円と線分の交点
緑の点はドラッグできます。
/**
* Copyright shohei909 ( http://wonderfl.net/user/shohei909 )
* MIT License ( http://www.opensource.org/licenses/mit-license.php )
* Downloaded from: http://wonderfl.net/c/4gBF
*/
// forked from shohei909's 垂直二等分線
// forked from shohei909's 垂線と鏡像
// forked from shohei909's 線分の交差判定
// forked from shohei909's Area of a Triangle(三角形の面積)
/*
緑の点はドラッグできます。
*/
package {
import flash.geom.Matrix;
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;
for( var i:int = 0; i < 2; i++ ){
dot = new Dot( 0xFF0000 );
canvas.addChild( dot )
dots.push( dot );
}
for( i = 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();
var d:Dot;
for( var i:int = 2; i < 6; i++ ){
g.lineStyle( 3, [0x6666CC,0x66CC66][(i >> 1)-1], 1 );
d = dots[i++];
g.moveTo( d.x, d.y );
d = dots[i];
g.lineTo( d.x, d.y );
}
g.lineStyle( 3, 0x66CC66, 1 );
d = dots[2];
var r:Number = GeomUtil.distance( d.x, d.y, dots[3].x, dots[3].y )
g.drawCircle( d.x, d.y, r );
var ps:Vector.<Point> = GeomUtil.lineXCircle(
dots[4].x, dots[4].y,
dots[5].x, dots[5].y,
dots[2].x, dots[2].y, r);
var pl:int = ps.length
for( i = 0; i < pl; i++ ){
var p:Point = ps[i]
d = dots[i];
d.visible = true;
d.move( p.x, p.y );
var div:Number = GeomUtil.divideRate(
dots[4].x, dots[4].y,
dots[5].x, dots[5].y,
d.x, d.y );
if( 0 < div && div < 1 ){ d.alpha = 1; }
else{ d.alpha = 0.5; }
}for( ; i < 2; i++ ){
d = dots[i];
d.visible = false;
}
}
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.geom.Matrix;
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 lineXLine(
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 ) ;
}
/** 直線と円の交点 */
static public function lineXCircle(
sx:Number, sy:Number,
ex:Number, ey:Number,
x:Number, y:Number, r:Number ):Vector.<Point>{
var vec:Vector.<Point> = new Vector.<Point>;
var p:Point = perpendicular( sx, sy, ex, ey, x, y );
var dx:Number, dy:Number, px:Number, py:Number;
var d:Number = (dx = x - (px = p.x)) * dx + (dy = y - (py = p.y)) * dy;
var r2:Number = r * r
if( d == r2 ){
vec.push( new Point(px, py) );
}else if( d < r2 ){
var ab:Number = Math.sqrt( (dx = sx - ex) * dx + (dy = sy - ey) * dy );
d = Math.sqrt( r2 - d );
dx = d * (dx / ab);
dy = d * (dy / ab);
vec.push( new Point( px + dx, py + dy), new Point( px - dx, py - dy) );
}
return vec;
}
/** 直線ABと点Cからの垂線の交点 */
static public function perpendicular(
ax:Number, ay:Number,
bx:Number, by:Number,
cx:Number, cy:Number ):Point {
var dx:Number, dy:Number;
var al:Number = (dx = bx - ax) * dx + (dy = by - ay) * dy;
if( al == 0 ){ return null; }
var k:Number = - (dx * (ax - cx) + dy * (ay - cy)) / al
return new Point( k * dx + ax, k * dy + ay );
}
/** 線分ABの内分点(0<r<1)、外分点(r<0,1<r) */
static public function divide(
ax:Number, ay:Number,
bx:Number, by:Number,
r:Number = 0.5):Point {
return new Point( ax + r * (bx - ax), ay + r * (by - ay) );
}
/** AC/AB */
static public function divideRate(
ax:Number, ay:Number,
bx:Number, by:Number,
cx:Number, cy:Number):Number {
var dx:Number = (cx - ax) / (bx - ax);
var dy:Number = (cy - ay) / (by - ay);
if( dx == dy ){ return dx }
else if( isNaN( dx ) ){ return dy; }
else if( isNaN( dy ) ){ return dx; }
else{ return dx; }
}
/** 点Aを中心とする回転行列を生成 */
static public function rotate(
ax:Number, ay:Number,
d:Number = 90):Matrix {
var r:Number = Math.PI * d / 180;
var s:Number = Math.sin( r ), c:Number = Math.cos( r );
return new Matrix( c, -s, s, c, ax - c * ax + s * ay, ay - s * ax - c * ay );
}
/** 2点間の距離 */
static public function distance(
ax:Number, ay:Number,
bx:Number, by:Number):Number{
return Math.sqrt((ax = ax - bx) * ax + (ay = ay - by) * ay);
}
}