1 /* -*- Mode: C; tab-width: 4 -*- emacs friendly */
2 /* gflux - creates a fluctuating 3D grid
3 * requires OpenGL or MesaGL
5 * Copyright (c) Josiah Pease, 2000, 2003
6 * Permission to use, copy, modify, distribute, and sell this software and its
7 * documentation for any purpose is hereby granted without fee, provided that
8 * the above copyright notice appear in all copies and that both that
9 * copyright notice and this permission notice appear in supporting
10 * documentation. No representations are made about the suitability of this
11 * software for any purpose. It is provided "as is" without express or
14 * Thanks go to all those who worked on...
15 * MesaGL, OpenGL, UtahGLX, XFree86, gcc, vim, rxvt, the PNM (anymap) format
16 * xscreensaver and the thousands of other tools, apps and daemons that make
18 * Personal thanks to Kevin Moss, Paul Sheahee and Jamie Zawinski
20 * some xscreensaver code lifted from superquadrics. Most other glx hacks
21 * used as reference at some time.
23 * This hack and others can cause UtahGLX to crash my X server
24 * wireframe looks good with software only rendering anyway
25 * If anyone can work out why and supply a fix I'd love to hear from them
27 * Josiah Pease <gfluxcode@jpease.force9.co.uk> 21 July 2000
30 * 10 June 2000 : wireframe rippling grid standalone written
31 * 18 June 2000 : xscreensaver code added
32 * 25 June 2000 : solid and light added
33 * 04 July 2000 : majour bug hunt, xscreensaver code rewritten
34 * 08 July 2000 : texture mapping, rotation and zoom added
35 * 21 July 2000 : cleaned up code from bug hunts, manpage written
36 * 24 November 2000 : fixed x co-ord calculation in solid - textured
37 * 05 March 2001 : put back non pnmlib code with #ifdefs
38 * 11 May 2002 : fixed image problems with large images
43 #define DEFAULTS "*delay: 20000\n" \
47 "*suppressRotationAnimation: True\n" \
49 # define refresh_gflux 0
50 # define release_gflux 0
51 # include "xlockmore.h" /* from the xscreensaver distribution */
52 #else /* !STANDALONE */
53 # include "xlock.h" /* from the xlockmore distribution */
54 #endif /* !STANDALONE */
56 #ifdef USE_GL /* whole file */
60 # include <X11/Xmu/Drawing.h>
62 # include <Xmu/Drawing.h>
67 #define countof(x) (sizeof((x))/sizeof((*x)))
74 #include "grab-ximage.h"
75 #include "gltrackball.h"
78 static enum {wire=0,solid,light,checker,grab} _draw;
80 # define DEF_SQUARES "19"
81 # define DEF_RESOLUTION "4"
84 # define DEF_SPEED "0.05"
85 # define DEF_ROTATIONX "0.01"
86 # define DEF_ROTATIONY "0.0"
87 # define DEF_ROTATIONZ "0.1"
88 # define DEF_WAVES "3"
89 # define DEF_WAVE_CHANGE "50"
90 # define DEF_WAVE_HEIGHT "1.0"
91 # define DEF_WAVE_FREQ "3.0"
92 # define DEF_ZOOM "1.0"
96 static int _squares; /* grid size */
97 static int _resolution; /* wireframe resolution */
101 static float _rotationx;
102 static float _rotationy;
103 static float _rotationz;
107 static int _waveChange;
108 static float _waveHeight;
109 static float _waveFreq;
115 static XrmOptionDescRec opts[] = {
116 {"-squares", ".gflux.squares", XrmoptionSepArg, 0},
