343 lines
6.9 KiB
C++
343 lines
6.9 KiB
C++
// ZBuffer.cpp: implementation of the CZBuffer class.
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//
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//////////////////////////////////////////////////////////////////////
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#include "stdafx.h"
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#include "Test.h"
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#include "ZBuffer.h"
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#include "math.h"
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#define Round(d) int(floor(d+0.5))
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#ifdef _DEBUG
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#undef THIS_FILE
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static char THIS_FILE[]=__FILE__;
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#define new DEBUG_NEW
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#endif
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//////////////////////////////////////////////////////////////////////
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// Construction/Destruction
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//////////////////////////////////////////////////////////////////////
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CZBuffer::CZBuffer()
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{
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P=NULL;
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pHeadE=NULL;
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pCurrentB=NULL;
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pEdge=NULL;
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pCurrentE=NULL;
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pHeadB=NULL;
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zBuffer=NULL;
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}
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CZBuffer::~CZBuffer()
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{
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if(P!=NULL)
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{
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delete []P;
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P=NULL;
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}
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for(int i=0;i<Width;i++)
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{
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delete[] zBuffer[i];
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zBuffer[i]=NULL;
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}
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if(zBuffer!=NULL)
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{
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delete zBuffer;
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zBuffer=NULL;
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}
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ClearMemory();
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}
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void CZBuffer::SetPoint(CPi3 p[],int m)
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{
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if(P!=NULL)
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{
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delete []P;
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P=NULL;
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}
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P=new CPi3[m];
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for(int i=0;i<m;i++)
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P[i]=p[i];
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PNum=m;
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}
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void CZBuffer::CreateBucket()//创建桶表
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{
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int yMin,yMax;
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yMin=yMax=P[0].y;
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for(int i=1;i<PNum;i++)//查找多边形所覆盖的最小和最大扫描线
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{
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if(P[i].y<yMin)
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yMin=P[i].y;//扫描线的最小值
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if(P[i].y>yMax)
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yMax=P[i].y;//扫描线的最大值
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}
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for(int y=yMin;y<=yMax;y++)
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{
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if(yMin==y)//建立桶头结点
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{
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pHeadB=new CBucket;//建立桶的头结点
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pCurrentB=pHeadB;//pCurrentB为CBucket当前结点指针
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pCurrentB->ScanLine=yMin;
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pCurrentB->pET=NULL;//没有链接边表
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pCurrentB->pNext=NULL;
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}
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else//其他扫描线
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{
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pCurrentB->pNext=new CBucket;//建立桶的其他结点
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pCurrentB=pCurrentB->pNext;
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pCurrentB->ScanLine=y;
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pCurrentB->pET=NULL;
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pCurrentB->pNext=NULL;
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}
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}
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}
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void CZBuffer::CreateEdge()//创建边表
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{
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for(int i=0;i<PNum;i++)
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{
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pCurrentB=pHeadB;
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int j=(i+1)%PNum;//边的第二个顶点，P[i]和P[j]构成边
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if(P[i].y<P[j].y)//边的终点比起点高
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{
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pEdge=new CAET;
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pEdge->x=P[i].x;//计算ET表的值
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pEdge->yMax=P[j].y;
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pEdge->k=(P[j].x-P[i].x)/(P[j].y-P[i].y);//代表1/k
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pEdge->ps=P[i];//绑定顶点和颜色
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pEdge->pe=P[j];
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pEdge->pNext=NULL;
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while(pCurrentB->ScanLine!=P[i].y)//在桶内寻找该边的yMin
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{
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pCurrentB=pCurrentB->pNext;//移到yMin所在的桶结点
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}
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}
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if(P[j].y<P[i].y)//边的终点比起点低
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{
