*suppressRotationAnimation: True\n" \ # define free_geodesic 0 # define release_geodesic 0 #undef countof #define countof(x) (sizeof((x))/sizeof((*x))) #include "xlockmore.h" #include "colors.h" #include "normals.h" #include "rotator.h" #include "gltrackball.h" #include #ifdef USE_GL /* whole file */ #include "gllist.h" #define DEF_SPIN "True" #define DEF_WANDER "True" #define DEF_SPEED "1.0" #define DEF_MODE "mesh" typedef struct { double a, o; } LL; /* latitude + longitude */ typedef struct { GLXContext *glx_context; rotator *rot; trackball_state *trackball; Bool button_down_p; int ncolors; XColor *colors; int ccolor, ccolor2; GLfloat color1[4], color2[4]; GLfloat depth; GLfloat delta; GLfloat thickness; GLfloat thickdelta; GLfloat morph_ratio; Bool random_p; enum { WIRE, MESH, SOLID, STELLATED, STELLATED2 } mode; } geodesic_configuration; static geodesic_configuration *bps = NULL; static Bool do_spin; static GLfloat speed; static Bool do_wander; static char *mode_str; static XrmOptionDescRec opts[] = { { "-spin", ".spin", XrmoptionNoArg, "True" }, { "+spin", ".spin", XrmoptionNoArg, "False" }, { "-speed", ".speed", XrmoptionSepArg, 0 }, { "-wander", ".wander", XrmoptionNoArg, "True" }, { "+wander", ".wander", XrmoptionNoArg, "False" }, { "-mode", ".mode", XrmoptionSepArg, 0 }, { "-wireframe", ".mode", XrmoptionNoArg, "wire" }, }; static argtype vars[] = { {&do_spin, "spin", "Spin", DEF_SPIN, t_Bool}, {&do_wander, "wander", "Wander", DEF_WANDER, t_Bool}, {&speed, "speed", "Speed", DEF_SPEED, t_Float}, {&mode_str, "mode", "Mode", DEF_MODE, t_String}, }; ENTRYPOINT ModeSpecOpt geodesic_opts = { countof(opts), opts, countof(vars), vars, NULL}; /* Renders a triangle specified by 3 cartesian endpoints. */ static void triangle0 (ModeInfo *mi, XYZ p1, XYZ p2, XYZ p3) { geodesic_configuration *bp = &bps[MI_SCREEN(mi)]; int wire = MI_IS_WIREFRAME(mi); GLfloat r = bp->thickness; if (bp->mode == SOLID || bp->mode == STELLATED || bp->mode == STELLATED2) r = 1; if (r <= 0.001) r = 0.001; glMaterialfv (GL_FRONT, GL_AMBIENT_AND_DIFFUSE, bp->color1); if (wire) r = 1; if (r <= 0) ; else if (r >= 1) /* solid triangular face */ { glFrontFace (GL_CCW); glBegin (wire ? GL_LINE_LOOP : GL_TRIANGLES); do_normal (p1.x, p1.y, p1.z, p2.x, p2.y, p2.z, p3.x, p3.y, p3.z); glVertex3f (p1.x, p1.y, p1.z); glVertex3f (p2.x, p2.y, p2.z); glVertex3f (p3.x, p3.y, p3.z); glEnd(); mi->polygon_count++; } else /* mesh: triangular face with a triangular hole */ { XYZ p1b, p2b, p3b, c; GLfloat d = 0.98; c.x = (p1.x + p2.x + p3.x) / 3; c.y = (p1.y + p2.y + p3.y) / 3; c.z = (p1.z + p2.z + p3.z) / 3; p1b.x = p1.x + (r * (c.x - p1.x)); p1b.y = p1.y + (r * (c.y - p1.y)); p1b.z = p1.z + (r * (c.z - p1.z)); p2b.x = p2.x + (r * (c.x - p2.x)); p2b.y = p2.y + (r * (c.y - p2.y)); p2b.z = p2.z + (r * (c.z - p2.z)); p3b.x = p3.x + (r * (c.x - p3.x)); p3b.y = p3.y + (r * (c.y - p3.y)); p3b.z = p3.z + (r * (c.z - p3.z)); /* Outside faces */ do_normal (p1.x, p1.y, p1.z, p2.x, p2.y, p2.z, p3.x, p3.y, p3.z); glBegin (wire ? GL_LINE_LOOP : GL_QUADS); glVertex3f (p1.x, p1.y, p1.z); glVertex3f (p1b.x, p1b.y, p1b.z); glVertex3f (p3b.x, p3b.y, p3b.z); glVertex3f (p3.x, p3.y, p3.z); mi->polygon_count++; glVertex3f (p1.x, p1.y, p1.z); glVertex3f (p2.x, p2.y, p2.z); glVertex3f (p2b.x, p2b.y, p2b.z); glVertex3f (p1b.x, p1b.y, p1b.z); mi->polygon_count++; glVertex3f (p2.x, p2.y, p2.z); glVertex3f (p3.x, p3.y, p3.z); glVertex3f (p3b.x, p3b.y, p3b.z); glVertex3f (p2b.x, p2b.y, p2b.z); mi->polygon_count++; glEnd(); /* Inside faces */ glMaterialfv (GL_FRONT, GL_AMBIENT_AND_DIFFUSE, bp->color2); do_normal (p3.x, p3.y, p3.z, p3b.x, p3b.y, p3b.z, p1b.x, p1b.y, p1b.z); glBegin (wire ? GL_LINE_LOOP : GL_QUADS); glVertex3f (d * p3.x, d * p3.y, d * p3.z); glVertex3f (d * p3b.x, d * p3b.y, d * p3b.z); glVertex3f (d * p1b.x, d * p1b.y, d * p1b.z); glVertex3f (d * p1.x, d * p1.y, d * p1.z); mi->polygon_count++; glVertex3f (d * p1b.x, d * p1b.y, d * p1b.z); glVertex3f (d * p2b.x, d * p2b.y, d * p2b.z); glVertex3f (d * p2.x, d * p2.y, d * p2.z); glVertex3f (d * p1.x, d * p1.y, d * p1.z); mi->polygon_count++; glVertex3f (d * p2b.x, d * p2b.y, d * p2b.z); glVertex3f (d * p3b.x, d * p3b.y, d * p3b.z); glVertex3f (d * p3.x, d * p3.y, d * p3.z); glVertex3f (d * p2.x, d * p2.y, d * p2.z); mi->polygon_count++; glEnd(); /* Connecting edges */ glMaterialfv (GL_FRONT, GL_AMBIENT_AND_DIFFUSE, bp->color1); glBegin (wire ? GL_LINE_LOOP : GL_QUADS); do_normal (p1b.x, p1b.y, p1b.z, p2b.x, p2b.y, p2b.z, p2b.x * d, p2b.y * d, p2b.z * d); glVertex3f (p1b.x, p1b.y, p1b.z); glVertex3f (p2b.x, p2b.y, p2b.z); glVertex3f (p2b.x * d, p2b.y * d, p2b.z * d); glVertex3f (p1b.x * d, p1b.y * d, p1b.z * d); mi->polygon_count++; do_normal (p2b.x, p2b.y, p2b.z, p3b.x, p3b.y, p3b.z, p3b.x * d, p3b.y * d, p3b.z * d); glVertex3f (p2b.x, p2b.y, p2b.z); glVertex3f (p3b.x, p3b.y, p3b.z); glVertex3f (p3b.x * d, p3b.y * d, p3b.z * d); glVertex3f (p2b.x * d, p2b.y * d, p2b.z * d); mi->polygon_count++; do_normal (p3b.x, p3b.y, p3b.z, p1b.x, p1b.y, p1b.z, p1b.x * d, p1b.y * d, p1b.z * d); glVertex3f (p3b.x, p3b.y, p3b.z); glVertex3f (p1b.x, p1b.y, p1b.z); glVertex3f (p1b.x * d, p1b.y * d, p1b.z * d); glVertex3f (p3b.x * d, p3b.y * d, p3b.z * d); mi->polygon_count++; glEnd(); } } /* Renders a triangle specified by 3 polar endpoints. */ static void triangle1 (ModeInfo *mi, LL v1, LL v2, LL v3) { XYZ p1, p2, p3; p1.x = cos (v1.a) * cos (v1.o); p1.y = cos (v1.a) * sin (v1.o); p1.z = sin (v1.a); p2.x = cos (v2.a) * cos (v2.o); p2.y = cos (v2.a) * sin (v2.o); p2.z = sin (v2.a); p3.x = cos (v3.a) * cos (v3.o); p3.y = cos (v3.a) * sin (v3.o); p3.z = sin (v3.a); triangle0 (mi, p1, p2, p3); } /* Computes the midpoint of a line between two polar coords. */ static void midpoint2 (LL v1, LL v2, LL *vm_ret, XYZ *p1_ret, XYZ *p2_ret, XYZ *pm_ret) { XYZ p1, p2, pm; LL vm; GLfloat hyp; p1.x = cos (v1.a) * cos (v1.o); p1.y = cos (v1.a) * sin (v1.o); p1.z = sin (v1.a); p2.x = cos (v2.a) * cos (v2.o); p2.y = cos (v2.a) * sin (v2.o); p2.z = sin (v2.a); pm.x = (p1.x + p2.x) / 2; pm.y = (p1.y + p2.y) / 2; pm.z = (p1.z + p2.z) / 2; vm.o = atan2 (pm.y, pm.x); hyp = sqrt (pm.x * pm.x + pm.y * pm.y); vm.a = atan2 (pm.z, hyp); *p1_ret = p1; *p2_ret = p2; *pm_ret = pm; *vm_ret = vm; } /* Computes the midpoint of a triangle specified in polar coords. */ static void midpoint3 (LL v1, LL v2, LL v3, LL *vm_ret, XYZ *p1_ret, XYZ *p2_ret, XYZ *p3_ret, XYZ *pm_ret) { XYZ p1, p2, p3, pm; LL vm; GLfloat hyp; p1.x = cos (v1.a) * cos (v1.o); p1.y = cos (v1.a) * sin (v1.o); p1.z = sin (v1.a); p2.x = cos (v2.a) * cos (v2.o); p2.y = cos (v2.a) * sin (v2.o); p2.z = sin (v2.a); p3.x = cos (v3.a) * cos (v3.o); p3.y = cos (v3.a) * sin (v3.o); p3.z = sin (v3.a); pm.x = (p1.x + p2.x + p3.x) / 3; pm.y = (p1.y + p2.y + p3.y) / 3; pm.z = (p1.z + p2.z + p3.z) / 3; vm.o = atan2 (pm.y, pm.x); hyp = sqrt (pm.x * pm.x + pm.y * pm.y); vm.a = atan2 (pm.z, hyp); *p1_ret = p1; *p2_ret = p2; *p3_ret = p3; *pm_ret = pm; *vm_ret = vm; } /* Renders a triangular geodesic facet to the given depth. */ static void triangle (ModeInfo *mi, LL v1, LL v2, LL v3, int depth) { geodesic_configuration *bp = &bps[MI_SCREEN(mi)]; if (depth <= 0) triangle1 (mi, v1, v2, v3); else { LL v12, v23, v13; XYZ p1, p2, p3, p12, p23, p13; GLfloat r = bp->morph_ratio; midpoint2 (v1, v2, &v12, &p1, &p2, &p12); midpoint2 (v2, v3, &v23, &p2, &p3, &p23); midpoint2 (v1, v3, &v13, &p1, &p3, &p13); depth--; if (depth == 0 && r != 0 && (bp->mode == STELLATED || bp->mode == STELLATED2)) { /* morph between flat and stellated faces */ XYZ pc, pc2; LL vc; midpoint3 (v1, v2, v3, &vc, &p1, &p2, &p3, &pc); pc2.x = cos (vc.a) * cos (vc.o); pc2.y = cos (vc.a) * sin (vc.o); pc2.z = sin (vc.a); pc.x = pc.x + r * (pc2.x - pc.x); pc.y = pc.y + r * (pc2.y - pc.y); pc.z = pc.z + r * (pc2.z - pc.z); triangle0 (mi, p1, p2, pc); triangle0 (mi, p2, p3, pc); triangle0 (mi, p3, p1, pc); } else if (depth == 0 && r < 1) { /* morph between flat and sphere-oid faces */ XYZ p12b, p23b, p13b; p12b.x = cos (v12.a) * cos (v12.o); p12b.y = cos (v12.a) * sin (v12.o); p12b.z = sin (v12.a); p23b.x = cos (v23.a) * cos (v23.o); p23b.y = cos (v23.a) * sin (v23.o); p23b.z = sin (v23.a); p13b.x = cos (v13.a) * cos (v13.o); p13b.y = cos (v13.a) * sin (v13.o); p13b.z = sin (v13.a); p12.x = p12.x + r * (p12b.x - p12.x); p12.y = p12.y + r * (p12b.y - p12.y); p12.z = p12.z + r * (p12b.z - p12.z); p23.x = p23.x + r * (p23b.x - p23.x); p23.y = p23.y + r * (p23b.y - p23.y); p23.z = p23.z + r * (p23b.z - p23.z); p13.x = p13.x + r * (p13b.x - p13.x); p13.y = p13.y + r * (p13b.y - p13.y); p13.z = p13.z + r * (p13b.z - p13.z); triangle0 (mi, p1, p12, p13); triangle0 (mi, p12, p2, p23); triangle0 (mi, p13, p23, p3); triangle0 (mi, p12, p23, p13); } else { triangle (mi, v1, v12, v13, depth); triangle (mi, v12, v2, v23, depth); triangle (mi, v13, v23, v3, depth); triangle (mi, v12, v23, v13, depth); } } } /* Renders a geodesic sphere to the given depth (frequency). */ static void make_geodesic (ModeInfo *mi, int depth) { GLfloat th0 = atan (0.5); /* lat division: 26.57 deg */ GLfloat s = M_PI / 5; /* lon division: 72 deg */ int i; for (i = 0; i < 10; i++) { GLfloat th1 = s * i; GLfloat th2 = s * (i+1); GLfloat th3 = s * (i+2); LL v1, v2, v3, vc; v1.a = th0; v1.o = th1; v2.a = th0; v2.o = th3; v3.a = -th0; v3.o = th2; vc.a = M_PI/2; vc.o = th2; if (i & 1) /* north */ { triangle (mi, v1, v2, vc, depth); triangle (mi, v2, v1, v3, depth); } else /* south */ { v1.a = -v1.a; v2.a = -v2.a; v3.a = -v3.a; vc.a = -vc.a; triangle (mi, v2, v1, vc, depth); triangle (mi, v1, v2, v3, depth); } } } /* Window management, etc */ ENTRYPOINT void reshape_geodesic (ModeInfo *mi, int width, int height) { GLfloat h = (GLfloat) height / (GLfloat) width; int y = 0; if (width > height * 5) { /* tiny window: show middle */ height = width * 9/16; y = -height/2; h = height / (GLfloat) width; } glViewport (0, y, (GLint) width, (GLint) height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective (30.0, 1/h, 1.0, 100.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); gluLookAt( 0.0, 0.0, 30.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0); # ifdef HAVE_MOBILE /* Keep it the same relative size when rotated. */ { int o = (int) current_device_rotation(); if (o != 0 && o != 180 && o != -180) glScalef (1/h, 1/h, 1/h); } # endif glClear(GL_COLOR_BUFFER_BIT); } ENTRYPOINT void init_geodesic (ModeInfo *mi) { geodesic_configuration *bp; int wire = MI_IS_WIREFRAME(mi); MI_INIT (mi, bps); bp = &bps[MI_SCREEN(mi)]; bp->glx_context = init_GL(mi); reshape_geodesic (mi, MI_WIDTH(mi), MI_HEIGHT(mi)); /* This comes first because it sets wire. */ if (!mode_str || !*mode_str) mode_str = DEF_MODE; if (!strcasecmp(mode_str, "random")) { bp->random_p = 1; bp->mode = MESH + (random() % (STELLATED2 - MESH + 1)); } else if (!strcasecmp(mode_str, "mesh")) { bp->mode = MESH; } else if (!strcasecmp(mode_str, "solid")) { bp->mode = SOLID; } else if (!strcasecmp(mode_str, "stellated")) { bp->mode = STELLATED; } else if (!strcasecmp(mode_str, "stellated2")) { bp->mode = STELLATED2; } else if (!strcasecmp(mode_str, "wire")) { bp->mode = WIRE; MI_IS_WIREFRAME(mi) = wire = 1; } else { fprintf (stderr, "%s: unknown mode: %s\n", progname, mode_str); exit (1); } { static GLfloat cspec[4] = {1.0, 1.0, 1.0, 1.0}; static const