Direct3D高程图立体显示

在微软的DirectX Sample Browser中，有个RaycastTerrain例子，做得很好，将一张平面的地形图，在底面添加了一个底部，四周的高度差再封闭起来，然后再添加一个浅蓝色的背景，平面图形的立体感很强，而且灯光和阴影的效果也做得很棒！

这个例子是基于C++的，这里模仿这个例子，给出一个基于C#的实现。思路也大致类似，找一张bmp格式的深度图，经过像素值的计算处理，生成Y轴方向的高度值，再经过纹理贴图，形成一个底部为空的三维立体图形。此时为了增强上述的立体效果，可以在底面添加一个底部，这里为了加快渲染的速度，底部做成一四边形，用两个三角形渲染，四边形的顶点可以参考bmp深度图的四个角的顶点坐标。对于底部的高度的选取，即Y轴方向的高度值的选取，可以选在bmp深度图Y最小坐标值或者Y最小坐标值的下方，所以需要计算出这个Y最小坐标值。因此定义如下函数，求bmp深度图Y最小坐标值：

public float GetMinHeight(string bitmapPath)
        {
            float minHeight = 65535.0f;
            Bitmap bitmap = new Bitmap(bitmapPath);
            xCount = (bitmap.Width - 1) / 2;
            yCount = (bitmap.Height - 1) / 2;
            cellWidth = bitmap.Width / xCount;
            cellHeight = bitmap.Height / yCount;
            for(int i=0;i<yCount+1;i++)
                for(int j=0;j<xCount+1;j++)
                {
                    Color color = bitmap.GetPixel((int)(j * cellWidth), (int)(i * cellHeight));
                    float height = float.Parse(color.R.ToString()) +
                    float.Parse(color.G.ToString()) + float.Parse(color.B.ToString());
                    height /= 10;
                    if (height < minHeight)
                        minHeight = height;
                }
            return minHeight;
        }

为了增加底部的显示效果，可以通过贴图来完成。为了增加实时渲染的效果，可以在OnCreateDevice中响应底部三角形顶点定义函数。底部2个三角形的顶点定义函数实现如下：

public void OnCreateBottomVertexBuffer(object sender,EventArgs e)
        {
            CustomVertex.PositionNormalTextured[] bottomVerts = (CustomVertex.PositionNormalTextured[])bottomVertexBuffer.Lock(0, 0);//绘制底面正方形的6个顶点
            string bitmapPath = @"F:\\workdir\\VC# Based DirectX\\height.BMP";
            float minHeight = GetMinHeight(bitmapPath);
            float xWidth = GetBitMapWidth(bitmapPath);
            float yHeight = GetBitMapHeight(bitmapPath);
            bottomVerts[0].Position = new Vector3(0.0f, minHeight-5.0f, 0.0f);
            bottomVerts[0].Normal = new Vector3(0, 0, -1);
            bottomVerts[0].Tu = 0.0f;//顶点0纹理坐标Tu
            bottomVerts[0].Tv = 20.0f;//纹理图片沿Y轴方向重复贴图20次

            bottomVerts[1].Position = new Vector3(0.0f, minHeight - 5.0f, yHeight);
            bottomVerts[1].Normal = new Vector3(0, 0, -1);
            bottomVerts[1].Tu = 0.0f;
            bottomVerts[1].Tv = 0.0f;

            bottomVerts[2].Position = new Vector3(xWidth, minHeight - 5.0f, yHeight);
            bottomVerts[2].Normal = new Vector3(0, 0, -1);
            bottomVerts[2].Tu = 20.0f;
            bottomVerts[2].Tv = 0.0f;

            bottomVerts[3].Position = new Vector3(0.0f, minHeight - 5.0f, 0.0f);
            bottomVerts[3].Normal = new Vector3(0, 0, -1);
            bottomVerts[3].Tu = 0.0f;
            bottomVerts[3].Tv = 20.0f;

            bottomVerts[4].Position = new Vector3(xWidth, minHeight - 5.0f, yHeight);
            bottomVerts[4].Normal = new Vector3(0, 0, -1);
            bottomVerts[4].Tu = 20.0f;
            bottomVerts[4].Tv = 0.0f;

            bottomVerts[5].Position = new Vector3(xWidth, minHeight - 5.0f, 0.0f);
            bottomVerts[5].Normal = new Vector3(0, 0, -1);
            bottomVerts[5].Tu = 20.0f;
            bottomVerts[5].Tv = 20.0f;
            bottomVertexBuffer.Unlock();
        }

