Mathf.Cos

参数

返回

float 介于 -1 与 1 之间的返回值。

描述

返回角度 f 的余弦。

**注意：**如果此函数使用非常大的数字，此方法的输入角度值具有可接受范围，超出该范围，计算会失败。在 Windows 上，可接受范围大约是 -9223372036854775295 到 9223372036854775295 之间。此范围在其他平台上可能有所不同。对于可接受范围之外的值，Cos 方法返回输入值，而不是抛出异常。

另请参阅：Sin、Tan

using UnityEngine;
using System.Collections;

public class PolyDrawExample : MonoBehaviour
{
    public int numberOfSides;
    public float polygonRadius;
    public Vector2 polygonCenter;

    void Update()
    {
        DebugDrawPolygon(polygonCenter, polygonRadius, numberOfSides);
    }

    // Draw a polygon in the XY plane with a specfied position, number of sides
    // and radius.
    void DebugDrawPolygon(Vector2 center, float radius, int numSides)
    {
        // The corner that is used to start the polygon (parallel to the X axis).
        Vector2 startCorner = new Vector2(radius, 0) + center;

        // The "previous" corner point, initialised to the starting corner.
        Vector2 previousCorner = startCorner;

        // For each corner after the starting corner...
        for (int i = 1; i < numSides; i++)
        {
            // Calculate the angle of the corner in radians.
            float cornerAngle = 2f * Mathf.PI / (float)numSides * i;

            // Get the X and Y coordinates of the corner point.
            Vector2 currentCorner = new Vector2(Mathf.Cos(cornerAngle) * radius, Mathf.Sin(cornerAngle) * radius) + center;

            // Draw a side of the polygon by connecting the current corner to the previous one.
            Debug.DrawLine(currentCorner, previousCorner);

            // Having used the current corner, it now becomes the previous corner.
            previousCorner = currentCorner;
        }

        // Draw the final side by connecting the last corner to the starting corner.
        Debug.DrawLine(startCorner, previousCorner);
    }
}