unity3d/用户自由改变背景色

通过鼠标单击（或触摸点）发射射线，获取贴图上的某点的像素值，因为Texture2D也给我们提供 GetPixel API，同时碰触会给我们返回这个textureCoord值，也就是图形学里已经经过设备坐标化后的纹理坐标。但是要获取正确的贴图坐标颜色值，还必须要分别在U、V坐标上乘以贴图的宽和高（刚开始这个可让我debug了个够啊），同时我们的贴图必须设置成可读写的（默认是不支持的），还有就是贴图格式设置成RAGB32的。代码如下：（同时自己也PS合成了一张色彩原理贴图，共享在我的贴图相册）

 

using UnityEngine;using System.Collections; public class ColorSelect : MonoBehaviour {public Camera cam;void Start(){if(cam == null){cam = GameObject.FindGameObjectWithTag("MainCamera").GetComponent<Camera>();}}void Update (){// Only when we press the mouseif (Input.touchCount < 1) //应用于手机触摸版return;/*if(!Input.GetMouseButton(0)) //应用于PC或WEB版的鼠标单击return;*/ // Only if we hit something, do we continue//Vector3 TouchPosition = new Vector3(Input.GetTouch(0).position.x,Input.GetTouch(0).position.y,0); //应用鼠标Vector3 TouchPosition = Input.mousePosition; //触摸RaycastHit hit = new RaycastHit();if (!Physics.Raycast (cam.ScreenPointToRay(TouchPosition),out hit))return;// Just in case, also make sure the collider also has a renderer// material and texture. Also we should ignore primitive colliders.Renderer renderer = hit.collider.renderer;if(renderer == null)return;//Debug.Log("throught renderer~");MeshCollider meshCollider = hit.collider as MeshCollider;if(meshCollider == null)return;//Debug.Log("throught mesh collider");if (renderer.sharedMaterial == null ||renderer.sharedMaterial.mainTexture == null)return;//Debug.Log("done~");// Now draw a pixel where we hit the objectTexture2D tex = renderer.material.mainTexture as Texture2D;//Debug.Log("Get Texture:"+tex.name);Vector2 pixelUV = hit.textureCoord;//Debug.Log("pixelUV:"+pixelUV);pixelUV.x *= tex.width;pixelUV.y *= tex.height;Color color = tex.GetPixel((int)pixelUV.x,(int)pixelUV.y);//Debug.Log("color:"+color);cam.backgroundColor = color;}}