剩下的问题就是如何封闭底部的四面高度差，方法也很简单，可以一面一面地进行。以下图为例：

对于一张BMP格式的位图，将其划分为xCount*yCount个单元，每个单元的宽度为cellWidth，高度为cellHeight，则cellWidth=Width/xCount，cellHeight=Height/yCount。要想封住其四个边的高度差，以沿X轴方向的边缘高度差面为例，需要声明2(xCount+1)个顶点来记录相应的坐标值。其中xCount+1个点落在与X轴平行的那个边上，这些点都是Vector3类型的，这些点的Y坐标为底部平面的Y值，是一个定值，X坐标依次为每一个像素点单元所在的X坐标，Z坐标就是0。剩下的xCount+1个顶点则为X轴边缘高度差面与三维立体图的交点，即高度方向纵切图与上顶面的交点，该交点的Y坐标就是相应的像素点的高度值，X坐标依次为每一个像素点单元所在的X坐标，Z坐标也是0.其定义实现如下：

float minY = GetMinHeight(bitmapPath) - 5.0f;
            borderVertexBuffer1 = new VertexBuffer(typeof(CustomVertex.PositionColored),
                2 * (xCount + 1),//四周的一个面封闭总共所需要的顶点的数目
                device,
                Usage.Dynamic | Usage.WriteOnly,
                CustomVertex.PositionColored.Format,
                Pool.Default);
            borderVertices1 = new CustomVertex.PositionColored[2 * (xCount + 1)];//定义顶点
            int k;
            for (k = 0; k < xCount + 1; k++)//X轴上的点的定义
            {
                borderVertices1[k].Position = new Vector3(k * cellWidth, minY, 0.0f);
                borderVertices1[k].Color = System.Drawing.Color.Aqua.ToArgb();
            }
            for (; k < 2 * (xCount + 1); k++)//高程图上的边界点的定义
            {
                Color color = bitmap.GetPixel((int)((k - xCount - 1) * cellWidth), 0);
                float height = float.Parse(color.R.ToString()) + float.Parse(color.G.ToString()) + float.Parse(color.B.ToString());
                height /= 10;
                borderVertices1[k].Position = new Vector3((k - xCount - 1) * cellWidth, height, 0);//i * cellHeight=0
                borderVertices1[k].Color = System.Drawing.Color.Aqua.ToArgb();
            }
            borderVertexBuffer1.SetData(borderVertices1, 0, LockFlags.None);

这2(xCount+1)个顶点可以形成xCount个小矩形，每个矩形可以分为2个小三角形，每个小三角形可以由3个顶点来绘制，为了加快绘制的速度，可以考虑用顶点索引来完成。声明一个顶点索引数组，其大小为2*3*xCount*1.这个顶点索引数组依次记录了要绘制的三角形的顶点的编号。如下图所示：

所以对于沿X轴方向的边缘高度差面的绘制就是如何绘制这些顶点三角形。其绘制顺序如下：

(V[0],V[1],V[xCount+1]), (V[1],V[xCount+1],V[xCount+2]),…,

(V[xCount],V[2*(xCount+1)-2],V[2*(xCount+1)-1])。

很有规律性，用一个for循环就可以搞定，其定义实现如下：

borderIndexBuffer1 = new IndexBuffer(typeof(int),
                6 * xCount * 1,
                device,
                Usage.WriteOnly,
                Pool.Default);
            borderIndices1 = new int[6 * xCount * 1];//初始化索引顶点

            for (int j = 0; j < xCount; j++)
            {
                borderIndices1[6 * (j)] = j;
                borderIndices1[6 * (j) + 1] = j + (xCount + 1);
                borderIndices1[6 * (j) + 2] = j + 1;
                borderIndices1[6 * (j) + 3] = j + 1;
                borderIndices1[6 * (j) + 4] = j + (xCount + 1);
                borderIndices1[6 * (j) + 5] = j + (xCount + 1) + 1;
            }
            borderIndexBuffer1.SetData(borderIndices1, 0, LockFlags.None);

渲染的时候直接调用DrawIndexedPrimitives即可。

/*第1个边界三角形*/
            device.SetStreamSource(0, borderVertexBuffer1, 0);
            device.VertexFormat = CustomVertex.PositionColored.Format;
            device.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, 2 * (xCount + 1), 0, borderIndices1.Length / 3);

同理其他3个边缘高度差面的绘制类似。下面贴上几张效果图：

P.S.附上主界面工程的代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Microsoft.DirectX;
using Microsoft.DirectX.Direct3D;

namespace 高程图01
{
    public partial class MainForm : Form
    {
        private Device device = null;//定义绘图设备
        bool pause = false;

        public Vector3 CamPostion = new Vector3(0, 100, 100);//定义摄像机位置
        public Vector3 CamTarget = new Vector3(125, 30, 125);//定义摄像机目标位置

        private float angleY = 0.01f;//定义绕Y轴旋转变量

        private int mouseLastX, mouseLastY;//记录鼠标按下时的坐标位置
        private bool isRotateByMouse = false;//记录是否由鼠标控制旋转
        private bool isMoveByMouse = false;//记录是否由鼠标控制移动

        private CustomVertex.PositionTextured[] vertices;//定义顶点变量
        private Texture texture;//定义贴图变量
        private Material material;//定义材质变量

        private VertexBuffer vertexBuffer;//定义顶点缓冲变量
        private IndexBuffer indexBuffer;//定义索引缓冲变量
        private int[] indices;//定义索引号变量

        private int xCount = 5, yCount = 4;//定义横向和纵向网格数目
        private float cellHeight = 1f, cellWidth = 1f;//定义单元的宽度和长度