117 {"-resolution", ".gflux.resolution", XrmoptionSepArg, 0},
118 /* {"-draw", ".gflux.draw", XrmoptionSepArg, 0},*/
119 {"-mode", ".gflux.mode", XrmoptionSepArg, 0},
120 {"-wireframe", ".gflux.mode", XrmoptionNoArg, "wire"},
121 {"-flat", ".gflux.flat", XrmoptionSepArg, 0},
122 {"-speed", ".gflux.speed", XrmoptionSepArg, 0},
123 {"-rotationx", ".gflux.rotationx", XrmoptionSepArg, 0},
124 {"-rotationy", ".gflux.rotationy", XrmoptionSepArg, 0},
125 {"-rotationz", ".gflux.rotationz", XrmoptionSepArg, 0},
126 {"-waves", ".gflux.waves", XrmoptionSepArg, 0},
127 {"-waveChange", ".gflux.waveChange", XrmoptionSepArg, 0},
128 {"-waveHeight", ".gflux.waveHeight", XrmoptionSepArg, 0},
129 {"-waveFreq", ".gflux.waveFreq", XrmoptionSepArg, 0},
130 {"-zoom", ".gflux.zoom", XrmoptionSepArg, 0},
134 static argtype vars[] = {
135 {&_squares, "squares", "Squares", DEF_SQUARES, t_Int},
136 {&_resolution, "resolution", "Resolution", DEF_RESOLUTION, t_Int},
137 /* {&_draw, "draw", "Draw", DEF_DRAW, t_Int},*/
138 {&_flat, "flat", "Flat", DEF_FLAT, t_Int},
139 {&_speed, "speed", "Speed", DEF_SPEED, t_Float},
140 {&_rotationx, "rotationx", "Rotationx", DEF_ROTATIONX, t_Float},
141 {&_rotationy, "rotationy", "Rotationy", DEF_ROTATIONY, t_Float},
142 {&_rotationz, "rotationz", "Rotationz", DEF_ROTATIONZ, t_Float},
143 {&_waves, "waves", "Waves", DEF_WAVES, t_Int},
144 {&_waveChange, "waveChange", "WaveChange", DEF_WAVE_CHANGE, t_Int},
145 {&_waveHeight, "waveHeight", "WaveHeight", DEF_WAVE_HEIGHT, t_Float},
146 {&_waveFreq, "waveFreq", "WaveFreq", DEF_WAVE_FREQ, t_Float},
147 {&_zoom, "zoom", "Zoom", DEF_ZOOM, t_Float},
151 static OptionStruct desc[] =
153 {"-squares num", "size of grid in squares (19)"},
154 {"-resolution num", "detail of lines making grid, wireframe only (4)"},
155 /* {"-draw num", "draw method to use: 0=wireframe 1=solid 2=lit (0)"},*/
156 {"-flat num", "shading method, not wireframe: 0=smooth 1=flat (0)"},
157 {"-speed num", "speed of waves (0.05)"},
158 {"-rotationx num", "speed of xrotation (0.01)"},
159 {"-rotationy num", "speed of yrotation (0.00)"},
160 {"-rotationz num", "speed of zrotation (0.10)"},
161 {"-waves num", "number of simultanious waves (3)"},
162 {"-waveChange num", "number of cyles for a wave to change (50)"},
163 {"-waveHeight num", "height of waves (1.0)"},
164 {"-waveFreq num", "max frequency of a wave (3.0)"},
165 {"-zoom num", "camera control (1.0)"},
168 ENTRYPOINT ModeSpecOpt gflux_opts = {countof(opts), opts, countof(vars), vars, desc};
171 ModStruct gflux_description =
172 {"gflux", "init_gflux", "draw_gflux", NULL,
173 "draw_gflux", "init_gflux", NULL, &gflux_opts,
174 1000, 1, 2, 1, 4, 1.0, "",
175 "GFlux: an OpenGL gflux", 0, NULL};
178 /* structure for holding the gflux data */
179 typedef struct gfluxstruct {
181 int screen_width, screen_height;
182 GLXContext *glx_context;
185 #define MAXWAVES 10 /* should be dynamic */
187 double freq[MAXWAVES];
188 double dispy[MAXWAVES];
189 double dispx[MAXWAVES];
195 int img_width, img_height;
196 int (*drawFunc)(struct gfluxstruct *);
198 trackball_state *trackball;
210 Bool waiting_for_image_p;
