1 /* -*- Mode: C; tab-width: 4 -*- */
2 /* invert --- shere inversion */
3
4 #if 0
5 static const char sccsid[] = "@(#)invert.c 5.01 2001/03/01 xlockmore";
6 #endif
7
8 /*-
9 * invert.c - Sphere inversion
10 *
11 * See xlock.c for copying information.
12 *
13 * Revision History:
14 * 01-Nov-2000: Allocation checks
15 * 199?: Written
16 *
17 * Tim Rowley (code from the Geometry Center <URL:http://www.geom.umn.edu/>
18 *
19 * This is a sphere eversion of William P. Thurston which was the subject
20 * of the Geometry Center film "Outside In". The code is based on the
21 * software which was used to create the RIB files for the film.
22 * Trying to figure it out from the full eversion is difficult. If you get
23 * a chance to look at the original film, it leads up the eversion nicely.
24 * There is more information about the eversion, including the script from
25 * the film, at: http://www.geom.umn.edu/docs/outreach/oi/
26 *
27 * Demonstration of turning a sphere inside out without creating
28 * any kinks (two surfaces can occupy the same space at the same time).
29 *
30 * Revision History:
31 * 01-Mar-2001: Added FPS stuff E.Lassauge <lassauge AT users.sourceforge.net>
32 */
33
34 #ifdef VMS
35 #include <types.h>
36 #endif
37
38 #ifdef STANDALONE
39 #define MODE_invert
40 #define DEFAULTS "*delay: 10000 \n" \
41 "*showFps: False \n" \
42 "*wireframe: False \n"
43
44 #define invert_handle_event 0
45 #define free_invert 0
46 #define reshape_invert 0
47 #include "xlockmore.h"
48 #else /* !STANDALONE */
49 #include "xlock.h"
50 #include "visgl.h"
51 #endif /* !STANDALONE */
52
53 #ifdef MODE_invert
54
55 #include "i_linkage.h"
56 #define STEPS 75
57
58 ENTRYPOINT ModeSpecOpt invert_opts =
59 {0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL};
60
61 #ifdef USE_MODULES
62 ModStruct invert_description =
63 {(char *) "invert", (char *) "init_invert",
64 (char *) "draw_invert", (char *) "release_invert",
65 (char *) "draw_invert", (char *) "init_invert",
66 (char *) NULL, &invert_opts,
67 80000, 1, 1, 1, 64, 1.0, (char *) "",
68 (char *) "Shows a sphere inverted without wrinkles", 0, NULL};
69
70 #endif
71
72
73 static spherestruct *spheres = (spherestruct *) NULL;
74
75 /* new window size or exposure */
76 static void
reshape(int width,int height)77 reshape(int width, int height)
78 {
79 GLfloat h = (GLfloat) height / (GLfloat) width;
80
81 glViewport(0, 0, (GLint) width, (GLint) height);
82 glMatrixMode(GL_PROJECTION);
83 glLoadIdentity();
84 glFrustum(-1.0, 1.0, -h, h, 5.0, 60.0);
85 glMatrixMode(GL_MODELVIEW);
86 glLoadIdentity();
87 glTranslatef(0.0, 0.0, -10.0);
88
89 /* The depth buffer will be cleared, if needed, before the
90 * next frame. Right now we just want to black the screen.
91 */
92 glClear(GL_COLOR_BUFFER_BIT);
93 }
94
95
96 static void
pinit(void)97 pinit(void)
98 {
99 /*
100 GLfloat front_mat[] = {.8, .7, .4, 1.0};
101 GLfloat back_mat[] = {.508, .333, .774, 1.0};
102 */
103
104 GLfloat front_ambient[] = {.16, .14, .08, 1.0};
105 GLfloat front_diffuse[] = {.56, .49, .28, 1.0};
106 GLfloat front_specular[] = {1, 1, 0.8, 1.0};
107
108 GLfloat back_ambient[] = {.1016, .0666, .1548, 1.0};
109 GLfloat back_diffuse[] = {.254, .166, .387, 1.0};
110 GLfloat back_specular[] = {.4, .2, .5, 1.0};
111
112 /* spherestruct *gp = &spheres[MI_SCREEN(mi)]; */
113 static GLfloat pos[4] =
114 {5.0, 5.0, 10.0, 0.0};
115
116 glLightfv(GL_LIGHT0, GL_POSITION, pos);
117 glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_TRUE);
118 glEnable(GL_LIGHTING);
119 glEnable(GL_LIGHT0);