        Material bottomMaterial;//底部材质变量
        Texture bottomTexture;//底部纹理变量
        VertexBuffer bottomVertexBuffer = null;//保存建立底部正方形的顶点

        private VertexBuffer borderVertexBuffer1 = null;
        private CustomVertex.PositionColored[] borderVertices1;//定义顶点变量
        private IndexBuffer borderIndexBuffer1;//定义四周顶点索引缓冲变量
        private int[] borderIndices1;//定义四周顶点的索引号变量

        private VertexBuffer borderVertexBuffer2 = null;
        private CustomVertex.PositionColored[] borderVertices2;//定义顶点变量
        private IndexBuffer borderIndexBuffer2;//定义四周顶点索引缓冲变量
        private int[] borderIndices2;//定义四周顶点的索引号变量

        private VertexBuffer borderVertexBuffer3 = null;
        private CustomVertex.PositionColored[] borderVertices3;//定义顶点变量
        private IndexBuffer borderIndexBuffer3;//定义四周顶点索引缓冲变量
        private int[] borderIndices3;//定义四周顶点的索引号变量

        private VertexBuffer borderVertexBuffer4 = null;
        private CustomVertex.PositionColored[] borderVertices4;//定义顶点变量
        private IndexBuffer borderIndexBuffer4;//定义四周顶点索引缓冲变量
        private int[] borderIndices4;//定义四周顶点的索引号变量

        public MainForm()
        {
            InitializeComponent();
        }
        public bool InitializeDirect3D()
        {
            try
            {
                PresentParameters presentParams = new PresentParameters();
                presentParams.Windowed = true; //指定以Windows窗体形式显示
                presentParams.SwapEffect = SwapEffect.Discard; //当前屏幕绘制后它将自动从内存中删除
                presentParams.AutoDepthStencilFormat = DepthFormat.D16;
                presentParams.EnableAutoDepthStencil = true;
                presentParams.PresentationInterval = PresentInterval.Immediate;
                device = new Device(0, DeviceType.Hardware, this, CreateFlags.SoftwareVertexProcessing, presentParams); //实例化device对象
                device.DeviceReset += new System.EventHandler(this.OnResetDevice);
                this.OnCreateDevice(device, null);
                this.OnResetDevice(device, null);
            }
            catch (DirectXException e)
            {
                MessageBox.Show(e.ToString(), "Error"); //处理异常
                return false;
            }
            return true;
        }
        //导入贴图和材质
        public void OnCreateDevice(object sender, EventArgs e)
        {
            Device device = (Device)sender;
            material = new Material();
            material.Diffuse = Color.White;
            material.Specular = Color.LightGray;
            material.SpecularSharpness = 15.0F;
            device.Material = material;
            texture = TextureLoader.FromFile(device, @"F:\\workdir\\VC# Based DirectX\\texture.jpg");

            //底部材料和贴图
            bottomMaterial = new Material();
            bottomMaterial.Ambient = Color.FromArgb(200, 255, 255, 255);
            bottomMaterial.Diffuse = Color.FromArgb(200, 255, 255, 255);
            bottomTexture = TextureLoader.FromFile(device,@"..\..\..\p1.bmp");
            bottomVertexBuffer = new VertexBuffer(typeof(CustomVertex.PositionNormalTextured), 6, device, 0, CustomVertex.PositionNormalTextured.Format, Pool.Default);
            bottomVertexBuffer.Created += new System.EventHandler(this.OnCreateBottomVertexBuffer);
            this.OnCreateBottomVertexBuffer(device, null);
        }
        //底部顶点
        public void OnCreateBottomVertexBuffer(object sender,EventArgs e)
        {
            CustomVertex.PositionNormalTextured[] bottomVerts = (CustomVertex.PositionNormalTextured[])bottomVertexBuffer.Lock(0, 0);//绘制底面正方形的6个顶点
            string bitmapPath = @"F:\\workdir\\VC# Based DirectX\\height.BMP";
            float minHeight = GetMinHeight(bitmapPath);
            float xWidth = GetBitMapWidth(bitmapPath);
            float yHeight = GetBitMapHeight(bitmapPath);
            bottomVerts[0].Position = new Vector3(0.0f, minHeight-5.0f, 0.0f);
            bottomVerts[0].Normal = new Vector3(0, 0, -1);
            bottomVerts[0].Tu = 0.0f;//顶点0纹理坐标Tu
            bottomVerts[0].Tv = 20.0f;//纹理图片沿Y轴方向重复贴图20次

            bottomVerts[1].Position = new Vector3(0.0f, minHeight - 5.0f, yHeight);
            bottomVerts[1].Normal = new Vector3(0, 0, -1);
            bottomVerts[1].Tu = 0.0f;
            bottomVerts[1].Tv = 0.0f;

            bottomVerts[2].Position = new Vector3(xWidth, minHeight - 5.0f, yHeight);
            bottomVerts[2].Normal = new Vector3(0, 0, -1);
            bottomVerts[2].Tu = 20.0f;
            bottomVerts[2].Tv = 0.0f;

            bottomVerts[3].Position = new Vector3(0.0f, minHeight - 5.0f, 0.0f);
            bottomVerts[3].Normal = new Vector3(0, 0, -1);
            bottomVerts[3].Tu = 0.0f;
            bottomVerts[3].Tv = 20.0f;

