z_buffer(vc+opengl)

#ifdef _WINDOWS #include <windows.h> #endif #include "MyOpenGL.h" #include <math.h> #include <string.h> #include <fstream> #include <iostream> #include <iterator> #define RANDOM_COLOR const Color objectColor={100,100,200}; ObjModel::ObjModel() { } ObjModel::~ObjModel() { } int charToInt(char *&pt) { int x=0; while(*pt>='0'&&*pt<='9') { x=x*10+(*pt-'0'); pt++; } return x; } DataIndex extract(char * buf) { DataIndex index; char *pt=buf; index.faceIndex=charToInt(pt); *pt++; if (*pt>='0'&&*pt<='9') index.coordIndex=charToInt(pt); *pt++; if (*pt>='0'&&*pt<='9') index.normalIndex=charToInt(pt); return index; } bool ObjModel::Read(const char *filename) { bool flag=TRUE; std::ifstream input; input.open(filename); if (!input) return 0; // read the data of the object char buf[256]; DataIndex tempIndex; std::vector<int> tempfaceIndex; // maybe triangles , quards , or polygons std::vector<int> tempNormalIndex; std::vector<int> tempCoordIndex; // buffer of the data Point temp; input>>buf; while((buf[0])!=EOF) { switch (buf[0]) { // this may be a point,a vertex normal,a texture coord or just a letter case 'v': switch (buf[1]) { case 'n': input>>temp.x>>temp.y>>temp.z>>buf; vertexNormals.push_back(temp); break; case 't': input>>temp.x>>temp.y>>temp.z>>buf; textureCoords.push_back(temp); break; case '\0': input>>temp.x>>temp.y>>temp.z>>buf; vertices.push_back(temp); if (flag) { maxx=minx=temp.x; maxy=miny=temp.y; flag=!flag; } if (temp.x>maxx) maxx=temp.x; if (temp.y>maxy) maxy=temp.y; if (temp.x<minx) minx=temp.x; if (temp.y<miny) miny=temp.y; break; default: input>>buf; break; } break; case 'f': switch (buf[1]) { case '\0': input>>buf; while (buf[0]>'0'&&buf[0]<='9') { tempIndex=extract(buf); tempfaceIndex.push_back(tempIndex.faceIndex); tempNormalIndex.push_back(tempIndex.normalIndex); tempCoordIndex.push_back(tempIndex.coordIndex); input>>buf; } faceIndex.push_back(tempfaceIndex); normalIndex.push_back(tempNormalIndex); coordIndex.push_back(tempCoordIndex); tempfaceIndex.clear(); tempNormalIndex.clear(); tempCoordIndex.clear(); break; default: input>>buf; break; } break; default: input>>buf; break; }//switch if (input.eof()) break; }//while numVertices=vertices.size(); numVertexNormals=vertexNormals.size(); numTextureCoords=textureCoords.size(); numFaces=faceIndex.size(); return 1; } MyOpenGL::MyOpenGL() { } MyOpenGL::~MyOpenGL() { } bool MyOpenGL::Init(const char *filename) { glClearColor(0.0,0.0,0.0,0.0); m_angle=0.0f; model=new ObjModel(); model->Read(filename); glPixelStorei(GL_UNPACK_ALIGNMENT, 1); return true; } bool MyOpenGL::Shutdown() { return true; } void MyOpenGL::SetupProjection(int width,int height) { if (height==0) height=1; glViewport(0,0,width,height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(52.0f,(GLfloat)width/(GLfloat)height,1.0f,1000.0f); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); m_windowWidth=width; m_windowHeight=height; } void MyOpenGL::Prepare(float dt) { m_angle+=0.1f; } void MyOpenGL::setToScreenCoordinate() { double scale,xoffset,yoffset; //首先判断物体的纵横比与窗口的比例，较长的物体按长度来放缩否则按高度放缩 /******按y方向缩放至屏幕大小,其中计算后的y坐标范围在[0,m_windowHeight-1]之间，可以避免z_buffer越界******/ if (((model->maxx-model->minx)*m_windowHeight)<((model->maxy-model->miny)*m_windowWidth)) scale=(m_windowHeight-1)/(model->maxy-model->miny); else scale=(m_windowWidth-1)/(model->maxx-model->minx); xoffset=(m_windowWidth-1-scale*(model->maxx-model->minx))/2-model->minx*scale; yoffset=(m_windowHeight-1-scale*(model->maxy-model->miny))/2-model->miny*scale; for (std::vector<Point>::iterator it=model->vertices.begin();it!