git.hungrycats.org Git - xscreensaver/blob - hacks/strange.c

   1 /* -*- Mode: C; tab-width: 4 -*-
   2  * strange --- Strange attractors are not so hard to find...
   3  */
   4 #if !defined( lint ) && !defined( SABER )
   5 static const char sccsid[] = "@(#)strange.c        4.02 97/04/01 xlockmore";
   6 #endif
   7
   8 /* Copyright (c) 1997 by Massimino Pascal (Pascal.Massimon@ens.fr)
   9  *
  10  * Permission to use, copy, modify, and distribute this software and its
  11  * documentation for any purpose and without fee is hereby granted,
  12  * provided that the above copyright notice appear in all copies and that
  13  * both that copyright notice and this permission notice appear in
  14  * supporting documentation.
  15  *
  16  * This file is provided AS IS with no warranties of any kind.  The author
  17  * shall have no liability with respect to the infringement of copyrights,
  18  * trade secrets or any patents by this file or any part thereof.  In no
  19  * event will the author be liable for any lost revenue or profits or
  20  * other special, indirect and consequential damages.
  21  *
  22  * Revision History:
  23  * 10-May-97: jwz@netscape.com: turned into a standalone program.
  24  *                        Made it render into an offscreen bitmap and then copy
  25  *                        that onto the screen, to reduce flicker.
  26  */
  27
  28 #ifdef STANDALONE
  29 # define PROGCLASS                                      "Strange"
  30 # define HACK_INIT                                      init_strange
  31 # define HACK_DRAW                                      draw_strange
  32 # define strange_opts                           xlockmore_opts
  33 # define DEFAULTS       "*delay:                2000  \n"                       \
  34                                         "*ncolors:              100   \n"
  35 # define SMOOTH_COLORS
  36 # include "xlockmore.h"                         /* from the xscreensaver distribution */
  37 #else  /* !STANDALONE */
  38 # include "xlock.h"                                     /* from the xlockmore distribution */
  39 #endif /* !STANDALONE */
  40
  41 ModeSpecOpt strange_opts = {
  42   0, NULL, 0, NULL, NULL };
  43
  44 /*****************************************************/
  45 /*****************************************************/
  46
  47 typedef float DBL;
  48 typedef int PRM;
  49
  50 #define UNIT (1<<12)
  51 #define UNIT2 (1<<14)
  52 /* #define UNIT2 (3140*UNIT/1000) */
  53
  54 #define SKIP_FIRST      100
  55 #define MAX_POINTS      5500
  56 #define DBL_To_PRM(x)  (PRM)( (DBL)(UNIT)*(x) )
  57
  58
  59 #define DO_FOLD(a) (a)<0 ? -Fold[ (-(a))&(UNIT2-1) ] : Fold[ (a)&(UNIT2-1) ]
  60
  61 /*
  62    #define DO_FOLD(a) (a)<-UNIT2 ? -Fold[(-(a))%UNIT2] : (a)<0 ? -Fold[ -(a) ]
  63
  64    :  \ (a)>UNIT2 ? Fold[ (a)%UNIT2 ] : Fold[ (a) ] */
  65 /* #define DO_FOLD(a) DBL_To_PRM( sin( (DBL)(a)/UNIT ) ) */
  66 /*
  67    #define DO_FOLD(a) (a)<0 ? DBL_To_PRM( exp( 16.0*(a)/UNIT2 ) )-1.0 : \
  68    DBL_To_PRM( 1.0-exp( -16.0*(a)/UNIT2 ) ) */
  69
  70 /******************************************************************/
  71
  72 #define MAX_PRM 3*5
  73
  74 typedef struct {
  75         DBL         Prm1[MAX_PRM], Prm2[MAX_PRM];
  76         void        (*Iterate) (PRM, PRM, PRM *, PRM *);
  77         XPoint     *Buffer1, *Buffer2;
  78         int         Cur_Pt, Max_Pt;
  79         int         Col, Count, Speed;
  80         int         Width, Height;
  81     Pixmap      dbuf;   /* jwz */
  82     GC          dbuf_gc;
  83 } ATTRACTOR;
  84
  85 static ATTRACTOR *Root;
  86 static PRM  xmin, xmax, ymin, ymax;
  87 static PRM  Prm[MAX_PRM];
  88 static PRM *Fold = NULL;
  89
  90 /******************************************************************/