            bottomVerts[4].Position = new Vector3(xWidth, minHeight - 5.0f, yHeight);
            bottomVerts[4].Normal = new Vector3(0, 0, -1);
            bottomVerts[4].Tu = 20.0f;
            bottomVerts[4].Tv = 0.0f;

            bottomVerts[5].Position = new Vector3(xWidth, minHeight - 5.0f, 0.0f);
            bottomVerts[5].Normal = new Vector3(0, 0, -1);
            bottomVerts[5].Tu = 20.0f;
            bottomVerts[5].Tv = 20.0f;

            bottomVertexBuffer.Unlock();
        }
        //避免精度损失
        public float GetBitMapHeight(string bitmapPath)
        {
            Bitmap bitmap = new Bitmap(bitmapPath);
            xCount = (bitmap.Width - 1) / 2;
            yCount = (bitmap.Height - 1) / 2;
            cellWidth = bitmap.Width / xCount;
            cellHeight = bitmap.Height / yCount;
            return (float)(yCount * cellHeight);
        }
        //避免精度损失
        public float GetBitMapWidth(string bitmapPath)
        {
            Bitmap bitmap = new Bitmap(bitmapPath);
            xCount = (bitmap.Width - 1) / 2;
            yCount = (bitmap.Height - 1) / 2;
            cellWidth = bitmap.Width / xCount;
            cellHeight = bitmap.Height / yCount;
            return (float)(xCount*cellWidth);
        }

        //获得高度图Y方向上的最小高度值
        public float GetMinHeight(string bitmapPath)
        {
            float minHeight = 65535.0f;
            Bitmap bitmap = new Bitmap(bitmapPath);
            xCount = (bitmap.Width - 1) / 2;
            yCount = (bitmap.Height - 1) / 2;
            cellWidth = bitmap.Width / xCount;
            cellHeight = bitmap.Height / yCount;
            for(int i=0;i<yCount+1;i++)
                for(int j=0;j<xCount+1;j++)
                {
                    Color color = bitmap.GetPixel((int)(j * cellWidth), (int)(i * cellHeight));
                    float height = float.Parse(color.R.ToString()) +
                    float.Parse(color.G.ToString()) + float.Parse(color.B.ToString());
                    height /= 10;
                    if (height < minHeight)
                        minHeight = height;
                }
            return minHeight;
        }
        /**
         * 通过Bitmap类获得BMP图片对象，然后根据其Width属性和Height属性设置生成三角网中横向和纵向单元数，
         * 同时设置单元尺寸，在设置高程值中通过获取图片中相应位置的颜色值，
         * 然后通过一个相对比例得到一个相对的高程值，最后将该值赋予定义的顶点坐标值
         */
        public void OnResetDevice(object sender, EventArgs e)
        {
            Device device = (Device)sender;
            device.RenderState.ZBufferEnable = true;//允许使用深度测试
            //device.RenderState.Ambient = Color.Black;//环境光为黑色

            string bitmapPath = @"F:\\workdir\\VC# Based DirectX\\height.BMP";
            Bitmap bitmap = new Bitmap(bitmapPath);
            xCount = (bitmap.Width - 1) / 2;
            yCount = (bitmap.Height - 1) / 2;
            cellWidth = bitmap.Width / xCount;
            cellHeight = bitmap.Height / yCount;

            vertexBuffer = new VertexBuffer(typeof(CustomVertex.PositionTextured), 
                (xCount + 1) * (yCount + 1), 
                device,
                Usage.Dynamic | Usage.WriteOnly, 
                CustomVertex.PositionColored.Format, 
                Pool.Default);
            vertices = new CustomVertex.PositionTextured[(xCount + 1) * (yCount + 1)];//定义顶点
            for (int i = 0; i < yCount + 1; i++)
            {
                for (int j = 0; j < xCount + 1; j++)
                {
                    Color color = bitmap.GetPixel((int)(j * cellWidth), (int)(i * cellHeight));
                    float height = float.Parse(color.R.ToString()) + float.Parse(color.G.ToString()) + float.Parse(color.B.ToString());
                    height /= 10;
                    vertices[j + i * (xCount + 1)].Position = new Vector3(j * cellWidth, height, i * cellHeight);
                    vertices[j + i * (xCount + 1)].Tu = (float)j / (xCount + 1);
                    vertices[j + i * (xCount + 1)].Tv = (float)i / (yCount + 1);
                }
            }
            vertexBuffer.SetData(vertices, 0, LockFlags.None);
            /*为了使得摄像机目标位于图片中间，可以设置摄像机目标位置于图片中心位置*/
            CamTarget = new Vector3(bitmap.Width / 2, 0f, bitmap.Height / 2);//设置摄像机目标位置

            indexBuffer = new IndexBuffer(typeof(int), 6 * xCount * yCount, device, Usage.WriteOnly, Pool.Default);
            indices = new int[6 * xCount * yCount];
            for (int i = 0; i < yCount; i++)
            {
                for (int j = 0; j < xCount; j++)
                {
                    indices[6 * (j + i * xCount)] = j + i * (xCount + 1);
                    indices[6 * (j + i * xCount) + 1] = j + (i + 1) * (xCount + 1);
                    indices[6 * (j + i * xCount) + 2] = j + i * (xCount + 1) + 1;
                    indices[6 * (j + i * xCount) + 3] = j + i * (xCount + 1) + 1;
                    indices[6 * (j + i * xCount) + 4] = j + (i + 1) * (xCount + 1);
                    indices[6 * (j + i * xCount) + 5] = j + (i + 1) * (xCount + 1) + 1;
                }
            }
            indexBuffer.SetData(indices, 0, LockFlags.None);