GLfloat shiny = 128.0; static GLfloat pos[4] = {1.0, 1.0, 1.0, 0.0}; static GLfloat amb[4] = {0.0, 0.0, 0.0, 1.0}; static GLfloat dif[4] = {1.0, 1.0, 1.0, 1.0}; static GLfloat spc[4] = {0.0, 1.0, 1.0, 1.0}; glLightfv(GL_LIGHT0, GL_POSITION, pos); glLightfv(GL_LIGHT0, GL_AMBIENT, amb); glLightfv(GL_LIGHT0, GL_DIFFUSE, dif); glLightfv(GL_LIGHT0, GL_SPECULAR, spc); glMaterialfv (GL_FRONT, GL_SPECULAR, cspec); glMateriali (GL_FRONT, GL_SHININESS, shiny); glLineWidth (3); } if (! wire) { glEnable (GL_DEPTH_TEST); glEnable (GL_BLEND); glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); } /* Actually this looks pretty good in -wire with lighting! */ glEnable (GL_LIGHTING); glEnable (GL_LIGHT0); if (! bp->rot) { double spin_speed = 0.25 * speed; double wander_speed = 0.01 * speed; double spin_accel = 0.2; bp->rot = make_rotator (do_spin ? spin_speed : 0, do_spin ? spin_speed : 0, do_spin ? spin_speed : 0, spin_accel, do_wander ? wander_speed : 0, True); bp->trackball = gltrackball_init (True); } if (MI_COUNT(mi) < 1) MI_COUNT(mi) = 1; bp->ncolors = 1024; if (! bp->colors) bp->colors = (XColor *) calloc(bp->ncolors, sizeof(XColor)); make_smooth_colormap (0, 0, 0, bp->colors, &bp->ncolors, False, 0, False); bp->ccolor = 0; bp->depth = 1; /* start 1 up from the icosahedron */ bp->delta = 0.003; #if 0 bp->thickness = 1; bp->thickdelta = 0.0007; #else bp->thickness = 0.1; bp->thickdelta = 0; #endif } ENTRYPOINT Bool geodesic_handle_event (ModeInfo *mi, XEvent *event) { geodesic_configuration *bp = &bps[MI_SCREEN(mi)]; if (gltrackball_event_handler (event, bp->trackball, MI_WIDTH (mi), MI_HEIGHT (mi), &bp->button_down_p)) return True; else if (screenhack_event_helper (MI_DISPLAY(mi), MI_WINDOW(mi), event)) { mode_str = "random"; init_geodesic (mi); return True; } return False; } ENTRYPOINT void draw_geodesic (ModeInfo *mi) { int wire = MI_IS_WIREFRAME(mi); geodesic_configuration *bp = &bps[MI_SCREEN(mi)]; Display *dpy = MI_DISPLAY(mi); Window window = MI_WINDOW(mi); if (!bp->glx_context) return; glXMakeCurrent(MI_DISPLAY(mi), MI_WINDOW(mi), *(bp->glx_context)); if (! wire) glShadeModel(GL_SMOOTH); glEnable(GL_DEPTH_TEST); glEnable(GL_NORMALIZE); glEnable(GL_CULL_FACE); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glPushMatrix (); { double x, y, z; get_position (bp->rot, &x, &y, &z, !bp->button_down_p); glTranslatef((x - 0.5) * 8, (y - 0.5) * 8, (z - 0.5) * 15); gltrackball_rotate (bp->trackball); get_rotation (bp->rot, &x, &y, &z, !bp->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); } bp->color1[0] = bp->colors[bp->ccolor].red / 65536.0; bp->color1[1] = bp->colors[bp->ccolor].green / 65536.0; bp->color1[2] = bp->colors[bp->ccolor].blue / 65536.0; bp->color1[3] = 1; bp->color2[0] = bp->colors[bp->ccolor2].red / 65536.0; bp->color2[1] = bp->colors[bp->ccolor2].green / 