213 static gfluxstruct *gfluxes = NULL;
216 static void initLighting(void);
217 static void grabTexture(gfluxstruct *);
218 static void createTexture(gfluxstruct *);
219 static int displaySolid(gfluxstruct *); /* drawFunc implementations */
220 static int displayLight(gfluxstruct *);
221 static int displayTexture(gfluxstruct *);
222 static int displayWire(gfluxstruct *);
223 static void calcGrid(gfluxstruct *);
224 static double getGrid(gfluxstruct *,double,double,double);
226 /* as macro for speed */
227 /* could do with colour cycling here */
228 /* void genColour(double);*/
229 #define genColour(X) \
231 gp->colour[0] = 0.0;\
232 gp->colour[1] = 0.5+0.5*(X);\
233 gp->colour[2] = 0.5-0.5*(X);\
236 /* BEGINNING OF FUNCTIONS */
240 gflux_handle_event (ModeInfo *mi, XEvent *event)
242 gfluxstruct *gp = &gfluxes[MI_SCREEN(mi)];
244 if (gltrackball_event_handler (event, gp->trackball,
245 MI_WIDTH (mi), MI_HEIGHT (mi),
248 else if (screenhack_event_helper (MI_DISPLAY(mi), MI_WINDOW(mi), event))
261 userRot(gfluxstruct *gp)
263 gltrackball_rotate (gp->trackball);
266 /* draw the gflux once */
267 ENTRYPOINT void draw_gflux(ModeInfo * mi)
269 gfluxstruct *gp = &gfluxes[MI_SCREEN(mi)];
270 Display *display = MI_DISPLAY(mi);
271 Window window = MI_WINDOW(mi);
273 if (!gp->glx_context) return;
275 /* Just keep running before the texture has come in. */
276 /* if (gp->waiting_for_image_p) return; */
278 glXMakeCurrent(display, window, *(gp->glx_context));
281 mi->polygon_count = gp->drawFunc(gp);
282 if (mi->fps_p) do_fps (mi);
283 glXSwapBuffers(display, window);
287 /* Standard reshape function */
289 reshape_gflux(ModeInfo *mi, int width, int height)
291 glViewport( 0, 0, width, height );
292 glMatrixMode(GL_PROJECTION);
294 glFrustum(-_zoom,_zoom,-0.8*_zoom,0.8*_zoom,2,6);
295 glTranslatef(0.0,0.0,-4.0);
296 glMatrixMode(GL_MODELVIEW);
299 # ifdef HAVE_MOBILE /* Keep it the same relative size when rotated. */
301 GLfloat h = MI_HEIGHT(mi) / (GLfloat) MI_WIDTH(mi);
302 int o = (int) current_device_rotation();
303 if (o != 0 && o != 180 && o != -180)
304 glScalef (1/h, 1/h, 1/h);
310 /* main OpenGL initialization routine */
311 static void initializeGL(ModeInfo *mi, GLsizei width, GLsizei height)
313 gfluxstruct *gp = &gfluxes[MI_SCREEN(mi)];
315 reshape_gflux(mi, width, height);
316 glViewport( 0, 0, width, height );
318 gp->tex_xscale = 1.0; /* maybe changed later */
319 gp->tex_yscale = 1.0;
323 gp->drawFunc = (displaySolid);
324 glEnable(GL_DEPTH_TEST);
327 gp->drawFunc = (displayLight);
328 glEnable(GL_DEPTH_TEST);
332 gp->drawFunc = (displayTexture);
333 glEnable(GL_DEPTH_TEST);
338 gp->drawFunc = (displayTexture);
339 glEnable(GL_DEPTH_TEST);
345 gp->drawFunc = (displayWire);
346 glDisable(GL_DEPTH_TEST);
350 if(_flat) glShadeModel(GL_FLAT);
351 else glShadeModel(GL_SMOOTH);
356 /* xgflux initialization routine */
357 ENTRYPOINT void init_gflux(ModeInfo * mi)
359 int screen = MI_SCREEN(mi);
362 MI_INIT(mi, gfluxes, NULL);
363 gp = &gfluxes[screen];
365 gp->trackball = gltrackball_init (True);
367 gp->time = frand(1000.0); /* don't run two screens in lockstep */
