制造镜面反射脚本
制作镜面反射脚本
这里面我转一个镜面反射，再阐述一些遇到的问题，先建立以个Shader，名字可以叫做MirrorReflection，脚本如下：
Shader "FX/Mirror Reflection"
{Properties
{_MainTex("Base(RGB)",2D)="white"{}
_ReflectionTex("Reflection",2D)="white"{TexGen ObjectLinear}
}
// two texture cards: full thing
Subshader
{Pass
{SetTexture[_MainTex]{combine texture}
SetTexture[_ReflectionTex]{matrix [_ProjMatrix] combine texture*previous}
}
}
// fallback: just main texture
Subshader
{Pass
{SetTexture [_MainTex]{combine texture}
}
}
}
在建立一个cs脚本，名字叫做MirrorReflection，脚本如下：
using UnityEngine;
using System.Collections;
//实际上 This is in fact just the Water script from Pro Standard Assets,
// just with refraction stuff removed.
[ExecuteInEditMode]// Make mirror live-update even when not in play mode
public class MirrorReflection:MonoBehaviour
{public bool m_DisablePixelLights=true;
public int m_TextureSize=256;
public float m_ClipPlaneOffset=0.07f;
public LayerMask m_ReflectLayers=-1;
private Hashtable m_ReflectionCameras=new Hashtable(); // Camera ->Camera table
private RenderTexture m_ReflectionTexture=null;
private int m_OldReflectionTextureSize=0;
private static bool s_InsideRendering=false;
// This is called when it's known that the object will be rendered by some
// camera. We render reflections and do other updates here.
// Because the script executes in edit mode,reflections for the scene view
// camera will just work!
public void OnWillRenderObject()
{if(!enabled || !renderer || !renderer.sharedMaterial || !renderer.enabled )return;
Camera cam=Camera.current;
if(!cam )return;
// Safeguard from recursive reflections.
if(s_InsideRendering )return;
s_InsideRendering=true;
Camera reflectionCamera;
CreateMirrorObjects(cam,out reflectionCamera );
// find out the reflection plane:position and normal in world space
Vector3 pos=transform.position;
Vector3 normal=transform.up;
// Optionally disable pixel lights for reflection
int oldPixelLightCount=QualitySettings.pixelLightCount;
if(m_DisablePixelLights )QualitySettings.pixelLightCount=0;
UpdateCameraModes(cam,reflectionCamera );
// Render reflection
// Reflect camera around reflection plane
float d=-Vector3.Dot(normal,pos)-m_ClipPlaneOffset;
Vector4 reflectionPlane=new Vector4(normal.x,normal.y,normal.z,d);
Matrix4x4 reflection=Matrix4x4.zero;
CalculateReflectionMatrix(ref reflection,reflectionPlane);
Vector3 oldpos=cam.transform.position;
Vector3 newpos=reflection.MultiplyPoint(oldpos );
reflectionCamera.worldToCameraMatrix=cam.worldToCameraMatrix * reflection;
// Setup oblique projection matrix so that near plane is our reflection
// plane. This way we clip everything below/above it for free.
Vector4 clipPlane=CameraSpacePlane(reflectionCamera,pos,normal,1.0f );
Matrix4x4 projection=cam.projectionMatrix;
CalculateObliqueMatrix(ref projection,clipPlane);
reflectionCamera.projectionMatrix=projection;
reflectionCamera.cullingMask=~(1<<4)& m_ReflectLayers.value; // never render water layer
reflectionCamera.targetTexture=m_ReflectionTexture;
GL.SetRevertBackfacing(true);
reflectionCamera.transform.position=newpos;
Vector3 euler=cam.transform.eulerAngles;
reflectionCamera.transform.eulerAngles=new Vector3(0,euler.y,euler.z);
reflectionCamera.Render();
reflectionCamera.transform.position=oldpos;
GL.SetRevertBackfacing(false);
Material[]materials=renderer.sharedMaterials;
foreach(Material mat in materials ){
if(mat.HasProperty("_ReflectionTex"))
mat.SetTexture("_ReflectionTex",m_ReflectionTexture );
}
// Set matrix on the shader that transforms UVs from object space into screen
// space. We want to just project reflection texture on screen.
Matrix4x4 scaleOffset=Matrix4x4.TRS(
new Vector3(0.5f,0.5f,0.5f),Quaternion.identity,new Vector3(0.5f,0.5f,0.5f));
Vector3 scale=transform.lossyScale;
Matrix4x4 mtx=transform.localToWorldMatrix * Matrix4x4.Scale(new Vector3(1.0f/scale.x,1.0f/scale.y,1.0f/scale.z));
mtx=scaleOffset * cam.projectionMatrix * cam.worldToCameraMatrix * mtx;
foreach(Material mat in materials ){
mat.SetMatrix("_ProjMatrix",mtx );
}
// Restore pixel light count
if(m_DisablePixelLights )
QualitySettings.pixelLightCount=oldPixelLightCount;
s_InsideRendering=false;
}
// Cleanup all the objects we possibly have created
void OnDisable()
{
if(m_ReflectionTexture ){
DestroyImmediate(m_ReflectionTexture );
m_ReflectionTexture=null;
}
foreach(DictionaryEntry kvp in m_ReflectionCameras )
DestroyImmediate(((Camera)kvp.Value).gameObject );
m_ReflectionCameras.Clear();
}
private void UpdateCameraModes(Camera src,Camera dest )
{
if(dest==null )
return;
// set camera to clear the same way as current camera
dest.clearFlags=src.clearFlags;
dest.backgroundColor=src.backgroundColor;
if(src.clearFlags==CameraClearFlags.Skybox )
{
Skybox sky=src.GetComponent(typeof(Skybox))as Skybox;
Skybox mysky=dest.GetComponent(typeof(Skybox))as Skybox;
if(!sky || !sky.material )
{
mysky.enabled=false;
}
else
{
mysky.enabled=true;
mysky.material=sky.material;
}
}
// update other values to match current camera.