            /*******第1个边界********/
            float minY = GetMinHeight(bitmapPath) - 5.0f;
            borderVertexBuffer1 = new VertexBuffer(typeof(CustomVertex.PositionColored),
                2 * (xCount + 1),//四周的一个面封闭总共所需要的顶点的数目
                device,
                Usage.Dynamic | Usage.WriteOnly,
                CustomVertex.PositionColored.Format,
                Pool.Default);
            borderVertices1 = new CustomVertex.PositionColored[2 * (xCount + 1)];//定义顶点
            int k;
            for (k = 0; k < xCount + 1; k++)//X轴上的点的定义
            {
                borderVertices1[k].Position = new Vector3(k * cellWidth, minY, 0.0f);
                borderVertices1[k].Color = System.Drawing.Color.Aqua.ToArgb();
            }
            for (; k < 2 * (xCount + 1); k++)//高程图上的边界点的定义
            {
                Color color = bitmap.GetPixel((int)((k - xCount - 1) * cellWidth), 0);
                float height = float.Parse(color.R.ToString()) + float.Parse(color.G.ToString()) + float.Parse(color.B.ToString());
                height /= 10;
                borderVertices1[k].Position = new Vector3((k - xCount - 1) * cellWidth, height, 0);//i * cellHeight=0
                borderVertices1[k].Color = System.Drawing.Color.Aqua.ToArgb();
            }

            borderVertexBuffer1.SetData(borderVertices1, 0, LockFlags.None);

            borderIndexBuffer1 = new IndexBuffer(typeof(int),
                6 * xCount * 1,
                device,
                Usage.WriteOnly,
                Pool.Default);
            borderIndices1 = new int[6 * xCount * 1];//初始化索引顶点

            for (int j = 0; j < xCount; j++)
            {
                borderIndices1[6 * (j)] = j;
                borderIndices1[6 * (j) + 1] = j + (xCount + 1);
                borderIndices1[6 * (j) + 2] = j + 1;
                borderIndices1[6 * (j) + 3] = j + 1;
                borderIndices1[6 * (j) + 4] = j + (xCount + 1);
                borderIndices1[6 * (j) + 5] = j + (xCount + 1) + 1;
            }
            borderIndexBuffer1.SetData(borderIndices1, 0, LockFlags.None);

            /**第2个四周边界**/
            borderVertexBuffer2 = new VertexBuffer(typeof(CustomVertex.PositionColored),
                2 * (xCount + 1),//四周的一个面封闭总共所需要的顶点的数目
                device,
                Usage.Dynamic | Usage.WriteOnly,
                CustomVertex.PositionColored.Format,
                Pool.Default);
            borderVertices2 = new CustomVertex.PositionColored[2 * (xCount + 1)];//定义顶点
            for (k = 0; k < xCount + 1; k++)//X轴平行方向上的点的定义
            {
                borderVertices2[k].Position = new Vector3(k * cellWidth, minY, yCount*cellHeight);
                borderVertices2[k].Color = System.Drawing.Color.Aqua.ToArgb();
            }
            for (; k < 2 * (xCount + 1); k++)//高程图上的边界点的定义
            {
                Color color = bitmap.GetPixel((int)((k - xCount - 1) * cellWidth), (int)(yCount*cellHeight));//不能直接写死
                float height = float.Parse(color.R.ToString()) + float.Parse(color.G.ToString()) + float.Parse(color.B.ToString());
                height /= 10;
                borderVertices2[k].Position = new Vector3((k - xCount - 1) * cellWidth, height, yCount * cellHeight);
                borderVertices2[k].Color = System.Drawing.Color.Aqua.ToArgb();
            }

            borderVertexBuffer2.SetData(borderVertices2, 0, LockFlags.None);

            borderIndexBuffer2 = new IndexBuffer(typeof(int),
                6 * xCount * 1,
                device,
                Usage.WriteOnly,
                Pool.Default);
            borderIndices2 = new int[6 * xCount * 1];//初始化索引顶点

            for (int j = 0; j < xCount; j++)
            {
                borderIndices2[6 * (j)] = j;
                borderIndices2[6 * (j) + 1] = j + (xCount + 1);
                borderIndices2[6 * (j) + 2] = j + 1;
                borderIndices2[6 * (j) + 3] = j + 1;
                borderIndices2[6 * (j) + 4] = j + (xCount + 1);
                borderIndices2[6 * (j) + 5] = j + (xCount + 1) + 1;
            }
            borderIndexBuffer2.SetData(borderIndices2, 0, LockFlags.None);
            
