Breaseman算法绘制圆形|中点算法绘制圆形_程序片段
1. Breaseman算法绘制圆形程序
由于算法的特殊性，限制绘制第一象限部分，其他部分通过旋转绘制。
1 void CCGProjectWorkView::bresenHam_1P4Circle(int radium, const float lineColor[]) 2 { 3 int pointX, pointY, deltD, deltHD, deltDV, direction; 4 pointX = 0; 5 pointY = radium; 6 deltD = 2*(1-radium); 7 8 glColor3f(lineColor[0], lineColor[1], lineColor[2]); 9 glBegin(GL_POINTS); 10 while (pointY >= 0) 11 { 12 glVertex3f(pointX, pointY, 0); 13 if (deltD < 0)//D点在圆内 14 { 15 deltHD = 2*(deltD+pointY)-1; 16 if (deltHD <= 0) 17 direction = 1;// H 点距离最近 18 else 19 direction = 2;// D 点距离最近 20 } 21 else if (deltD > 0)//D点在圆外 22 { 23 deltDV = 2*(deltD -pointX)-1; 24 if(deltDV <= 0)// D点里的最贱 25 direction = 2; 26 else 27 direction = 3;//V点距离最近 28 } 29 else 30 direction = 2;//D在圆上 31 switch(direction) 32 { 33 case 1: 34 //H点位置 35 pointX++; 36 deltD += 2*pointX+1; 37 break; 38 case 2: 39 //D点位置 40 pointX++; 41 pointY--; 42 deltD += 2*(pointX-pointY+1); 43 break; 44 case 3: 45 //V点位置 46 pointY--; 47 deltD += (-2*pointY+1); 48 break; 49 default : 50 break; 51 } 52 } 53 glEnd(); 54 55 }
2. 中点算法绘制圆形
由于算法的特殊性，程序限制第一象限的1/8部分。
1 //之画出正上方位于第一象限的左边的1/8园 2 void CCGProjectWorkView::midPoint_1P8Circle(int radium, const float lineColor[]) 3 { 4 int pointX, pointY, r; 5 float distJugeFactor; 6 r = radium; 7 int deltX, deltY;//评判因子中x与y的个分量的递推分量 8 deltX = 3; 9 deltY = 2 - r - r; 10 distJugeFactor = 1 - r; 11 12 pointX = 0; 13 pointY = radium; 14 glColor3f(lineColor[0], lineColor[1], lineColor[2]); 15 glBegin(GL_POINTS); 16 glVertex3f(pointX, pointY, 0); 17 while (pointX < pointY) 18 { 19 if (distJugeFactor < 0)//中点位于圆内 20 { 21 distJugeFactor += deltX; 22 deltX += 2; 23 pointX++; 24 } 25 else 26 { 27 distJugeFactor += deltX + deltY; 28 deltX += 2; 29 deltY += 2; 30 pointX++; 31 pointY--; 32 } 33 glVertex3f(pointX, pointY, 0); 34 } 35 glEnd(); 36 37 }