X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=hacks%2Ffluidballs.c;h=0ce65db3f590bdfd0d44adebed3614ef435e6792;hb=96a411663168b0ba5432b407a83be55f3df0c802;hp=e6761dc72eac67e43ede292d3c546ecc33897dcb;hpb=3f9592851ce4ed76a9979bfdd6ec7dc5c457e183;p=xscreensaver diff --git a/hacks/fluidballs.c b/hacks/fluidballs.c index e6761dc7..0ce65db3 100644 --- a/hacks/fluidballs.c +++ b/hacks/fluidballs.c @@ -11,25 +11,37 @@ * Ported to X11 and xscreensaver by jwz, 27-Feb-2002. * * http://astronomy.swin.edu.au/~pbourke/modelling/fluid/ + * + * Some physics improvements by Steven Barker */ -/* cjb notes - * - * Future ideas: +/* Future ideas: * Specifying a distribution in the ball sizes (with a gamma curve, possibly). * Brownian motion, for that extra touch of realism. + * + * It would be nice to detect when there are more balls than fit in + * the window, and scale the number of balls back. Useful for the + * xscreensaver-demo preview, which is often too tight by default. */ #include #include "screenhack.h" #include +#ifdef HAVE_DOUBLE_BUFFER_EXTENSION +#include "xdbe.h" +#endif /* HAVE_DOUBLE_BUFFER_EXTENSION */ typedef struct { Display *dpy; Window window; XWindowAttributes xgwa; + Pixmap b, ba; /* double-buffer to reduce flicker */ +#ifdef HAVE_DOUBLE_BUFFER_EXTENSION + XdbeBackBuffer backb; +#endif /* HAVE_DOUBLE_BUFFER_EXTENSION */ + GC draw_gc; /* most of the balls */ GC draw_gc2; /* the ball being dragged with the mouse */ GC erase_gc; @@ -52,11 +64,13 @@ typedef struct { float *r; /* ball radiuses */ float *m; /* ball mass, precalculated */ - float e; /* coefficient of friction, I think? */ + float e; /* coeficient of elasticity */ float max_radius; /* largest radius of any ball */ Bool random_sizes_p; /* Whether balls should be various sizes up to max. */ Bool shake_p; /* Whether to mess with gravity when things settle. */ + Bool dbuf; /* Whether we're using double buffering. */ + Bool dbeclear_p; /* ? */ float shake_threshold; int time_since_shake; @@ -66,10 +80,22 @@ typedef struct { int font_baseline; int frame_count; int collision_count; - + char fps_str[1024]; + } b_state; +/* Draws the frames per second string */ +static void +draw_fps_string (b_state *state) +{ + XFillRectangle (state->dpy, state->b, state->erase_gc, + 0, state->xgwa.height - state->font_height, + state->xgwa.width, state->font_height); + XDrawImageString (state->dpy, state->b, state->font_gc, + 0, state->xgwa.height - state->font_baseline, + state->fps_str, strlen(state->fps_str)); +} /* Finds the origin of the window relative to the root window, by walking up the window tree until it reaches the top. @@ -117,6 +143,7 @@ static void check_window_moved (b_state *state) { float oxmin = state->xmin; + float oxmax = state->xmax; float oymin = state->ymin; float oymax = state->ymax; int wx, wy; @@ -127,14 +154,29 @@ check_window_moved (b_state *state) state->xmax = state->xmin + state->xgwa.width; state->ymax = state->ymin + state->xgwa.height - state->font_height; - /* Only need to erase the window if the origin moved */ - if (oxmin != state->xmin || oymin != state->ymin) - XClearWindow (state->dpy, state->window); - else if (state->fps_p && oymax != state->ymax) - XFillRectangle (state->dpy, state->window, state->erase_gc, - 0, state->xgwa.height - state->font_height, - state->xgwa.width, state->font_height); - + if (state->dbuf && (state->ba)) + { + if (oxmax != state->xmax || oymax != state->ymax) + { + XFreePixmap (state->dpy, state->ba); + state->ba = XCreatePixmap (state->dpy, state->window, + state->xgwa.width, state->xgwa.height, + state->xgwa.depth); + XFillRectangle (state->dpy, state->ba, state->erase_gc, 0, 0, + state->xgwa.width, state->xgwa.height); + state->b = state->ba; + } + } + else + { + /* Only need to erase the window if the origin moved */ + if (oxmin != state->xmin || oymin != state->ymin) + XClearWindow (state->dpy, state->window); + else if (state->fps_p && oymax != state->ymax) + XFillRectangle (state->dpy, state->b, state->erase_gc, + 0, state->xgwa.height - state->font_height, + state->xgwa.width, state->font_height); + } } @@ -186,7 +228,6 @@ recolor (b_state *state) XSetForeground (state->dpy, state->draw_gc2, state->fg2.pixel); } - /* Initialize the state structure and various X data. */ static b_state * @@ -198,10 +239,37 @@ init_balls (Display *dpy, Window window) XGCValues gcv; state->dpy = dpy; + state->window = window; check_window_moved (state); + state->dbuf = get_boolean_resource ("doubleBuffer", "Boolean"); + state->dbeclear_p = get_boolean_resource ("useDBEClear", "Boolean"); + + if (state->dbuf) + { +#ifdef HAVE_DOUBLE_BUFFER_EXTENSION + if (state->dbeclear_p) + state->b = xdbe_get_backbuffer (dpy, window, XdbeBackground); + else + state->b = xdbe_get_backbuffer (dpy, window, XdbeUndefined); + state->backb = state->b; +#endif /* HAVE_DOUBLE_BUFFER_EXTENSION */ + + if (!state->b) + { + state->ba = XCreatePixmap (state->dpy, state->window, + state->xgwa.width, state->xgwa.height, + state->xgwa.depth); + state->b = state->ba; + } + } + else + { + state->b = state->window; + } + /* Select ButtonRelease events on the external window, if no other app has already selected it (only one app can select it at a time: BadAccess. */ if (! (state->xgwa.all_event_masks & ButtonReleaseMask)) @@ -212,18 +280,23 @@ init_balls (Display *dpy, Window window) state->dpy, state->xgwa.colormap); gcv.background = get_pixel_resource("background", "Background", state->dpy, state->xgwa.colormap); - state->draw_gc = XCreateGC (state->dpy, state->window, + state->draw_gc = XCreateGC (state->dpy, state->b, GCForeground|GCBackground, &gcv); gcv.foreground = get_pixel_resource("mouseForeground", "MouseForeground", state->dpy, state->xgwa.colormap); - state->draw_gc2 = XCreateGC (state->dpy, state->window, + state->draw_gc2 = XCreateGC (state->dpy, state->b, GCForeground|GCBackground, &gcv); gcv.foreground = gcv.background; - state->erase_gc = XCreateGC (state->dpy, state->window, + state->erase_gc = XCreateGC (state->dpy, state->b, GCForeground|GCBackground, &gcv); + + if (state->ba) + XFillRectangle (state->dpy, state->ba, state->erase_gc, 0, 0, + state->xgwa.width, state->xgwa.height); + recolor (state); extx = state->xmax - state->xmin; @@ -243,7 +316,7 @@ init_balls (Display *dpy, Window window) state->accy = get_float_resource ("gravity", "Gravity"); if (state->accy < -1.0 || state->accy > 1.0) state->accy = 0.01; - state->e = get_float_resource ("friction", "Friction"); + state->e = get_float_resource ("elasticity", "Elacitcity"); if (state->e < 0.2 || state->e > 1.0) state->e = 0.97; state->tc = get_float_resource ("timeScale", "TimeScale"); @@ -266,7 +339,7 @@ init_balls (Display *dpy, Window window) gcv.font = font->fid; gcv.foreground = get_pixel_resource("textColor", "Foreground", state->dpy, state->xgwa.colormap); - state->font_gc = XCreateGC(dpy, window, + state->font_gc = XCreateGC(dpy, state->b, GCFont|GCForeground|GCBackground, &gcv); state->font_height = font->ascent + font->descent; state->font_baseline = font->descent; @@ -297,6 +370,9 @@ init_balls (Display *dpy, Window window) state->m[i] = pow(state->r[i],3) * M_PI * 1.3333; } + memcpy (state->opx, state->px, sizeof (*state->opx) * (state->count + 1)); + memcpy (state->opy, state->py, sizeof (*state->opx) * (state->count + 1)); + return state; } @@ -346,11 +422,11 @@ check_wall_clock (b_state *state, float max_d) { static int tick = 0; state->frame_count++; - + if (tick++ > 20) /* don't call gettimeofday() too often -- it's slow. */ { - static struct timeval last = { 0, }; struct timeval now; + static struct timeval last = { 0, 0 }; # ifdef GETTIMEOFDAY_TWO_ARGS struct timezone