OpenGL DDA画线算法

要求:构造完整的DDA画线算法程序

DDA算法:计算机图形学中基于直线的微分方程来生成直线的算法。

具体步骤:

  1. 输入两个端点,将左端点保存在中;
  2. 计算;
  3. 根据m的值,分情况计算:
#include 
#include 
#include 

using namespace std;

GLint x1,y1,x2,y2;

void drawLine(GLint x1,GLint y1,GLint x2,GLint y2)
{
    float m = 1.0*(y2-y1)/(x2-x1);
    glClear(GL_COLOR_BUFFER_BIT);
    glBegin(GL_POINTS);
    float x,y;
    if (m>=-1 || m<=1)
        for(x=x1,y=y1;x<=x2;x++,y+=m)
            glVertex2f(x,y);
    else if (m>1) {
        m=1/m;
        for(x=x1,y=y1;y<=y2;x+=m,y++)
            glVertex2f(x,y);
    } else {
        m=1/m;
        for(x=x1,y=y1;y<=y2;x-=m,y++)
            glVertex2f(x,y);
    }
    glEnd();
    glFlush();
}

void display(void)
{
    glClearColor(1,1,1,1);
    glColor3f(1,0,0);
    gluOrtho2D(0,400,0,300);
    glClear(GL_COLOR_BUFFER_BIT);
    drawLine(x1,y1,x2,y2);
}

int main()
{
    glutInitWindowSize(400, 300);
    glutCreateWindow("DDA Algorithm");
    cout<<"请输入起点(x1,y1)和终点(x2,y2)的坐标:\n"<<"(0>x1>>y1>>x2>>y2;
    glutDisplayFunc(display);
    glutMainLoop();
    return 0;
}

你可能感兴趣的:(OpenGL DDA画线算法)