// even if we are supplying custom camera&projection matrices,
// some of values are used elsewhere(e.g. skybox uses far plane)
dest.farClipPlane=src.farClipPlane;
dest.nearClipPlane=src.nearClipPlane;
dest.orthographic=src.orthographic;
dest.fieldOfView=src.fieldOfView;
dest.aspect=src.aspect;
dest.orthographicSize=src.orthographicSize;
}
// On-demand create any objects we need
private void CreateMirrorObjects(Camera currentCamera,out Camera reflectionCamera )
{
reflectionCamera=null;
// Reflection render texture
if(!m_ReflectionTexture || m_OldReflectionTextureSize !=m_TextureSize )
{
if(m_ReflectionTexture )
DestroyImmediate(m_ReflectionTexture );
m_ReflectionTexture=new RenderTexture(m_TextureSize,m_TextureSize,16 );
m_ReflectionTexture.name="__MirrorReflection" + GetInstanceID();
m_ReflectionTexture.isPowerOfTwo=true;
m_ReflectionTexture.hideFlags=HideFlags.DontSave;
m_OldReflectionTextureSize=m_TextureSize;
}
// Camera for reflection
reflectionCamera=m_ReflectionCameras[currentCamera]as Camera;
if(!reflectionCamera )// catch both not-in-dictionary and in-dictionary-but-deleted-GO
{
GameObject go=new GameObject("Mirror Refl Camera id" + GetInstanceID()+ " for " + currentCamera.GetInstanceID(),typeof(Camera),typeof(Skybox));
reflectionCamera=go.camera;
reflectionCamera.enabled=false;
reflectionCamera.transform.position=transform.position;
reflectionCamera.transform.rotation=transform.rotation;
reflectionCamera.gameObject.AddComponent("FlareLayer");
go.hideFlags=HideFlags.HideAndDontSave;
m_ReflectionCameras[currentCamera]=reflectionCamera;
}
}
// Extended sign:returns -1,0 or 1 based on sign of a
private static float sgn(float a)
{if(a>0.0f)return 1.0f;
if(a<0.0f)return -1.0f;
return 0.0f;
}
// Given position/normal of the plane,calculates plane in camera space.
private Vector4 CameraSpacePlane(Camera cam,Vector3 pos,Vector3 normal,float sideSign)
{
Vector3 offsetPos=pos + normal * m_ClipPlaneOffset;
Matrix4x4 m=cam.worldToCameraMatrix;
Vector3 cpos=m.MultiplyPoint(offsetPos );
Vector3 cnormal=m.MultiplyVector(normal ).normalized * sideSign;
return new Vector4(cnormal.x,cnormal.y,cnormal.z,-Vector3.Dot(cpos,cnormal));
}
//调整给定的射影矩阵以便最近的平面Adjusts the given projection matrix so that near plane is the given clipPlane
// clipPlane is given in camera space. See article in Game Programming Gems 5.
private static void CalculateObliqueMatrix(ref Matrix4x4 projection,Vector4 clipPlane)
{Vector4 q=projection.inverse * new Vector4(sgn(clipPlane.x),sgn(clipPlane.y),1.0f,1.0f);
Vector4 c=clipPlane *(2.0F /(Vector4.Dot(clipPlane,q)));
// third row=clip plane -fourth row
projection[2]=c.x -projection[3];
projection[6]=c.y -projection[7];
projection[10]=c.z -projection[11];
projection[14]=c.w -projection[15];
}
//围绕给定的平面计算折射矩阵
private static void CalculateReflectionMatrix(ref Matrix4x4 reflectionMat,Vector4 plane)
{reflectionMat.m00=(1F -2F*plane[0]*plane[0]);
reflectionMat.m01=(-2F*plane[0]*plane[1]);
reflectionMat.m02=(-2F*plane[0]*plane[2]);
reflectionMat.m03=(-2F*plane[3]*plane[0]);
reflectionMat.m10=(-2F*plane[1]*plane[0]);
reflectionMat.m11=(1F -2F*plane[1]*plane[1]);
reflectionMat.m12=(-2F*plane[1]*plane[2]);
reflectionMat.m13=(-2F*plane[3]*plane[1]);
reflectionMat.m20=(-2F*plane[2]*plane[0]);
reflectionMat.m21=(-2F*plane[2]*plane[1]);
reflectionMat.m22=(1F -2F*plane[2]*plane[2]);
reflectionMat.m23=(-2F*plane[3]*plane[2]);
reflectionMat.m30=0F;
reflectionMat.m31=0F;
reflectionMat.m32=0F;
reflectionMat.m33=1F;
}
}
值得注意的是，地面，或者镜面尽量用U3d里面自建的plane,把shader和cs脚本直接赋予到该plane上就出效果了。其他物体不必赋予。