Draw a sphere
Pure Raku
The C code is modified to output a .pgm file.
my $width = my $height = 255; # must be odd
my @light = normalize([ 3, 2, -5 ]);
my $depth = 255;
sub MAIN ($outfile = 'sphere-perl6.pgm') {
spurt $outfile, "P5\n$width $height\n$depth\n"; # .pgm header
my $out = open( $outfile, :a, :bin ) orelse .die;
$out.write( Blob.new(draw_sphere( ($width-1)/2, .9, .2) ) );
$out.close;
}
sub normalize (@vec) { @vec »/» ([+] @vec »*« @vec).sqrt }
sub dot (@x, @y) { -([+] @x »*« @y) max 0 }
sub draw_sphere ( $rad, $k, $ambient ) {
my @pixels[$height];
my $r2 = $rad * $rad;
my @range = -$rad .. $rad;
@range.hyper.map: -> $x {
my @row[$width];
@range.map: -> $y {
if (my $x2 = $x * $x) + (my $y2 = $y * $y) < $r2 {
my @vector = normalize([$x, $y, ($r2 - $x2 - $y2).sqrt]);
my $intensity = dot(@light, @vector) ** $k + $ambient;
my $pixel = (0 max ($intensity * $depth).Int) min $depth;
@row[$y+$rad] = $pixel;
}
else {
@row[$y+$rad] = 0;
}
}
@pixels[$x+$rad] = @row;
}
flat |@pixels.map: *.list;
}
Cairo graphics library
use Cairo;
given Cairo::Image.create(Cairo::FORMAT_ARGB32, 256, 256) {
given Cairo::Context.new($_) {
my Cairo::Pattern::Solid $bg .= create(.5,.5,.5);
.rectangle(0, 0, 256, 256);
.pattern($bg);
.fill;
$bg.destroy;
my Cairo::Pattern::Gradient::Radial $shadow .=
create(105.2, 102.4, 15.6, 102.4, 102.4, 128.0);
$shadow.add_color_stop_rgba(0, .3, .3, .3, .3);
$shadow.add_color_stop_rgba(1, .1, .1, .1, .02);
.pattern($shadow);
.arc(136.0, 134.0, 110, 0, 2 * pi);
.fill;
$shadow.destroy;
my Cairo::Pattern::Gradient::Radial $sphere .=
create(115.2, 102.4, 25.6, 102.4, 102.4, 128.0);
$sphere.add_color_stop_rgba(0, 1, 1, .698, 1);
$sphere.add_color_stop_rgba(1, .923, .669, .144, 1);
.pattern($sphere);
.arc(128.0, 128.0, 110, 0, 2 * pi);
.fill;
$sphere.destroy;
};
.write_png('sphere2-perl6.png');
}
See sphere2-perl6.png (offsite .png image)
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