As常用的公式（留着）
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
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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
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计算两点间距离：
dx = x2 – x1;
dy = y2 – y1;
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dist = Math.sqrt(dx*dx + dy*dy);
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maps.x = maps.x-(maps.x-mouseX)/5; ?//////跟随鼠标
//==========================================================================================================
移除出界对象：?
if(sprite.x - sprite.width / 2 > right || sprite.x + sprite.width / 2 < left || sprite.y – sprite.height / 2 > bottom || sprite.y + sprite.height / 2 < top)
?{?
// 移除影片的代码?
}
//===========================================================
重置出界对象：
?if(sprite.x - sprite.width / 2 > right || sprite.x + sprite.width / 2 < left || sprite.y – sprite.height / 2 > bottom || sprite.y + sprite.height / 2 < top)?
{?
// 重置影片的位置和速度?
}
//=======================================================
屏幕环绕出界对象：
?if (sprite.x - sprite.width / 2 > right) { sprite.x = left - sprite.width / 2; } else if (sprite.x + sprite.width / 2 < left) { sprite.x = right + sprite.width / 2; } if (sprite.y – sprite.height / 2 > bottom)?
{?
sprite.y = top – sprite.height / 2;?
}?
else if (sprite.y + sprite.height / 2 < top)?
{?
sprite.y = bottom + sprite.height / 2;?
}
//=============================================================
摩擦力应用（正确方法）：
?speed = Math.sqrt(vx * vx + vy * vy);?
?angle = Math.atan2(vy, vx);?
?if (speed > friction)?
{?
speed -= friction;
?}?
else?
{?
speed = 0;?
}?
vx = Math.cos(angle) * speed;?
vy = Math.sin(angle) * speed;
/////////////////////========================================
摩擦力应用（简便方法）：?
vx *= friction; vy *= friction;
//=====================================================
缓动公式:
sprite.x += (targetX - sprite.x) * easing;//easing为缓动系数变量
sprite.y += (targetY - sprite.y) * easing;
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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);
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//判断碰撞需要知道两个 ball 之间的角度，使用 Math.atan2(dy, dx)
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var angle:Number = Math.atan2(dy, dx); var sin:Number = Math.sin(angle); var cos:Number = Math.cos(angle);
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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;
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?
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多物体碰撞检测：
var numObjects:uint = 10;
for (var i:uint = 0; i < numObjects ‐ 1; i++) {
// 使用变量 i提取引用
var objectA = objects[i];
for (var j:uint = i+1; j<numObjects; j++) {
//使用变量 j 提取引用
var objectB = objects[j];
//在 objectA 与 objectB 之间进行碰撞检测
}
}
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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;
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坐标旋转：
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?x1 = Math.cos(angle) * x - Math.sin(angle) * y;?
?y1 = Math.cos(angle) * y + Math.sin(angle) * x;
反坐标旋转：
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?x1 = Math.cos(angle) * x + Math.sin(angle) * y;?
?y1 = Math.cos(angle) * y - Math.sin(angle) * x;
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//=============================================================单轴上的动量守恒 距离碰撞检测：
?? ? ? ? ? (m0 – m1) * v0 + 2 * m1 * v1
?v0Final=--------------------------------
?? ? ? ? ? ? ?m0 + m1
//======================================================mass=质量 ?vx为速度
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var vx0Final:Number = ((ball0.mass - ball1.mass) * ball0.vx + 2 * ball1.mass * ball1.vx) / (ball0.mass + ball1.mass);
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//===================================================================================================优化后的代码
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var vxTotal:Number = ball0.vx - ball1.vx;
ball0.vx = ((ball0.mass - ball1.mass) * ball0.vx + 2 * ball1.mass * ball1.vx) / (ball0.mass + ball1.mass);
ball1.vx = vxTotal + ball0.vx;
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//=============================================
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引力的一般公式：
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force = G * m1 * m2 / distance2
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ActionScript 实现万有引力:
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function gravitate(partA:Ball, partB:Ball):void
{
var dx:Number = partB.x ‐ partA.x;
var dy:Number = partB.y ‐ partA.y;
var distSQ:Number = dx * dx + dy * dy;
var dist:Number = Math.sqrt(distSQ);
var force:Number = partA.mass * partB.mass / distSQ;
var ax:Number = force * dx / dist;
var ay:Number = force * dy / dist;
partA.vx += ax / partA.mass;
partA.vy += ay / partA.mass;
partB.vx ‐= ax / partB.mass;
partB.vy ‐= ay / partB.mass;
}
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波形运动:
public function onEnterFrame1(event:Event):void {
ball.y=centerScale+Math.sin(angle)*range;
angle+=speed;
}
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心跳:
public function onEnterFrame1(event:Event):void {
ball.scaleX=centerScale+Math.sin(angle)*range;
ball.scaleY=centerScale+Math.sin(angle)*range;
angle+=speed;
}
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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;
}
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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;
}
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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)
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转换为十进制:
trace(hexValue);
十进制转换为十六进制:
decimalValue.toString(16)
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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;
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按位计算得到颜色值:
color24 = red << 16 | green << 8 | blue;
color32 = alpha << 24 | red << 16 | green << 8 | blue;
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过控制点的曲线:
// xt, yt是你想要让曲线通过的那一点
// x0, y0 和x2, y2 是曲线的终点
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x1 = xt * 2 – (x0 + x2) / 2;
y1 = yt * 2 – (y0 + y2) / 2;
moveTo(x0, y0);
curveTo(x1, y1, x2, y2);
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