/* twang, twist around screen bits, v1.3 * by Dan Bornstein, danfuzz@milk.com * Copyright (c) 2003 Dan Bornstein. All rights reserved. * * 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. * * See the included man page for more details. */ #include #include "screenhack.h" #include #ifdef HAVE_XSHM_EXTENSION #include "xshm.h" #endif #define FLOAT double /* random float in the range (-1..1) */ #define RAND_FLOAT_PM1 \ (((FLOAT) ((random() >> 8) & 0xffff)) / ((FLOAT) 0x10000) * 2 - 1) /* random float in the range (0..1) */ #define RAND_FLOAT_01 \ (((FLOAT) ((random() >> 8) & 0xffff)) / ((FLOAT) 0x10000)) /* parameters that are user configurable */ /* whether or not to use xshm */ #ifdef HAVE_XSHM_EXTENSION static Bool useShm; #endif /* delay (usec) between iterations */ static int delay; /* the maximum number of columns of tiles */ static int maxColumns; /* the maximum number of rows of tiles */ static int maxRows; /* the size (width and height) of a tile */ static int tileSize; /* the width of the border around each tile */ static int borderWidth; /* the chance, per iteration, of an interesting event happening */ static FLOAT eventChance; /* friction: the fraction (0..1) by which velocity decreased per iteration */ static FLOAT friction; /* springiness: the fraction (0..1) of the orientation that turns into * velocity towards the center */ static FLOAT springiness; /* transference: the fraction (0..1) of the orientations of orthogonal * neighbors that turns into velocity (in the same direction as the * orientation) */ static FLOAT transference; /* non-user-modifiable immutable definitions */ /* width and height of the window */ static int windowWidth; static int windowHeight; static Display *display; /* the display to draw on */ static Window window; /* the window to draw on */ static Screen *screen; /* the screen to draw on */ static XImage *sourceImage; /* image source of stuff to draw */ static XImage *workImage; /* work area image, used when rendering */ static XImage *backgroundImage; /* image filled with background pixels */ static GC backgroundGC; /* GC for the background color */ static GC foregroundGC; /* GC for the foreground color */ static GC borderGC; /* GC for the border color */ unsigned long backgroundPixel; /* background color as a pixel value */ unsigned long borderPixel; /* border color as a pixel value */ #ifdef HAVE_XSHM_EXTENSION XShmSegmentInfo shmInfo; #endif /* the model */ typedef struct { int x; /* x coordinate of the center of the tile */ int y; /* y coordinate of the center of the tile */ FLOAT angle; /* angle of the tile (-pi..pi) */ FLOAT zoom; /* log of the zoom of the tile (-1..1) */ FLOAT vAngle; /* angular velocity (-pi/4..pi/4) */ FLOAT vZoom; /* zoomular velocity (-0.25..0.25) */ } Tile; static Tile *tiles; /* array of tiles (left->right, top->bottom, row major) */ static int rows; /* number of rows of tiles */ static int columns; /* number of columns of tiles */ static Tile **sortedTiles; /* array of tile pointers, sorted by zoom */ static int tileCount; /* total number of tiles */ #define TILE_AT(col,row) (&tiles[(row) * columns + (col)]) #define MAX_VANGLE (M_PI / 4.0) #define MAX_VZOOM 0.25 #define RAND_ANGLE (RAND_FLOAT_PM1 * M_PI) #define RAND_ZOOM (RAND_FLOAT_PM1) #define RAND_VANGLE (RAND_FLOAT_PM1 * MAX_VANGLE) #define RAND_VZOOM (RAND_FLOAT_PM1 * MAX_VZOOM) /* * overall setup stuff */ /* grab the source image */ static void grabImage (XWindowAttributes *xwa) { XFillRectangle (display, window, backgroundGC, 0, 0, windowWidth, windowHeight); backgroundImage = XGetImage (display, window, 0, 0, windowWidth, windowHeight, ~0L, ZPixmap); load_random_image (screen, window, window, NULL); sourceImage = XGetImage (display, window, 0, 0, windowWidth, windowHeight, ~0L, ZPixmap); #ifdef HAVE_XSHM_EXTENSION workImage = NULL; if (useShm) { workImage = create_xshm_image (display, xwa->visual, xwa->depth, ZPixmap, 0, &shmInfo, windowWidth, windowHeight); if (!workImage) { useShm = False; fprintf (stderr, "create_xshm_image