  91 /******************************************************************/
  92
  93 static DBL  Amp_Prm[MAX_PRM] =
  94 {
  95         1.0, 3.5, 3.5, 2.5, 4.7,
  96         1.0, 3.5, 3.6, 2.5, 4.7,
  97         1.0, 1.5, 2.2, 2.1, 3.5
  98 };
  99 static DBL  Mid_Prm[MAX_PRM] =
 100 {
 101         0.0, 1.5, 0.0, .5, 1.5,
 102         0.0, 1.5, 0.0, .5, 1.5,
 103         0.0, 1.5, -1.0, -.5, 2.5,
 104 };
 105
 106 static      DBL
 107 Gauss_Rand(DBL c, DBL A, DBL S)
 108 {
 109         DBL         y;
 110
 111         y = (DBL) LRAND() / MAXRAND;
 112         y = A * (1.0 - exp(-y * y * S)) / (1.0 - exp(-S));
 113         if (NRAND(2))
 114                 return (c + y);
 115         else
 116                 return (c - y);
 117 }
 118
 119 static void
 120 Random_Prm(DBL * Prm)
 121 {
 122         int         i;
 123
 124         for (i = 0; i < MAX_PRM; ++i)
 125                 Prm[i] = Gauss_Rand(Mid_Prm[i], Amp_Prm[i], 4.0);
 126 }
 127
 128 /***************************************************************/
 129
 130    /* 2 examples of non-linear map */
 131
 132 static void
 133 Iterate_X2(PRM x, PRM y, PRM * xo, PRM * yo)
 134 {
 135         PRM         xx, yy, xy, x2y, y2x, Tmp;
 136
 137         xx = (x * x) / UNIT;
 138         x2y = (xx * y) / UNIT;
 139         yy = (y * y) / UNIT;
 140         y2x = (yy * x) / UNIT;
 141         xy = (x * y) / UNIT;
 142
 143         Tmp = Prm[1] * xx + Prm[2] * xy + Prm[3] * yy + Prm[4] * x2y;
 144         Tmp = Prm[0] - y + (Tmp / UNIT);
 145         *xo = DO_FOLD(Tmp);
 146         Tmp = Prm[6] * xx + Prm[7] * xy + Prm[8] * yy + Prm[9] * y2x;
 147         Tmp = Prm[5] + x + (Tmp / UNIT);
 148         *yo = DO_FOLD(Tmp);
 149 }
 150
 151 static void
 152 Iterate_X3(PRM x, PRM y, PRM * xo, PRM * yo)
 153 {
 154         PRM         xx, yy, xy, x2y, y2x, Tmp_x, Tmp_y, Tmp_z;
 155
 156         xx = (x * x) / UNIT;
 157         x2y = (xx * y) / UNIT;
 158         yy = (y * y) / UNIT;
 159         y2x = (yy * x) / UNIT;
 160         xy = (x * y) / UNIT;
 161
 162         Tmp_x = Prm[1] * xx + Prm[2] * xy + Prm[3] * yy + Prm[4] * x2y;
 163         Tmp_x = Prm[0] - y + (Tmp_x / UNIT);
 164         Tmp_x = DO_FOLD(Tmp_x);
 165
 166         Tmp_y = Prm[6] * xx + Prm[7] * xy + Prm[8] * yy + Prm[9] * y2x;
 167         Tmp_y = Prm[5] + x + (Tmp_y / UNIT);
 168
 169         Tmp_y = DO_FOLD(Tmp_y);
 170
 171         Tmp_z = Prm[11] * xx + Prm[12] * xy + Prm[13] * yy + Prm[14] * y2x;
 172         Tmp_z = Prm[10] + x + (Tmp_z / UNIT);
 173         Tmp_z = UNIT + Tmp_z * Tmp_z / UNIT;
 174
 175         *xo = (Tmp_x * UNIT) / Tmp_z;
 176         *yo = (Tmp_y * UNIT) / Tmp_z;
 177 }
 178
 179 static void (*Funcs[2]) (PRM, PRM, PRM *, PRM *) = {
 180         Iterate_X2, Iterate_X3
 181 };
 182
 183 /***************************************************************/
 184
 185 void
 186 draw_strange(ModeInfo * mi)
 187 {
 188         int         i, j, n, Max_Colors, Cur_Pt;
 189         PRM         x, y, xo, yo;
 190         DBL         u;
 191         ATTRACTOR  *A;
 192         XPoint     *Buf;
 193         Display    *display;
 194         GC          gc;
 195         Window      window;
 196         DBL         Lx, Ly;
 197         void        (*Iterate) (PRM, PRM, PRM *, PRM *);
 198
 199         display = MI_DISPLAY(mi);
 200         window = MI_WINDOW(mi);
 201         gc = MI_GC(mi);
 202         Max_Colors = MI_NPIXELS(mi);
 203
 204         A = &Root[MI_SCREEN(mi)];
 205
 206         Cur_Pt = A->Cur_Pt;
 207         Iterate = A->Iterate;
 208
 209         u = (DBL) (A->Count) / 1000.0;
 210         for (j = MAX_PRM - 1; j >= 0; --j)
 211                 Prm[j] = DBL_To_PRM((1.0 - u) * A->Prm1[j] + u * A->Prm2[j]);
 212
