一些AS3中常用到的公式小結(jié)
2020-07-17 13:15:05
供稿：網(wǎng)友
基本三角函數(shù)的計(jì)算：
角的正弦值 = 對(duì)邊 / 斜邊
角的余弦值 = 鄰邊 / 斜邊
角的正切值 = 對(duì)邊 / 鄰邊
角度制與弧度制的相互轉(zhuǎn)換：
弧度 = 角度 * Math.PI / 180
角度 = 弧度 * 180 / Math.PI
計(jì)算兩點(diǎn)間距離：
dx = x2 – x1;
dy = y2 – y1;
dist = Math.sqrt(dx*dx + dy*dy);
緩動(dòng)公式:
sprite.x += (targetX – sprite.x) * easing;//easing為緩動(dòng)系數(shù)變量
sprite.y += (targetY – sprite.y) * easing;
彈性公式:
vx += (targetX – sprite.x) * spring;//spring為彈性系數(shù)
vy += (targetY – sprite.y) * spring;
sprite.x += (vx *= friction);//friction為摩擦力
sprite.y += (vy *= friction);
偏移彈性公式:
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;
向鼠標(biāo)旋轉(zhuǎn)(或向某點(diǎn)旋轉(zhuǎn))
dx = mouseX – sprite.x;
dy = mouseY – sprite.y;
sprite.rotation = Math.atan2(dy, dx) * 180 / Math.PI;
波形運(yùn)動(dòng):
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;
}
圓心旋轉(zhuǎn):
public function onEnterFrame(event:Event):void {
ball.x=centerX+Math.cos(angle)*radius;
ball.y=centerY+Math.sin(angle)*radius;
angle+=speed;
}
橢圓旋轉(zhuǎn):
public function onEnterFrame(event:Event):void {
ball.x=centerX+Math.cos(angle)*radiusX;
ball.y=centerY+Math.sin(angle)*radiusY;
angle+=speed;
}
顏色運(yùn)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)
轉(zhuǎn)換為十進(jìn)制:
trace(hexValue);
十進(jìn)制轉(zhuǎn)換為十六進(jìn)制:
decimalValue.toString(16)
顏色提取:
red = color24 >> 16;
green = color24 >> 8 & 0xFF;
blue = color24 & 0xFF;
alpha = color32 >> 24;
red = color32 >> 16 & 0xFF;
green = color32 >> 8 & 0xFF;
blue = color232 & 0xFF;
按位計(jì)算得到顏色值:
color24 = red << 16 | green << 8 | blue;
color32 = alpha << 24 | red << 16 | green << 8 | blue;
過(guò)控制點(diǎn)的曲線:
// xt, yt是你想要讓曲線通過(guò)的那一點(diǎn)
// x0, y0 和x2, y2 是曲線的終點(diǎn)
//PS.發(fā)現(xiàn)很多人轉(zhuǎn)帖都是直接復(fù)制粘貼，也不翻譯一下
xt * 2 – (x0 + x2) / 2;
y1 = yt * 2 – (y0 + y2) / 2;
moveTo(x0, y0);
curveTo(x1, y1, x2, y2);