tzp; gettimeofday(&now, &tzp); @@ -367,24 +443,19 @@ check_wall_clock (b_state *state, float max_d) state->time_since_shake += (now.tv_sec - last.tv_sec); - if (state->fps_p) - { - static char buf[1024]; - float elapsed = ((now.tv_sec + (now.tv_usec / 1000000.0)) - - (last.tv_sec + (last.tv_usec / 1000000.0))); - float fps = state->frame_count / elapsed; - float cps = state->collision_count / elapsed; - - sprintf (buf, " FPS: %.2f Collisions: %.f/frame Max motion: %.3f", - fps, cps/fps, max_d); - - XFillRectangle (state->dpy, state->window, state->erase_gc, - 0, state->xgwa.height - state->font_height, - state->xgwa.width, state->font_height); - XDrawImageString (state->dpy, state->window, state->font_gc, - 0, state->xgwa.height - state->font_baseline, - buf, strlen(buf)); - } + if (state->fps_p) + { + float elapsed = ((now.tv_sec + (now.tv_usec / 1000000.0)) - + (last.tv_sec + (last.tv_usec / 1000000.0))); + float fps = state->frame_count / elapsed; + float cps = state->collision_count / elapsed; + + sprintf (state->fps_str, + " FPS: %.2f Collisions: %.3f/frame Max motion: %.3f", + fps, cps/fps, max_d); + + draw_fps_string(state); + } state->frame_count = 0; state->collision_count = 0; @@ -392,7 +463,6 @@ check_wall_clock (b_state *state, float max_d) } } - /* Erases the balls at their previous positions, and draws the new ones. */ static void @@ -416,20 +486,26 @@ repaint_balls (b_state *state) x2b = (state->px[a] + state->r[a] - state->xmin); y2b = (state->py[a] + state->r[a] - state->ymin); -/* if (x1a != x1b || y1a != y1b) -- leaves turds if we optimize this */ - { - gc = state->erase_gc; - XFillArc (state->dpy, state->window, gc, - x1a, y1a, x2a-x1a, y2a-y1a, - 0, 360*64); - } - + if (!state->dbeclear_p +#ifdef HAVE_DOUBLE_BUFFER_EXTENSION + || !state->backb +#endif /* HAVE_DOUBLE_BUFFER_EXTENSION */ + ) + { +/* if (x1a != x1b || y1a != y1b) -- leaves turds if we optimize this */ + { + gc = state->erase_gc; + XFillArc (state->dpy, state->b, gc, + x1a, y1a, x2a-x1a, y2a-y1a, + 0, 360*64); + } + } if (state->mouse_ball == a) gc = state->draw_gc2; else gc = state->draw_gc; - XFillArc (state->dpy, state->window, gc, + XFillArc (state->dpy, state->b, gc, x1b, y1b, x2b-x1b, y2b-y1b, 0, 360*64); @@ -447,6 +523,25 @@ repaint_balls (b_state *state) state->opy[a] = state->py[a]; } + if (state->fps_p && state->dbeclear_p) + draw_fps_string(state); + +#ifdef HAVE_DOUBLE_BUFFER_EXTENSION + if (state->backb) + { + XdbeSwapInfo info[1]; + info[0].swap_window = state->window; + info[0].swap_action = (state->dbeclear_p ? XdbeBackground : XdbeUndefined); + XdbeSwapBuffers (state->dpy, info, 1); + } + else +#endif /* HAVE_DOUBLE_BUFFER_EXTENSION */ + if (state->dbuf) + { + XCopyArea (state->dpy, state->b, state->window, state->erase_gc, + 0, 0, state->xgwa.width, state->xgwa.height, 0, 0); + } + if (state->shake_p && state->time_since_shake > 5) { max_d /= state->max_radius; @@ -468,7 +563,7 @@ update_balls (b_state *state) { int a, b; float d, vxa, vya, vxb, vyb, dd, cdx, cdy; - float ma, mb, vela, velb, vela1, velb1; + float ma, mb, vca, vcb, dva, dvb; float dee2; check_window_moved (state); @@ -492,71 +587,69 @@ update_balls (b_state *state) } /* For each ball, compute the influence of every other ball. */ - for (a=1; a <= state->count; a++) - if (a != state->mouse_ball) - for (b=1; b <= state->count; b++) - if (a != b) - { - d = ((state->px[a] - state->px[b]) * - (state->px[a] - state->px[b]) + - (state->py[a] - state->py[b]) * - (state->py[a] - state->py[b])); - dee2 = (state->r[a] + state->r[b]) * - (state->r[a] + state->r[b]); - if (d < dee2) - { - state->collision_count++; - d = sqrt(d); - dd = state->r[a] + state->r[b] - d; - /* A pair of balls that have already collided in this - * current frame (and therefore touching each other) - * should not have another collision calculated, hence - * the fallthru if "dd ~= 0.0". - */ - if ((dd < -0.01) || (dd > 0.01)) - { - cdx = (state->px[b] - state->px[a]) / d; - cdy = (state->py[b] - state->py[a]) / d; - - /* Move each ball apart from the other by half the - * 'collision' distance. - */ - state->px[a] -= 0.5 * dd * cdx; - state->py[a] -= 0.5 * dd * cdy; - state->px[b] += 0.5 * dd * cdx; - state->py[b] += 0.5 * dd * cdy; - - ma = state->m[a]; - mb = state->m[b]; - vxa = state->vx[a]; - vya = state->vy[a]; - vxb = state->vx[b]; - vyb = state->vy[b]; - - vela = sqrt((vxa * vxa) + (vya * vya)); - velb = sqrt((vxb * vxb) + (vyb * vyb)); - - vela1 = vela * ((ma - mb) / (ma + mb)) + - velb * ((2 * mb) / (ma + mb)); - velb1 = vela * ((2 * ma) / (ma + mb)) + - velb * ((mb - ma) / (ma + mb)); - - vela1 *= state->e; /* "air resistance" */ - velb1 *= state->e; + for (a=1; a <= state->count - 1; a++) + for (b=a + 1; b <= state->count; b++) + { + d = ((state->px[a] - state->px[b]) * + (state->px[a] - state->px[b]) + + (state->py[a] - state->py[b]) * + (state->py[a] - state->py[b])); + dee2 = (state->r[a] + state->r[b]) * + (state->r[a] + state->r[b]); + if (d < dee2) + { + state->collision_count++; + d = sqrt(d); + dd = state->r[a] + state->r[b] - d; + + cdx = (state->px[b] - state->px[a]) / d; + cdy = (state->py[b] - state->py[a]) / d; + + /* Move each ball apart from the other by half the + * 'collision' distance. + */ + state->px[a] -= 0.5 * dd * cdx; + state->py[a] -= 0.5 * dd * cdy; + state->px[b] += 0.5 * dd * cdx; + state->py[b] += 0.5 * dd * cdy; + + ma = state->m[a]; + mb = state->m[b]; + + vxa = state->vx[a]; + vya = state->vy[a]; + vxb = state->vx[b]; + vyb = state->vy[b]; + + vca = vxa * cdx + vya * cdy; /* the component of each velocity */ + vcb = vxb * cdx + vyb * cdy; /* along the axis of the collision */ + + /* elastic collison */ + dva = (vca * (ma - mb) + vcb * 2 * mb) / (ma + mb) - vca; + dvb = (vcb * (mb - ma) + vca * 2 * ma) / (ma + mb) - vcb; + + dva *= state->e; /* some energy lost to inelasticity */ + dvb *= state->e; + #if 0 - vela1 += (frand (50) - 25) / ma; /* brownian motion */ - velb1 += (frand (50) - 25) / mb; + dva += (frand (50) - 25) / ma; /* q: why are elves so chaotic? */ + dvb += (frand (50) - 25) / mb; /* a: brownian motion. */ #endif - state->vx[a] = -cdx * vela1; - state->vy[a] = -cdy * vela1; - state->vx[b] = cdx * velb1; - state->vy[b] = cdy * velb1; - } - } - } - /* Force all balls to be on screen. - */ + vxa += dva * cdx; + vya += dva * cdy; + vxb += dvb * cdx; + vyb += dvb * cdy; + + state->vx[a] = vxa; + state->vy[a] = vya; + state->vx[b] = vxb; + state->vy[b] = vyb; + } + } + + /* Force all balls to be on screen. + */ for (a=1; a <= state->count; a++) { if (state->px[a] <= (state->xmin + state->r[a])) @@ -655,11 +748,16 @@ char *defaults [] = { "*random: True", "*gravity: 0.01", "*wind: 0.00", - "*friction: 0.8", + "*elasticity: 0.97", "*timeScale: 1.0", "*doFPS: False", "*shake: True", "*shakeThreshold: 0.015", + "*doubleBuffer: True", +#ifdef HAVE_DOUBLE_BUFFER_EXTENSION + "*useDBE: True", + "*useDBEClear: True", +#endif /* HAVE_DOUBLE_BUFFER_EXTENSION */ 0 }; @@ -670,13 +768,15 @@ XrmOptionDescRec options [] = { { "-count", ".count", XrmoptionSepArg, 0 }, { "-gravity", ".gravity", XrmoptionSepArg, 0 }, { "-wind", ".wind", XrmoptionSepArg, 0 }, - { "-friction", ".friction", XrmoptionSepArg, 0 }, + { "-elasticity", ".elasticity", XrmoptionSepArg, 0 }, { "-fps", ".doFPS", XrmoptionNoArg, "True" }, { "-no-fps", ".doFPS", XrmoptionNoArg, "False" }, { "-shake", ".shake", XrmoptionNoArg, "True" }, { "-no-shake", ".shake", XrmoptionNoArg, "False" }, { "-random", ".random", XrmoptionNoArg, "True" }, { "-nonrandom", ".random", XrmoptionNoArg, "False" }, + { "-db", ".doubleBuffer", XrmoptionNoArg, "True" }, + { "-no-db", ".doubleBuffer", XrmoptionNoArg, "False" }, { 0, 0, 0, 0 } };