3D系列4.10 完美镜像

你是否问过自己如何在游戏中创建一面镜子?它们的工作原理就像水面:首先,从镜子中看到的场景被绘制到一张纹理。然后,这张纹理覆盖在镜子上。

上一章我们学习了如何绘制反射纹理,本章我们将把这张纹理贴在镜面上:即水面上。通过这种方式,水面看起来好像一面漂亮的镜子。这是通过投影纹理实现的,可参见教程3的相关章节。上一章我们绘制了反射贴图,本章我们可以创建水面了。

我们只使用两个大三角形放置反射纹理。所以首先定义顶点缓冲和顶点声明:

VertexBuffer waterVertexBuffer; 
VertexDeclaration waterVertexDeclaration; 

下面的方法创建两个覆盖整个水面的三角形:

private void SetUpWaterVertices()
 {
     VertexPositionTexture[] waterVertices = new VertexPositionTexture[6];
 
     waterVertices[0] = new VertexPositionTexture(new Vector3(0, waterHeight, 0), new Vector2(0, 1));
     waterVertices[2] = new VertexPositionTexture(new Vector3(terrainWidth, waterHeight, -terrainLength), new Vector2(1, 0));
     waterVertices[1] = new VertexPositionTexture(new Vector3(0, waterHeight, -terrainLength), new Vector2(0, 0));
 
     waterVertices[3] = new VertexPositionTexture(new Vector3(0, waterHeight, 0), new Vector2(0, 1));
     waterVertices[5] = new VertexPositionTexture(new Vector3(terrainWidth, waterHeight, 0), new Vector2(1, 1));
     waterVertices[4] = new VertexPositionTexture(new Vector3(terrainWidth, waterHeight, -terrainLength), new Vector2(1, 0));
 
     waterVertexBuffer = new VertexBuffer(device, waterVertices.Length * VertexPositionTexture.SizeInBytes, BufferUsage.WriteOnly);
     waterVertexBuffer.SetData(waterVertices);
 }

虽然严格的说你无需传递纹理坐标就能实现投影纹理(因为纹理坐标是在顶点着色器中计算的),但本系列的后面我们需要在这指定纹理坐标,所以我们使用VertexPositionTexture类型的顶点。

这个方法的其他部分来自于第一个系列。别忘了在LoadVertices 方法中调用这个方法:

SetUpWaterVertices(); 
waterVertexDeclaration = new VertexDeclaration(device, VertexPositionTexture.VertexElements);

这个方法绘制了两个三角形,使用接下来要创建的Water technique:

private void DrawWater(float time)
 {
     effect.CurrentTechnique = effect.Techniques["Water"];
     Matrix worldMatrix = Matrix.Identity;
     effect.Parameters["xWorld"].SetValue(worldMatrix);
     effect.Parameters["xView"].SetValue(viewMatrix);
     effect.Parameters["xReflectionView"].SetValue(reflectionViewMatrix);
     effect.Parameters["xProjection"].SetValue(projectionMatrix);
     effect.Parameters["xReflectionMap"].SetValue(reflectionMap);
     effect.Parameters["xRefractionMap"].SetValue(refractionMap);
 
     effect.Begin();
     foreach (EffectPass pass in effect.CurrentTechnique.Passes)
     {
         pass.Begin();
 
         device.Vertices[0].SetSource(waterVertexBuffer, 0, VertexPositionTexture.SizeInBytes);
         device.VertexDeclaration = waterVertexDeclaration;
         int noVertices = waterVertexBuffer.SizeInBytes / VertexPositionTexture.SizeInBytes;
         device.DrawPrimitives(PrimitiveType.TriangleList, 0, noVertices / 3);
 
         pass.End();
     }
     effect.End();
 }

我们传递了上两章创建的贴图。我们只需在Draw 方法底部调用这个方法,而不是从DrawRefectionMap或DrawRefractionMap (试着找出这样做的原因)方法中调用:

DrawWater(time); 

让我们看一下HLSL代码,快速复习一下系列3中的代码,下面是必须的HLSL变量:

float4x4 xReflectionView;
Texture xReflectionMap;

sampler ReflectionSampler = sampler_state { texture = <xReflectionMap> ; magfilter = LINEAR; minfilter = LINEAR; mipfilter=LINEAR; AddressU = mirror; AddressV = mirror;};
Texture xRefractionMap;

sampler RefractionSampler = sampler_state { texture = <xRefractionMap> ; magfilter = LINEAR; minfilter = LINEAR; mipfilter=LINEAR; AddressU = mirror; AddressV = mirror;};

新technique的结构:

//------- Technique: Water -------- 
struct WVertexToPixel
{
    float4 Position : POSITION; 
    float4 ReflectionMapSamplingPos : TEXCOORD1; 
}; 

struct WPixelToFrame 
{
    float4 Color : COLOR0; 
};

