3D系列4.16 在指定区域放置树木
本章我们要添加许多树。要获得最好的结果, 我们要在地形上添加一些树林而不是随机放置。
本章要处理的主要问题是:如何创建这些树林的边界?解决方法是使用一张噪点贴图。本系列的最后一章中,你会学习如何自己创建噪点贴图。本章使用的噪点贴图如下所示:
解决方法很简单:如果噪点贴图上的像素的白色值大于某个临界值,我们就会在地形上添加一棵树。因此首先将treeMap.jpg导入到项目中。
然后,看一下GenerateTreePositions方法并做适当变化。第一个变化是方法定义,我们需要将噪点贴图作为参数:
private List<Vector3> GenerateTreePositions(Texture2D treeMap, VertexMultitextured[] terrainVertices)
方法内部的代码变化如下所示:
Color[] treeMapColors = new Color[treeMap.Width * treeMap.Height]; treeMap.GetData(treeMapColors); int[,] noiseData = new int[treeMap.Width, treeMap.Height]; for (int x = 0; x < treeMap.Width; x++) for (int y = 0; y < treeMap.Height; y++) noiseData[x, y] = treeMapColors[y + x * treeMap.Height].R; List<Vector3> treeList = new List<Vector3> (); Random random = new Random(); for (int x = 0; x < terrainWidth; x++) { for (int y = 0; y < terrainLength; y++) { //add trees } } return treeList;
首先将图像转换为一个1D的颜色数组:首先创建一个1D数组,然后使用GetData方法将纹理中的数据复制到这个数组中。然后,这个1D数组被重新排列为一个整数2D数组。对每个像素,获取它的红色分量(它的值介于0和255之间)。因为当前噪点贴图是一张灰度图,所以红色通道的值与绿色和蓝色通道是相同的。
准备好2D数组后,我们创建一个Vector3集合,它也是这个方法的返回值,还有一个随机函数生成器用来使树木不会排成一行。
最后的两个循环遍历地形网格,对每个顶点,我们判断是否需要放置树木,所以需要进行以下检测:
- 高度合适吗?我们不想再在河中央或山顶放置树木。
- 地形平吗?我们不想在峭壁上放置树木。
- 树木的密度如何?我们想在树林中间放置许多树木,而树林边缘的树木密度小。
让我们一个接一个解决上面的问题。
第一个问题很简单:我们只需获取当前位置的高度,检查它是否在可接受的范围之内。所以在循环中用下面的代码替换掉注释:
float terrainHeight = heightData[x, y]; if ((terrainHeight > 8) && (terrainHeight < 14)) { }
这会让树木只放置在地形高度为8至14之间的位置。然后是地形的坡度。我们可以添加一些复杂的算法检测邻近顶点的高度,但事实上我们有更好的东西:每个顶点的法线。法线表示每个顶点垂直于地形的方向。所以在水平的地面上,法线是向上的。这就是我们想要检测的:法线与UP向量靠得有多近,这可以通过点乘这两个向量获得。所以在if-check中放置以下代码:
float flatness = Vector3.Dot(terrainVertices[x + y * terrainWidth].Normal, new Vector3(0, 1, 0));
如果顶点的法线和(0,1,) Up向量是相同的,点乘的结果为1。如果两者垂直则为0。因为点乘结果就是两个向量间夹角的余弦值,下面的代码可以检测地形的坡度不超过15度:
float minFlatness = (float)Math.Cos(MathHelper.ToRadians(15)); if (flatness> minFlatness) { }
15度对应的点乘结果为0.966,所以我们检测地形的坡度是否比它小。最后,我们还需检测噪点贴图是否允许在当前位置放置树木。所以,我们需要采用对应当前位置的噪点贴图上的点。在if-check中添加以下代码:
float relx = (float)x / (float)terrainWidth; float rely = (float)y / (float)terrainLength; float noiseValueAtCurrentPosition = noiseData[(int)(relx * treeMap.Width), (int)(rely * treeMap.Height)]; float treeDensity; if (noiseValueAtCurrentPosition > 200) treeDensity = 5; else if (noiseValueAtCurrentPosition > 150) treeDensity = 4; else if (noiseValueAtCurrentPosition > 100) treeDensity = 3; else treeDensity = 0;
因为我们想让地形的分辨率与噪点贴图的分辨率无关,所以使用相对坐标。Relx和rely的值介于0和1之间,让我们可以在正确的位置采样噪点贴图。当前位置的噪点值存储在noiseValueAtCurrentPosition变量中,这个变量的值介于0和255之间。
从这个值我们可以决定当前位置应该添加多少树木。如果这个值很大,说明在树林中间,在这个地形顶点周围添加5棵树!这个数量对应当前的噪点值,当噪点值小于某个临界值时树木数量为0。
这样,我们就可以确实知道当前地形顶点上应该放置多少树木。下面的代码生成新树木的位置:
for (int currDetail = 0; currDetail < treeDensity; currDetail++) { float rand1 = (float)random.Next(1000) / 1000.0f; float rand2 = (float)random.Next(1000) / 1000.0f; Vector3 treePos = new Vector3((float)x - rand1, 0, -(float)y - rand2); treePos.Y = heightData[x, y]; treeList.Add(treePos); }
首先生成两个随机数,并缩放到[0,1]区间,使用这两个随机数添加当前顶点的X和Z坐标,使用地形高度作为Y坐标。最后,将新位置添加到集合中。
在LoadVertices方法中,我们还需要加载treeMap.jpg纹理,将它传递到GenerateTreePositions方法!所以,使用以下代码替换掉LoadVertices方法底部的代码:
Texture2D treeMap = Content.Load<Texture2D> ("treeMap"); List<Vector3> treeList = GenerateTreePositions(treeMap, terrainVertices); CreateBillboardVerticesFromList(treeList);
好了,CreateBillboardVerticesFromList和DrawBillboard方法前面已经定义了,绘制树木的两个三角形是定义在GenerateTreePositions方法中的。现在运行代码!程序截图如下。如果移动相机,你会发现两个缺陷:
- 当你站在山顶看树木时你会看到最主要的缺陷,这个错误也是下一章的主要内容。
- 树木并不会被水面反射!
这个因为没有在DrawReflectionMap方法中绘制树木,所以,在调用DrawSkyDome方法之后,添加以下调用:
DrawBillboards(reflectionViewMatrix);
这样你就可以看到水面上树木的反射了。
本章只有XNA代码有变化,红色代码为相对于上一章改变的部分:
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; VertexBuffer treeVertexBuffer; VertexDeclaration treeVertexDeclaration; Effect effect; Effect bbEffect; 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; Texture2D waterBumpMap; Texture2D treeTexture; Texture2D treeMap; Model skyDome; const float waterHeight = 5.0f; RenderTarget2D refractionRenderTarget; Texture2D refractionMap; RenderTarget2D reflectionRenderTarget; Texture2D reflectionMap; Vector3 windDirection = new Vector3(0, 0, 1); 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"); bbEffect = Content.Load<Effect> ("bbEffect"); 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); Texture2D treeMap = Content.Load<Texture2D> ("treeMap"); List<Vector3> treeList = GenerateTreePositions(treeMap, terrainVertices); CreateBillboardVerticesFromList(treeList); } 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"); waterBumpMap = Content.Load<Texture2D> ("waterbump"); treeTexture = Content.Load<Texture2D> ("tree"); treeMap = Content.Load<Texture2D> ("treeMap"); } 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); } private void CreateBillboardVerticesFromList(List<Vector3> treeList) { VertexPositionTexture[] billboardVertices = new VertexPositionTexture[treeList.Count * 6]; int i = 0; foreach (Vector3 currentV3 in treeList) { billboardVertices[i++] = new VertexPositionTexture(currentV3, new Vector2(0, 0)); billboardVertices[i++] = new VertexPositionTexture(currentV3, new Vector2(1, 0)); billboardVertices[i++] = new VertexPositionTexture(currentV3, new Vector2(1, 1)); billboardVertices[i++] = new VertexPositionTexture(currentV3, new Vector2(0, 0)); billboardVertices[i++] = new VertexPositionTexture(currentV3, new Vector2(1, 1)); billboardVertices[i++] = new VertexPositionTexture(currentV3, new Vector2(0, 1)); } treeVertexBuffer = new VertexBuffer(device, billboardVertices.Length * VertexPositionTexture.SizeInBytes, BufferUsage.WriteOnly); treeVertexBuffer.SetData(billboardVertices); treeVertexDeclaration = new VertexDeclaration(device, VertexPositionTexture.VertexElements); } private List<Vector3> GenerateTreePositions(Texture2D treeMap, VertexMultitextured[] terrainVertices) { Color[] treeMapColors = new Color[treeMap.Width * treeMap.Height]; treeMap.GetData(treeMapColors); int[,] noiseData = new int[treeMap.Width, treeMap.Height]; for (int x = 0; x < treeMap.Width; x++) for (int y = 0; y < treeMap.Height; y++) noiseData[x, y] = treeMapColors[y + x * treeMap.Height].R; List<Vector3> treeList = new List<Vector3> (); Random random = new