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昨晚写的点类和直线类，并做了两个测试，效果在后面
/**
* 绘制实点类
*
* @作者 章精设(zjs35)
* @版本 v1
*/
class game.Point {
private var _x:Number;
private var _y:Number;
public function Point(x:Number, y:Number) {
this._x = x;
this._y = y;
}
public function toString() {
trace([_x, _y]);
}
public function get x() {
return _x;
}
public function set x(x:Number):Void {
this._x = x;
}
public function get y() {
return _y;
}
public function set y(y:Number):Void {
this._y = y;
}
public function reset(x, y) {
this._x = x;
this._y = y;
}
public function setPosition(mc) {
mc._x = _x;
mc._y = _y;
}
public static function distance(p1:Point, p2:Point) {
var dx = p2.x-p1.x;
var dy = p2.y-p1.y;
return Math.sqrt(dx*dx+dy*dy);
}
}
/**
* 绘制实直线类
*
* @作者 章精设(zjs35)
* @版本 v1
*/
import game.Point;
import fc.graphics.*;
import fc.graphics.draw2d.GDI;
//两点式直线类
class game.Line {
//决定直线的两点
private var _p1:Point;
private var _p2:Point;
private var _GDI:GDI;
//构造函数
public function Line(p1:Point, p2:Point) {
_p1 = p1;
_p2 = p2;
}
public function toString():String {
return "instance of Line Class ";
}
//返回第一个点
public function get p1():Point {
return _p1;
}
//返回第二个点
public function get p2():Point {
return _p2;
}
//重新设置两点
public function reset(p1:Point, p2:Point):Void {
_p1 = p1;
_p2 = p2;
}
//返回中点
public function midPoint():Point {
return new Point((_p1.x+_p2.x)/2, (_p1.y+_p2.y)/2);
}
//求直线的倾斜角，以角度表示
public function angle():Number {
return fc.math.Degree.atan2D(_p2.y-_p1.y, _p2.x-_p1.x);
}
//求直线的斜率
public function slope():Number {
if (_p1.x == _p2.x) {
return undefined;
}
return (_p2.y-_p1.y)/(_p2.x-_p1.x);
}
//绘制直线
public function draw(mc, pen:Pen):Void {
_GDI = GDI.getInstance();
_GDI.target = mc;
//t.clear();
_GDI.line(pen, new fc.graphics.draw2d.Line(_p1.x, _p1.y, _p2.x, _p2.y));
}
public function clear(mc):Void {
_GDI.target = mc;
_GDI.clear();
}
//定比
public function ratio(r) {
}
//点是否在直线上（两点之间)
public function dotOfLine(p:Point):Boolean {
var d1 = Point.distance(p, _p1);
var d2 = Point.distance(p, _p2);
var d3 = Point.distance(_p1, _p2);
//0.01用于避免浮点数
return d1+d2-d3<0.01;
}
//点到直线的距离
public function dotToLine(p:Point):Number {
var l:Line = this.uprightness(p);
var point:Point = this.pointOfIntersection(l);
//有交点时返回距离
if (point != undefined) {
return Point.distance(point, p);
}
}
//求过点p的垂线
public function uprightness(p:Point):Line {
var k = this.slope();
//没考虑k=0的情况
var t1:Point = new Point(0, p.y+1/k*p.x);
var t2:Point = new Point(k*p.y+p.x, 0);
if (k == 0) {
var t1:Point = new Point(p.x, 0);
var t2:Point = new Point(p.x, Stage.height);
} else if (k == undefined) {
var t1:Point = new Point(0, p.y);
var t2:Point = new Point(Stage.width, p.y);
}
return new Line(t1, t2);
}
//两直线的交点
public function pointOfIntersection(line:Line):Point {
//直线1的参数
var t1 = this.transCommon();
var a1 = t1.a;
var b1 = t1.b;
var c1 = t1.c;
//直线2的参数
var t2 = line.transCommon();
var a2 = t2.a;
var b2 = t2.b;
var c2 = t2.c;
//计算交点
var p = new Point((c2*b1-c1*b2)/(a1*b2-a2*b1), (a1*c2-a2*c1)/(a2*b1-a1*b2));
//交点在两点直线的两点之间
if (this.dotOfLine(p) && line.dotOfLine(p)) {
return p;
}
}
//直线的位置关系,true示平行，false示相交
public function position(l:Line) {
return this.slope() == l.slope();
}
//直线方程的形式转换：两点式转换为一般式
public function transCommon():Object {
var k = this.slope();
var t1, t2, t3;
if (k == undefined) {
t1 = 1;
t2 = 0;
t3 = -_p1.x;
} else {
t1 = -k;
t2 = 1;
t3 = k*_p1.x-_p1.y;
}
return {a:t1, b:t2, c:t3};
}
//两直线所成的角
}
效果1，还有bug
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