Uinty3d 镜面反射代码

镜面反射代码
文件名MirrorReflection.cs
using UnityEngine;
using System.Collections;

// 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) );
    }

    // 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];
    }

    // Calculates reflection matrix around the given plane
    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;
    }
}
文件名MirrorReflection.shader
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 }
           }
     }
}

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