因为两个三角形是平的,我们无需传递法线数据;我们知道它是指向上方的。我们只需计算反射贴图的采样坐标。代码来自于系列3:

WVertexToPixel WaterVS(float4 inPos : POSITION, float2 inTex: TEXCOORD)
{    
    WVertexToPixel Output = (WVertexToPixel)0;

    float4x4 preViewProjection = mul (xView, xProjection);
    float4x4 preWorldViewProjection = mul (xWorld, preViewProjection);
    float4x4 preReflectionViewProjection = mul (xReflectionView, xProjection);
    float4x4 preWorldReflectionViewProjection = mul (xWorld, preReflectionViewProjection);

    Output.Position = mul(inPos, preWorldViewProjection);
    Output.ReflectionMapSamplingPos = mul(inPos, preWorldReflectionViewProjection);

    return Output;
}

我们只计算两个输出值:当前顶点的2D平面坐标和从相机看起来的对应2D位置。我们使用第二个2D位置作为反射纹理的采样坐标,代码还是来自于系列3:

WPixelToFrame WaterPS(WVertexToPixel PSIn)
{
    WPixelToFrame Output = (WPixelToFrame)0;        
    
    float2 ProjectedTexCoords;
    ProjectedTexCoords.x = PSIn.ReflectionMapSamplingPos.x/PSIn.ReflectionMapSamplingPos.w/2.0f + 0.5f;
    ProjectedTexCoords.y = -PSIn.ReflectionMapSamplingPos.y/PSIn.ReflectionMapSamplingPos.w/2.0f + 0.5f;    

    Output.Color = tex2D(ReflectionSampler, ProjectedTexCoords);    
    
    return Output;
}

还有technique定义:

technique Water 
{
    pass Pass0 
    {
        VertexShader = compile vs_1_1 WaterVS(); 
        PixelShader = compile ps_2_0 WaterPS(); 
    }
} 

当运行代码时,你可以看到以下截图:

程序截图

这是非常重要的一步,一个重要的改进是在水面上添加一些波浪,这将在下一章中进行。

下面是XNA代码,红色部分为相对于上一章添加的代码:

using System;
 using System.Collections.Generic;
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Audio;
 using Microsoft.Xna.Framework.Content;
 using Microsoft.Xna.Framework.GamerServices;
 using Microsoft.Xna.Framework.Graphics;
 using Microsoft.Xna.Framework.Input;
 using Microsoft.Xna.Framework.Net;
 using Microsoft.Xna.Framework.Storage;
 
 namespace XNAseries4
 {
     public struct VertexMultitextured
     {
         public Vector3 Position;
         public Vector3 Normal;
         public Vector4 TextureCoordinate;
         public Vector4 TexWeights;
 
         public static int SizeInBytes = (3 + 3 + 4 + 4) * sizeof(float);
         public static VertexElement[] VertexElements = new VertexElement[]
         {
             new VertexElement( 0, 0, VertexElementFormat.Vector3, VertexElementMethod.Default, VertexElementUsage.Position, 0 ),
             new VertexElement( 0, sizeof(float) * 3, VertexElementFormat.Vector3, VertexElementMethod.Default, VertexElementUsage.Normal, 0 ),
             new VertexElement( 0, sizeof(float) * 6, VertexElementFormat.Vector4, VertexElementMethod.Default, VertexElementUsage.TextureCoordinate, 0 ),
             new VertexElement( 0, sizeof(float) * 10, VertexElementFormat.Vector4, VertexElementMethod.Default, VertexElementUsage.TextureCoordinate, 1 ),
         };
     }
 
     public class Game1 : Microsoft.Xna.Framework.Game
     {
         GraphicsDeviceManager graphics;
         GraphicsDevice device;
 
         int terrainWidth;
         int terrainLength;
         float[,] heightData;
 
         VertexBuffer terrainVertexBuffer;
         IndexBuffer terrainIndexBuffer;
         VertexDeclaration terrainVertexDeclaration;
 
         VertexBuffer waterVertexBuffer;
         VertexDeclaration waterVertexDeclaration;
 
         Effect effect;
         Matrix viewMatrix;
         Matrix projectionMatrix;
         Matrix reflectionViewMatrix;
 
         Vector3 cameraPosition = new Vector3(130, 30, -50);
         float leftrightRot = MathHelper.PiOver2;
         float updownRot = -MathHelper.Pi / 10.0f;
         const float rotationSpeed = 0.3f;
         const float moveSpeed = 30.0f;
         MouseState originalMouseState;
 
         Texture2D grassTexture;
         Texture2D sandTexture;
         Texture2D rockTexture;
         Texture2D snowTexture;
         Texture2D cloudMap;
         
