118 lines
3.5 KiB
TypeScript
118 lines
3.5 KiB
TypeScript
module es {
|
||
export class MathHelper {
|
||
public static readonly Epsilon: number = 0.00001;
|
||
public static readonly Rad2Deg = 57.29578;
|
||
public static readonly Deg2Rad = 0.0174532924;
|
||
/**
|
||
* 表示pi除以2的值(1.57079637)
|
||
*/
|
||
public static readonly PiOver2 = Math.PI / 2;
|
||
|
||
/**
|
||
* 将弧度转换成角度。
|
||
* @param radians 用弧度表示的角
|
||
*/
|
||
public static toDegrees(radians: number) {
|
||
return radians * 57.295779513082320876798154814105;
|
||
}
|
||
|
||
/**
|
||
* 将角度转换为弧度
|
||
* @param degrees
|
||
*/
|
||
public static toRadians(degrees: number) {
|
||
return degrees * 0.017453292519943295769236907684886;
|
||
}
|
||
|
||
/**
|
||
* mapps值(在leftMin - leftMax范围内)到rightMin - rightMax范围内的值
|
||
* @param value
|
||
* @param leftMin
|
||
* @param leftMax
|
||
* @param rightMin
|
||
* @param rightMax
|
||
*/
|
||
public static map(value: number, leftMin: number, leftMax: number, rightMin: number, rightMax: number) {
|
||
return rightMin + (value - leftMin) * (rightMax - rightMin) / (leftMax - leftMin);
|
||
}
|
||
|
||
public static lerp(value1: number, value2: number, amount: number) {
|
||
return value1 + (value2 - value1) * amount;
|
||
}
|
||
|
||
public static clamp(value: number, min: number, max: number) {
|
||
if (value < min)
|
||
return min;
|
||
|
||
if (value > max)
|
||
return max;
|
||
|
||
return value;
|
||
}
|
||
|
||
/**
|
||
* 给定圆心、半径和角度，得到圆周上的一个点。0度是3点钟。
|
||
* @param circleCenter
|
||
* @param radius
|
||
* @param angleInDegrees
|
||
*/
|
||
public static pointOnCirlce(circleCenter: Vector2, radius: number, angleInDegrees: number) {
|
||
let radians = MathHelper.toRadians(angleInDegrees);
|
||
return new Vector2(Math.cos(radians) * radians + circleCenter.x,
|
||
Math.sin(radians) * radians + circleCenter.y);
|
||
}
|
||
|
||
/**
|
||
* 如果值为偶数，返回true
|
||
* @param value
|
||
*/
|
||
public static isEven(value: number) {
|
||
return value % 2 == 0;
|
||
}
|
||
|
||
/**
|
||
* 数值限定在0-1之间
|
||
* @param value
|
||
*/
|
||
public static clamp01(value: number) {
|
||
if (value < 0)
|
||
return 0;
|
||
|
||
if (value > 1)
|
||
return 1;
|
||
|
||
return value;
|
||
}
|
||
|
||
public static angleBetweenVectors(from: Vector2, to: Vector2) {
|
||
return Math.atan2(to.y - from.y, to.x - from.x);
|
||
}
|
||
|
||
/**
|
||
* 增加t并确保它总是大于或等于0并且小于长度
|
||
* @param t
|
||
* @param length
|
||
*/
|
||
public static incrementWithWrap(t: number, length: number){
|
||
t ++;
|
||
if (t == length)
|
||
return 0;
|
||
|
||
return t;
|
||
}
|
||
|
||
/**
|
||
* 由上移量向上移。start可以小于或大于end。例如:开始是2，结束是10，移位是4，结果是6
|
||
* @param start
|
||
* @param end
|
||
* @param shift
|
||
*/
|
||
public static approach(start: number, end: number, shift: number): number {
|
||
if (start < end)
|
||
return Math.min(start + shift, end);
|
||
|
||
return Math.max(start - shift, end);
|
||
}
|
||
}
|
||
}
|