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pEdge=new CAET;
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pEdge->x=P[j].x;
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pEdge->yMax=P[i].y;
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pEdge->k=(P[i].x-P[j].x)/(P[i].y-P[j].y);
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pEdge->ps=P[i];
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pEdge->pe=P[j];
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pEdge->pNext=NULL;
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while(pCurrentB->ScanLine!=P[j].y)
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{
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pCurrentB=pCurrentB->pNext;
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}
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}
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if(int(P[j].y)!=P[i].y)
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{
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pCurrentE=pCurrentB->pET;
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if(pCurrentE==NULL)
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{
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pCurrentE=pEdge;
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pCurrentB->pET=pCurrentE;
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}
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else
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{
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while(pCurrentE->pNext!=NULL)
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{
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pCurrentE=pCurrentE->pNext;
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}
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pCurrentE->pNext=pEdge;
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}
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}
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}
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}
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void CZBuffer::Gouraud(CDC *pDC)//填充多边形
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{
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double CurDeep=0.0;//当前扫描线的深度
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double DeepStep=0.0;//当前扫描线随着x增长的深度步长
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double A,B,C,D;//平面方程Ax+By+Cz＋D=0的系数
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CVector V01(P[0],P[1]),V02(P[0],P[2]);
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CVector VN=Cross(V01,V02);
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A=VN.x;B=VN.y;C=VN.z;
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D=-A*P[0].x-B*P[0].y-C*P[0].z;
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DeepStep=-A/C;//计算扫描线深度步长增量
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CAET *pT1,*pT2;
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pHeadE=NULL;
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for(pCurrentB=pHeadB;pCurrentB!=NULL;pCurrentB=pCurrentB->pNext)
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{
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for(pCurrentE=pCurrentB->pET;pCurrentE!=NULL;pCurrentE=pCurrentE->pNext)
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{
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pEdge=new CAET;
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pEdge->x=pCurrentE->x;
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pEdge->yMax=pCurrentE->yMax;
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pEdge->k=pCurrentE->k;
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pEdge->ps=pCurrentE->ps;
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pEdge->pe=pCurrentE->pe;
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pEdge->pNext=NULL;
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AddEt(pEdge);
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}
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ETOrder();
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pT1=pHeadE;
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if(pT1==NULL)
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{
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return;
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}
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while(pCurrentB->ScanLine>=pT1->yMax)//下闭上开
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{
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CAET * pAETTEmp=pT1;
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pT1=pT1->pNext;
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delete pAETTEmp;
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pHeadE=pT1;
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if(pHeadE==NULL)
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return;
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}
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if(pT1->pNext!=NULL)
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{
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pT2=pT1;
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pT1=pT2->pNext;
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}
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while(pT1!=NULL)
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{
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if(pCurrentB->ScanLine>=pT1->yMax)//下闭上开
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{
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CAET* pAETTemp =pT1;
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pT2->pNext=pT1->pNext;
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pT1=pT2->pNext;
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delete pAETTemp;
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}
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else
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{
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pT2=pT1;
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pT1=pT2->pNext;
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}
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}
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CRGB ca,cb,cf;//ca、cb代边上任意点的颜色，cf代表面上任意点的颜色
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ca=Interpolation(pCurrentB->ScanLine,pHeadE->ps.y,pHeadE->pe.y,pHeadE->ps.c,pHeadE->pe.c);
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cb=Interpolation(pCurrentB->ScanLine,pHeadE->pNext->ps.y,pHeadE->pNext->pe.y,pHeadE->pNext->ps.c,pHeadE->pNext->pe.c);
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BOOL bInFlag=FALSE;//区间内外测试标志，初始值为假表示区间外部
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double xleft,xright;//扫描线和有效边相交区间的起点和终点坐标
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for(pT1=pHeadE;pT1!=NULL;pT1=pT1->pNext)
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{
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if(FALSE==bInFlag)
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{
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xleft=pT1->x;
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CurDeep=-(xleft*A+pCurrentB->ScanLine*B+D)/C;//z=-(Ax+By-D)/C
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bInFlag=TRUE;
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}
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else
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{
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xright=pT1->x;
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for(double x=xleft;x<xright;x++)//左闭右开
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{
