Unity2D 里的场景缩放实现

闲时以 Unity2D 练手时想实现端游里的场景缩放功能，而网上的代码几乎全是 3D 场景缩放相关，所以我自己编写了个 2D 场景缩放脚本（C#）。

代码如下：

using UnityEngine;
using System.Collections;

public class SceneScaleController : MonoBehaviour {

    private float normalCameraSize;
    private float minCameraSize;
    private float maxCameraSize;

    private const float cScaleRange = 0.8f;
    private const float cScaleFactor = 0.05f;

    private enum SceneScaleType {sstNone, sstShrink, sstEnlarge};
    private SceneScaleType scaleType = SceneScaleType.sstNone;

    private enum SceneScaleState {sssNormal, sssShrinked, sstEnlarged};
    private SceneScaleState scaleState = SceneScaleState.sssNormal;

    void Start() {
        normalCameraSize = Camera.main.orthographicSize;
        minCameraSize = normalCameraSize - cScaleRange;
        maxCameraSize = normalCameraSize + cScaleRange;
    }

    void Update() {
        if (scaleType == SceneScaleType.sstNone) {
            float factor = Input.GetAxis("Mouse ScrollWheel");
            if ((factor > ) && (scaleState != SceneScaleState.sssShrinked)) {
                scaleType = SceneScaleType.sstShrink;
            } else if ((factor < ) && (scaleState != SceneScaleState.sstEnlarged)) {
                scaleType = SceneScaleType.sstEnlarge;
            }
        } else if (scaleType == SceneScaleType.sstEnlarge) {
            float sz = Camera.main.orthographicSize;
            sz += cScaleFactor;

            if (scaleState == SceneScaleState.sssNormal) {
                if (sz >= maxCameraSize) {
                    sz = maxCameraSize;
                    scaleType = SceneScaleType.sstNone;
                    scaleState = SceneScaleState.sstEnlarged;
                }
                Camera.main.orthographicSize = sz;
            } else if (scaleState == SceneScaleState.sssShrinked) {
                if (sz >= normalCameraSize) {
                    sz = normalCameraSize;
                    scaleType = SceneScaleType.sstNone;
                    scaleState = SceneScaleState.sssNormal;
                }
                Camera.main.orthographicSize = sz;
            }
        } else if (scaleType == SceneScaleType.sstShrink) {
            float sz = Camera.main.orthographicSize;
            sz -= cScaleFactor;

            if (scaleState == SceneScaleState.sssNormal) {
                if (sz <= minCameraSize) {
                    sz = minCameraSize;
                    scaleType = SceneScaleType.sstNone;
                    scaleState = SceneScaleState.sssShrinked;
                }
                Camera.main.orthographicSize = sz;
            } else if (scaleState == SceneScaleState.sstEnlarged) {
                if (sz <= normalCameraSize) {
                    sz = normalCameraSize;
                    scaleType = SceneScaleType.sstNone;
                    scaleState = SceneScaleState.sssNormal;
                }
                Camera.main.orthographicSize = sz;
            }
        }
    }
}

将脚本挂到 Main Camera 上，滚动鼠标滚轮，场景即发生缩放了。