From 45bbd5469d1dd119b8ef6e6c177b9ecc8cb5537d Mon Sep 17 00:00:00 2001
From: Dobrica Pavlinusic <dpavlin@rot13.org>
Date: Wed, 19 May 2010 15:29:29 +0200
Subject: [PATCH] use Math::CatmullRom to draw spline through points

---
 trace-path.pl | 47 ++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 40 insertions(+), 7 deletions(-)

diff --git a/trace-path.pl b/trace-path.pl
index 9a27b35..5884405 100755
--- a/trace-path.pl
+++ b/trace-path.pl
@@ -8,6 +8,7 @@ use SDL::Rect;
 use SDL::Color;
 use SDL::Constants;
 use SDL::Event;
+use Math::CatmullRom;
 
 use Carp qw/confess/;
 use Data::Dump qw/dump/;
@@ -28,9 +29,27 @@ our $event = SDL::Event->new;
 our $mouse_down = 0;
 
 our $white = SDL::Color->new( 0xff, 0xff, 0xff );
+our $red   = SDL::Color->new( 0xff, 0x00, 0x00 );
+our $black = SDL::Color->new( 0x00, 0x00, 0x00 );
 
 my ( $last_x, $last_y ) = ( 0,0 );
 
+my $max_path_length = 100;
+my @path;
+
+sub curve {
+	my $curve = Math::CatmullRom->new( splice @path, 0, $#path + $#path / 2 );
+	my @curve = $curve->curve( $mouse_trashold * $max_path_length );
+	warn "curve ", dump @curve;
+
+	my $i = 0;
+	while ( $i < $#curve ) {
+		my $rect = SDL::Rect->new( -x => int($curve[$i++]), -y => int($curve[$i++]), -w => 1, -h => 1 );
+		$app->fill( $rect, $red );
+		$app->update( $rect );
+	}
+}
+
 sub handle_events {
 
 	while ( $event->wait ) {
@@ -45,8 +64,17 @@ sub handle_events {
 		} elsif ( $type == SDL_QUIT() ) {
 			exit;
 		} elsif ( $type == SDL_KEYDOWN() ) {
-			warn "key down ", $event->key_name,$/;
-			exit if $event->key_name =~ m/^[xq]$/;
+			my $key = $event->key_name;
+			warn "key down $key\n";
+			exit if $key =~ m/^[xq]$/;
+			if ( $key eq 's' ) {
+				curve;
+			} elsif ( $key eq 'd' ) {
+				@path = ();
+				my $rect = SDL::Rect->new( -x => 0, -y => 0, -w => $w, -h => $h );
+				$app->fill( $rect, $black );
+				$app->update( $rect );
+			}
 		} elsif ( $type == SDL_KEYUP() ) {
 			warn "key up ", $event->key_name,$/;
 		} elsif ( $type == SDL_MOUSEMOTION() ) {
@@ -56,11 +84,16 @@ sub handle_events {
 			my $dx = abs( $last_x - $x );
 			my $dy = abs( $last_y - $y );
 			if ( $mouse_down && ( $dx > $mouse_trashold || $dy > $mouse_trashold ) ) {
-				my $rect = SDL::Rect->new( -x => $event->motion_x, -y => $event->motion_y, -w => 3, -h => 3 );
-				$app->fill( $rect, $white );
-				$app->update( $rect );
-				$last_x = $x;
-				$last_y = $y;
+				if ( $#path < $max_path_length ) {
+					push @path, $x, $y;
+					my $rect = SDL::Rect->new( -x => $event->motion_x, -y => $event->motion_y, -w => 3, -h => 3 );
+					$app->fill( $rect, $white );
+					$app->update( $rect );
+					$last_x = $x;
+					$last_y = $y;
+				} else {
+					$mouse_down = 0;
+				}
 			}
 		} else {
 			warn "unknown $type\n";
-- 
2.20.1