Particle fountain
Implement a particle fountain.
Emulate a fountain of water droplets in a gravitational field bring sprayed up and then falling back down.
The particle fountain should be generally ordered but individually chaotic; the particles should being going mostly in the same direction, but should have slightly different vectors.
Your fountain should have at least several hundred particles in motion at any one time, and ideally several thousand.
It is optional to have the individual particle interact with each other.
If at all possible, link to a short video clip of your fountain in action.
Phix
You can run my first stab at this online here, though I get a perfectly formed but tiny version and I doubt any of the key handling works. I have asked for ideas elsewhere and will acccept any here.
-- -- demo\rosetta\Particle_fountain.exw -- ================================== -- with javascript_semantics include pGUI.e Ihandle dlg, canvas cdCanvas cddbuffer, cdcanvas constant title = "Particle fountain" constant help_text = """ Use UP and DOWN arrow keys to modify the saturation of the particle colors. Use PAGE UP and PAGE DOWN keys to modify the "spread" of the particles. Toggle reciprocation off / on with the SPACE bar. Use LEFT and RIGHT arrow keys to modify angle range for reciprocation. Press the "q" key to quit. """ constant particlenum = 3000 -- each particle is {x,y,color,life,dx,dy} sequence particles = repeat({0,0,0,0,0,0},particlenum) atom t1 = time()+1 integer fps = 0 bool reciprocate = true atom range = 1.5, spread = 1.5, saturation = 0.4, start = time(), df = 0.0001 function redraw_cb(Ihandle /*ih*/, integer /*posx*/, /*posy*/) integer {w, h} = IupGetIntInt(canvas, "DRAWSIZE") cdCanvasActivate(cddbuffer) cdCanvasClear(cddbuffer) for i=1 to length(particles) do atom {x,y,color,life} = particles[i] if life>0 then cdCanvasPixel(cddbuffer, x, h-y, color) end if end for cdCanvasFlush(cddbuffer) return IUP_DEFAULT end function function map_cb(Ihandle ih) cdcanvas = cdCreateCanvas(CD_IUP, ih) cddbuffer = cdCreateCanvas(CD_DBUFFER, cdcanvas) cdCanvasSetBackground(cddbuffer, CD_BLACK) return IUP_DEFAULT end function function hsv_to_rgb(atom h, s, v) atom r,g,b if s=0 then {r,g,b} = {v,v,v} else integer i = floor(h*6) atom f = h*6-i, p = v*(1-s), q = v*(1-s*f), t = v*(1-s*(1-f)) switch i do case 0, 6: {r,g,b} = {v, t, p} case 1: {r,g,b} = {q, v, p} case 2: {r,g,b} = {p, v, t} case 3: {r,g,b} = {p, q, v} case 4: {r,g,b} = {t, p, v} case 5: {r,g,b} = {v, p, q} end switch end if return cdEncodeColor(r*255, g*255, b*255) end function function timer_cb(Ihandle /*ih*/) integer {w, h} = IupGetIntInt(canvas, "DRAWSIZE") fps += 1 df = time()-start start = time() for i=1 to particlenum do atom {x,y,color,life,dx,dy} = particles[i] if life<=0 then if rnd()<df then life = 2.5 -- time to live x = w/2 -- starting position x y = h/10 -- and y -- randomize velocity so points reach different heights: atom r = iff(reciprocate?range*sin(time()):0) dx = (spread*rnd()-spread/2+r)*10 -- starting velocity x dy = (rnd()-2.9) * h/20.5 -- and y color = hsv_to_rgb(round(remainder(time(),5)/5,100), saturation, 1) end if else if y>h/10 and dy>0 then dy *= -0.3 -- "bounce" end if dy += (h/10)*df -- adjust velocity x += dx*df -- adjust position x y += dy*df -- and y life -= df