#!/usr/bin/env perl
#
# Bezier Surface example
#

use SDL;
use SDLx::App;
use SDL::Event;
use SDL::OpenGL;

my $app = SDLx::App->new( -w => 800, -h => 600, -d => 16, -gl => 1 );

my @points = (
	[ -1.5, -1.5, 4.0 ],
	[ -0.5, -1.5, 2.0 ],
	[ -0.5, -1.5, -1.0 ],
	[ 1.5,  -1.5, 2.0 ],
	[ -1.5, -0.5, 1.0 ],
	[ -0.5, -0.5, 3.0 ],
	[ 0.5,  -0.5, 0.0 ],
	[ 1.5,  -0.5, -1.0 ],
	[ -1.5, 0.5,  4.0 ],
	[ -0.5, 0.5,  0.0 ],
	[ 0.5,  0.5,  3.0 ],
	[ 1.5,  0.5,  4.0 ],
	[ -1.5, 1.5,  -2.0 ],
	[ -0.5, 1.5,  -2.0 ],
	[ 0.5,  1.5,  0.0 ],
	[ 1.5,  1.5,  -1.0 ],
);

my $ctrlpoints = pack "d48", map {@$_} @points;

sub init {

	glViewport( 0, 0, 800, 600 );
	glMatrixMode( GL_PROJECTION() );
	glLoadIdentity();

	glFrustum( -0.1, 0.1, -0.075, 0.075, 0.3, 100.0 );

	glMatrixMode( GL_MODELVIEW() );
	glLoadIdentity();

	glTranslate( 0, 0, -15 );

	glClearColor( 0.0, 0.0, 0.0, 0.0 );
	glMap2( GL_MAP2_VERTEX_3(), 0, 1, 3, 4, 0, 1, 12, 4, $ctrlpoints );
	glEnable( GL_MAP2_VERTEX_3() );
	glMapGrid2( 20, 0, 1, 20, 0, 1 );
	glEnable(GL_DEPTH_TEST);
	glShadeModel( GL_SMOOTH() );
}

sub initlight {

	glEnable( GL_LIGHTING() );
	glEnable( GL_LIGHT0() );

	glLight( GL_LIGHT0(), GL_AMBIENT(),  0.2, 0.2, 0.2, 1.0 );
	glLight( GL_LIGHT0(), GL_POSITION(), 0.0, 0.0, 2.0, 1.0 );

	glMaterial( GL_FRONT(), GL_DIFFUSE(),  0.6, 0.6, 0.6, 1.0 );
	glMaterial( GL_FRONT(), GL_SPECULAR(), 1.0, 1.0, 1.0, 1.0 );
	glMaterial( GL_FRONT(), GL_SHININESS(), 50.0 );

}

my ( $a1, $a2 ) = ( 89, 305 );

sub display {
	glClear( GL_COLOR_BUFFER_BIT() | GL_DEPTH_BUFFER_BIT() );
	glColor( 1.0, 1.0, 1.0 );
	glPushMatrix();
	glRotate( $a1 % 360, 0.0, 1.0, 1.0 );
	glRotate( $a2 % 360, 1.0, 1.0, 0.0 );
	if ($toggle) {
		glEvalMesh2( GL_FILL, 0, 20, 0, 20 );
	} else {
		glBegin(GL_LINE_STRIP);
		for my $j ( 0 .. 8 ) {
			for my $i ( 0 .. 30 ) {
				glEvalCoord2( $i / 30, $j / 8 );
			}
			for my $i ( 0 .. 30 ) {
				glEvalCoord2( $j / 8, $i / 30 );
			}
		}
		glEnd();
	}
	glPopMatrix();
	$app->sync();
}

print STDERR <<USAGE;
$0
	Press:	t 	Toggle wireframe / solid
		f 	Toggle fullscreen
		q	Quit
		any	Rotate Bezier Surface
USAGE

init();
initlight();
display();

my $event = SDL::Event->new;
$app->loop(
	{   SDL_QUIT()    => sub { exit(); },
		SDL_KEYDOWN() => sub {
			my ($event) = @_;
			if ( $event->key_sym() == SDLK_f ) {
				$app->fullscreen();
				display();
			} elsif ( $event->key_sym() == SDLK_t ) {
				$toggle = $toggle ? 0 : 1;
				display();
			} elsif ( $event->key_sym() == SDLK_q ) {
				exit();
			} else {
				$a1 += 33;
				$a2 += 5;
				display();
			}
		},
	}
);