OpenGL 密室光线反射demo

//rorger, 2011 //mishi.cpp //密室光线反射 //last modified:2011-05-05 23:24 #include "myglbase.h" #include "glut.h" #include "windows.h" #include "math.h" #include "mymath.h" #include "vector" using namespace std; //线段类 class Line2Segment { public: Point2 first ; Point2 second ; Vector2 norm() { Vector2 c = second - first ; Vector2 normalVector = c.GetNormalVector(); return normalVector; } Line2Segment() { first.x=first.y=0; second.x=second.y=0; } Line2Segment(Point2 first,Point2 second) { this->first = first; this->second = second; } Line2Segment(Line2Segment& line2) { first = line2.first; second = line2.second; } }; //点法向量表示的直线类 class Line2 { public: Point2 pt ; Vector2 norm; Line2() { pt.x=pt.y=0; norm.x=0; norm.y=0; } Line2(Point2 pt,Vector2 norm) { this->pt=pt; this->norm=norm; } Line2(const Line2& line2) { pt=line2.pt; norm = line2.norm; } }; //点法向量表示的多边形 class Line2List { public: vector<Line2> line; int num() { return line.size(); } void push_back(Line2 newLine) { line.push_back(newLine); } Line2& operator[](int index) { if ((unsigned int)index >= line.size()) //注意size是unsigned int { throw "Out of range in Line2List"; } return line[index]; } }; class PolygonList { public: vector<Line2List> polygons; int num() { return polygons.size(); } void push_back(Line2List newPolygon) { polygons.push_back(newPolygon); } Line2List& operator[](int index) { if ((unsigned int)index >= polygons.size()) //注意size是unsigned int { throw "Out of range in Line2List"; } return polygons[index]; } }; /* a: Vector2 -射入向量 n: Vector2 -直线法向量 r: Vector2 -a经过直线反射后的向量 */ int GetReflectVector(Vector2 a,Vector2 n, Vector2& r) { if(n.GetLength() != 0) { n.Normalized(); //对n进行归一化,以便于利用公式 r=a-2*(a*n)*n; //公式请参考计算机图像学,这里a不要求归一化 return 1; } else return 0 ; } int chopCIRadial(float&tIn,float&tOut,float number,float denom,Vector2 norm,Vector2& normInHit,Vector2& normOutHit) { float tHit ; if(denom < 0) //射线是射入 { tHit = number / denom ; if (tOut != -1.0) { if (tHit >tOut) { return 0 ; } } if(tHit>=tIn) { tIn = tHit; normInHit = norm; } } else if(denom > 0) //射线射出 { tHit = number / denom; if (tHit<tIn) { return 0 ; } if (tOut==-1.0) //这是第一次初始化使用的 { tOut = tHit; normOutHit = norm; } else if (tHit<tOut) //最早出去的 { tOut = tHit; normOutHit = norm; } } else if(number<=0) //denom为0，射线与直线平行 { return 0 ; //在外半空间 } return 1; } /* S: Point2 - 射线端点 c: Vector - 射线方向 L: Line2List&- 多边形截取区域 tIn: float& - 截取的射入时间 tOut: float& -截取的射出时间 normIn: Vector2& - 射入时击中的边的法向量 normOut: Vector2& - 射出时击中的边的法向量 */ int CyrusBeckClipRadial(Point2 S,Vector2 c,Line2List& L,float& tIn,float& tOut,Point2& pIn,Point2& pOut,Vector2& normIn,Vector2& normOut) { float number,denom; float tInTemp = 0.0,tOutTemp=-1.0; Point2 pInTemp,pOutTemp ; Vector2 normInTemp,normOutTemp ; Vector2 tmp ; for (int i=0;i<L.num();i++) { //利用公式 tHit=n*(B-A)/(n*c) 其中A和c是目的直线参数表示，B和n是另一条直线点法向量 tmp = L.line[i].pt - S; number = L.line[i].norm * tmp ; denom = L.line[i].norm * c ; if (!chopCIRadial(tInTemp,tOutTemp,number,denom,L.line[i].norm,normInTemp,normOutTemp)) { return 0 ; //提前结束 } if (tInTemp>0.0 ) { if(tIn==0.0) { tIn = tInTemp; normIn = normInTemp; } else { tIn=max(tIn,tInTemp); if (tIn == tInTemp) { normIn = normInTemp; } } } if (tOutTemp>=0.0) { if (tOut==-1.0) { tOut = tOutTemp; normOut = normOutTemp ; } else { tOut = min(tOut,tOutTemp); //最早出去的 if (tOut == tOutTemp) { normOut = normOutTemp; } } } } pIn = S+c*tIn; pOut = S+c*tOut; return 1; } /* S: Point2 - 射线入射端点 c: Vector2 - 射线方向向量 polygonList: PolygonList& - 多边形集 pOut: Point2& - 取得最早的击中点 norm: Vector2& -取得最早击中点时边的法向量 */ int CyrusBeckClipRadial(Point2 S,Vector2 c,PolygonList& polygonList,Point2& pOut ,Vector2& norm) { float tIn=0.0,tOut=-1.0,tInResult=0.0,tOutResult=-1.0,tHit=0.0; Point2 pInTemp,pInResult,pOutTemp,pOutResult ; Vector2 normInTemp,normOutTemp; for (int i=0;i<polygonList.num();i++) { tIn=0.0; tOut=-1.0; //取得每个多边形的射入时间和射出时间，取最小值 if(!CyrusBeckClipRadial(S,c,polygonList[i],tIn,tOut,pInTemp,pOutTemp,normInTemp,normOutTemp)) { continue; } else //如果射入时间大于0，那么必然是内柱的情况； //如果射出时间大于0，那么必然是墙壁的情况; //还有一种小角度的情况(我只考虑了墙壁) { if (tIn >0.0 && !IsEqual(tIn,0.0)) { if (tHit == 0.0) // 首次 { tHit = tIn; norm = normInTemp; } else { tHit = min(tHit,tIn); //取得最小的射入时间 if (tHit == tIn) { norm = normInTemp; } } } else if (tOut >0.0 && !IsEqual(tOut,0.0)) { if (tHit == 0.0) // 首次 { tHit=tOut; norm = normOutTemp; } else { tHit = min(tOut,tHit); //取得最小的射出时间 if (tHit == tOut) { norm = normOutTemp; } } } else //小角度反射时的处理情况 { if (tOut>0.0 && tHit==0.0) { tHit = tOut; norm = normOutTemp; } } } } pOut = S+c*tHit; return 1 ; } //测试下吧 void testReflects() { //这是外墙,点是顺时针表示 float outerPillar[6][2]= { {1,0.5},{0.3,5},{2.5,8}, {6,9},{8,4},{7,1} }; //这是内柱,点是顺时针表示 float innerPillar[5][2]= { {1.8,5.5},{2.5,6.5},{3.5,7}, {4,4.5},{3,4.5} }; //这是内柱,点是顺时针表示 float innerPillar2[3][2]= { {4.55,2.2},{5,5},{6.5,3.5} }; //这是内柱,点是顺时针表示 float innerPillar3[5][2]= { {1.8,2.5},{2.5,3.5},{3.5,4}, {4,1.5},{3,1.5} }; Line2List outerPolygon,innerPolygon,innerPolygon2,innerPolygon3; Line2 tempLine2 ; Point2 tempPoint ; Point2 tempPoint2; Vector2 tempNorm; glColor3f(0.0,1.0,0.0); glBegin(GL_LINE_LOOP); for (int i=0;i<6;i++) { tempPoint.x = outerPillar[i][0]; tempPoint.y = outerPillar[i][1]; tempPoint2.x = outerPillar[(i+1)%6][0]; tempPoint2.y = outerPillar[(i+1)%6][1]; tempLine2.norm = ((Vector2)(tempPoint2-tempPoint)).GetNormalVector(); tempLine2.pt = tempPoint; outerPolygon.push_back(tempLine2); glVertex2d(tempPoint.x,tempPoint.y); } glEnd(); glBegin(GL_LINE_LOOP); for (int i=0;i<5;i++) { tempPoint.x = innerPillar[i][0]; tempPoint.y = innerPillar[i][1]; tempPoint2.x = innerPillar[(i+1)%5][0]; tempPoint2.y = innerPillar[(i+1)%5][1]; tempLine2.norm = ((Vector2)(tempPoint2-tempPoint)).GetNormalVector(); tempLine2.pt = tempPoint; innerPolygon.push_back(tempLine2); glVertex2d(tempPoint.x,tempPoint.y); } glEnd(); glBegin(GL_LINE_LOOP); for (int i=0;i<3;i++) { tempPoint.x = innerPillar2[i][0]; tempPoint.y = innerPillar2[i][1]; tempPoint2.x = innerPillar2[(i+1)%3][0]; tempPoint2.y = innerPillar2[(i+1)%3][1]; tempLine2.norm = ((Vector2)(tempPoint2-tempPoint)).GetNormalVector(); tempLine2.pt = tempPoint; innerPolygon2.push_back(tempLine2); glVertex2d(tempPoint.x,tempPoint.y); } glEnd(); glBegin(GL_LINE_LOOP); for (int i=0;i<5;i++) { tempPoint.x = innerPillar3[i][0]; tempPoint.y = innerPillar3[i][1]; tempPoint2.x = innerPillar3[(i+1)%5][0]; tempPoint2.y = innerPillar3[(i+1)%5][1]; tempLine2.norm