Unity 3D 海水的实现2 折射与反射 离屏相机的渲染.doc

Unity 3D 海水的实现2 折射与反射 离屏相机的渲染接下来的目标是实现海水的折射和反射，书中使用的Unity应该是4.x时代的，Unity自带基础包是5.x的，然后我再在网上看了一个例子，看了下来基本原理都差不多。 还记得移动端简单阴影的实现吧，对，就是添加一个相机把照到的玩家传给Shader后，显示在地上，原理是一样的。 首先获取到玩家的相机，新建相机到玩家当前相机，经过一个反射矩阵的旋转后，截取海平面以上的渲染，然后再将渲染出来的Texture传递给Shader处理；折射更加简单，不用矩阵旋转，当前位置的海平面以下渲染出Texture，再传递给Shader。 下面是代码，生成Mesh的代码，我就去掉了：csharp view plain copy 在CODE上查看代码片派生到我的代码片public class Ocean : MonoBehaviour / 一片区域网格横纵数量 public int width = 32; public int height = 32; int g_height; / 组成网格横纵的线条数量 int g_width; Vector2 sizeInv; / 区域的数量和大小 public int tiles = 2; public Vector3 size = new Vector3(150f, 1f, 150f); / 材质 public Material material; public Shader oceanShader; public Transform player; public Transform sun; public Vector4 SunDir; / 网格相关 Vector3 vertices; /顶点 Vector3 normals; /法线 Vector4 tangents; /三角 Mesh baseMesh; / LOD，越在靠后List的Mesh，网格越少 int maxLOD = 4; ListList tiles_LOD; / 折射反射相关 public bool renderReflection = true; /是否启用反射折射 public int renderTexWidth = 128; public int renderTexHeight = 128; RenderTexture reflectionTexture = null; RenderTexture refractionTexture = null; Camera offscreenCam = null; bool reflectionRefractionEnabled = false; /是否初始化完成 / Use this for initialization void Start() / 折射反射 sizeInv = new Vector2(1f / size.x, 1f / size.z); SetupOffscreenRendering(); / 添加离屏相机 if (!renderReflection) EnableReflection(false); else EnableReflection(true); / 计算线条数量 g_height = height + 1; g_width = width + 1; / LOD，Mesh所在的List的LOD List编号越小，Mesh的网格越多 tiles_LOD = new ListList(); for (int LOD = 0; LOD maxLOD; LOD+) tiles_LOD.Add(new List(); for (int y = 0; y tiles; +y) for (int x = 0; x tiles; +x) Debug.Log(创建了一片水); float cy = y - Mathf.Floor(tiles * 0.5f); float cx = x - Mathf.Floor(tiles * 0.5f); / 创建一片水 GameObject tile = new GameObject(WaterTile); / 坐标以当前节点为中心 tile.transform.parent = transform; tile.transform.localPosition = new Vector3(cx * size.x, 0f, cy * size.z); / 添加Mesh渲染组件 tile.AddComponent(); tile.AddComponent().material = material; tile.layer = LayerMask.NameToLayer(Water); tiles_LOD0.Add(tile.GetComponent().mesh); GenerateHeightmap(); / 设置折射反射 void SetupOffscreenRendering() / 创建折射反射图 RecalculateRenderTextures(); / 创建Camera实现离屏渲染 GameObject cam = new GameObject(); = DeepWaterOffscreenCam; cam.transform.parent = transform; offscreenCam = cam.AddComponent(); offscreenCam.clearFlags = CameraClearFlags.Color; offscreenCam.depth = -1; offscreenCam.enabled = false; / 当设置reflection和refraction被禁用的时候，设置lod为1 void EnableReflection(bool isActive) renderReflection = isActive; if (!isActive) / 关闭反射折射，使用波光粼粼的图片替代 material.SetTexture(_Reflection, null); material.SetTexture(_Refraction, null); oceanShader.maximumLOD = 1; else / 启用反射折射 OnDisable(); oceanShader.maximumLOD = 2; RecalculateRenderTextures(); / 重新生成反射折射的缓存图片 void RecalculateRenderTextures() if (renderReflection) reflectionTexture = new RenderTexture(renderTexWidth, renderTexHeight, 0); refractionTexture = new RenderTexture(renderTexWidth, renderTexHeight, 0); reflectionTexture.wrapMode = TextureWrapMode.Clamp; refractionTexture.wrapMode = TextureWrapMode.Clamp; reflectionTexture.isPowerOfTwo = true; refractionTexture.isPowerOfTwo = true; material.SetTexture(_Reflection, reflectionTexture); material.SetTexture(_Refraction, refractionTexture); material.SetVector(_Size, new Vector4(size.x, size.y, size.z, 0f); / 删除反射折射使用的缓存图片 void OnDisable() if (reflectionTexture != null) DestroyImmediate(reflectionTexture); if (refractionTexture != null) DestroyImmediate(refractionTexture); reflectionTexture = null; refractionTexture = null; / 折射反射渲染物体 void RenderObject() if (Camera.current = offscreenCam) return; if (reflectionTexture = null | refractionTexture = null) return; if (renderReflection) RenderReflectionAndRefraction(); public LayerMask renderLayers = -1; / 具体的渲染，使用第二个相机拷贝当前相机的设置 