end if particles[i] = {x,y,color,life,dx,dy} end for IupRedraw(canvas) if time()>t1 then IupSetStrAttribute(dlg,"TITLE","%s (%d, %d fps/s)",{title,particlenum,fps}) t1 = time()+1 fps = 0 end if return IUP_DEFAULT end function function key_cb(Ihandle /*dlg*/, atom c) if c=K_ESC or lower(c)='q' then return IUP_CLOSE elsif c=K_F1 then IupMessage(title,help_text) elsif c=K_UP then saturation = min(saturation+0.1,1) elsif c=K_DOWN then saturation = max(saturation-0.1,0) elsif c=K_PGUP then spread = min(spread+0.1,5) elsif c=K_PGDN then spread = max(spread-0.1,0.2) elsif c=K_RIGHT then range = min(range+0.1,2) elsif c=K_LEFT then range = max(range-0.1,0.1) elsif c=K_SP then reciprocate = not reciprocate end if return IUP_CONTINUE end function procedure main() IupOpen() canvas = IupGLCanvas("RASTERSIZE=800x800") IupSetCallbacks({canvas}, {"ACTION", Icallback("redraw_cb"), "MAP_CB", Icallback("map_cb")}) dlg = IupDialog(canvas,`TITLE="%s"`,{title}) IupSetCallback(dlg, "KEY_CB", Icallback("key_cb")) Ihandle timer = IupTimer(Icallback("timer_cb"), 1000/25) IupShowXY(dlg,IUP_CENTER,IUP_CENTER) IupSetAttribute(canvas, "RASTERSIZE", NULL) if platform()!=JS then IupMainLoop() IupClose() end if end procedure main()
Perl
<lang perl>#!/usr/bin/perl
use strict; # https://rosettacode.org/wiki/Particle_fountain use warnings; use Tk;
my $size = 900; my @particles; my $maxparticles = 500; my @colors = qw( red green blue yellow cyan magenta orange white );
my $mw = MainWindow->new; my $c = $mw->Canvas( -width => $size, -height => $size, -bg => 'black',
)->pack;
$mw->Button(-text => 'Exit', -command => sub {$mw->destroy},
)->pack(-fill => 'x');
step(); MainLoop; -M $0 < 0 and exec $0;
sub step
{
$c->delete('all');
$c->createLine($size / 2 - 10, $size, $size / 2, $size - 10,
$size / 2 + 10, $size, -fill => 'white' );
for ( @particles )
{
my ($ox, $oy, $vx, $vy, $color) = @$_;
my $x = $ox + $vx;
my $y = $oy + $vy;
$c->createRectangle($ox, $oy, $x, $y, -fill => $color, -outline => $color);
if( $y < $size )
{
$_->[0] = $x;
$_->[1] = $y;
$_->[3] += 0.006; # gravity :)
}
else { $_ = undef }
}
@particles = grep defined, @particles;
if( @particles < $maxparticles and --$| )
{
push @particles, [ $size >> 1, $size - 10,
(1 - rand 2) / 2.5 , -3 - rand 0.05, $colors[rand @colors] ];
}
$mw->after(1 => \&step);
}</lang>
Raku
Has options to vary the direction at which the fountain sprays, the "spread" angle and the color of the emitted particles. <lang perl6>use NativeCall; use SDL2::Raw;
my int ($w, $h) = 800, 800; my SDL_Window $window; my SDL_Renderer $renderer;
my int $particlenum = 3000;
SDL_Init(VIDEO);
$window = SDL_CreateWindow(
"Raku Particle System!", SDL_WINDOWPOS_CENTERED_MASK, SDL_WINDOWPOS_CENTERED_MASK, $w, $h, RESIZABLE
); $renderer = SDL_CreateRenderer( $window, -1, ACCELERATED );
SDL_ClearError();
my num @positions = 0e0 xx ($particlenum * 2); my num @velocities = 0e0 xx ($particlenum * 2); my num @lifetimes = 0e0 xx $particlenum;
my CArray[int32] $points .= new; my int $numpoints; my Num $saturation = 4e-1; my Num $spread = 15e-1; my &reciprocate = sub { 0 } my $range = 1.5;
sub update (num \df) {
my int $xidx = 0;
my int $yidx = 1;
my int $pointidx = 0;
loop (my int $idx = 0; $idx < $particlenum; $idx = $idx + 1) {
my int $willdraw = 0;
if (@lifetimes[$idx] <= 0e0) {