370 char *s = get_string_resource (mi->dpy, "mode", "Mode");
371 if (!s || !*s) _draw = grab;
372 else if (!strcasecmp (s, "wire")) _draw = wire;
373 else if (!strcasecmp (s, "solid")) _draw = solid;
374 else if (!strcasecmp (s, "light")) _draw = light;
375 else if (!strcasecmp (s, "checker")) _draw = checker;
376 else if (!strcasecmp (s, "grab")) _draw = grab;
380 "%s: mode must be one of: wire, solid, "
381 "light, checker, or grab; not \"%s\"\n",
388 gp->window = MI_WINDOW(mi);
389 if ((gp->glx_context = init_GL(mi)) != NULL) {
390 reshape_gflux(mi, MI_WIDTH(mi), MI_HEIGHT(mi));
391 initializeGL(mi, MI_WIDTH(mi), MI_HEIGHT(mi));
398 static void createTexture(gfluxstruct *gp)
401 unsigned int data[] = { 0xFFFFFFFF, 0xAAAAAAAA, 0xFFFFFFFF, 0xAAAAAAAA,
402 0xAAAAAAAA, 0xFFFFFFFF, 0xAAAAAAAA, 0xFFFFFFFF,
403 0xFFFFFFFF, 0xAAAAAAAA, 0xFFFFFFFF, 0xAAAAAAAA,
404 0xAAAAAAAA, 0xFFFFFFFF, 0xAAAAAAAA, 0xFFFFFFFF };
406 gp->tex_xscale = size;
407 gp->tex_yscale = size;
409 glGenTextures (1, &gp->texName);
410 glBindTexture (GL_TEXTURE_2D, gp->texName);
412 glTexImage2D (GL_TEXTURE_2D, 0, 3, size, size, 0,
413 GL_RGBA, GL_UNSIGNED_BYTE, data);
415 glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
416 glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
418 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
419 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
424 image_loaded_cb (const char *filename, XRectangle *geometry,
425 int image_width, int image_height,
426 int texture_width, int texture_height,
429 gfluxstruct *gp = (gfluxstruct *) closure;
430 gp->img_geom = *geometry;
432 gp->tex_xscale = (GLfloat) image_width / texture_width;
433 gp->tex_yscale = -(GLfloat) image_height / texture_height;
434 gp->img_width = image_width;
435 gp->img_height = image_height;
437 glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
438 glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
439 (gp->mipmap_p ? GL_LINEAR_MIPMAP_LINEAR : GL_LINEAR));
441 gp->waiting_for_image_p = False;
445 grabTexture(gfluxstruct *gp)
447 if (MI_IS_WIREFRAME(gp->modeinfo))
450 gp->waiting_for_image_p = True;
452 load_texture_async (gp->modeinfo->xgwa.screen, gp->modeinfo->window,
453 *gp->glx_context, 0, 0, gp->mipmap_p, gp->texName,
454 image_loaded_cb, gp);
458 static void initLighting(void)
460 static const float ambientA[] = {0.0, 0.0, 0.0, 1.0};
461 static const float diffuseA[] = {1.0, 1.0, 1.0, 1.0};
462 static const float positionA[] = {5.0, 5.0, 15.0, 1.0};
464 static const float front_mat_shininess[] = {30.0};
465 static const float front_mat_specular[] = {0.5, 0.5, 0.5, 1.0};
467 static const float mat_diffuse[] = {0.5, 0.5, 0.5, 1.0};
469 glMaterialfv(GL_FRONT, GL_SHININESS, front_mat_shininess);
470 glMaterialfv(GL_FRONT, GL_SPECULAR, front_mat_specular);
472 glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, mat_diffuse);
474 glLightfv(GL_LIGHT0, GL_AMBIENT, ambientA);
475 glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuseA);
476 glLightfv(GL_LIGHT0, GL_POSITION, positionA);
477 glEnable(GL_LIGHTING);
479 glLightModelf(GL_LIGHT_MODEL_TWO_SIDE,1);