 213         x = y = DBL_To_PRM(.0);
 214         for (n = SKIP_FIRST; n; --n) {
 215                 (*Iterate) (x, y, &xo, &yo);
 216                 x = xo + NRAND(8) - 4;
 217                 y = yo + NRAND(8) - 4;
 218         }
 219
 220         xmax = 0;
 221         xmin = UNIT * 4;
 222         ymax = 0;
 223         ymin = UNIT * 4;
 224         A->Cur_Pt = 0;
 225         Buf = A->Buffer2;
 226         Lx = (DBL) A->Width / UNIT / 2.2;
 227         Ly = (DBL) A->Height / UNIT / 2.2;
 228         for (n = A->Max_Pt; n; --n) {
 229                 (*Iterate) (x, y, &xo, &yo);
 230                 Buf->x = (short) (Lx * (x + DBL_To_PRM(1.1)));
 231                 Buf->y = (short) (Ly * (DBL_To_PRM(1.1) - y));
 232                 /* (void) fprintf( stderr, "X,Y: %d %d    ", Buf->x, Buf->y ); */
 233                 Buf++;
 234                 A->Cur_Pt++;
 235                 if (xo > xmax)
 236                         xmax = xo;
 237                 else if (xo < xmin)
 238                         xmin = xo;
 239                 if (yo > ymax)
 240                         ymax = yo;
 241                 else if (yo < ymin)
 242                         ymin = yo;
 243                 x = xo + NRAND(8) - 4;
 244                 y = yo + NRAND(8) - 4;
 245         }
 246
 247         XSetForeground(display, gc, MI_WIN_BLACK_PIXEL(mi));
 248
 249         if (A->dbuf)    /* jwz */
 250           {
 251                 XSetForeground(display, A->dbuf_gc, 0);
 252 /*          XDrawPoints(display, A->dbuf, A->dbuf_gc, A->Buffer1,
 253                                     Cur_Pt,CoordModeOrigin);*/
 254                 XFillRectangle(display, A->dbuf, A->dbuf_gc, 0,0, A->Width, A->Height);
 255           }
 256         else
 257           XDrawPoints(display, window, gc, A->Buffer1, Cur_Pt, CoordModeOrigin);
 258
 259         if (Max_Colors < 2)
 260                 XSetForeground(display, gc, MI_WIN_WHITE_PIXEL(mi));
 261         else
 262                 XSetForeground(display, gc, MI_PIXEL(mi, A->Col % Max_Colors));
 263
 264         if (A->dbuf)
 265           {
 266                 XSetForeground(display, A->dbuf_gc, 1);
 267                 XDrawPoints(display, A->dbuf, A->dbuf_gc, A->Buffer2, A->Cur_Pt,
 268                                         CoordModeOrigin);
 269           }
 270         else
 271           XDrawPoints(display, window, gc, A->Buffer2, A->Cur_Pt, CoordModeOrigin);
 272
 273         if (A->dbuf)
 274           XCopyPlane(display, A->dbuf, window, gc, 0,0,A->Width,A->Height,0,0, 1);
 275
 276         Buf = A->Buffer1;
 277         A->Buffer1 = A->Buffer2;
 278         A->Buffer2 = Buf;
 279
 280         if ((xmax - xmin < DBL_To_PRM(.2)) && (ymax - ymin < DBL_To_PRM(.2)))
 281                 A->Count += 4 * A->Speed;
 282         else
 283                 A->Count += A->Speed;
 284         if (A->Count >= 1000) {
 285                 for (i = MAX_PRM - 1; i >= 0; --i)
 286                         A->Prm1[i] = A->Prm2[i];
 287                 Random_Prm(A->Prm2);
 288                 A->Count = 0;
 289         }
 290         A->Col++;
 291 }
 292
 293
 294 /***************************************************************/
 295
 296 void
 297 init_strange(ModeInfo * mi)
 298 {
 299         ATTRACTOR  *Attractor;
 300
 301         if (Root == NULL) {
 302                 Root = (ATTRACTOR *) calloc(
 303                                      MI_NUM_SCREENS(mi), sizeof (ATTRACTOR));
 304                 if (Root == NULL)
 305                         return;
 306         }
 307         if (Fold == NULL) {
 308                 int         i;
 309
 310                 Fold = (PRM *) calloc(UNIT2 + 1, sizeof (PRM));
 311                 if (Fold == NULL)
 312                         return;