void RenderReflectionAndRefraction() / 获取当前角色身上的主相机 Camera renderCamera = Camera.main; Matrix4x4 originalWorldToCam = renderCamera.worldToCameraMatrix; / 获取世界到相机的矩阵，如果改变了相机的矩阵就不会再根据原Transform渲染，除非调用ResetWorldToCameraMatrix int cullingMask = (1 4) & renderLayers.value; /剪裁Mask，忽略水本身 / 计算反射矩阵 float d = -transform.position.y; Matrix4x4 lection = Matrix4x4.zero; CameraHelper.CalculateReflectionMatrix(ref reflection, new Vector4(0f, 1f, 0f, d); /这里不明白，总是弄出了反射矩阵 / 根据反射矩阵计算离屏相机位置和矩阵 offscreenCam.backgroundColor = RenderSettings.fogColor; offscreenCam.transform.position = reflection.MultiplyPoint(renderCamera.transform.position); /当前相机置换到反射矩阵中 offscreenCam.transform.rotation = renderCamera.transform.rotation; offscreenCam.worldToCameraMatrix = originalWorldToCam * reflection; offscreenCam.cullingMask = cullingMask; /设置剪裁mask offscreenCam.targetTexture = reflectionTexture; /将反射缓存图片添加到离屏相机里，跟之前阴影是一个原理 / 因为反射截取到的图片是翻转的，所以需要设置翻转 GL.SetRevertBackfacing(true); / 获取剪裁平面，transform.position.y是当前海水的高度，最后两个值的正负表示剪裁的方向 Vector4 cameraSpaceClipPlane = CameraHelper.CameraSpacePlane(offscreenCam, new Vector3(0.0f, transform.position.y, 0.0f), Vector3.up, 1.0f); Matrix4x4 projection = renderCjectionMatrix; /获得渲染相机的投影矩阵 Matrix4x4 obliqueProjection = projection; offscreenCam.fieldOfView = renderCamera.fieldOfView; /设置FOV offscreenCam.aspect = renderCamera.aspect; /设置宽高比 CameraHelper.CalculateObliqueMatrix(ref obliqueProjection, cameraSpaceClipPlane); / 开始真正的渲染 offscreenCjectionMatrix = obliqueProjection; if (!renderReflection) offscreenCam.cullingMask = 0; offscreenCam.Render(); GL.SetRevertBackfacing(false); / 折射渲染 offscreenCam.cullingMask = cullingMask; offscreenCam.targetTexture = refractionTexture; obliqueProjection = projection; / 将渲染相机的各个参数设置给离屏相机 offscreenCam.transform.position = renderCamera.transform.position; offscreenCam.transform.rotation = renderCamera.transform.rotation; offscreenCam.worldToCameraMatrix = originalWorldToCam; / 获取剪裁平面，计算投影矩阵 cameraSpaceClipPlane = CameraHelper.CameraSpacePlane(offscreenCam, new Vector3(0.0f, transform.position.y, 0.0f), Vector3.up, -1.0f); CameraHelper.CalculateObliqueMatrix(ref obliqueProjection, cameraSpaceClipPlane); offscreenCjectionMatrix = obliqueProjection; offscreenCam.Render(); offscreenCjectionMatrix = projection; offscreenCam.targetTexture = null; / 初始化Mesh信息，请参考上一节 void GenerateHeightmap() / 这边应该是Update的，但写在Update中会报GUI Window tries to begin rendering while something else has not ished rendering的错误 void OnGUI() / 设置玩家、太阳角度，并更新反射折射，折射反射是根据玩家视角来计算的 if (player = null) player = GameObject.FindGameObjectWithTag(Player).GetComponent(); if (sun != null) SunDir = sun.transform.forward; material.SetVector(_SunDir, SunDir); if (renderReflection) RenderObject(); 然后是CameraHelper的脚本：csharp view plain copy 在CODE上查看代码片派生到我的代码片public class CameraHelper private static float sgn(float a) if (a 0.0f) return 1.0f; if (a 0.0f) return -1.0f; return 0.0f; public 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); projection2 = c.x - projection3; projection6 = c.y - projection7; projection10 = c.z - projection11; projection14 = c.w - projection15; public static Vector4 CameraSpacePlane(Camera cam, Vector3 pos, Vector3 normal, float sideSign) Vector3 offsetPos = pos + normal * 0.02f; 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); public static void CalculateReflectionMatrix(ref Matrix4x4 reflectionMat, Vector4 plane) reflectionMat.m00 = (1F - 2F * plane0 * plane0); reflectionMat.m01 = (-2F * plane0 * plane1); reflectionMat.m02 = (-2F * plane0 * plane2); reflectionMat.m03 = (-2F * plane0 * plane3); reflectionMat.m10 = (-2F * plane1 * plane0); reflectionMat.m11 = (1F - 2F * plane1 * plane1); reflectionMat.m12 = (-2F * plane1 * plane2); reflectionMat.m13 = (-2F * plane1 * plane3); reflectionMat.m20 = (-2F * plane2 * plan