A Small Perl Graphical Header

I wanted to make a basic header image for my website, normally I would just use python/PIL but I made the rash decision to jump out of my comfort zone and went for Perl/OpenGL. Very simple but I'm proud of it.

BEGIN{ unshift(@INC,"../blib"); }  # in case OpenGL is built but not i
+nstalled
BEGIN{ unshift(@INC,"../blib/arch"); } # 5.002 gamma needs this
BEGIN{ unshift(@INC,"../blib/lib"); } # 5.002 gamma needs this
use OpenGL;
use warnings;
glpOpenWindow;
glClearColor(0,0,0,1);
glClear(GL_COLOR_BUFFER_BIT);
glOrtho(-3,3,-3,3,-3,3);
glColor3f(1,0,0);
sub rect{
if(defined($_[5])){$green =$_[5]}else{$green =0;}
glColor3f(($i/(180*$loops)/2,$green,abs(100-($i/360))/2));
if(defined($_[4])){$rot =int($_[4]);$rot*= 0.017453;}else{$rot =0;}
my@topleft=($_[0],$_[1]);my@bottomright=($_[2],$_[3]);
glBegin(GL_POLYGON);
@offset=(cos($rot)/2.5,sin($rot)/2.5);
  glVertex2f($topleft[0]-$offset[0],$topleft[1]+$offset[1]);
  glVertex2f($topleft[0]-$offset[0],$bottomright[1]+$offset[1]);
  glVertex2f($bottomright[0]+$offset[0],$bottomright[1]-$offset[1]);
  glVertex2f($bottomright[0]+$offset[0],$topleft[1]-$offset[1]);
glEnd();
glpFlush();
}
$loops=6;$radius=2.5;
for ($i=0;$i<180*$loops;$i++){
$radius =$radius/1.00061;$yoff=cos($i/157);
rect(-1*$radius,-1*$yoff*1.5,1*$radius,1*$yoff*1.5,$i);}
rect(-2.5,-1,2.5,1,0,.2);
rect(-2.47,-.97,2.47,.97,0,0);
rect(-2.4,-.94,2.43,.943,0,.2);
glpMainLoop;
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if I 'use strict' it returns for every variable, global symbol $x requires an explicit package name. Am I doing something wrong?

Comment on A Small Perl Graphical Header
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Re: A Small Perl Graphical Header
by jdporter (Canon) on Mar 20, 2012 at 04:57 UTC

Obviously you need to declare your variables (using my).

I think you could stand to improve your code formatting. try this on:

use strict;
use warnings;


glpOpenWindow;
glClearColor(0,0,0,1);
glClear(GL_COLOR_BUFFER_BIT);
glOrtho(-3,3,-3,3,-3,3);
glColor3f(1,0,0);

my $loops = 6;
my $radius = 2.5;

sub rect($$$$$$)
{
    my( $ulx, $uly, $lrx, $lry, $rot, $green ) = @_;

    glColor3f( $rot/(180*$loops)/2, $green, abs(100-($rot/360))/2 );
    # the following must come after the preceding.
    $rot = defined($rot) ? int($rot) * 0.017453 : 0;

    my $ofsx = cos($rot)/2.5;
    my $ofsy = sin($rot)/2.5;
    glBegin(GL_POLYGON);
    glVertex2f( $ulx-$ofsx, $uly+$ofsy );
    glVertex2f( $ulx-$ofsx, $lry+$ofsy );
    glVertex2f( $lrx+$ofsx, $lry-$ofsy );
    glVertex2f( $lrx+$ofsx, $uly-$ofsy );
    glEnd();
    glpFlush();
}

for ( my $i = 0; $i<180*$loops; $i++ )
{
    $radius /= 1.00061;
    my $yoff = cos($i/157);
    rect( -1*$radius, -1*$yoff*1.5, 1*$radius, 1*$yoff*1.5, $i, 0 );
}
rect( -2.5 ,  -1  , 2.5 , 1    , 0, 0.2 );
rect( -2.47, -0.97, 2.47, 0.97 , 0, 0   );
rect( -2.4 , -0.94, 2.43, 0.943, 0, 0.2 );
glpMainLoop;

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I reckon we are the only monastery ever to have a dungeon stuffed with 16,000 zombies.

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A Small Perl Graphical Header

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