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#!/usr/bin/perl -w
# This code was created by Jeff Molofee '99
# (ported to SDL by Sam Lantinga '2000)
# (ported to Perl/SDL by Wayne Keenan '2000)
#
# If you've found this code useful, please let me know.
#
# Visit me at www.demonews.com/hosted/nehe
use strict;
use Getopt::Long;
use SDL::App;
use SDL::OpenGL;
use SDL::Event;
my $arg_screen_width =640;
my $arg_screen_height=512;
my $arg_fullscreen=0;
GetOptions(
"width:i" => \$arg_screen_width,
"height:i" => \$arg_screen_height,
"fullscreen!" => \$arg_fullscreen,
) or die $!;
main();
exit;
sub main
{
my $done=0;
my $app = new SDL::App ( -title => "Jeff Molofee's GL Code Tutorial ... NeHe '99",
-icon => "icon.png",
-width => $arg_screen_width,
-height =>$arg_screen_height,
-d => 16,
-opengl => 1,
);
$app->fullscreen() if $arg_fullscreen;
SDL::ShowCursor(0);
my $event = new SDL::Event;
$event->set(SDL_SYSWMEVENT,SDL_IGNORE);#
InitGL($arg_screen_width, $arg_screen_height);
while ( ! $done ) {
DrawGLScene();
$app->sync();
$event->pump;
$event->poll;
if ( $event->type == SDL_QUIT ) {
$done = 1;
}
if ( $event->type == SDL_KEYDOWN ) {
if ( $event->key_sym == SDLK_ESCAPE ) {
$done = 1;
}
}
}
}
#########################################################################
#Pretty much in original form, but 'Perlised'
sub InitGL
{
my ($Width, $Height)=@_;
glViewport(0, 0, $Width, $Height);
glClearColor(0.0, 0.0, 0.0, 0.0); # This Will Clear The Background Color To Black
glClearDepth(1.0); # Enables Clearing Of The Depth Buffer
glDepthFunc(GL_LESS); # The Type Of Depth Test To Do
glEnable(GL_DEPTH_TEST); # Enables Depth Testing
glShadeModel(GL_SMOOTH); # Enables Smooth Color Shading
glMatrixMode(GL_PROJECTION);
glLoadIdentity(); # Reset The Projection Matrix
gluPerspective(45.0, $Width/$Height, 0.1, 100.0); # Calculate The Aspect Ratio Of The Window
glMatrixMode(GL_MODELVIEW);
}
# The main drawing function.
sub DrawGLScene
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); # Clear The Screen And The Depth Buffer
glLoadIdentity(); # Reset The View
glTranslate(-1.5,0.0,-6.0); # Move Left 1.5 Units And Into The Screen 6.0
# draw a triangle (in smooth coloring mode)
glBegin(GL_POLYGON); # start drawing a polygon
glColor(1.0,0.0,0.0); # Set The Color To Red
glVertex( 0.0, 1.0, 0.0); # Top
glColor(0.0,1.0,0.0); # Set The Color To Green
glVertex( 1.0,-1.0, 0.0); # Bottom Right
glColor(0.0,0.0,1.0); # Set The Color To Blue
glVertex(-1.0,-1.0, 0.0); # Bottom Left
glEnd(); # we're done with the polygon (smooth color interpolation)
glTranslate(3.0,0.0,0.0); # Move Right 3 Units
# draw a square (quadrilateral)
glColor(0.5,0.5,1.0); # set color to a blue shade.
glBegin(GL_QUADS); # start drawing a polygon (4 sided)
glVertex(-1.0, 1.0, 0.0); # Top Left
glVertex( 1.0, 1.0, 0.0); # Top Right
glVertex( 1.0,-1.0, 0.0); # Bottom Right
glVertex(-1.0,-1.0, 0.0); # Bottom Left
glEnd(); # done with the polygon
}
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