if (rand < df) {
@lifetimes[$idx] = 25e-1; # time to live
@positions[$xidx] = ($w / 20e0).Num; # starting position x
@positions[$yidx] = ($h / 10).Num; # and y
@velocities[$xidx] = ($spread * rand - $spread/2 + reciprocate()) * 10; # starting velocity x
@velocities[$yidx] = (rand - 2.9e0) * $h / 20.5; # and y (randomized slightly so points reach different heights)
$willdraw = 1;
}
} else {
if @positions[$yidx] > $h / 10 && @velocities[$yidx] > 0 {
@velocities[$yidx] = @velocities[$yidx] * -0.3e0; # "bounce"
}
@velocities[$yidx] = @velocities[$yidx] + $h/10.Num * df; # adjust velocity
@positions[$xidx] = @positions[$xidx] + @velocities[$xidx] * df; # adjust position x
@positions[$yidx] = @positions[$yidx] + @velocities[$yidx] * df; # and y
@lifetimes[$idx] = @lifetimes[$idx] - df;
$willdraw = 1;
}
if ($willdraw) {
$points[$pointidx++] = (@positions[$xidx] * 10).floor; # gather all of the points that
$points[$pointidx++] = (@positions[$yidx] * 10).floor; # are still going to be rendered
}
$xidx = $xidx + 2;
$yidx = $xidx + 1;
}
$numpoints = ($pointidx - 1) div 2;
}
sub render {
SDL_SetRenderDrawColor($renderer, 0x0, 0x0, 0x0, 0xff); SDL_RenderClear($renderer);
SDL_SetRenderDrawColor($renderer, |hsv2rgb(((now % 5) / 5).round(.01), $saturation, 1), 0x7f); SDL_RenderDrawPoints($renderer, $points, $numpoints);
SDL_RenderPresent($renderer);
}
enum KEY_CODES (
K_UP => 82, K_DOWN => 81, K_LEFT => 80, K_RIGHT => 79, K_SPACE => 44, K_PGUP => 75, K_PGDN => 78, K_Q => 20,
);
say q:to/DOCS/; Use UP and DOWN arrow keys to modify the saturation of the particle colors. Use PAGE UP and PAGE DOWN keys to modify the "spread" of the particles. Toggle reciprocation off / on with the SPACE bar. Use LEFT and RIGHT arrow keys to modify angle range for reciprocation. Press the "q" key to quit. DOCS
my $event = SDL_Event.new;
my num $df = 0.0001e0;
main: loop {
my $start = now;
while SDL_PollEvent($event) {
my $casted_event = SDL_CastEvent($event);
given $casted_event {
when *.type == QUIT {
last main;
}
when *.type == WINDOWEVENT {
if .event == RESIZED {
$w = .data1;
$h = .data2;
}
}
when *.type == KEYDOWN {
if KEY_CODES(.scancode) -> $comm {
given $comm {
when 'K_UP' { $saturation = (($saturation + .1) min 1e0) }
when 'K_DOWN' { $saturation = (($saturation - .1) max 0e0) }
when 'K_PGUP' { $spread = (($spread + .1) min 5e0) }
when 'K_PGDN' { $spread = (($spread - .1) max 2e-1) }
when 'K_RIGHT' { $range = (($range + .1) min 2e0) }
when 'K_LEFT' { $range = (($range - .1) max 1e-1) }
when 'K_SPACE' { &reciprocate = reciprocate() == 0 ?? sub { $range * sin(now) } !! sub { 0 } }
when 'K_Q' { last main }
}
}
}
}
}
update($df);
render();
$df = (now - $start).Num;
print fps();
}
say ;
sub fps {
state $fps-frames = 0;
state $fps-now = now;
state $fps = ;
$fps-frames++;
if now - $fps-now >= 1 {
$fps = [~] "\r", ' ' x 20, "\r",
sprintf "FPS: %5.1f ", ($fps-frames / (now - $fps-now));
$fps-frames = 0;
$fps-now = now;
}
$fps
}
sub hsv2rgb ( $h, $s, $v ){
state %cache;
%cache{"$h|$s|$v"} //= do {
my $c = $v * $s;
my $x = $c * (1 - abs( (($h*6) % 2) - 1 ) );
my $m = $v - $c;
[(do given $h {
when 0..^1/6 { $c, $x, 0 }
when 1/6..^1/3 { $x, $c, 0 }
when 1/3..^1/2 { 0, $c, $x }
when 1/2..^2/3 { 0, $x, $c }
when 2/3..^5/6 { $x, 0, $c }
when 5/6..1 { $c, 0, $x }
} ).map: ((*+$m) * 255).Int]
}
}</lang>