Unity3d 镜面反射 

网上能找到的基本上是固定管道或表面渲染的shader，

特此翻译为顶点、片段渲染的Shader，

本源码只涉及shader与cs部分，

Editor部分使用NGUI绘制的，

请自行下载NGUI 

unity3d 版本:v4.3.1

ReflectionEffect.cs

using UnityEngine;
using System.Collections;
using System;

/// <summary>
/// 反射效果
/// </summary>
[AddComponentMenu("GameCore/SpecialEffect/Reflection")]
[ExecuteInEditMode]
public class ReflectionEffect : MonoBehaviour
{
    public Camera MainCamera;
    public bool DisablePixelLights = true;
    public int TextureSize = 512;
    public float ClipPlaneOffset = 0;
    public LayerMask 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 = MainCamera;
        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 (DisablePixelLights)
            QualitySettings.pixelLightCount = 0;

        CoreTool.CloneCameraModes(cam, reflectionCamera);

        // Render reflection
        // Reflect camera around reflection plane
        float d = -Vector3.Dot(normal, pos) - ClipPlaneOffset;
        Vector4 reflectionPlane = new Vector4(normal.x, normal.y, normal.z, d);


        Matrix4x4 reflection = CoreTool.CalculateReflectionMatrix(Matrix4x4.zero, 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 = CoreTool.CameraSpacePlane(reflectionCamera, pos, normal, 1.0f, ClipPlaneOffset);

        Matrix4x4 projection = cam.projectionMatrix;

        projection = CoreTool.CalculateObliqueMatrix(projection, clipPlane);

        reflectionCamera.projectionMatrix = projection;

        reflectionCamera.cullingMask = ~(1 << 4) & 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 (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();
    }

    // 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 != TextureSize)
        {
            if (m_ReflectionTexture)
                DestroyImmediate(m_ReflectionTexture);
            m_ReflectionTexture = new RenderTexture(TextureSize, TextureSize,0);
            m_ReflectionTexture.name = "__MirrorReflection" + GetInstanceID();
            m_ReflectionTexture.isPowerOfTwo = true;
            m_ReflectionTexture.hideFlags = HideFlags.DontSave;
            m_ReflectionTexture.antiAliasing = 4;
            m_ReflectionTexture.anisoLevel = 0;
            m_OldReflectionTextureSize = 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;
        }
    }
}

ReflectionEffectEditor.cs

using System.Collections;
using System;
using UnityEditor;
using UnityEngine;
/// <summary>
/// 反射效果
/// </summary>
[CustomEditor(typeof(ReflectionEffect))]
public class ReflectionEffectEditor : Editor
{
    string[] _renderTextureOptions = new string[8] { "16", "32", "64", "128", "256", "512", "1024", "2048" };
    int _renderTextureWidthDefaultIndex = 5;
    int _renderTextureWidthIndex = 5;
    public override void OnInspectorGUI()
    {
        SerializedProperty sp = NGUIEditorTools.DrawProperty("Main Camera", this.serializedObject, "MainCamera");
        SetMainCamera(sp);

        if (NGUIEditorTools.DrawHeader("Reflection Settings"))
        {
            NGUIEditorTools.BeginContents();
            {
                NGUIEditorTools.DrawProperty("Disable PixelLights", this.serializedObject, "DisablePixelLights");
                NGUIEditorTools.DrawProperty("Reflect Layers", this.serializedObject, "ReflectLayers");                
                NGUIEditorTools.DrawProperty("ClipPlane Offset", this.serializedObject, "ClipPlaneOffset");
            }
            NGUIEditorTools.EndContents();
        }
        if (NGUIEditorTools.DrawHeader("Render Texture Settings"))
        {
            NGUIEditorTools.BeginContents();
            {
                sp = this.serializedObject.FindProperty("TextureSize");

