Raster bars
unit sub MAIN (
Int :b(:$bar-height) is copy = 60; #= Height of the individual "Raster bars", minimum 32 (pixels)
Int :d(:$dir) is copy = -1; #= Scroll direction: -1 is "up" 1 is "down"
Int :s(:$step) is copy = 4; #= Scroll speed (pixels per step
Int :g(:$gap) is copy = $bar-height + 50; #= Gap between bars (pixels)
Int :a(:$angle) is copy = 0; #= Angle to orient bars off horizontal (-60 to 60 degrees)
Int :sw(:$sway) is copy = 0; #= Swaying on / off
Real :r(:$rnd) is copy = 0; #= Delay between randomize events
);
say q:to/END/;
Use Up / Down arrows to change the scroll speed.
Use Left / Right arrows to adjust the gap between the raster bars.
Use Pg Up / Pg Dn to adjust raster bar height.
Use Z / X to change the angle of the raster bars.
Use Space bar to pause / resume scrolling.
Use Left Ctrl to toggle the scroll direction.
Press R to toggle Randomize on / off.
If Randomize is active, adjust the randomize delay with < / >
Press S to toggle Swaying on / off.
If Swaying is active, adjust the period with D / F
Press Q to exit.
END
use SDL2::Raw;
use Cairo;
my $width = 800;
my $height = 800;
SDL_Init(VIDEO);
my $window = SDL_CreateWindow(
'Raster Bars - Raku',
SDL_WINDOWPOS_CENTERED_MASK,
SDL_WINDOWPOS_CENTERED_MASK,
$width, $height, RESIZABLE
);
my $render = SDL_CreateRenderer($window, -1, ACCELERATED +| PRESENTVSYNC);
my @bars = (^128).map: { gen-bar( rand xx 3 ) };
my $event = SDL_Event.new;
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_LCTRL => 224,
K_Z => 29,
K_X => 27,
K_Q => 20,
K_R => 21,
K_S => 22,
K_D => 7,
K_F => 9,
K_LT => 54,
K_GT => 55,
);
my $port = +@bars * $gap;
my $y = $dir > 0 ?? $height - $port !! $height ;
my $now = now;
my $period = 2;
main: loop {
handle-event($event) while SDL_PollEvent($event);
randomize if $rnd and now - $now > $rnd;
if $dir > 0 {
$y = $height - $port if $y > 0 - ceiling $height / cos(π * $angle / 180).abs
} else {
$y = 0 - ceiling $height / cos(π * $angle / 180).abs if $y < $height - $port
}
$y = $step * $dir + $y;
$angle = (((now * $period) % τ).sin * 35).Int if $sway;
for ^@bars {
my $offset = $sway ?? $gap !! ceiling $gap / cos(π * $angle / 180).abs;
SDL_RenderCopyEx( $render, @bars[$_], Nil,
SDL_Rect.new( -($width*4), $y + $offset * $_, $width * 10, $bar-height),
$angle.Num, SDL_Point.new(:x((4.5*$width).Int),:y($y + $offset * $_)), 0
)
}
SDL_RenderPresent($render);
SDL_RenderClear($render);
print fps;
}
put '';
SDL_Quit();
sub gen-bar (@color) {
my $bar = Cairo::Image.create( Cairo::FORMAT_ARGB32, 1, 128 );
given Cairo::Context.new($bar) {
my Cairo::Pattern::Gradient::Linear $lpat .= create(0.0, 0.0, 0.0, 128.0);
$lpat.add_color_stop_rgba( 1, |(@color »*» .3), 1);
$lpat.add_color_stop_rgba( .2, |(@color), 1);
$lpat.add_color_stop_rgba(.75, |(@color), 1);
$lpat.add_color_stop_rgba( 0, |(@color »+» .5), 1);
.rectangle(0, 0, 1, 128);
.pattern($lpat);
.fill;
$lpat.destroy;
}
my $bar_texture = SDL_CreateTexture(
$render, %PIXELFORMAT<ARGB8888>,
STATIC, 1, 128
);
SDL_UpdateTexture(
$bar_texture,
SDL_Rect.new(:x(0), :y(0), :w(1), :h(128)),
$bar.data, $bar.stride // 1
);
$bar_texture
}
sub handle-event ($event) {
my $casted_event = SDL_CastEvent($event);
given $casted_event {
when *.type == QUIT { last main }
when *.type == KEYDOWN {
if KEY_CODES(.scancode) -> $comm {
given $comm {
when 'K_UP' { $step += 1 }
when 'K_DOWN' { $step -= 1 if $step > 1 }
when 'K_LEFT' { $gap = $gap < 32 ?? $gap !! $gap - 1; $port = +@bars * $gap; }
when 'K_RIGHT' { $gap++; $port += +@bars; }
when 'K_PGUP' { $bar-height += 2 }
when 'K_PGDN' { $bar-height = $bar-height >= 34 ?? $bar-height - 2 !! $bar-height }
when 'K_SPACE' { $step = $step ?? 0 !! 1 }
when 'K_LCTRL' { $dir *= -1 }
when 'K_Z' { $angle = $angle > -45 ?? $angle - 5 !! $angle }
when 'K_X' { $angle = $angle < 45 ?? $angle + 5 !! $angle }
when 'K_R' { $rnd = $rnd ?? 0 !! 1 }
when 'K_S' { $sway xor= 1 }
when 'K_F' { $period += .1 }
when 'K_D' { $period = $period - .1 max .1; }
when 'K_GT' { $rnd += .2 }
when 'K_LT' { $rnd = $rnd > .2 ?? $rnd -.2 !! .2 }
when 'K_Q' { last main }
}
} #else { say .scancode, "\n" }
}
when *.type == WINDOWEVENT {
if .event == RESIZED {
$width = .data1;
$height = .data2 + $bar-height;
}
}
}
}
sub randomize {
$dir = (-1,1).pick;
$step = (4..8).pick;
$bar-height = (32..200).pick;
$gap = $bar-height + (1..100).pick;
$angle = (-45, *+5 ... 45).pick;
$port = +@bars * $gap;
if $dir > 0 {
$y = $height - $port;
} else {
$y = 0 - ceiling ($height max $width) / cos(π * $angle / 180).abs;
}
$now = now;
}
sub fps {
state $fps-frames = 0;
state $fps-now = now;
state $fps = '';
$fps-frames++;
if now - $fps-now >= 1 {
$fps = [~] "\b" x 40, ' ' x 20, "\b" x 20 ,
sprintf "FPS: %5.2f ", ($fps-frames / (now - $fps-now)).round(.01);
$fps-frames = 0;
$fps-now = now;
}
$fps
}
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