            /**第3个四周边界**/
            borderVertexBuffer3 = new VertexBuffer(typeof(CustomVertex.PositionColored),
                2 * (yCount + 1),//四周的一个面封闭总共所需要的顶点的数目
                device,
                Usage.Dynamic | Usage.WriteOnly,
                CustomVertex.PositionColored.Format,
                Pool.Default);
            borderVertices3 = new CustomVertex.PositionColored[2 * (yCount + 1)];//定义顶点
            for (k = 0; k < yCount + 1; k++)//Z轴平行方向上的点的定义
            {
                borderVertices3[k].Position = new Vector3(0, minY, k * cellHeight);
                borderVertices3[k].Color = System.Drawing.Color.Aqua.ToArgb();
            }
            for (; k < 2 * (yCount + 1); k++)//高程图上的边界点的定义
            {
                Color color = bitmap.GetPixel(0, (int)((k - xCount - 1) * cellHeight));//边界点不能直接传进去写死，容易产生溢出的异常
                float height = float.Parse(color.R.ToString()) + float.Parse(color.G.ToString()) + float.Parse(color.B.ToString());
                height /= 10;
                borderVertices3[k].Position = new Vector3(0, height, (k - xCount - 1) * cellHeight);//i * cellHeight=0
                borderVertices3[k].Color = System.Drawing.Color.Aqua.ToArgb();
            }

            borderVertexBuffer3.SetData(borderVertices3, 0, LockFlags.None);

            borderIndexBuffer3 = new IndexBuffer(typeof(int),
                6 * yCount * 1,
                device,
                Usage.WriteOnly,
                Pool.Default);
            borderIndices3 = new int[6 * yCount * 1];//初始化索引顶点

            for (int j = 0; j < yCount; j++)
            {
                borderIndices3[6 * (j)] = j;
                borderIndices3[6 * (j) + 1] = j + (yCount + 1);
                borderIndices3[6 * (j) + 2] = j + 1;
                borderIndices3[6 * (j) + 3] = j + 1;
                borderIndices3[6 * (j) + 4] = j + (yCount + 1);
                borderIndices3[6 * (j) + 5] = j + (yCount + 1) + 1;
            }
            borderIndexBuffer3.SetData(borderIndices3, 0, LockFlags.None);

            /**第4个四周边界**/
            borderVertexBuffer4 = new VertexBuffer(typeof(CustomVertex.PositionColored),
                2 * (yCount + 1),//四周的一个面封闭总共所需要的顶点的数目
                device,
                Usage.Dynamic | Usage.WriteOnly,
                CustomVertex.PositionColored.Format,
                Pool.Default);
            borderVertices4 = new CustomVertex.PositionColored[2 * (yCount + 1)];//定义顶点
            for (k = 0; k < yCount + 1; k++)//Z轴平行方向上的点的定义
            {
                borderVertices4[k].Position = new Vector3(xCount*cellWidth, minY, k * cellHeight);
                borderVertices4[k].Color = System.Drawing.Color.Aqua.ToArgb();
            }
            for (; k < 2 * (yCount + 1); k++)//高程图上的边界点的定义
            {
                Color color = bitmap.GetPixel((int)(xCount * cellWidth), (int)((k - xCount - 1) * cellHeight));//边界点不能直接传进去写死，容易产生溢出的异常
                float height = float.Parse(color.R.ToString()) + float.Parse(color.G.ToString()) + float.Parse(color.B.ToString());
                height /= 10;
                borderVertices4[k].Position = new Vector3(xCount * cellWidth, height, (k - xCount - 1) * cellHeight);//i * cellHeight=0
                borderVertices4[k].Color = System.Drawing.Color.Aqua.ToArgb();
            }

            borderVertexBuffer4.SetData(borderVertices4, 0, LockFlags.None);

            borderIndexBuffer4 = new IndexBuffer(typeof(int),
                6 * yCount * 1,
                device,
                Usage.WriteOnly,
                Pool.Default);
            borderIndices4 = new int[6 * yCount * 1];//初始化索引顶点

            for (int j = 0; j < yCount; j++)
            {
                borderIndices4[6 * (j)] = j;
                borderIndices4[6 * (j) + 1] = j + (yCount + 1);
                borderIndices4[6 * (j) + 2] = j + 1;
                borderIndices4[6 * (j) + 3] = j + 1;
                borderIndices4[6 * (j) + 4] = j + (yCount + 1);
                borderIndices4[6 * (j) + 5] = j + (yCount + 1) + 1;
            }
            borderIndexBuffer4.SetData(borderIndices4, 0, LockFlags.None);

            device.SamplerState[0].MagFilter = TextureFilter.Linear;//使用纹理滤波器进行线性滤波
        }

        public void Render()//渲染
        {
            if (device == null)   //如果device为空则不渲染
                return;
            if (pause) //如果窗口被切换或者最小化则停止渲染，减少CPU压力
                return;