481 glEnable(GL_NORMALIZE); /* would it be faster ... */
482 glEnable(GL_COLOR_MATERIAL);
483 glColorMaterial(GL_FRONT_AND_BACK,GL_AMBIENT_AND_DIFFUSE);
486 /************************************/
487 /* draw implementations */
488 /* somewhat inefficient since they */
489 /* all calculate previously */
490 /* calculated values again */
491 /* storing the values in an array */
492 /* is a posibility */
493 /************************************/
494 static int displayTexture(gfluxstruct *gp)
499 double dx = 2.0/((double)_squares);
500 double dy = 2.0/((double)_squares);
502 double du = 2.0/((double)_squares);
503 double dv = 2.0/((double)_squares);
505 double xs = gp->tex_xscale;
506 double ys = gp->tex_yscale;
508 double minx, miny, maxx, maxy;
512 minx = (GLfloat) gp->img_geom.x / gp->img_width;
513 miny = (GLfloat) gp->img_geom.y / gp->img_height;
514 maxx = ((GLfloat) (gp->img_geom.x + gp->img_geom.width) /
516 maxy = ((GLfloat) (gp->img_geom.y + gp->img_geom.height) /
520 minx = (minx * 2) - 1;
521 miny = (miny * 2) - 1;
522 maxx = (maxx * 2) - 1;
523 maxy = (maxy * 2) - 1;
533 glMatrixMode (GL_TEXTURE);
535 glTranslatef(-1,-1,0);
537 glMatrixMode (GL_MODELVIEW);
541 glRotatef(gp->anglex,1,0,0);
542 glRotatef(gp->angley,0,1,0);
543 glRotatef(gp->anglez,0,0,1);
544 glScalef(1,1,(GLfloat)_waveHeight);
545 glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
546 glEnable(GL_TEXTURE_2D);
549 glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
550 glBindTexture(GL_TEXTURE_2D, gp->texName);
551 check_gl_error("texture binding");
553 glColor3f(0.5,0.5,0.5);
555 for(x = minx, u = minu; x < maxx - 0.01; x += dx, u += du) {
556 glBegin(GL_QUAD_STRIP);
557 for (y = miny, v = minv; y <= maxy + 0.01; y += dy, v += dv) {
558 z = getGrid(gp,x,y,gp->time);
559 glTexCoord2f(u*xs,v*ys);
561 getGrid(gp,x+dx,y,gp->time)-getGrid(gp, x-dx,y,gp->time),
562 getGrid(gp,x,y+dy,gp->time)-getGrid(gp, x,y-dy,gp->time),
567 z = getGrid(gp,x+dx,y,gp->time);
568 glTexCoord2f((u+du)*xs,v*ys);
570 getGrid(gp,x+dx+dx,y,gp->time)-getGrid(gp, x,y,gp->time),
571 getGrid(gp,x+dx,y+dy,gp->time)-getGrid(gp, x+dx,y-dy,gp->time),
574 glVertex3f(x+dx,y,z);
580 /* Draw a border around the grid.
582 glColor3f(0.4, 0.4, 0.4);
583 glDisable(GL_TEXTURE_2D);
584 glEnable (GL_LINE_SMOOTH);
586 glBegin(GL_LINE_LOOP);
588 for (x = minx; x <= maxx; x += dx) {
589 glVertex3f (x, y, getGrid (gp, x, y, gp->time));
593 for (y = miny; y <= maxy; y += dy) {
594 glVertex3f (x, y, getGrid (gp, x, y, gp->time));
598 for (x = maxx; x >= minx; x -= dx) {
599 glVertex3f (x, y, getGrid (gp, x, y, gp->time));
603 for (y = maxy; y >= miny; y -= dy) {
604 glVertex3f (x, y, getGrid (gp, x, y, gp->time));
608 glEnable(GL_TEXTURE_2D);
610 if (! gp->button_down_p) {
612 gp->anglex -= _rotationx;
613 gp->angley -= _rotationy;
614 gp->anglez -= _rotationz;
619 static int displaySolid(gfluxstruct *gp)
624 double dx = 2.0/((double)_squares);
625 double dy = 2.0/((double)_squares);
628 glRotatef(gp->anglex,1,0,0);
629 glRotatef(gp->angley,0,1,0);
630 glRotatef(gp->anglez,0,0,1);
632 glScalef(1,1,(GLfloat)_waveHeight);