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cf=Interpolation(x,xleft,xright,ca,cb);
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if(CurDeep<=zBuffer[Round(x)+Width/2][pCurrentB->ScanLine+Height/2])//如果当前采样点的深度小于帧缓冲器中原采样点的深度
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{
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zBuffer[Round(x)+Width/2][pCurrentB->ScanLine+Height/2]=CurDeep;//使用当前采样点的深度更新深度缓冲器
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pDC->SetPixelV(Round(x),pCurrentB->ScanLine,RGB(cf.red*255,cf.green*255,cf.blue*255));//绘制当前采样点
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}
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CurDeep+=DeepStep;
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}
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bInFlag=FALSE;
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}
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}
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for(pT1=pHeadE;pT1!=NULL;pT1=pT1->pNext)//边的连续性
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pT1->x=pT1->x+pT1->k;
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}
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}
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void CZBuffer::AddEt(CAET *pNewEdge)//合并ET表
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{
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CAET *pCE;
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pCE=pHeadE;
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if(pCE==NULL)
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{
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pHeadE=pNewEdge;
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pCE=pHeadE;
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}
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else
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{
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while(pCE->pNext!=NULL)
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{
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pCE=pCE->pNext;
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}
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pCE->pNext=pNewEdge;
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}
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}
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void CZBuffer::ETOrder()//边表的冒泡排序算法
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{
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CAET *pT1,*pT2;
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int Count=1;
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pT1=pHeadE;
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if(pT1==NULL)
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return;
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if(pT1->pNext==NULL)//如果该ET表没有再连ET表
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return;//桶结点只有一条边，不需要排序
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while(pT1->pNext!=NULL)//统计边结点的个数
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{
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Count++;
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pT1=pT1->pNext;
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}
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for(int i=0;i<Count-1;i++)//冒泡排序
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{
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CAET **pPre=&pHeadE;
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pT1=pHeadE;
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for(int j=0;j<Count-1-i;j++)
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{
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pT2=pT1->pNext;
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if ((pT1->x>pT2->x)||((pT1->x==pT2->x)&&(pT1->k>pT2->k)))
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{
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pT1->pNext=pT2->pNext;
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pT2->pNext=pT1;
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*pPre=pT2;
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pPre=&(pT2->pNext);//调整位置为下次遍历准备
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}
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else
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{
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pPre=&(pT1->pNext);
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pT1=pT1->pNext;
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}
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}
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}
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}
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CRGB CZBuffer::Interpolation(double t,double t1,double t2,CRGB clr1,CRGB clr2)//颜色线性插值
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{
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CRGB color;
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color=(t-t2)/(t1-t2)*clr1+(t-t1)/(t2-t1)*clr2;
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return color;
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}
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void CZBuffer::InitDeepBuffer(int Width,int Height,double Depth)//初始化深度缓冲
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{
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int i;
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this->Width=Width,this->Height=Height;
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zBuffer=new double *[Width];
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for(int i=0;i<Width;i++)
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zBuffer[i]=new double[Height];
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for(i=0;i<Width;i++)//初始化深度缓冲
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for(int j=0;j<Height;j++)
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zBuffer[i][j]=Depth;
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}
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void CZBuffer::ClearMemory()
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{
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DeleteAETChain(pHeadE);
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CBucket *pBucket=pHeadB;
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while (pBucket !=NULL)//针对每一个桶
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{
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CBucket * pBucketTemp = pBucket->pNext;
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DeleteAETChain(pBucket->pET);
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delete pBucket;
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pBucket=pBucketTemp;
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}
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pHeadB=NULL;
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pHeadE=NULL;
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}
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void CZBuffer::DeleteAETChain(CAET* pAET)
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{
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while (pAET!=NULL)
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{
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CAET* pAETTemp=pAET->pNext;
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delete pAET;
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pAET=pAETTemp;
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}
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} |