 313                 for (i = 0; i <= UNIT2; ++i) {
 314                         DBL         x;
 315
 316                         /* x = ( DBL )(i)/UNIT2; */
 317                         /* x = sin( M_PI/2.0*x ); */
 318                         /* x = sqrt( x ); */
 319                         /* x = x*x; */
 320                         /* x = x*(1.0-x)*4.0; */
 321                         x = (DBL) (i) / UNIT;
 322                         x = sin(x);
 323                         Fold[i] = DBL_To_PRM(x);
 324                 }
 325         }
 326         Attractor = &Root[MI_SCREEN(mi)];
 327
 328         Attractor->Buffer1 = (XPoint *) calloc(MAX_POINTS, sizeof (XPoint));
 329         if (Attractor->Buffer1 == NULL)
 330                 goto Abort;
 331         Attractor->Buffer2 = (XPoint *) calloc(MAX_POINTS, sizeof (XPoint));
 332         if (Attractor->Buffer2 == NULL)
 333                 goto Abort;
 334         Attractor->Max_Pt = MAX_POINTS;
 335
 336         Attractor->Width = MI_WIN_WIDTH(mi);
 337         Attractor->Height = MI_WIN_HEIGHT(mi);
 338         Attractor->Cur_Pt = 0;
 339         Attractor->Count = 0;
 340         Attractor->Col = NRAND(MI_NPIXELS(mi));
 341         Attractor->Speed = 4;
 342
 343         Attractor->Iterate = Funcs[NRAND(2)];
 344         Random_Prm(Attractor->Prm1);
 345         Random_Prm(Attractor->Prm2);
 346
 347         Attractor->dbuf = XCreatePixmap(MI_DISPLAY(mi), MI_WINDOW(mi),
 348                                                                         Attractor->Width, Attractor->Height, 1);
 349         if (Attractor->dbuf)
 350           {
 351                 XGCValues gcv;
 352                 gcv.foreground = 0;
 353                 gcv.background = 0;
 354                 gcv.function = GXcopy;
 355                 Attractor->dbuf_gc = XCreateGC(MI_DISPLAY(mi), Attractor->dbuf,
 356                                                                            GCForeground|GCBackground|GCFunction,
 357                                                                            &gcv);
 358                 XFillRectangle(MI_DISPLAY(mi), Attractor->dbuf,
 359                                            Attractor->dbuf_gc, 0,0, Attractor->Width,
 360                                            Attractor->Height);
 361                 XSetBackground(MI_DISPLAY(mi), MI_GC(mi), MI_WIN_BLACK_PIXEL(mi));
 362                 XSetFunction(MI_DISPLAY(mi), MI_GC(mi), GXcopy);
 363           }
 364
 365         XClearWindow(MI_DISPLAY(mi), MI_WINDOW(mi));
 366         return;
 367
 368       Abort:
 369         if (Attractor->Buffer1 != NULL)
 370                 free(Attractor->Buffer1);
 371         if (Attractor->Buffer2 != NULL)
 372                 free(Attractor->Buffer2);
 373         Attractor->Buffer1 = NULL;
 374         Attractor->Buffer2 = NULL;
 375         Attractor->Cur_Pt = 0;
 376         return;
 377 }
 378
 379 /***************************************************************/
 380
 381 void
 382 release_strange(ModeInfo * mi)
 383 {
 384         int         i;
 385
 386         if (Root == NULL)
 387                 return;
 388
 389         for (i = 0; i < MI_NUM_SCREENS(mi); ++i) {
 390                 if (Root[i].Buffer1 != NULL)
 391                         free(Root[i].Buffer1);
 392                 if (Root[i].Buffer2 != NULL)
 393                         free(Root[i].Buffer2);
 394                 if (Root[i].dbuf)
 395                     XFreePixmap(MI_DISPLAY(mi), Root[i].dbuf);
 396                 if (Root[i].dbuf_gc)
 397                     XFreeGC(MI_DISPLAY(mi), Root[i].dbuf_gc);
 398         }
 399         free(Root);
 400         Root = NULL;
 401         if (Fold != NULL)
 402                 free(Fold);
 403         Fold = NULL;
 404 }