線分の交差判定
点はドラッグで移動できます。
/**
* Copyright shohei909 ( http://wonderfl.net/user/shohei909 )
* MIT License ( http://www.opensource.org/licenses/mit-license.php )
* Downloaded from: http://wonderfl.net/c/eWup
*/
// forked from shohei909's Area of a Triangle(三角形の面積)
package {
import flash.geom.Point;
import flash.filters.GlowFilter;
import flash.geom.Rectangle;
import com.bit101.components.*;
import flash.events.Event;
import flash.display.*;
public class FlashTest extends Sprite {
public var dots:Array = [];
public var r:Rectangle = new Rectangle( 10, 10, 445, 420 );
public var canvas:Sprite = new Sprite();
public var target:Object;
public function FlashTest() {
addChild( new Bitmap( new BitmapData(465,465,false,0x111111) ) )
addChild( canvas );
var dot:Dot = new Dot( 0xFF0000 );
canvas.addChild( dot )
dots.push( dot );
for( var i:int = 0; i < 4; i++ ){
dot = new Dot();
dot.move( int( r.x + r.width* Math.random() ), int( r.y + r.height*Math.random() ) );
dot.addEventListener( "mouseDown", start );
dot.addEventListener( "mouseUp", stop );
stage.addEventListener( "mouseMove", move );
dot.buttonMode = true;
canvas.addChild( dot );
dots.push( dot );
}
update();
}
private function update():void{
var g:Graphics = canvas.graphics;
g.clear();
g.lineStyle( 3, 0x66CC66, 1 );
var d:Dot;
for( var i:int = 1; i < 5; i ){
d = dots[i++];
g.moveTo( d.x, d.y );
d = dots[i++];
g.lineTo( d.x, d.y );
}
var p:Point = GeomUtil.intersection(
dots[1].x, dots[1].y,
dots[2].x, dots[2].y,
dots[3].x, dots[3].y,
dots[4].x, dots[4].y );
if(p) dots[0].move( p.x, p.y );
if( GeomUtil.segmentHitTest(
dots[1].x, dots[1].y,
dots[2].x, dots[2].y,
dots[3].x, dots[3].y,
dots[4].x, dots[4].y ) ){ dots[0].alpha = 1 }
else{ dots[0].alpha = 0.3 }
}
private function start(e:Event):void{
target = e.target;
}
private function move(e:Event):void{
if( target ){
target.move( mouseX, mouseY );
update();
}
}
private function stop(e:Event):void{
target = null;
}
}
}
import flash.text.AntiAliasType;
import flash.events.Event;
import flash.geom.Point;
import flash.display.Graphics;
import flash.display.Sprite;
import com.bit101.components.*;
class Dot extends Sprite{
private var lbl:Label;
function Dot( color:uint = 0x00FF00){
var g:Graphics = graphics;
g.beginFill( color, 1 );
g.drawRect( -5, -5, 10, 10 );
Style.LABEL_TEXT = 0xBB6666;
lbl = new Label( this, 0, 0, "" )
lbl.textField.antiAliasType = AntiAliasType.ADVANCED;
move(x,y);
}
public function move(x:Number,y:Number):void{
this.x = x; this.y = y; lbl.text = "(" + x.toFixed(1) + "," + y.toFixed(1) + ")";
}
}
class GeomUtil{
/** 三角形の面積 */
static public function triangleSum(
ax:Number, ay:Number,
bx:Number, by:Number,
cx:Number, cy:Number ):Number{
var s:Number = 0.5 * ((cy-ay)*(bx-ax)-(cx-ax)*(by-ay))
return s>0?s:-s;
}
/** 線分の交差判定 */
static public function segmentHitTest(
sx1:Number, sy1:Number,
ex1:Number, ey1:Number,
sx2:Number, sy2:Number,
ex2:Number, ey2:Number ):Boolean{
var cx:Number, cy:Number, dx:Number, dy:Number;
var r:Number = ( cx = sx1 - ex1 ) * ( dy = sy2 - ey2 ) - ( cy = sy1 - ey1 ) * ( dx = sx2 - ex2 );
if( r == 0 ){ return false; }
var ax:Number = sx1 - sx2;
var ay:Number = sy1 - sy2;
var s:Number = (dy * ax - dx * ay ) / r
var t:Number = (cy * ax - cx * ay ) / r
if( 0 <= t && t < 1 && 0 <= s && s < 1 ){ return true; }
return false;
}
/** 二つの直線の交点 */
static public function intersection(
sx1:Number, sy1:Number,
ex1:Number, ey1:Number,
sx2:Number, sy2:Number,
ex2:Number, ey2:Number ):Point{
var cx:Number, cy:Number, dx:Number, dy:Number;
var r:Number = ( cx = sx1 - ex1 ) * ( dy = sy2 - ey2 ) - ( cy = sy1 - ey1 ) * ( dx = sx2 - ex2 );
if( r == 0 ){ return null; }
var ax:Number = sx1 - sx2;
var ay:Number = sy1 - sy2;
var s:Number = (dx * ay - dy * ax) / r;
return new Point( sx1 + s * cx, sy1 + s * cy ) ;
}
}