         Model skyDome;
 
         const float waterHeight = 5.0f;        
         RenderTarget2D refractionRenderTarget;
         Texture2D refractionMap;
         RenderTarget2D reflectionRenderTarget;
         Texture2D reflectionMap;
 
         public Game1()
         {
             graphics = new GraphicsDeviceManager(this);
             Content.RootDirectory = "Content";
         }
 
         protected override void Initialize()
         {
             graphics.PreferredBackBufferWidth = 500;
             graphics.PreferredBackBufferHeight = 500;
 
             graphics.ApplyChanges();
             Window.Title = "Riemer's XNA Tutorials -- Series 4";
 
             base.Initialize();
         }
 
         protected override void LoadContent()
         {
             device = GraphicsDevice;

            effect = Content.Load<Effect> ("Series4Effects");
            UpdateViewMatrix();
            projectionMatrix = Matrix.CreatePerspectiveFieldOfView(MathHelper.PiOver4, device.Viewport.AspectRatio, 0.3f, 1000.0f);

            Mouse.SetPosition(device.Viewport.Width / 2, device.Viewport.Height / 2);
            originalMouseState = Mouse.GetState();


            skyDome = Content.Load<Model> ("dome");            skyDome.Meshes[0].MeshParts[0].Effect = effect.Clone(device);

            PresentationParameters pp = device.PresentationParameters;
            refractionRenderTarget = new RenderTarget2D(device, pp.BackBufferWidth, pp.BackBufferHeight, 1, device.DisplayMode.Format);
            reflectionRenderTarget = new RenderTarget2D(device, pp.BackBufferWidth, pp.BackBufferHeight, 1, device.DisplayMode.Format);

            LoadVertices();
            LoadTextures();
        }

        private void LoadVertices()
        {

            Texture2D heightMap = Content.Load<Texture2D> ("heightmap");            LoadHeightData(heightMap);

            VertexMultitextured[] terrainVertices = SetUpTerrainVertices();
            int[] terrainIndices = SetUpTerrainIndices();
            terrainVertices = CalculateNormals(terrainVertices, terrainIndices);
            CopyToTerrainBuffers(terrainVertices, terrainIndices);
            terrainVertexDeclaration = new VertexDeclaration(device, VertexMultitextured.VertexElements);


             SetUpWaterVertices();
             waterVertexDeclaration = new VertexDeclaration(device, VertexPositionTexture.VertexElements);
         }
 
         private void LoadTextures()
         {

            grassTexture = Content.Load<Texture2D> ("grass");
            sandTexture = Content.Load<Texture2D> ("sand");
            rockTexture = Content.Load<Texture2D> ("rock");
            snowTexture = Content.Load<Texture2D> ("snow");
            cloudMap = Content.Load<Texture2D> ("cloudMap");        }

        private void LoadHeightData(Texture2D heightMap)
        {
            float minimumHeight = float.MaxValue;
            float maximumHeight = float.MinValue;

            terrainWidth = heightMap.Width;
            terrainLength = heightMap.Height;

            Color[] heightMapColors = new Color[terrainWidth * terrainLength];
            heightMap.GetData(heightMapColors);

            heightData = new float[terrainWidth, terrainLength];
            for (int x = 0; x < terrainWidth; x++)
                for (int y = 0; y < terrainLength; y++)
                {
                    heightData[x, y] = heightMapColors[x + y * terrainWidth].R;
                    if (heightData[x, y] < minimumHeight) minimumHeight = heightData[x, y];
                    if (heightData[x, y] > maximumHeight) maximumHeight = heightData[x, y];
                }

            for (int x = 0; x < terrainWidth; x++)
                for (int y = 0; y < terrainLength; y++)
                    heightData[x, y] = (heightData[x, y] - minimumHeight) / (maximumHeight - minimumHeight) * 30.0f;
        }

        private VertexMultitextured[] SetUpTerrainVertices()
        {
            VertexMultitextured[] terrainVertices = new VertexMultitextured[terrainWidth * terrainLength];

            for (int x = 0; x < terrainWidth; x++)
            {
                for (int y = 0; y < terrainLength; y++)
                {
                    terrainVertices[x + y * terrainWidth].Position = new Vector3(x, heightData[x, y], -y);
                    terrainVertices[x + y * terrainWidth].TextureCoordinate.X = (float)x / 30.0f;
                    terrainVertices[x + y * terrainWidth].TextureCoordinate.Y = (float)y / 30.0f;

                    terrainVertices[x + y * terrainWidth].TexWeights.X = MathHelper.Clamp(1.0f - Math.Abs(heightData[x, y] - 0) / 8.0f, 0, 1);
                    terrainVertices[x + y * terrainWidth].TexWeights.Y = MathHelper.Clamp(1.0f - Math.Abs(heightData[x, y] - 12) / 6.0f, 0, 1);
                    terrainVertices[x + y * terrainWidth].TexWeights.Z = MathHelper.Clamp(1.0f - Math.Abs(heightData[x, y] - 20) / 6.0f, 0, 1);
                    terrainVertices[x + y * terrainWidth].TexWeights.W = MathHelper.Clamp(1.0f - Math.Abs(heightData[x, y] - 30) / 6.0f, 0, 1);

