OpenGL應用——實現中點Bresenham算法

算法本體還是照搬書上的，既然已經能搞DDA了，這個就很輕鬆了

聲明：以下知識全部來源於互聯網，本人並不懂其中原理

#include <GL/gl.h>
#include <GL/glut.h>
#include <iostream>
#include <cmath>
using namespace std;
void init()
{
    glClearColor (0.0, 0.0, 0.0, 0.0);
    glMatrixMode (GL_PROJECTION);
    gluOrtho2D (0.0, 200.0, 0.0, 150.0);
}
void MIDB()
{
    glClear(GL_COLOR_BUFFER_BIT);
    int x0,y0,x1,y1; //直線端點座標
    x0=0;
    y0=0;
    x1=58;
    y1=56;
    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;
    while(x<=x1)
    {
        glPointSize(5);
        glBegin(GL_POINTS);
        glVertex2i(x,y);
        glEnd();
        glFlush();
        x++;
        if(d<0)
        {
            y++;
            d+=UpIncre;
        }
        else
            d+=DownIncre;
    }
}
int main(int argc, char *argv[])
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
    glutInitWindowPosition(100, 100);
    glutInitWindowSize(500, 500);
    glutCreateWindow("第一個opengl程序");
    init();
    glutDisplayFunc(MIDB);
    glutMainLoop();
    return 0;
}