=model->vertices.end();it++) { it->x=doubleToInt(it->x*scale+xoffset); it->y=doubleToInt(it->y*scale+yoffset); it->z=doubleToInt(it->z*scale); } model->maxy=model->maxy*scale+yoffset; model->miny=model->miny*scale+yoffset; model->maxx=model->maxx*scale+xoffset; model->minx=model->minx*scale+xoffset; } void MyOpenGL::z_buffer() { //第一步，将物体坐标进行简单的投影变换，将其坐标转换为屏幕坐标，使其大小符合窗口的大小，并固定我们所看到的为物体的正视图，可以通过旋转物体来观察其他表面。 setToScreenCoordinate(); //首先建立分类的多边形表和边表l扫描顺序从上到下：在处理最上面一条扫 //描线之前，活化的多边形表和边表是空的l在处理每条扫描线时，作如下工作 //l 把帧缓冲器的相应行置成底色l 把z缓冲器的各个单元置成最小值(表示离视 //点最远) constructSortTable(); //开两个一维数组(xresolution)分别作为当前扫描线的z缓冲器和帧缓冲器,z缓冲器初始值为最小值，帧缓冲器为背景色 double z_depth[800]; Color frameBuf[800]; std::vector<SortEdgeTable>::iterator tempEdgeTable[3]; ActivePolygonTable tempActivePolygonTable; int lines=0; double zx; bool flag=false; std::vector<ActivePolygonTable>::iterator activePolygonPtr; Color aa; int stopline=256; /*********逐扫描线进行处理********/ for (int scanLine=m_windowHeight-1;scanLine>=0;scanLine--) { if (scanLine==stopline) stopline-=1; /*********把帧缓冲器的相应行置成底色 把z缓冲器的各个单元置成最小值(表示离视点最远)*********/ for (int i=0;i<m_windowWidth;i++) { z_depth[i]=-99999999; image[scanLine][i].r=0; image[scanLine][i].g=0; image[scanLine][i].b=0; } /******检查分类的多边形表，如果有新的多边形涉及该扫描线，则把它放入活化的多边形表中******/ for (std::vector<SortPolygonTable>::iterator polygonPtr=sortPolygonTable[scanLine].begin();polygonPtr!=sortPolygonTable[scanLine].end();) { //将该多边形加入活化多边形表中 tempActivePolygonTable.a=polygonPtr->a; tempActivePolygonTable.b=polygonPtr->b; tempActivePolygonTable.c=polygonPtr->c; tempActivePolygonTable.d=polygonPtr->d; tempActivePolygonTable.dy=polygonPtr->dy; tempActivePolygonTable.id=polygonPtr->id; tempActivePolygonTable.color=polygonPtr->color; if (tempActivePolygonTable.id==2) tempActivePolygonTable.id=2; lines=0; ///******把该多边形在oxy平面上的投影和扫描线相交的边加入到活化边表中,必定有两条边******/ for (std::vector<SortEdgeTable>::iterator edgePtr=sortEdgeTable[scanLine].begin();edgePtr!=sortEdgeTable[scanLine].end();) { if (edgePtr->id==polygonPtr->id) lines++; if (lines==1&&edgePtr->id==polygonPtr->id) { tempActivePolygonTable.activeEdgeTable.xl=edgePtr->x; tempActivePolygonTable.activeEdgeTable.dxl=edgePtr->dx; tempActivePolygonTable.activeEdgeTable.dyl=edgePtr->dy; tempActivePolygonTable.activeEdgeTable.xr=edgePtr->x; tempActivePolygonTable.activeEdgeTable.dxr=edgePtr->dx; tempActivePolygonTable.activeEdgeTable.dyr=edgePtr->dy; tempActivePolygonTable.activeEdgeTable.dzx=-polygonPtr->a/polygonPtr->c; tempActivePolygonTable.activeEdgeTable.dzy=polygonPtr->b/polygonPtr->c; tempActivePolygonTable.activeEdgeTable.id=polygonPtr->id; sortEdgeTable[scanLine].erase(edgePtr,edgePtr+1); edgePtr=sortEdgeTable[scanLine].begin(); continue; } if (lines==2&&edgePtr->id==polygonPtr->id) { //temp中0号位存左边 if (tempActivePolygonTable.activeEdgeTable.xl>edgePtr->x||(abs(tempActivePolygonTable.activeEdgeTable.xl-edgePtr->x)<1e-8&&tempActivePolygonTable.activeEdgeTable.dxl>edgePtr->dx)) { tempActivePolygonTable.activeEdge