                    float total = terrainVertices[x + y * terrainWidth].TexWeights.X;
                    total += terrainVertices[x + y * terrainWidth].TexWeights.Y;
                    total += terrainVertices[x + y * terrainWidth].TexWeights.Z;
                    total += terrainVertices[x + y * terrainWidth].TexWeights.W;

                    terrainVertices[x + y * terrainWidth].TexWeights.X /= total;
                    terrainVertices[x + y * terrainWidth].TexWeights.Y /= total;
                    terrainVertices[x + y * terrainWidth].TexWeights.Z /= total;
                    terrainVertices[x + y * terrainWidth].TexWeights.W /= total;
                }
            }

            return terrainVertices;
        }

        private int[] SetUpTerrainIndices()
        {
            int[] indices = new int[(terrainWidth - 1) * (terrainLength - 1) * 6];
            int counter = 0;
            for (int y = 0; y < terrainLength - 1; y++)
            {
                for (int x = 0; x < terrainWidth - 1; x++)
                {
                    int lowerLeft = x + y * terrainWidth;
                    int lowerRight = (x + 1) + y * terrainWidth;
                    int topLeft = x + (y + 1) * terrainWidth;
                    int topRight = (x + 1) + (y + 1) * terrainWidth;

                    indices[counter++] = topLeft;
                    indices[counter++] = lowerRight;
                    indices[counter++] = lowerLeft;

                    indices[counter++] = topLeft;
                    indices[counter++] = topRight;
                    indices[counter++] = lowerRight;
                }
            }

            return indices;
        }

        private VertexMultitextured[] CalculateNormals(VertexMultitextured[] vertices, int[] indices)
        {
            for (int i = 0; i < vertices.Length; i++)
                vertices[i].Normal = new Vector3(0, 0, 0);

            for (int i = 0; i < indices.Length / 3; i++)
            {
                int index1 = indices[i * 3];
                int index2 = indices[i * 3 + 1];
                int index3 = indices[i * 3 + 2];

                Vector3 side1 = vertices[index1].Position - vertices[index3].Position;
                Vector3 side2 = vertices[index1].Position - vertices[index2].Position;
                Vector3 normal = Vector3.Cross(side1, side2);

                vertices[index1].Normal += normal;
                vertices[index2].Normal += normal;
                vertices[index3].Normal += normal;
            }

            for (int i = 0; i < vertices.Length; i++)
                vertices[i].Normal.Normalize();

            return vertices;
        }

        private void CopyToTerrainBuffers(VertexMultitextured[] vertices, int[] indices)
        {
            terrainVertexBuffer = new VertexBuffer(device, vertices.Length * VertexMultitextured.SizeInBytes, BufferUsage.WriteOnly);
            terrainVertexBuffer.SetData(vertices);

            terrainIndexBuffer = new IndexBuffer(device, typeof(int), indices.Length, BufferUsage.WriteOnly);
            terrainIndexBuffer.SetData(indices);
        }


         private void SetUpWaterVertices()
         {
             VertexPositionTexture[] waterVertices = new VertexPositionTexture[6];
 
             waterVertices[0] = new VertexPositionTexture(new Vector3(0, waterHeight, 0), new Vector2(0, 1));
             waterVertices[2] = new VertexPositionTexture(new Vector3(terrainWidth, waterHeight, -terrainLength), new Vector2(1, 0));
             waterVertices[1] = new VertexPositionTexture(new Vector3(0, waterHeight, -terrainLength), new Vector2(0, 0));
 
             waterVertices[3] = new VertexPositionTexture(new Vector3(0, waterHeight, 0), new Vector2(0, 1));
             waterVertices[5] = new VertexPositionTexture(new Vector3(terrainWidth, waterHeight, 0), new Vector2(1, 1));
             waterVertices[4] = new VertexPositionTexture(new Vector3(terrainWidth, waterHeight, -terrainLength), new Vector2(1, 0));
 
             waterVertexBuffer = new VertexBuffer(device, waterVertices.Length * VertexPositionTexture.SizeInBytes, BufferUsage.WriteOnly);
             waterVertexBuffer.SetData(waterVertices);
         }
 
         protected override void UnloadContent()
         {
         }
 
         protected override void Update(GameTime gameTime)
         {
             if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                 this.Exit();
 
             float timeDifference = (float)gameTime.ElapsedGameTime.TotalMilliseconds / 1000.0f;
             ProcessInput(timeDifference);
 
             base.Update(gameTime);
         }
 
         private void ProcessInput(float amount)
         {
             MouseState currentMouseState = Mouse.GetState();
             if (currentMouseState != originalMouseState)
             {
                 float xDifference = currentMouseState.X - originalMouseState.X;
                 float yDifference = currentMouseState.Y - originalMouseState.Y;
                 leftrightRot -= rotationSpeed * xDifference * amount;
                 updownRot -= rotationSpeed * yDifference * amount;
                 Mouse.SetPosition(device.Viewport.Width / 2, device.Viewport.Height / 2);
                 UpdateViewMatrix();
             }
 