            Matrix viewMatrix = Matrix.LookAtLH(CamPostion, CamTarget, new Vector3(0, 1, 0));
            device.Transform.Projection = Matrix.PerspectiveFovLH((float)Math.PI / 4, this.Width / this.Height, 0.3f, 500f);
            device.Transform.View = viewMatrix;

            device.Clear(ClearFlags.Target | ClearFlags.ZBuffer, Color.DarkSlateBlue, 1.0f, 0);  //清除windows界面为深蓝色
            device.BeginScene();
            //在此添加渲染图形代码
            device.RenderState.CullMode = Cull.None;
            device.RenderState.FillMode = FillMode.Solid;
            device.RenderState.Lighting = false;

            device.SetTexture(0, texture);//设置贴图

            device.VertexFormat = CustomVertex.PositionTextured.Format;
            device.SetStreamSource(0, vertexBuffer, 0);
            device.Indices = indexBuffer;
            device.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, (xCount + 1) * (yCount + 1), 0, indices.Length / 3);

            device.Transform.World = Matrix.Translation(0.0f, 0.0f, 0.0f);//底部世界变换
            device.Material = bottomMaterial;//底部使用的材质

            StateBlock sb = new StateBlock(device, StateBlockType.All);
            sb.Capture();//将device以前的设置保存到sb

            device.RenderState.DiffuseMaterialSource = ColorSource.Material;
            device.RenderState.AlphaBlendEnable = true;
            device.SetTexture(0, bottomTexture);
            device.TextureState[0].ColorOperation = TextureOperation.Modulate;
            device.TextureState[0].ColorArgument1 = TextureArgument.TextureColor;
            device.TextureState[0].ColorArgument2 = TextureArgument.Diffuse;
            device.TextureState[0].AlphaOperation = TextureOperation.Modulate;
            device.TextureState[0].AlphaArgument1 = TextureArgument.TextureColor;
            device.TextureState[0].AlphaArgument2 = TextureArgument.Diffuse;
            device.RenderState.SourceBlend = Blend.SourceColor;
            device.RenderState.DestinationBlend = Blend.InvSourceAlpha;
            device.SetStreamSource(0, bottomVertexBuffer, 0);
            device.VertexFormat = CustomVertex.PositionNormalTextured.Format;
            device.DrawPrimitives(PrimitiveType.TriangleList, 0, 2);
            sb.Apply();

            /*第1个边界三角形*/
            device.SetStreamSource(0, borderVertexBuffer1, 0);
            device.VertexFormat = CustomVertex.PositionColored.Format;
            device.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, 2 * (xCount + 1), 0, borderIndices1.Length / 3);
            /*第2个边界三角形*/
             device.SetStreamSource(0, borderVertexBuffer2, 0);
             device.VertexFormat = CustomVertex.PositionColored.Format;
             device.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, 2 * (xCount + 1), 0, borderIndices2.Length / 3);
            /*第3个边界三角形*/
             device.SetStreamSource(0, borderVertexBuffer3, 0);
             device.VertexFormat = CustomVertex.PositionColored.Format;
             device.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, 2 * (yCount + 1), 0, borderIndices3.Length / 3);
             /*第4个边界三角形*/
             device.SetStreamSource(0, borderVertexBuffer4, 0);
             device.VertexFormat = CustomVertex.PositionColored.Format;
             device.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, 2 * (yCount + 1), 0, borderIndices4.Length / 3);
           
            device.EndScene();
            device.Present();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            InitializeDirect3D();
            this.Show();
            Render();
        }

        private void OnKeyDown(object sender, KeyEventArgs e)
        {
            Vector4 tempV4;
            Matrix currentView = device.Transform.View;//当前摄像机的视图矩阵
            switch (e.KeyCode)
            {
                case Keys.Left:
                    CamPostion.Subtract(CamTarget);
                    tempV4 = Vector3.Transform(CamPostion, Matrix.RotationQuaternion(
                            Quaternion.RotationAxis(new Vector3(currentView.M12, currentView.M22, currentView.M32), -angleY)));
                    CamPostion.X = tempV4.X + CamTarget.X;
                    CamPostion.Y = tempV4.Y + CamTarget.Y;
                    CamPostion.Z = tempV4.Z + CamTarget.Z;
                    break;
                case Keys.Right:
                    CamPostion.Subtract(CamTarget);
                    tempV4 = Vector3.Transform(CamPostion, Matrix.RotationQuaternion(
                            Quaternion.RotationAxis(new Vector3(currentView.M12, currentView.M22, currentView.M32), angleY)));
                    CamPostion.X = tempV4.X + CamTarget.X;
                    CamPostion.Y = tempV4.Y + CamTarget.Y;
                    CamPostion.Z = tempV4.Z + CamTarget.Z;
                    break;
                case Keys.Up:
                    CamPostion.Subtract(CamTarget);
                    tempV4 = Vector3.Transform(CamPostion, Matrix.RotationQuaternion(
                       Quaternion.RotationAxis(new Vector3(device.Transform.View.M11
                       , device.Transform.View.M21, device.Transform.View.M31), -angleY)));
                    CamPostion.X = tempV4.X + CamTarget.X;
                    CamPostion.Y = tempV4.Y + CamTarget.Y;
                    CamPostion.Z = tempV4.Z + CamTarget.Z;
                    break;
                case Keys.Down:
                    CamPostion.Subtract(CamTarget);
                    tempV4 = Vector3.Transform(CamPostion, Matrix.RotationQuaternion(
                       Quaternion.RotationAxis(new Vector3(device.Transform.View.M11
                       , device.Transform.View.M21, device.Transform.View.M31), angleY)));
                    CamPostion.X = tempV4.X + CamTarget.X;
                    CamPostion.Y = tempV4.Y + CamTarget.Y;
                    CamPostion.Z = tempV4.Z + CamTarget.Z;
                    break;
                case Keys.Add:
                    CamPostion.Subtract(CamTarget);
                    CamPostion.Scale(0.95f);
                    CamPostion.Add(CamTarget);
                    break;
                case Keys.Subtract:
                    CamPostion.Subtract(CamTarget);
                    CamPostion.Scale(1.05f);
                    CamPostion.Add(CamTarget);
                    break;
            }
            Matrix viewMatrix = Matrix.LookAtLH(CamPostion, CamTarget, new Vector3(0, 1, 0));
            device.Transform.View = viewMatrix;
            Render();
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            this.Render();
        }