Random(); for (int x = 0; x < terrainWidth; x++) { for (int y = 0; y < terrainLength; y++) { float terrainHeight = heightData[x, y]; if ((terrainHeight > 8) && (terrainHeight < 14)) { float flatness = Vector3.Dot(terrainVertices[x + y * terrainWidth].Normal, new Vector3(0, 1, 0)); float minFlatness = (float)Math.Cos(MathHelper.ToRadians(15)); if (flatness > minFlatness) { float relx = (float)x / (float)terrainWidth; float rely = (float)y / (float)terrainLength; float noiseValueAtCurrentPosition = noiseData[(int)(relx * treeMap.Width), (int)(rely * treeMap.Height)]; float treeDensity; if (noiseValueAtCurrentPosition > 200) treeDensity = 5; else if (noiseValueAtCurrentPosition > 150) treeDensity = 4; else if (noiseValueAtCurrentPosition > 100) treeDensity = 3; else treeDensity = 0; for (int currDetail = 0; currDetail < treeDensity; currDetail++) { float rand1 = (float)random.Next(1000) / 1000.0f; float rand2 = (float)random.Next(1000) / 1000.0f; Vector3 treePos = new Vector3((float)x - rand1, 0, -(float)y - rand2); treePos.Y = heightData[x, y]; treeList.Add(treePos); } } } } } return treeList; } 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.White, 1.0f, 0); DrawSkyDome(viewMatrix); DrawTerrain(viewMatrix); DrawWater(time); DrawBillboards(viewMatrix); 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); DrawSkyDome(reflectionViewMatrix); DrawTerrain(reflectionViewMatrix); DrawBillboards(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.Parameters["xWaterBumpMap"].SetValue(waterBumpMap); effect.Parameters["xWaveLength"].SetValue(0.1f); effect.Parameters["xWaveHeight"].SetValue(0.3f); effect.Parameters["xCamPos"].SetValue(cameraPosition); effect.Parameters["xTime"].SetValue(time); effect.Parameters["xWindForce"].SetValue(0.002f); effect.Parameters["xWindDirection"].SetValue(windDirection); 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(); } private void DrawBillboards(Matrix currentViewMatrix) { bbEffect.CurrentTechnique = bbEffect.Techniques["CylBillboard"]; bbEffect.Parameters["xWorld"].SetValue(Matrix.Identity); bbEffect.Parameters["xView"].SetValue(currentViewMatrix); bbEffect.Parameters["xProjection"].SetValue(projectionMatrix); bbEffect.Parameters["xCamPos"].SetValue(cameraPosition); bbEffect.Parameters["xAllowedRotDir"].SetValue(new Vector3(0, 1, 0)); bbEffect.Parameters["xBillboardTexture"].SetValue(treeTexture); device.RenderState.AlphaBlendEnable = true; device.RenderState.SourceBlend = Blend.SourceAlpha; device.RenderState.DestinationBlend = Blend.InverseSourceAlpha; bbEffect.Begin(); foreach (EffectPass pass in bbEffect.CurrentTechnique.Passes) { pass.Begin(); device.Vertices[0].SetSource(treeVertexBuffer, 0, VertexPositionTexture.SizeInBytes); device.VertexDeclaration = treeVertexDeclaration; int noVertices = treeVertexBuffer.SizeInBytes / VertexPositionTexture.SizeInBytes; int noTriangles = noVertices / 3; device.DrawPrimitives(PrimitiveType.TriangleList, 0, noTriangles); pass.End(); } bbEffect.End(); device.RenderState.AlphaBlendEnable = false; } } }
发布时间:2009/12/31 下午12:43:31 阅读次数:7898