             Vector3 moveVector = new Vector3(0, 0, 0);
             KeyboardState keyState = Keyboard.GetState();
             if (keyState.IsKeyDown(Keys.Up) || keyState.IsKeyDown(Keys.W))
                 moveVector += new Vector3(0, 0, -1);
             if (keyState.IsKeyDown(Keys.Down) || keyState.IsKeyDown(Keys.S))
                 moveVector += new Vector3(0, 0, 1);
             if (keyState.IsKeyDown(Keys.Right) || keyState.IsKeyDown(Keys.D))
                 moveVector += new Vector3(1, 0, 0);
             if (keyState.IsKeyDown(Keys.Left) || keyState.IsKeyDown(Keys.A))
                 moveVector += new Vector3(-1, 0, 0);
             if (keyState.IsKeyDown(Keys.Q))
                 moveVector += new Vector3(0, 1, 0);
             if (keyState.IsKeyDown(Keys.Z))
                 moveVector += new Vector3(0, -1, 0);
             AddToCameraPosition(moveVector * amount);
         }
 
         private void AddToCameraPosition(Vector3 vectorToAdd)
         {
             Matrix cameraRotation = Matrix.CreateRotationX(updownRot) * Matrix.CreateRotationY(leftrightRot);
             Vector3 rotatedVector = Vector3.Transform(vectorToAdd, cameraRotation);
             cameraPosition += moveSpeed * rotatedVector;
             UpdateViewMatrix();
         }
 
         private void UpdateViewMatrix()
         {
             Matrix cameraRotation = Matrix.CreateRotationX(updownRot) * Matrix.CreateRotationY(leftrightRot);
 
             Vector3 cameraOriginalTarget = new Vector3(0, 0, -1);
             Vector3 cameraOriginalUpVector = new Vector3(0, 1, 0);
             Vector3 cameraRotatedTarget = Vector3.Transform(cameraOriginalTarget, cameraRotation);
             Vector3 cameraFinalTarget = cameraPosition + cameraRotatedTarget;
             Vector3 cameraRotatedUpVector = Vector3.Transform(cameraOriginalUpVector, cameraRotation);
 
             viewMatrix = Matrix.CreateLookAt(cameraPosition, cameraFinalTarget, cameraRotatedUpVector);
 
             Vector3 reflCameraPosition = cameraPosition;
             reflCameraPosition.Y = -cameraPosition.Y + waterHeight * 2;
             Vector3 reflTargetPos = cameraFinalTarget;
             reflTargetPos.Y = -cameraFinalTarget.Y + waterHeight * 2;
 
             Vector3 cameraRight = Vector3.Transform(new Vector3(1, 0, 0), cameraRotation);
             Vector3 invUpVector = Vector3.Cross(cameraRight, reflTargetPos - reflCameraPosition);
 
             reflectionViewMatrix = Matrix.CreateLookAt(reflCameraPosition, reflTargetPos, invUpVector);
         }
 
         protected override void Draw(GameTime gameTime)
         {
             float time = (float)gameTime.TotalGameTime.TotalMilliseconds / 100.0f;
 
             DrawRefractionMap();
             DrawReflectionMap();
 
             device.Clear(ClearOptions.Target | ClearOptions.DepthBuffer, Color.Black, 1.0f, 0);
             DrawSkyDome(viewMatrix);
             DrawTerrain(viewMatrix);
             DrawWater(time);
 
             base.Draw(gameTime);
         }
 
         private void DrawTerrain(Matrix currentViewMatrix)
         {
             effect.CurrentTechnique = effect.Techniques["MultiTextured"];
             effect.Parameters["xTexture0"].SetValue(sandTexture);
             effect.Parameters["xTexture1"].SetValue(grassTexture);
             effect.Parameters["xTexture2"].SetValue(rockTexture);
             effect.Parameters["xTexture3"].SetValue(snowTexture);
 
             Matrix worldMatrix = Matrix.Identity;
             effect.Parameters["xWorld"].SetValue(worldMatrix);
             effect.Parameters["xView"].SetValue(currentViewMatrix);
             effect.Parameters["xProjection"].SetValue(projectionMatrix);            
 
             effect.Parameters["xEnableLighting"].SetValue(true);
             effect.Parameters["xAmbient"].SetValue(0.4f);
             effect.Parameters["xLightDirection"].SetValue(new Vector3(-0.5f, -1, -0.5f));
 
             effect.Begin();
             foreach (EffectPass pass in effect.CurrentTechnique.Passes)
             {
                 pass.Begin();
 
                 device.Vertices[0].SetSource(terrainVertexBuffer, 0, VertexMultitextured.SizeInBytes);
                 device.Indices = terrainIndexBuffer;
                 device.VertexDeclaration = terrainVertexDeclaration;
 
                 int noVertices = terrainVertexBuffer.SizeInBytes / VertexMultitextured.SizeInBytes;
                 int noTriangles = terrainIndexBuffer.SizeInBytes / sizeof(int) / 3;
                 device.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, noVertices, 0, noTriangles);
 
                 pass.End();
             }
             effect.End();
         }
 
         private void DrawSkyDome(Matrix currentViewMatrix)
         {
             device.RenderState.DepthBufferWriteEnable = false;
 
