DX9鼠标拾取网格轨迹

基于DXUT框架下鼠标拾取的网格，获取击中点。源代码已上传到资源

其中主要分为获取文件内部数据，获取鼠标的击中点，判断击中点是否于网格进行相交，击中点的记录。

获取文件内部数据，通过简单的读取分割字符串即可获取网格的顶点及面数据

int ReadXFile(void){char Buf[2000] = {0};//存放临时一行总元素数组,这个要足够大内存空间，否则内存太小读不完一直循环std::string TxtA;//临时存放的文本unsigned short VertMount = 0,i = 0,mount = 0;//顶点的数目,循环数目,顶点分割循环数目unsigned short VertInxMount = 0;//获取顶点索引数目char A[20] = {0};//定义一个临时数组存放临时内容char token[100]={0};//复制一行的数组到分割数组中char *tokenremain = token;//获得原始字符串指针，但该指针可变，适应下文分割语句char *tok1 = NULL;//分割后存坐标数值得指针char* BufZ = NULL;//临时存放读取的字符串比较//获取面模块unsigned short a = 0,b = 0,c = 0;//临时获取相对应面的顶点的索引的变量，用于放进数组中//获取.X文件内部矩阵模块std::string JuZhen;//源字符串float m[17]={0};//矩阵元素std::string B;//临时存放分割的数组Vert VertRHWTran;//矩阵转换临时存放结果，防止坐标值结果影响正在的计算std::ifstream fn("MaTong.x",std::ios::_Nocreate);//打开文件if (fn.fail() == 1)//检查文件是否失败{std::cerr<<"error opening the File\n"<<std::endl;}while(fn.eof() != 1)//文件没到尾就一直读取{fn.getline(Buf,sizeof(Buf));BufZ = Buf;//获取.X文件内部矩阵模块if(strcmp(BufZ," FrameTransformMatrix {") == 0)//检测字符串是否相等,读矩阵{fn.getline(Buf,sizeof(Buf));JuZhen = Buf;for (i = 1;i< 16;i++){mount = JuZhen.find(",",0);//首先找到分割符B = JuZhen.substr(0,mount);//取分割符前的m[i] = atof(B.c_str());//将字符串变为数字,JuZhen = JuZhen.substr(mount+1);//去掉已分割的字符串}m[16] = atof(JuZhen.c_str());//最后将剩下的一个不能分割的字符串转变为数字，完成全部提取}//获取顶点坐标及索引总模块if(strcmp(BufZ," Mesh  {") == 0)//检测字符串是否相等,读顶点{fn.getline(Buf,sizeof(Buf));BufZ = Buf;VertMount = atoi(BufZ);//获取顶点数目//获取顶点数目模块for ( i = 0;i < VertMount;i++){fn.getline(Buf,sizeof(Buf));strncpy( token, Buf, 50); // 最后一个位置为\0保留*/，复制指针内容到数组里去//分割坐标字符串模块tok1 = strtok(tokenremain,";");//第一次分割字符串，将，改变为\0,作用先跳一行strncpy( A, tok1, 19); // 将文本拷贝到数组VertRHW[i].x = atof(A);//获取x值for (mount = 0; mount < 2;mount++){tok1 = strtok(NULL,";");//继续分割字符串，指针改为空,停留strncpy( A, tok1, 19); // 将文本拷贝到数组switch(mount){case 0: VertRHW[i].y = atof(A);break;//赋值y值case 1:VertRHW[i].z = atof(A);break;//赋值Z值default:                  ;break;//其余为空语句，防止出错}}}//.X文件内部顶点矩阵装换模块for ( i = 0;i < VertMount;i++){VertRHWTran.x = VertRHW[i].x;VertRHWTran.y = VertRHW[i].y;VertRHWTran.z = VertRHW[i].z;//临时存放结果，防止矩阵转换时影响计算VertRHW[i].x = VertRHWTran.x*m[1]+VertRHWTran.y*m[5]+VertRHWTran.z*m[9]+m[13];VertRHW[i].y = VertRHWTran.x*m[2]+VertRHWTran.y*m[6]+VertRHWTran.z*m[10]+m[14];VertRHW[i].z = VertRHWTran.x*m[3]+VertRHWTran.y*m[7]+VertRHWTran.z*m[11]+m[15];}//获取顶点索引模块fn.getline(Buf,sizeof(Buf));BufZ = Buf;VertInxMount = atoi(BufZ);//获取顶点索引数目for (i = 0;i < VertInxMount;i++){fn.getline(Buf,sizeof(Buf));strncpy( token, Buf, 50); // 最后一个位置为\0保留*/，复制指针内容到数组里去//将多少个点与索引模块隔离模块tok1 = strtok(tokenremain,";");//第一次分割字符串//提取顶点索引模块for (mount = 0;mount < 3 ; mount++){tok1 = strtok(NULL,",");//第一次分割字符串，将，改变为\0,作用先跳一行strncpy( A, tok1, 19); // 将文本拷贝到数组VertInxRHW[3*i+mount] = atoi(A);//依次获取索引值}}fn.close();//获取完索引，关闭文件//综合结合顶点及索引的面模块MianMount = VertInxMount;for (mount= 0;mount < MianMount;mount++)//第几个面{for(i = 0;i < 3;i++){a = VertInxRHW[i+3*mount];switch (i){case 0 :VertMian[mount].Vertor1 = VertRHW[a];break;case 1 :VertMian[mount].Vertor2 = VertRHW[a];break;case 2 :VertMian[mount].Vertor3 = VertRHW[a];break;default:                                    ;break;}}}fn.close();//关闭文件return 1;//完成所有信息的提取，跳出函数，减小计算，返回1表示正常}}fn.close();//关闭文件return(0);//返回0，表示异常，没有获取顶点与索引};