65536.0; bp->color2[2] = bp->colors[bp->ccolor2].blue / 65536.0; bp->color2[3] = 1; bp->ccolor = (bp->ccolor + 1) % bp->ncolors; bp->ccolor2 = (bp->ccolor + bp->ncolors / 2) % bp->ncolors; mi->polygon_count = 0; glScalef (10, 10, 10); { GLfloat r = bp->depth - floor(bp->depth); GLfloat alpha, morph1, morph2; int d1, d2; /* Two ranges: first for fading in the new segments. Second for morphing the segments into position. */ GLfloat range = 0.15; GLfloat min1 = (0.5 - range) / 2; GLfloat max1 = 0.5 - min1; GLfloat min2 = 0.5 + min1; GLfloat max2 = 0.5 + max1; if (r < min1) /* old alone */ { d1 = d2 = floor (bp->depth); morph1 = morph2 = 1; alpha = 1; } else if (r < max1 && /* fade to new flat */ (bp->mode == MESH || bp->mode == STELLATED || bp->mode == STELLATED2)) { d1 = floor (bp->depth); d2 = ceil (bp->depth); morph1 = 1; morph2 = 0; alpha = (r - min1) / (max1 - min1); if (bp->mode == STELLATED || bp->mode == STELLATED2) { morph1 = 1 - alpha; /* de-stellate while fading out */ morph1 = 2 * (morph1 - 0.5); /* do it faster */ if (morph1 < 0) morph1 = 0; } } else if (r < min2) /* new flat */ { d1 = d2 = ceil (bp->depth); morph1 = morph2 = 0; alpha = 1; } else if (r < max2) /* morph */ { d1 = d2 = ceil (bp->depth); morph1 = morph2 = (r - min2) / (max2 - min2); alpha = 1; } else /* new alone */ { d1 = d2 = ceil (bp->depth); morph1 = morph2 = 1; alpha = 1; } mi->recursion_depth = d2 + r; if (bp->mode == STELLATED2) { morph1 = -morph1; morph2 = -morph2; } if (d1 != d2) { if (alpha > 0.5) /* always draw the more transparent one first */ { int s1; GLfloat s2; s1 = d1; d1 = d2; d2 = s1; s2 = morph1; morph1 = morph2; morph2 = s2; alpha = 1 - alpha; } bp->color1[3] = 1 - alpha; bp->color2[3] = 1 - alpha; if (! wire) glDisable (GL_POLYGON_OFFSET_FILL); bp->morph_ratio = morph1; make_geodesic (mi, d1); /* Make the less-transparent object take precedence */ if (!wire) { glEnable (GL_POLYGON_OFFSET_FILL); glPolygonOffset (1.0, 1.0); } } bp->color1[3] = alpha; bp->color2[3] = alpha; bp->morph_ratio = morph2; make_geodesic (mi, d2); } glPopMatrix (); if (mi->fps_p) do_fps (mi); glFinish(); glXSwapBuffers(dpy, window); if (! bp->button_down_p) { bp->depth += speed * bp->delta; bp->thickness += speed * bp->thickdelta; if (bp->depth > MI_COUNT(mi)-1) { bp->depth = MI_COUNT(mi)-1; bp->delta = -fabs (bp->delta); } else if (bp->depth < 0) { bp->depth = 0; bp->delta = fabs (bp->delta); /* Randomize the mode again when we hit the bottom state. #### I wish this did a fade instead of a jump-cut. */ if (bp->random_p) bp->mode = MESH + (random() % (STELLATED2 - MESH + 1)); } if (bp->thickness > 1) { bp->thickness = 1; bp->thickdelta = -fabs (bp->thickdelta); } else if (bp->thickness < 0) { bp->thickness = 0; bp->thickdelta = fabs (bp->thickdelta); } } } XSCREENSAVER_MODULE ("Geodesic", geodesic) #endif /* USE_GL */