        private void OnMouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                mouseLastX = e.X;
                mouseLastY = e.Y;
                isRotateByMouse = true;
            }
            else if (e.Button == MouseButtons.Middle)
            {
                mouseLastX = e.X;
                mouseLastY = e.Y;
                isMoveByMouse = true;
            }
        }

        private void OnMouseUp(object sender, MouseEventArgs e)
        {
            isRotateByMouse = false;
            isMoveByMouse = false;
        }

        private void OnMouseMove(object sender, MouseEventArgs e)
        {
            if (isRotateByMouse)
            {
                Matrix currentView = device.Transform.View;//当前摄像机的视图矩阵
                float tempAngleY = 2 * (float)(e.X - mouseLastX) / this.Width;
                CamPostion.Subtract(CamTarget);

                Vector4 tempV4 = Vector3.Transform(CamPostion, Matrix.RotationQuaternion(
                    Quaternion.RotationAxis(new Vector3(currentView.M12, currentView.M22, currentView.M32), tempAngleY)));
                CamPostion.X = tempV4.X;
                CamPostion.Y = tempV4.Y;
                CamPostion.Z = tempV4.Z;

                float tempAngleX = 4 * (float)(e.Y - mouseLastY) / this.Height;
                tempV4 = Vector3.Transform(CamPostion, Matrix.RotationQuaternion(
                    Quaternion.RotationAxis(new Vector3(currentView.M11, currentView.M21, currentView.M31), tempAngleX)));
                CamPostion.X = tempV4.X + CamTarget.X;
                CamPostion.Y = tempV4.Y + CamTarget.Y;
                CamPostion.Z = tempV4.Z + CamTarget.Z;
                Matrix viewMatrix = Matrix.LookAtLH(CamPostion, CamTarget, new Vector3(0, 1, 0));
                device.Transform.View = viewMatrix;

                mouseLastX = e.X;
                mouseLastY = e.Y;
                Render();
            }
            else if (isMoveByMouse)
            {
                Matrix currentView = device.Transform.View;//当前摄像机的视图矩阵
                float moveFactor = 0.01f;
                CamTarget.X += -moveFactor * ((e.X - mouseLastX) * currentView.M11 - (e.Y - mouseLastY) * currentView.M12);
                CamTarget.Y += -moveFactor * ((e.X - mouseLastX) * currentView.M21 - (e.Y - mouseLastY) * currentView.M22);
                CamTarget.Z += -moveFactor * ((e.X - mouseLastX) * currentView.M31 - (e.Y - mouseLastY) * currentView.M32);

                CamPostion.X += -moveFactor * ((e.X - mouseLastX) * currentView.M11 - (e.Y - mouseLastY) * currentView.M12);
                CamPostion.Y += -moveFactor * ((e.X - mouseLastX) * currentView.M21 - (e.Y - mouseLastY) * currentView.M22);
                CamPostion.Z += -moveFactor * ((e.X - mouseLastX) * currentView.M31 - (e.Y - mouseLastY) * currentView.M32);

                Matrix viewMatrix = Matrix.LookAtLH(CamPostion, CamTarget, new Vector3(0, 1, 0));
                device.Transform.View = viewMatrix;
                mouseLastX = e.X;
                mouseLastY = e.Y;
                Render();
            }
        }
        private void OnMouseWheel(object sender, MouseEventArgs e)
        {
            float scaleFactor = -(float)e.Delta / 2000 + 1f;
            CamPostion.Subtract(CamTarget);
            CamPostion.Scale(scaleFactor);
            CamPostion.Add(CamTarget);
            Matrix viewMatrix = Matrix.LookAtLH(CamPostion, CamTarget, new Vector3(0, 1, 0));
            device.Transform.View = viewMatrix;
            Render();
        }

        private void Form1_Resize(object sender, EventArgs e)//窗口切换时停止渲染
        {
            pause = ((this.WindowState == FormWindowState.Minimized) || !this.Visible);
        }
    }
}