120 glEnable(GL_DEPTH_TEST);
121 glShadeModel(GL_SMOOTH);
122
123 glMaterialfv(GL_FRONT, GL_AMBIENT, front_ambient);
124 glMaterialfv(GL_FRONT, GL_DIFFUSE, front_diffuse);
125 glMaterialfv(GL_FRONT, GL_SPECULAR, front_specular);
126 glMaterialf(GL_FRONT, GL_SHININESS, 32.0);
127
128 glMaterialfv(GL_BACK, GL_AMBIENT, back_ambient);
129 glMaterialfv(GL_BACK, GL_DIFFUSE, back_diffuse);
130 glMaterialfv(GL_BACK, GL_SPECULAR, back_specular);
131 glMaterialf(GL_BACK, GL_SHININESS, 38.0);
132 }
133
134 static void
free_invert_screen(Display * display,spherestruct * gp)135 free_invert_screen(Display *display, spherestruct *gp)
136 {
137 if (gp == NULL) {
138 return;
139 }
140 if (gp->glx_context) {
141 /* Display lists MUST be freed while their glXContext is current. */
142 #ifdef WIN32
143 wglMakeCurrent(hdc, gp->glx_context);
144 #else
145 glXMakeCurrent(display, gp->window, *(gp->glx_context));
146 #endif
147 if (glIsList(gp->frames)) {
148 glDeleteLists(gp->frames, STEPS);
149 gp->frames = 0;
150 /* Don't destroy the glXContext. init_GL does that. */
151 }
152 }
153 if (gp->partlist != NULL) {
154 free(gp->partlist);
155 gp->partlist = (char *) NULL;
156 }
157 gp = NULL;
158 }
159
160 ENTRYPOINT void
init_invert(ModeInfo * mi)161 init_invert(ModeInfo * mi)
162 {
163 spherestruct *gp;
164
165 MI_INIT(mi, spheres);
166 gp = &spheres[MI_SCREEN(mi)];
167 gp->window = MI_WINDOW(mi);
168
169 gp->time = 0;
170 gp->construction = 1;
171 gp->partlist = (char *) NULL;
172 gp->numsteps = STEPS;
173 gp->view_rotx = NRAND(360);
174 gp->view_roty = NRAND(360);
175 gp->view_rotz = NRAND(360);
176 if ((gp->glx_context = init_GL(mi)) != NULL) {
177 if ((gp->frames = glGenLists(STEPS)) == 0) {
178 free_invert_screen(MI_DISPLAY(mi), gp);
179 return;
180 }
181 reshape(MI_WIDTH(mi), MI_HEIGHT(mi));
182 pinit();
183 } else {
184 MI_CLEARWINDOW(mi);
185 }
186 }
187
188 ENTRYPOINT void
draw_invert(ModeInfo * mi)189 draw_invert(ModeInfo * mi)
190 {
191 Display *display = MI_DISPLAY(mi);
192 Window window = MI_WINDOW(mi);
193 /* int angle_incr = MI_CYCLES(mi) ? MI_CYCLES(mi) : 2; */
194 int rot_incr = MI_COUNT(mi) ? MI_COUNT(mi) : 1;
195 spherestruct *gp;
196
197 if (spheres == NULL)
198 return;
199 gp = &spheres[MI_SCREEN(mi)];
200
201 if (!gp->glx_context)
202 return;
203
204 MI_IS_DRAWN(mi) = True;
205
206 glDrawBuffer(GL_BACK);
207 #ifdef WIN32
208 wglMakeCurrent(hdc, gp->glx_context);
209 #else
210 glXMakeCurrent(display, window, *(gp->glx_context));
211 #endif
212 if (!invert_draw(gp)) {
213 free_invert_screen(display, gp);
214 return;
215 }
216
217 /* let's do something so we don't get bored */
218 if (gp->time == STEPS-1)
219 gp->construction = 0;
220 if (gp->time == STEPS-1)
221 gp->forwards = 0;
222 if (gp->time == 0)
223 gp->forwards = 1;
224 if (gp->forwards)
225 gp->time++;
226 else
227 gp->time--;
228 gp->view_rotx = (int) (gp->view_rotx + rot_incr) % 360;
229 gp->view_roty = (int) (gp->view_roty + rot_incr) % 360;
230 gp->view_rotz = (int) (gp->view_rotz + rot_incr) % 360;
231
232 glFinish();
233 if (MI_IS_FPS(mi)) do_fps (mi);
234 glXSwapBuffers(display, window);
235 }
236
237 ENTRYPOINT void
release_invert(ModeInfo * mi)238 release_invert(ModeInfo * mi)
239 {
240 if (spheres != NULL) {
241 int screen;
242
243 for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++)
244 free_invert_screen(MI_DISPLAY(mi), &spheres[screen]);
245 free(spheres);
246 spheres = (spherestruct *) NULL;
247 }
248 FreeAllGL(mi);
249 }
250
251 XSCREENSAVER_MODULE ("Invert", invert)
252
253 #endif /* MODE_invert */
254