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OpenGL通過(guò)中點(diǎn)法繪制直線和圓

更新時(shí)間：2020年02月20日 08:56:22 作者：陳紋欽

這篇文章主要為大家詳細(xì)介紹了OpenGL通過(guò)中點(diǎn)法繪制直線和圓，文中示例代碼介紹的非常詳細(xì)，具有一定的參考價(jià)值，感興趣的小伙伴們可以參考一下

本文實(shí)例為大家分享了OpenGL繪制直線和圓的具體代碼，供大家參考，具體內(nèi)容如下

#include <gl/glut.h>
#include <math.h>
 
static int i=1;
 
void Initial(void)
{
 glClearColor(1.0f, 1.0f, 1.0f, 1.0f); //設(shè)置窗口背景顏色為白色
 glMatrixMode(GL_PROJECTION); //指定設(shè)置投影參數(shù)
 gluOrtho2D(-200.0,200.0,-200.0,200.0); //設(shè)置投影參數(shù) //指的是視圖范圍，如果(0,200,0,200)的話就只能在第一象限顯示，就1/4圓，第1，3的參數(shù)是左下角坐標(biāo)，第2，4的參數(shù)是右上角坐標(biāo)
}
/*void Display(void)
{
 glClear(GL_COLOR_BUFFER_BIT); //用當(dāng)前背景色填充窗口
 glColor3f(1.0f, 0.0f, 0.0f);  //設(shè)置當(dāng)前的繪圖顏色為紅色
 glRectf(50.0f, 100.0f, 150.0f, 50.0f); //繪制一個(gè)矩形
  glFlush();    //處理所有的OpenGL程序
}
*/
 
void DDALine(int x0,int y0,int x1,int y1)
{
 //glVertex2f(10,10);
 int dx,dy,epsl,k;
 float x,y,xIncre,yIncre;
 dx = x1 - x0;
 dy = y1 - y0;
 x = x0;
 y = y0;
 
 if(abs(dx)>abs(dy))
 epsl=abs(dx);
 else
 epsl=abs(dy);
 
 xIncre=(float)dx/(float)epsl;
 yIncre=(float)dy/(float)epsl;
 glPointSize(2);
 glBegin(GL_POINTS);
 for(k = 0;k <= epsl; k++)
 {
 glColor3f(1.0f, 0.0f, 0.0f);
 glVertex2f(int(x+0.5),int(y+0.5));
 x += xIncre;
 y += yIncre;
 }
 glEnd();
 
}
 
 
 
void Mid_B(int x0,int y0,int x1,int y1)
{
 int dx,dy,d,UpIncre,DownIncre,x,y;
 if(x0 > x1)
 {
 x = x1;
 x1 = x0;
 x0 = x;
 y = y1;
 y1 = y0;
 y0 = y;
 }
 x = x0;
 y = y0;
 dx = x1 - x0;
 dy = y1 - y0;
 d = dx - 2*dy;
 UpIncre = 2*dx - 2*dy;
 DownIncre =- 2*dy;
 
 glPointSize(2);
 glBegin(GL_POINTS);
 while(x <= x1)
 {
 glColor3f(1.0f, 0.0f, 0.0f);
 glVertex2f(x,y);
 x++;
 if(d < 0)
 {
 y++;
 d += UpIncre;
 }
 else
 d += DownIncre;
 }
 glEnd();
 
}
 
void G_B(int x0,int y0,int x1,int y1)
{
 int x,y,dx,dy,e;
 dx = x1 - x0;
 dy = y1 - y0;
 e =- dx;
 x=x0;
 y=y0;
 
 glPointSize(2);
 glBegin(GL_POINTS);
 while(x <= x1)
 {
 glColor3f(1.0f, 0.0f, 0.0f);
 glVertex2f(x,y);
 x++;
 e = e + 2*dy;
 if(e > 0)
 {
 y++;
 e = e - 2*dx;
 }
 
 }
 glEnd();
}
 
void CirclePoint(int x, int y)
{
 glPointSize(2);
 glBegin(GL_POINTS);
 glColor3f(1.0f, 0.0f, 0.0f);
 glVertex2f(x,y);
 glVertex2f(y,x); 
 glVertex2f(-y,x); 
 glVertex2f(-x,y); 
 glVertex2f(-x,-y); 
 glVertex2f(-y,-x); 
 glVertex2f(y,-x); 
 glVertex2f(x,-y);
 glEnd();
}
 
void MidBresenhamCircle(int r)
{
 int x = 0, y = r, d = 1-r;
 //glPointSize(2);
 //glBegin(GL_POINTS);
 while(x <= y)
 {
 CirclePoint(x,y);
 
 if(d < 0)
 d += 2*x+3;
 else
 {
 d += 2*(x-y)+5;
 y--;
 }
 x++;
 }
 glEnd();
}
 
void ProcessMenu(int value)
{
 i = value; 
 glutPostRedisplay();
}
 
 
 
void Display(void)
{
 glClear(GL_COLOR_BUFFER_BIT); //用當(dāng)前背景色填充窗口
 glViewport(0,0,400,400); //前兩個(gè)參數(shù)改變?cè)c(diǎn)坐標(biāo)，后兩個(gè)參數(shù)改變圖形長(zhǎng)寬（放大縮?。?
 switch(i)
 {
 case 1:
 DDALine(2,3,55,83);
 break;
 case 2:
 Mid_B(2,3,55,83);
 break;
 case 3:
 G_B(2,3,55,83);
 break;
 case 4:
 MidBresenhamCircle(50);
 break;
 
 }
 glFlush(); 
}
 
int main(int argc, char* argv[])
 
{
 glutInit(&argc, argv); //初始化GLUT庫(kù),處理命令行參數(shù) 
 glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); //初始化窗口的顯示模式
 glutInitWindowSize(400,400);  //設(shè)置窗口的尺寸
 glutInitWindowPosition(100,100); //設(shè)置窗口的位置
 glutCreateWindow("直線");   //創(chuàng)建一個(gè)名為矩形的窗口
 
 int MainMenu = glutCreateMenu(ProcessMenu); //創(chuàng)建主菜單
 glutAddMenuEntry("DDA算法",1);
 glutAddMenuEntry("中點(diǎn)Bresenham算法",2);
 glutAddMenuEntry("改進(jìn)的Bresenham算法",3);
 glutAddMenuEntry("中點(diǎn)bresenham畫(huà)圓",4);
 glutAttachMenu(GLUT_RIGHT_BUTTON); 
 
 glutDisplayFunc(Display); //設(shè)置當(dāng)前窗口的顯示回調(diào)函數(shù)
 Initial();     //完成窗口初始化
 glutMainLoop();   //啟動(dòng)主GLUT事件處理循環(huán)
 return 0;
 
 
}

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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