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|
use strict;
use warnings;
# generates the blendfunc flags function in gl_rmain.c
my %blendfuncs =
(
GL_ONE => sub { (1, 1); },
GL_ZERO => sub { (0, 0); },
GL_SRC_COLOR => sub { ($_[0], $_[1]); },
GL_ONE_MINUS_SRC_COLOR => sub { (1-$_[0], 1-$_[1]); },
GL_SRC_ALPHA => sub { ($_[1], $_[1]); },
GL_ONE_MINUS_SRC_ALPHA => sub { (1-$_[1], 1-$_[1]); },
GL_DST_COLOR => sub { ($_[2], $_[3]); },
GL_ONE_MINUS_DST_COLOR => sub { (1-$_[2], 1-$_[3]); },
GL_DST_ALPHA => sub { ($_[3], $_[3]); },
GL_ONE_MINUS_DST_ALPHA => sub { (1-$_[3], 1-$_[3]); },
);
sub evalblend($$$$$$)
{
my ($fs, $fd, $s, $sa, $d, $da) = @_;
my @fs = $fs->($s, $sa, $d, $da);
my @fd = $fd->($s, $sa, $d, $da);
return (
$fs[0] * $s + $fd[0] * $d,
$fs[1] * $sa + $fd[1] * $da
);
}
sub isinvariant($$$$)
{
my ($fs, $fd, $s, $sa) = @_;
my ($d, $da) = (rand, rand);
my ($out, $outa) = evalblend $fs, $fd, $s, $sa, $d, $da;
return abs($out - $d) < 0.0001 && abs($outa - $da) < 0.0001;
}
sub isfogfriendly($$$$$)
{
my ($fs, $fd, $s, $sa, $foghack) = @_;
my ($d, $da) = (rand, rand);
my $fogamount = rand;
my $fogcolor = rand;
# compare:
# 1. blend(fog(s), sa, fog(d), da)
# 2. fog(blend(s, sa, d, da))
my ($out1, $out1a) = evalblend $fs, $fd, $s + ((defined $foghack ? $foghack eq 'ALPHA' ? $fogcolor*$sa : $foghack : $fogcolor) - $s) * $fogamount, $sa, $d + ($fogcolor - $d) * $fogamount, $da;
my ($out2, $out2a) = evalblend $fs, $fd, $s, $sa, $d, $da;
$out2 = $out2 + ($fogcolor - $out2) * $fogamount;
return abs($out1 - $out2) < 0.0001 && abs($out1a - $out2a) < 0.0001;
}
use Carp;
sub decide(&)
{
my ($sub) = @_;
my $good = 0;
my $bad = 0;
for(;;)
{
for(1..200)
{
my $r = $sub->();
++$good if $r;
++$bad if not $r;
}
#print STDERR "decide: $good vs $bad\n";
return 1 if $good > $bad + 150;
return 0 if $bad > $good + 150;
warn "No clear decision, continuing to test ($good : $bad)";
}
}
#die isfogfriendly $blendfuncs{GL_ONE}, $blendfuncs{GL_ONE}, 1, 0, 0;
# out1 = 0 + fog($d)
# out2 = fog(1 + $d)
sub willitblend($$)
{
my ($fs, $fd) = @_;
for my $s(0, 0.25, 0.5, 0.75, 1)
{
for my $sa(0, 0.25, 0.5, 0.75, 1)
{
if(decide { isinvariant($fs, $fd, $s, $sa); })
{
if(!decide { isinvariant($fs, $fd, 0, $sa); })
{
return 0; # no colormod possible
}
}
}
}
return 1;
}
sub willitfog($$)
{
my ($fs, $fd) = @_;
FOGHACK:
for my $foghack(undef, 0, 'ALPHA')
{
for my $s(0, 0.25, 0.5, 0.75, 1)
{
for my $sa(0, 0.25, 0.5, 0.75, 1)
{
if(!decide { isfogfriendly($fs, $fd, $s, $sa, $foghack); })
{
next FOGHACK;
}
}
}
return (1, $foghack);
}
return (0, undef);
}
print "\tr |= BLENDFUNC_ALLOWS_COLORMOD;\n";
for my $s(sort keys %blendfuncs)
{
for my $d(sort keys %blendfuncs)
{
#print STDERR "$s $d\n";
if(!willitblend $blendfuncs{$s}, $blendfuncs{$d})
{
print "\tif(src == $s && dst == $d) r &= ~BLENDFUNC_ALLOWS_COLORMOD;\n";
}
my ($result, $h) = willitfog $blendfuncs{$s}, $blendfuncs{$d};
if($result)
{
if(defined $h)
{
print "\tif(src == $s && dst == $d) r |= BLENDFUNC_ALLOWS_FOG_HACK$h;\n";
}
else
{
print "\tif(src == $s && dst == $d) r |= BLENDFUNC_ALLOWS_FOG;\n";
}
}
}
}
|