failed\n"); } } if (workImage == NULL) #endif /* HAVE_XSHM_EXTENSION */ /* just use XSubImage to acquire the right visual, depth, etc; * easier than the other alternatives */ workImage = XSubImage (sourceImage, 0, 0, windowWidth, windowHeight); } /* set up the system */ static void setup (void) { XWindowAttributes xgwa; XGCValues gcv; XGetWindowAttributes (display, window, &xgwa); screen = xgwa.screen; windowWidth = xgwa.width; windowHeight = xgwa.height; gcv.line_width = borderWidth; gcv.foreground = get_pixel_resource ("borderColor", "BorderColor", display, xgwa.colormap); borderPixel = gcv.foreground; borderGC = XCreateGC (display, window, GCForeground | GCLineWidth, &gcv); gcv.foreground = get_pixel_resource ("background", "Background", display, xgwa.colormap); backgroundPixel = gcv.foreground; backgroundGC = XCreateGC (display, window, GCForeground, &gcv); gcv.foreground = get_pixel_resource ("foreground", "Foreground", display, xgwa.colormap); foregroundGC = XCreateGC (display, window, GCForeground, &gcv); grabImage (&xgwa); } /* * the simulation */ /* event: randomize all the angular velocities */ static void randomizeAllAngularVelocities (void) { int c; int r; for (r = 0; r < rows; r++) { for (c = 0; c < columns; c++) { TILE_AT (c, r)->vAngle = RAND_VANGLE; } } } /* event: randomize all the zoomular velocities */ static void randomizeAllZoomularVelocities (void) { int c; int r; for (r = 0; r < rows; r++) { for (c = 0; c < columns; c++) { TILE_AT (c, r)->vZoom = RAND_VZOOM; } } } /* event: randomize all the velocities */ static void randomizeAllVelocities (void) { randomizeAllAngularVelocities (); randomizeAllZoomularVelocities (); } /* event: randomize all the angular orientations */ static void randomizeAllAngularOrientations (void) { int c; int r; for (r = 0; r < rows; r++) { for (c = 0; c < columns; c++) { TILE_AT (c, r)->angle = RAND_ANGLE; } } } /* event: randomize all the zoomular orientations */ static void randomizeAllZoomularOrientations (void) { int c; int r; for (r = 0; r < rows; r++) { for (c = 0; c < columns; c++) { TILE_AT (c, r)->zoom = RAND_ZOOM; } } } /* event: randomize all the orientations */ static void randomizeAllOrientations (void) { randomizeAllAngularOrientations (); randomizeAllZoomularOrientations (); } /* event: randomize everything */ static void randomizeEverything (void) { randomizeAllVelocities (); randomizeAllOrientations (); } /* event: pick one tile and randomize all its stats */ static void randomizeOneTile (void) { int c = RAND_FLOAT_01 * columns; int r = RAND_FLOAT_01 * rows; Tile *t = TILE_AT (c, r); t->angle = RAND_ANGLE; t->zoom = RAND_ZOOM; t->vAngle = RAND_VANGLE; t->vZoom = RAND_VZOOM; } /* event: pick one row and randomize everything about each of its tiles */ static void randomizeOneRow (void) { int c; int r = RAND_FLOAT_01 * rows; for (c = 0; c < columns; c++) { Tile *t = TILE_AT (c, r); t->angle = RAND_ANGLE; t->zoom = RAND_ZOOM; t->vAngle = RAND_VANGLE; t->vZoom = RAND_VZOOM; } } /* event: pick one column and randomize everything about each of its tiles */ static void randomizeOneColumn (void) { int c = RAND_FLOAT_01 * columns; int r; for (r = 0; r < rows; r++) { Tile *t = TILE_AT (c, r); t->angle = RAND_ANGLE; t->zoom = RAND_ZOOM; t->vAngle = RAND_VANGLE; t->vZoom = RAND_VZOOM; } } /* do model event processing */ static void modelEvents (void) { int which; if (RAND_FLOAT_01 > eventChance) { return; } which = RAND_FLOAT_01 * 10; switch (which) { case 0: randomizeAllAngularVelocities (); break; case 1: randomizeAllZoomularVelocities (); break; case 2: randomizeAllVelocities (); break; case 3: randomizeAllAngularOrientations (); break; case 4: randomizeAllZoomularOrientations (); break; case 5: randomizeAllOrientations (); break; case 6: randomizeEverything (); break; case 7: randomizeOneTile (); break; case 8: randomizeOneColumn (); break; case 9: randomizeOneRow (); break; } } /* update the model for one iteration */ static void updateModel (void) { int r; int c; /* for each tile, decrease its velocities according to the