                _renderTextureWidthIndex = GetTextureOptionsIndex(sp.intValue.ToString());
                EditorGUILayout.BeginHorizontal();
                EditorGUILayout.LabelField("Size:", GUILayout.Width(80));
                _renderTextureWidthIndex = EditorGUILayout.Popup(_renderTextureWidthIndex, _renderTextureOptions);
                EditorGUILayout.EndHorizontal();

                if (GUILayout.Button("Make Default Value"))
                {
                    _renderTextureWidthIndex = _renderTextureWidthDefaultIndex;
                }
                sp.intValue = http://www.mamicode.com/int.Parse(_renderTextureOptions[_renderTextureWidthIndex]);>
CoreTool.cs
using System.Collections;
using System;
using UnityEngine;

/// <summary>
/// 工具类
/// </summary>
public static class CoreTool
{
    #region Config配置
    /// <summary>
    /// 验证当前文件是否为配置文件
    /// </summary>
    /// <param name="filePath">文件路径</param>
    /// <returns></returns>
    public static bool IsConfig(string filePath)
    {
        return true;
    }
    #endregion

    #region Camera
    /// <summary>
    /// 将源摄像机状态克隆到目标相机
    /// </summary>
    /// <param name="src">源相机</param>
    /// <param name="dest">目标相机</param>
    public static void CloneCameraModes(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;
    }

    /// <summary>
    /// 计算反射矩阵
    /// </summary>
    /// <param name="reflectionMat">原始矩阵</param>
    /// <param name="plane">反射平面</param>
    /// <returns>反射矩阵</returns>
    public static Matrix4x4 CalculateReflectionMatrix(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;
        return reflectionMat;
    }

    /// <summary>
    /// 计算指定平面在摄像机中的空间位置
    /// </summary>
    /// <param name="cam">摄像机</param>
    /// <param name="pos">平面上的点</param>
    /// <param name="normal">平面法线</param>
    /// <param name="sideSign">1：平面正面，-1：平面反面</param>
    /// <param name="clipPlaneOffset">平面法线位置偏移量</param>
    /// <returns></returns>
    public static Vector4 CameraSpacePlane(Camera cam, Vector3 pos, Vector3 normal, float sideSign,float clipPlaneOffset)
    {        
        Vector3 offsetPos = pos + normal * 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));
    }

    /// <summary>
    /// 由剪裁面计算投影倾斜矩阵
    /// </summary>
    /// <param name="projection">投影矩阵</param>
    /// <param name="clipPlane">剪裁面</param>
    public static Matrix4x4 CalculateObliqueMatrix(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];
        return projection;
    }

    private static float sgn(float a)
    {
        if (a > 0.0f) return 1.0f;
        if (a < 0.0f) return -1.0f;
        return 0.0f;
    }
    #endregion
}


Shader
Shader "GameCore/SpecialEffect/Reflection" {
	Properties {
		_ReflectionTex ("Reflection", 2D) = "white" { TexGen ObjectLinear }
		_ReflectionColor("Color",Color) = (1,1,1,0.5)
	}
   SubShader {
		Tags { "Queue"="Transparent" "RenderType"="Transparent"}
		LOD 100	
		Blend SrcAlpha OneMinusSrcAlpha
		Pass {
			CGPROGRAM
				#pragma vertex vert
				#pragma fragment frag
				#include "UnityCG.cginc"

				uniform float4x4 _ProjMatrix;				
				uniform sampler2D _ReflectionTex;
				float4 _ReflectionColor;
				struct v2f {
					float4 pos : SV_POSITION;
					float3 uv : TEXCOORD0;
				};
									
				v2f vert(appdata_tan v) {
					v2f o;
					o.pos = mul (UNITY_MATRIX_MVP,v.vertex);
					float3 viewDir = ObjSpaceViewDir(v.vertex);
					o.uv = mul( _ProjMatrix,float4(viewDir,0));					
					return o;
				}
									
				float4 frag(v2f i) : COLOR {
					half4 reflcol = tex2Dproj( _ReflectionTex,i.uv);					
					return reflcol*_ReflectionColor;
				}
			ENDCG
		}
	}
}

源码链接: http://pan.baidu.com/s/1i3HrY7b 密码: dupd