获取鼠标的击中点，其中先进行屏膜的转换及矩阵的逆转换，对其进行三维点的还原，形成射线。

 D3DXMATRIX  pmatProj ;//获取相机矩阵   pd3dDevice->GetTransform(D3DTS_PROJECTION,&pmatProj);        POINT ptCursor;//定义一个鼠标结构        GetCursorPos( &ptCursor );//鼠标通过屏幕获取屏幕坐标点        ScreenToClient( DXUTGetHWND(), &ptCursor );//屏幕坐标点转为窗口坐标点D3DXVECTOR3 v;//计算屏幕射线v.x = ( ( ( 2.0f * ptCursor.x ) / pd3dsdBackBuffer->Width ) - 1 ) / pmatProj._11;//获取投影坐标点        v.y = -( ( ( 2.0f * ptCursor.y ) / pd3dsdBackBuffer->Height ) - 1 ) / pmatProj._22;        v.z = -1.0f;D3DXMATRIX  matView,matWorld;//获取相机矩阵pd3dDevice->GetTransform(D3DTS_WORLD,&matWorld);pd3dDevice->GetTransform(D3DTS_VIEW,&matView);D3DXMATRIX mWorldView = matWorld * matView;//2个矩阵相乘获得一个点的局部坐标转化为观察坐标的综合矩阵D3DXMATRIX m;        D3DXMatrixInverse( &m, NULL, &mWorldView );//获得上述综合矩阵的逆矩阵// 转换屏幕射线到3D空间        vPickRayDir.x = v.x * m._11 + v.y * m._21 + v.z * m._31;//射线向量点        vPickRayDir.y = v.x * m._12 + v.y * m._22 + v.z * m._32;        vPickRayDir.z = v.x * m._13 + v.y * m._23 + v.z * m._33;        vPickRayOrig.x = m._41;//射线起点        vPickRayOrig.y = m._42;        vPickRayOrig.z = m._43;

然后进行相交判断，与各个面进行相交判断，获取最近距离的面，

for (unsigned int mount = 0; mount < MianMount;mount++)//历遍全部面返回与射线相交最短距离的面{Vectorz1.x = VertMian[mount].Vertor1.x;Vectorz1.y = VertMian[mount].Vertor1.y;Vectorz1.z = VertMian[mount].Vertor1.z;Vectorz2.x = VertMian[mount].Vertor2.x;Vectorz2.y = VertMian[mount].Vertor2.y;Vectorz2.z = VertMian[mount].Vertor2.z;Vectorz3.x = VertMian[mount].Vertor3.x;Vectorz3.y = VertMian[mount].Vertor3.y;Vectorz3.z = VertMian[mount].Vertor3.z;bInt = D3DXIntersectTri(&Vectorz1, &Vectorz2, &Vectorz3, &vPickRayOrig, &vPickRayDir,&uz, &vz, &distanceZ);if( bInt ){g_dwIntersections = TRUE;if (g_IntersectionArray.dis == 0)//初始化获取与第一个相交面的距离{g_IntersectionArray.dis = distanceZ;}if (distanceZ <= g_IntersectionArray.dis )//判断上一个面与下一个面相交距离，返回相交距离的最小值{g_IntersectionArray.Vector1 =Vectorz1;g_IntersectionArray.Vector2 =Vectorz2;g_IntersectionArray.Vector3 =Vectorz3;g_IntersectionArray.u =uz;g_IntersectionArray.v =vz;g_IntersectionArray.MianNumMount = mount;g_IntersectionArray.dis = distanceZ;}}}

最后根据重心法求取其击中点

Vectorzz = g_IntersectionArray.Vector1+g_IntersectionArray.u*(g_IntersectionArray.Vector2 - g_IntersectionArray.Vector1)+g_IntersectionArray.v*(g_IntersectionArray.Vector3-g_IntersectionArray.Vector1);//求得三角形交点