Topic: AS3中常用到的公式小结

唐山flash原创动画 。本教程由 唐山卡动互动影视动漫 转载  如有版权问题请联系删除。

基本三角函数的计算:

角的正弦值 = 对边 / 斜边

角的余弦值 = 邻边 / 斜边

角的正切值 = 对边 / 邻边

 

角度制与弧度制的相互转换:

弧度 = 角度 * Math.PI / 180

角度 = 弧度 * 180 / Math.PI

 

计算两点间距离:

dx = x2 – x1;

dy = y2 – y1;

dist = Math.sqrt(dx*dx + dy*dy);

 

缓动公式:

sprite.x += (targetX sprite.x) * easing;//easing为缓动系数变量

sprite.y += (targetY – sprite.y) * easing;

 

弹性公式:

vx += (targetX sprite.x) * spring;//spring为弹性系数

vy += (targetY – sprite.y) * spring;

sprite.x += (vx *= friction);//friction为摩擦力

sprite.y += (vy *= friction);

 

偏移弹性公式:

var dx:Number = sprite.x – fixedX;

var dy:Number = sprite.y – fixedY;

var angle:Number = Math.atan2(dy, dx);

var targetX:Number = fixedX + Math.cos(angle) * springLength;

var targetY:Number = fixedX + Math.sin(angle) * springLength;

 

向鼠标旋转(或向某点旋转)

dx = mouseX – sprite.x;

dy = mouseY – sprite.y;

sprite.rotation = Math.atan2(dy, dx) * 180 / Math.PI;

 

波形运动:

public function onEnterFrame1(event:Event):void {

ball.y=centerScale+Math.sin(angle)*range;

angle+=speed;

}

 

心跳:

public function onEnterFrame1(event:Event):void {

ball.scaleX=centerScale+Math.sin(angle)*range;

ball.scaleY=centerScale+Math.sin(angle)*range;

angle+=speed;

}

 

圆心旋转:

public function onEnterFrame(event:Event):void {

ball.x=centerX+Math.cos(angle)*radius;

ball.y=centerY+Math.sin(angle)*radius;

angle+=speed;

}

 

椭圆旋转:

public function onEnterFrame(event:Event):void {

ball.x=centerX+Math.cos(angle)*radiusX;

ball.y=centerY+Math.sin(angle)*radiusY;

angle+=speed;

}

 

颜色运算得到透明值:

var t:uint=0×77ff8877

var s:uint=0xff000000

var h:uint=t&s

var m:uint=h>>>24

trace(m)

 

转换为十进制:

trace(hexValue);

十进制转换为十六进制:

decimalValue.toString(16)

 

颜色提取:

red = color24 >> 16;

green = color24 >> 8 & 0xFF;

blue = color24 & 0xFF;

alpha = color32 >> 24;

red = color32 >> 16 & 0xFF;

green = color32 >> 8 & 0xFF;

blue = color232 & 0xFF;

 

按位计算得到颜色值:

color24 = red << 16 | green << 8 | blue;

color32 = alpha << 24 | red << 16 | green << 8 | blue;

 

过控制点的曲线:

// xt, yt是你想要让曲线通过的那一点

// x0, y0 x2, y2 是曲线的终点

//PS.发现很多人转帖都是直接复制粘贴,也不翻译一下

xt * 2 – (x0 + x2) / 2;

y1 = yt * 2 – (y0 + y2) / 2;

moveTo(x0, y0);

curveTo(x1, y1, x2, y2);