friction, * and increase them based on its current orientation and the orientations * of its orthogonal neighbors */ for (r = 0; r < rows; r++) { for (c = 0; c < columns; c++) { Tile *t = TILE_AT (c, r); FLOAT a = t->angle; FLOAT z = t->zoom; FLOAT va = t->vAngle; FLOAT vz = t->vZoom; va -= t->angle * springiness; vz -= t->zoom * springiness; if (c > 0) { Tile *t2 = TILE_AT (c - 1, r); va += (t2->angle - a) * transference; vz += (t2->zoom - z) * transference; } if (c < (columns - 1)) { Tile *t2 = TILE_AT (c + 1, r); va += (t2->angle - a) * transference; vz += (t2->zoom - z) * transference; } if (r > 0) { Tile *t2 = TILE_AT (c, r - 1); va += (t2->angle - a) * transference; vz += (t2->zoom - z) * transference; } if (r < (rows - 1)) { Tile *t2 = TILE_AT (c, r + 1); va += (t2->angle - a) * transference; vz += (t2->zoom - z) * transference; } va *= (1.0 - friction); vz *= (1.0 - friction); if (va > MAX_VANGLE) va = MAX_VANGLE; else if (va < -MAX_VANGLE) va = -MAX_VANGLE; t->vAngle = va; if (vz > MAX_VZOOM) vz = MAX_VZOOM; else if (vz < -MAX_VZOOM) vz = -MAX_VZOOM; t->vZoom = vz; } } /* for each tile, update its orientation based on its velocities */ for (r = 0; r < rows; r++) { for (c = 0; c < columns; c++) { Tile *t = TILE_AT (c, r); FLOAT a = t->angle + t->vAngle; FLOAT z = t->zoom + t->vZoom; if (a > M_PI) a = M_PI; else if (a < -M_PI) a = -M_PI; t->angle = a; if (z > 1.0) z = 1.0; else if (z < -1.0) z = -1.0; t->zoom = z; } } } /* the comparator to us to sort the tiles (used immediately below); it'd * sure be nice if C allowed inner functions (or jeebus-forbid *real * closures*!) */ static int sortTilesComparator (const void *v1, const void *v2) { Tile *t1 = *(Tile **) v1; Tile *t2 = *(Tile **) v2; if (t1->zoom < t2->zoom) { return -1; } if (t1->zoom > t2->zoom) { return 1; } return 0; } /* sort the tiles in sortedTiles by zoom */ static void sortTiles (void) { qsort (sortedTiles, tileCount, sizeof (Tile *), sortTilesComparator); } /* render the given tile */ static void renderTile (Tile *t) { /* note: the zoom as stored per tile is log-based (centered on 0, with * 0 being no zoom, but the range for zoom-as-drawn is 0.4..2.5, * hence the alteration of t->zoom, below */ int x, y; int tx = t->x; int ty = t->y; FLOAT zoom = pow (2.5, t->zoom); FLOAT ang = -t->angle; FLOAT sinAng = sin (ang); FLOAT cosAng = cos (ang); FLOAT innerBorder = (tileSize - borderWidth) / 2.0; FLOAT outerBorder = innerBorder + borderWidth; int maxCoord = outerBorder * zoom * (fabs (sinAng) + fabs (cosAng)); int minX = tx - maxCoord; int maxX = tx + maxCoord; int minY = ty - maxCoord; int maxY = ty + maxCoord; FLOAT prey; if (minX < 0) minX = 0; if (maxX > windowWidth) maxX = windowWidth; if (minY < 0) minY = 0; if (maxY > windowHeight) maxY = windowHeight; sinAng /= zoom; cosAng /= zoom; for (y = minY, prey = y - ty; y < maxY; y++, prey++) { FLOAT prex = minX - tx; FLOAT srcx = prex * cosAng - prey * sinAng; FLOAT srcy = prex * sinAng + prey * cosAng; for (x = minX; x < maxX; x++, srcx += cosAng, srcy += sinAng) { if ((srcx < -innerBorder) || (srcx >= innerBorder) || (srcy < -innerBorder) || (srcy >= innerBorder)) { if ((srcx < -outerBorder) || (srcx >= outerBorder) || (srcy < -outerBorder) || (srcy >= outerBorder)) { continue; } XPutPixel (workImage, x, y, borderPixel); } else { unsigned long p = XGetPixel (sourceImage, srcx + tx, srcy + ty); XPutPixel (workImage, x, y, p); } } } } /* render and display the current model */ static void renderFrame (void) { int n; memcpy (workImage->data, backgroundImage->data, workImage->bytes_per_line * workImage->height); sortTiles (); for (n = 0; n < tileCount; n++) { renderTile (sortedTiles[n]); } #ifdef HAVE_XSHM_EXTENSION if (useShm) XShmPutImage (display, window, backgroundGC, workImage, 0, 0, 0, 0, windowWidth, windowHeight, False); else #endif /* HAVE_XSHM_EXTENSION */ XPutImage (display, window, backgroundGC, workImage, 0, 0, 0, 0, windowWidth, windowHeight); } /* set up the model */ static void setupModel (void) { int c; int r; int leftX; /* x of the