633 glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
635 for(x=-1;x<0.9999;x+=dx) {
636 glBegin(GL_QUAD_STRIP);
637 for(y=-1;y<=1;y+=dy) {
638 z = getGrid(gp, x,y,gp->time);
640 glColor3fv(gp->colour);
643 z = getGrid(gp, x+dx,y,gp->time);
645 glColor3fv(gp->colour);
646 glVertex3f(x+dx,y,z);
652 if (! gp->button_down_p) {
654 gp->anglex -= _rotationx;
655 gp->angley -= _rotationy;
656 gp->anglez -= _rotationz;
662 static int displayLight(gfluxstruct *gp)
667 double dx = 2.0/((double)_squares);
668 double dy = 2.0/((double)_squares);
671 glRotatef(gp->anglex,1,0,0);
672 glRotatef(gp->angley,0,1,0);
673 glRotatef(gp->anglez,0,0,1);
675 glScalef(1,1,(GLfloat)_waveHeight);
676 glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
678 for(x=-1;x<0.9999;x+=dx) {
679 glBegin(GL_QUAD_STRIP);
680 for(y=-1;y<=1;y+=dy) {
681 z = getGrid(gp, x,y,gp->time);
683 glColor3fv(gp->colour);
685 getGrid(gp, x+dx,y,gp->time)-getGrid(gp, x-dx,y,gp->time),
686 getGrid(gp, x,y+dy,gp->time)-getGrid(gp, x,y-dy,gp->time),
691 z = getGrid(gp, x+dx,y,gp->time);
693 glColor3fv(gp->colour);
695 getGrid(gp, x+dx+dx,y,gp->time)-getGrid(gp, x,y,gp->time),
696 getGrid(gp, x+dx,y+dy,gp->time)-getGrid(gp, x+dx,y-dy,gp->time),
699 glVertex3f(x+dx,y,z);
705 if (! gp->button_down_p) {
707 gp->anglex -= _rotationx;
708 gp->angley -= _rotationy;
709 gp->anglez -= _rotationz;
714 static int displayWire(gfluxstruct *gp)
719 double dx1 = 2.0/((double)(_squares*_resolution)) - 0.00001;
720 double dy1 = 2.0/((double)(_squares*_resolution)) - 0.00001;
721 double dx2 = 2.0/((double)_squares) - 0.00001;
722 double dy2 = 2.0/((double)_squares) - 0.00001;
725 glRotatef(gp->anglex,1,0,0);
726 glRotatef(gp->angley,0,1,0);
727 glRotatef(gp->anglez,0,0,1);
729 glScalef(1,1,(GLfloat)_waveHeight);
730 glClear(GL_COLOR_BUFFER_BIT);
732 for(x=-1;x<=1;x+=dx2) {
733 glBegin(GL_LINE_STRIP);
734 for(y=-1;y<=1;y+=dy1) {
735 z = getGrid(gp, x,y,gp->time);
737 glColor3fv(gp->colour);
743 for(y=-1;y<=1;y+=dy2) {
744 glBegin(GL_LINE_STRIP);
745 for(x=-1;x<=1;x+=dx1) {
746 z = getGrid(gp, x,y,gp->time);
748 glColor3fv(gp->colour);
755 if (! gp->button_down_p) {
757 gp->anglex -= _rotationx;
758 gp->angley -= _rotationy;
759 gp->anglez -= _rotationz;
764 /* generates new ripples */
765 static void calcGrid(gfluxstruct *gp)
769 if (gp->button_down_p) return;
771 tmp = 1.0/((double)_waveChange);
772 if(!(gp->counter%_waveChange)) {
773 gp->newWave = ((int)(gp->counter*tmp))%_waves;
774 gp->dispx[gp->newWave] = -frand(1.0);
775 gp->dispy[gp->newWave] = -frand(1.0);
776 gp->freq[gp->newWave] = _waveFreq * frand(1.0);
777 gp->wa[gp->newWave] = 0.0;
780 gp->wa[gp->newWave] += tmp;
781 gp->wa[(gp->newWave+1)%_waves] -= tmp;
784 /* returns a height for the grid given time and x,y space co-ords */
785 static double getGrid(gfluxstruct *gp, double x, double y, double a)
791 tmp = 1.0/((float)_waves);
792 for(i=0;i<_waves;i++) {
793 retval += gp->wa[i] * tmp * sin( gp->freq[i]
794 * ( (x+gp->dispx[i]) * (x+gp->dispx[i])
795 + (y+gp->dispy[i]) * (y+gp->dispy[i]) +a ) );
801 XSCREENSAVER_MODULE ("GFlux", gflux)