             Matrix[] modelTransforms = new Matrix[skyDome.Bones.Count];
             skyDome.CopyAbsoluteBoneTransformsTo(modelTransforms);
 
             Matrix wMatrix = Matrix.CreateTranslation(0, -0.3f, 0) * Matrix.CreateScale(100) * Matrix.CreateTranslation(cameraPosition);
             foreach (ModelMesh mesh in skyDome.Meshes)
             {
                 foreach (Effect currentEffect in mesh.Effects)
                 {
                     Matrix worldMatrix = modelTransforms[mesh.ParentBone.Index] * wMatrix;
                     currentEffect.CurrentTechnique = currentEffect.Techniques["Textured"];
                     currentEffect.Parameters["xWorld"].SetValue(worldMatrix);
                     currentEffect.Parameters["xView"].SetValue(currentViewMatrix);
                     currentEffect.Parameters["xProjection"].SetValue(projectionMatrix);
                     currentEffect.Parameters["xTexture"].SetValue(cloudMap);
                     currentEffect.Parameters["xEnableLighting"].SetValue(false);
                 }
                 mesh.Draw();
             }
             device.RenderState.DepthBufferWriteEnable = true;
         }
 
         private Plane CreatePlane(float height, Vector3 planeNormalDirection, Matrix currentViewMatrix, bool clipSide)
         {
             planeNormalDirection.Normalize();
             Vector4 planeCoeffs = new Vector4(planeNormalDirection, height);
             if (clipSide)
                 planeCoeffs *= -1;
 
             Matrix worldViewProjection = currentViewMatrix * projectionMatrix;
             Matrix inverseWorldViewProjection = Matrix.Invert(worldViewProjection);
             inverseWorldViewProjection = Matrix.Transpose(inverseWorldViewProjection);
 
             planeCoeffs = Vector4.Transform(planeCoeffs, inverseWorldViewProjection);
             Plane finalPlane = new Plane(planeCoeffs);
 
             return finalPlane;
         }
 
         private void DrawRefractionMap()
         {
             Plane refractionPlane = CreatePlane(waterHeight + 1.5f, new Vector3(0,-1,0), viewMatrix, false);
             device.ClipPlanes[0].Plane = refractionPlane;
             device.ClipPlanes[0].IsEnabled = true;
             device.SetRenderTarget(0, refractionRenderTarget);
             device.Clear(ClearOptions.Target | ClearOptions.DepthBuffer, Color.Black, 1.0f, 0);
             DrawTerrain(viewMatrix);
             device.ClipPlanes[0].IsEnabled = false;
 
             device.SetRenderTarget(0, null);
             refractionMap = refractionRenderTarget.GetTexture();
         }
 
         private void DrawReflectionMap()
         {
             Plane reflectionPlane = CreatePlane(waterHeight - 0.5f, new Vector3(0,-1,0), reflectionViewMatrix, true);
             device.ClipPlanes[0].Plane = reflectionPlane;
             device.ClipPlanes[0].IsEnabled = true;
             device.SetRenderTarget(0, reflectionRenderTarget);
             device.Clear(ClearOptions.Target | ClearOptions.DepthBuffer, Color.Black, 1.0f, 0);
             DrawTerrain(reflectionViewMatrix);
             DrawSkyDome(reflectionViewMatrix);            
             device.ClipPlanes[0].IsEnabled = false;
 
             device.SetRenderTarget(0, null);
             reflectionMap = reflectionRenderTarget.GetTexture();            
         }
 
         private void DrawWater(float time)
         {
             effect.CurrentTechnique = effect.Techniques["Water"];
             Matrix worldMatrix = Matrix.Identity;
             effect.Parameters["xWorld"].SetValue(worldMatrix);
             effect.Parameters["xView"].SetValue(viewMatrix);
             effect.Parameters["xReflectionView"].SetValue(reflectionViewMatrix);
             effect.Parameters["xProjection"].SetValue(projectionMatrix);
             effect.Parameters["xReflectionMap"].SetValue(reflectionMap);
             effect.Parameters["xRefractionMap"].SetValue(refractionMap);
 
             effect.Begin();
             foreach (EffectPass pass in effect.CurrentTechnique.Passes)
             {
                 pass.Begin();
 
                 device.Vertices[0].SetSource(waterVertexBuffer, 0, VertexPositionTexture.SizeInBytes);
                 device.VertexDeclaration = waterVertexDeclaration;
                 int noVertices = waterVertexBuffer.SizeInBytes / VertexPositionTexture.SizeInBytes;
                 device.DrawPrimitives(PrimitiveType.TriangleList, 0, noVertices / 3);
 
                 pass.End();
             }
             effect.End();
         }
     }
 }

下面是HLSL文件:

//----------------------------------------------------
//--                                                --
//--             www.riemers.net                 --
//--         Series 4: Advanced terrain             --
//--                 Shader code                    --
//--                                                --
//----------------------------------------------------

//------- Constants --------
float4x4 xView;

 float4x4 xReflectionView;

float4x4 xProjection;
float4x4 xWorld;
float3 xLightDirection;
float xAmbient;
bool xEnableLighting;

//------- Texture Samplers --------
Texture xTexture;

sampler TextureSampler = sampler_state { texture = <xTexture> ; magfilter = LINEAR; minfilter = LINEAR; mipfilter=LINEAR; AddressU = mirror; AddressV = mirror;};Texture xTexture0;

sampler TextureSampler0 = sampler_state { texture = <xTexture0> ; magfilter = LINEAR; minfilter = LINEAR; mipfilter=LINEAR; AddressU = wrap; AddressV = wrap;};Texture xTexture1;

sampler TextureSampler1 = sampler_state { texture = <xTexture1> ; magfilter = LINEAR; minfilter = LINEAR; mipfilter=LINEAR; AddressU = wrap; AddressV = wrap;};Texture xTexture2;

sampler TextureSampler2 = sampler_state { texture = <xTexture2> ; magfilter = LINEAR; minfilter = LINEAR; mipfilter=LINEAR; AddressU = mirror; AddressV = mirror;};Texture xTexture3;

sampler TextureSampler3 = sampler_state { texture = <xTexture3> ; magfilter = LINEAR; minfilter = LINEAR; mipfilter=LINEAR; AddressU = mirror; AddressV = mirror;};
 Texture xReflectionMap;

sampler ReflectionSampler = sampler_state { texture = <xReflectionMap> ; magfilter = LINEAR; minfilter = LINEAR; mipfilter=LINEAR; AddressU = mirror; AddressV = mirror;};Texture xRefractionMap;

sampler RefractionSampler = sampler_state { texture = <xRefractionMap> ; magfilter = LINEAR; minfilter = LINEAR; mipfilter=LINEAR; AddressU = mirror; AddressV = mirror;};

//------- Technique: Textured --------
struct TVertexToPixel
{
    float4 Position     : POSITION;    
    float4 Color        : COLOR0;
    float LightingFactor: TEXCOORD0;
    float2 TextureCoords: TEXCOORD1;
};

struct TPixelToFrame
{
    float4 Color : COLOR0;
};

TVertexToPixel TexturedVS( float4 inPos : POSITION, float3 inNormal: NORMAL, float2 inTexCoords: TEXCOORD0)
{    
    TVertexToPixel Output = (TVertexToPixel)0;
    float4x4 preViewProjection = mul (xView, xProjection);
    float4x4 preWorldViewProjection = mul (xWorld, preViewProjection);
    
    Output.Position = mul(inPos, preWorldViewProjection);    
    Output.TextureCoords = inTexCoords;
    
    float3 Normal = normalize(mul(normalize(inNormal), xWorld));    
    Output.LightingFactor = 1;
    if (xEnableLighting)
        Output.LightingFactor = saturate(dot(Normal, -xLightDirection));
    
    return Output;    
}

TPixelToFrame TexturedPS(TVertexToPixel PSIn)
{
    TPixelToFrame Output = (TPixelToFrame)0;        
    
    Output.Color = tex2D(TextureSampler, PSIn.TextureCoords);
    Output.Color.rgb *= saturate(PSIn.LightingFactor + xAmbient);

    return Output;
}

technique Textured_2_0
{
    pass Pass0
    {
        VertexShader = compile vs_2_0 TexturedVS();
        PixelShader = compile ps_2_0 TexturedPS();
    }
}

technique Textured
{
    pass Pass0
    {
        VertexShader = compile vs_1_1 TexturedVS();
        PixelShader = compile ps_1_1 TexturedPS();
    }
}

//------- Technique: Multitextured --------
struct MTVertexToPixel
{
    float4 Position         : POSITION;    
    float4 Color            : COLOR0;
    float3 Normal            : TEXCOORD0;
    float2 TextureCoords    : TEXCOORD1;
    float4 LightDirection    : TEXCOORD2;
    float4 TextureWeights    : TEXCOORD3;
    float Depth                : TEXCOORD4;
};

struct MTPixelToFrame
{
    float4 Color : COLOR0;
};