center of the top-left tile */ int topY; /* y of the center of the top-left tile */ if (tileSize > (windowWidth / 2)) { tileSize = windowWidth / 2; } if (tileSize > (windowHeight / 2)) { tileSize = windowHeight / 2; } columns = windowWidth / tileSize; rows = windowHeight / tileSize; if ((maxColumns != 0) && (columns > maxColumns)) { columns = maxColumns; } if ((maxRows != 0) && (rows > maxRows)) { rows = maxRows; } tileCount = rows * columns; leftX = (windowWidth - (columns * tileSize) + tileSize) / 2; topY = (windowHeight - (rows * tileSize) + tileSize) / 2; tiles = calloc (tileCount, sizeof (Tile)); sortedTiles = calloc (tileCount, sizeof (Tile *)); for (r = 0; r < rows; r++) { for (c = 0; c < columns; c++) { Tile *t = TILE_AT (c, r); t->x = leftX + c * tileSize; t->y = topY + r * tileSize; sortedTiles[c + r * columns] = t; } } randomizeEverything (); } /* do one iteration */ static void oneIteration (void) { modelEvents (); updateModel (); renderFrame (); } /* main and options and stuff */ char *progclass = "Twang"; char *defaults [] = { ".background: black", ".foreground: white", "*borderColor: blue", "*borderWidth: 3", "*delay: 10000", "*eventChance: 0.01", "*friction: 0.05", "*maxColumns: 0", "*maxRows: 0", "*springiness: 0.1", "*tileSize: 120", "*transference: 0.025", #ifdef HAVE_XSHM_EXTENSION "*useSHM: True", #endif 0 }; XrmOptionDescRec options [] = { { "-border-color", ".borderColor", XrmoptionSepArg, 0 }, { "-border-width", ".borderWidth", XrmoptionSepArg, 0 }, { "-delay", ".delay", XrmoptionSepArg, 0 }, { "-event-chance", ".eventChance", XrmoptionSepArg, 0 }, { "-friction", ".friction", XrmoptionSepArg, 0 }, { "-max-columns", ".maxColumns", XrmoptionSepArg, 0 }, { "-max-rows", ".maxRows", XrmoptionSepArg, 0 }, { "-springiness", ".springiness", XrmoptionSepArg, 0 }, { "-tile-size", ".tileSize", XrmoptionSepArg, 0 }, { "-transference", ".transference", XrmoptionSepArg, 0 }, #ifdef HAVE_XSHM_EXTENSION { "-shm", ".useSHM", XrmoptionNoArg, "True" }, { "-no-shm", ".useSHM", XrmoptionNoArg, "False" }, #endif { 0, 0, 0, 0 } }; /* initialize the user-specifiable params */ static void initParams (void) { int problems = 0; borderWidth = get_integer_resource ("borderWidth", "Integer"); if (borderWidth < 0) { fprintf (stderr, "error: border width must be at least 0\n"); problems = 1; } delay = get_integer_resource ("delay", "Delay"); if (delay < 0) { fprintf (stderr, "error: delay must be at least 0\n"); problems = 1; } eventChance = get_float_resource ("eventChance", "Double"); if ((eventChance < 0.0) || (eventChance > 1.0)) { fprintf (stderr, "error: eventChance must be in the range 0..1\n"); problems = 1; } friction = get_float_resource ("friction", "Double"); if ((friction < 0.0) || (friction > 1.0)) { fprintf (stderr, "error: friction must be in the range 0..1\n"); problems = 1; } maxColumns = get_integer_resource ("maxColumns", "Integer"); if (maxColumns < 0) { fprintf (stderr, "error: max columns must be at least 0\n"); problems = 1; } maxRows = get_integer_resource ("maxRows", "Integer"); if (maxRows < 0) { fprintf (stderr, "error: max rows must be at least 0\n"); problems = 1; } springiness = get_float_resource ("springiness", "Double"); if ((springiness < 0.0) || (springiness > 1.0)) { fprintf (stderr, "error: springiness must be in the range 0..1\n"); problems = 1; } tileSize = get_integer_resource ("tileSize", "Integer"); if (tileSize < 1) { fprintf (stderr, "error: tile size must be at least 1\n"); problems = 1; } transference = get_float_resource ("transference", "Double"); if ((transference < 0.0) || (transference > 1.0)) { fprintf (stderr, "error: transference must be in the range 0..1\n"); problems = 1; } #ifdef HAVE_XSHM_EXTENSION useShm = get_boolean_resource ("useSHM", "Boolean"); #endif if (problems) { exit (1); } } /* main function */ void screenhack (Display *dpy, Window win) { display = dpy; window = win; initParams (); setup (); setupModel (); for (;;) { oneIteration (); XSync (dpy, False); screenhack_handle_events (dpy); usleep (delay); } }