MTVertexToPixel MultiTexturedVS( float4 inPos : POSITION, float3 inNormal: NORMAL, float2 inTexCoords: TEXCOORD0, float4 inTexWeights: TEXCOORD1)
{    
    MTVertexToPixel Output = (MTVertexToPixel)0;
    float4x4 preViewProjection = mul (xView, xProjection);
    float4x4 preWorldViewProjection = mul (xWorld, preViewProjection);
    
    Output.Position = mul(inPos, preWorldViewProjection);
    Output.Normal = mul(normalize(inNormal), xWorld);
    Output.TextureCoords = inTexCoords;
    Output.LightDirection.xyz = -xLightDirection;
    Output.LightDirection.w = 1;    
    Output.TextureWeights = inTexWeights;
    Output.Depth = Output.Position.z/Output.Position.w;
    
    return Output;    
}

MTPixelToFrame MultiTexturedPS(MTVertexToPixel PSIn)
{
    MTPixelToFrame Output = (MTPixelToFrame)0;        
    
    float lightingFactor = 1;
    if (xEnableLighting)
        lightingFactor = saturate(saturate(dot(PSIn.Normal, PSIn.LightDirection)) + xAmbient);
        
    float blendDistance = 0.99f;
    float blendWidth = 0.005f;
    float blendFactor = clamp((PSIn.Depth-blendDistance)/blendWidth, 0, 1);
        
    float4 farColor;
    farColor = tex2D(TextureSampler0, PSIn.TextureCoords)*PSIn.TextureWeights.x;
    farColor += tex2D(TextureSampler1, PSIn.TextureCoords)*PSIn.TextureWeights.y;
    farColor += tex2D(TextureSampler2, PSIn.TextureCoords)*PSIn.TextureWeights.z;
    farColor += tex2D(TextureSampler3, PSIn.TextureCoords)*PSIn.TextureWeights.w;
    
    float4 nearColor;
    float2 nearTextureCoords = PSIn.TextureCoords*3;
    nearColor = tex2D(TextureSampler0, nearTextureCoords)*PSIn.TextureWeights.x;
    nearColor += tex2D(TextureSampler1, nearTextureCoords)*PSIn.TextureWeights.y;
    nearColor += tex2D(TextureSampler2, nearTextureCoords)*PSIn.TextureWeights.z;
    nearColor += tex2D(TextureSampler3, nearTextureCoords)*PSIn.TextureWeights.w;

    Output.Color = lerp(nearColor, farColor, blendFactor);
    Output.Color *= lightingFactor;
    
    return Output;
}

technique MultiTextured
{
    pass Pass0
    {
        VertexShader = compile vs_1_1 MultiTexturedVS();
        PixelShader = compile ps_2_0 MultiTexturedPS();
    }
}


 //------- Technique: Water --------
 struct WVertexToPixel
 {
     float4 Position                 : POSITION;
     float4 ReflectionMapSamplingPos    : TEXCOORD1;
 };
 
 struct WPixelToFrame
 {
     float4 Color : COLOR0;
 };
 
 WVertexToPixel WaterVS(float4 inPos : POSITION, float2 inTex: TEXCOORD)
 {    
     WVertexToPixel Output = (WVertexToPixel)0;
 
     float4x4 preViewProjection = mul (xView, xProjection);
     float4x4 preWorldViewProjection = mul (xWorld, preViewProjection);
     float4x4 preReflectionViewProjection = mul (xReflectionView, xProjection);
     float4x4 preWorldReflectionViewProjection = mul (xWorld, preReflectionViewProjection);
 
     Output.Position = mul(inPos, preWorldViewProjection);
     Output.ReflectionMapSamplingPos = mul(inPos, preWorldReflectionViewProjection);
 
     return Output;
 }
 
 WPixelToFrame WaterPS(WVertexToPixel PSIn)
 {
     WPixelToFrame Output = (WPixelToFrame)0;        
     
     float2 ProjectedTexCoords;
     ProjectedTexCoords.x = PSIn.ReflectionMapSamplingPos.x/PSIn.ReflectionMapSamplingPos.w/2.0f + 0.5f;
     ProjectedTexCoords.y = -PSIn.ReflectionMapSamplingPos.y/PSIn.ReflectionMapSamplingPos.w/2.0f + 0.5f;    
 
     Output.Color = tex2D(ReflectionSampler, ProjectedTexCoords);    
     
     return Output;
 }
 
 technique Water
 {
     pass Pass0
     {
         VertexShader = compile vs_1_1 WaterVS();
         PixelShader = compile ps_2_0 WaterPS();
     }
 }

发布时间:2009/12/15 14:00:02  阅读次数:6086

2006 - 2024,推荐分辨率1024*768以上,推荐浏览器Chrome、Edge等现代浏览器,截止2021年12月5日的访问次数:1872万9823 站长邮箱

沪ICP备18037240号-1

沪公网安备 31011002002865号