图形学基本算法：Bresenham算法

直接上代码VS2015 C#编写

#include"stdafx.h"
#include <GL/glut.h>
#include <iostream>
#include <cmath>
//LML SPQ写于2021
void init()
{
 glClearColor(1.0, 1.0, 1.0, 1.0);
 glMatrixMode(GL_PROJECTION);
 glLoadIdentity();
 gluOrtho2D(0.0, 200.0, 0.0, 150.0);
}
void midbr(int x0,int y0,int x1,int y1)
//算法条件：x1>x0,y1>y0,x1-x0>y1-y0,,斜率大于0小于1
//算法缺点：只能绘制斜率为正的直线
{
 int a = y0 - y1, b = x1 - x0;
 int d = 2 * a + b;
 int x = x0, y = y0;

 
 
 glVertex2i(x, y);
 while (x <= x1) {
  glVertex2i(x, y);
  if (d < 0) {
   d = d + 2 * (a + b);
   y++;
  }
  else {
   d += 2 * a;
  }
  x++;
 }


 
}
void display()
{
 glClear(GL_COLOR_BUFFER_BIT);
 glColor3f(0.0, 0.0, 0.0);
 glBegin(GL_POINTS);

 midbr(90, 100, 100, 110);
 midbr(90, 110, 100, 110);
 midbr(80, 100, 90, 100);
 midbr(80, 100, 90, 110);
 glEnd();

 glFlush();

}

int main(int argc, char** argv)
{
 glutInit(&argc, argv);
 glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
 glutInitWindowPosition(50, 100);
 glutInitWindowSize(640, 480);
 glutCreateWindow("Bresenham Draw Line");
 init();
 glutDisplayFunc(display);
 glutMainLoop();
 return 0;
}

Bresenham算法结果图：

直接用Opengl函数画直线：

//以下为函数画直线

#include"stdafx.h"
#include <GL/glut.h>
#include <iostream>
#include <cmath>
//测绘1803，李明路631801110312
void init()
{
 glClearColor(1.0, 1.0, 1.0, 1.0);
 glMatrixMode(GL_PROJECTION);
 glLoadIdentity();
 gluOrtho2D(0.0, 200.0, 0.0, 150.0);

}
void display()
{
 glClear(GL_COLOR_BUFFER_BIT);
 glColor3f(1.0, 0.0, 0.0);
 glBegin(GL_LINES);
 glVertex2i(100, 40);
 glVertex2i(100, 90);
 glVertex2i(100, 90);
 glVertex2i(60, 90);
 glVertex2i(60, 90);
 glVertex2i(60, 40);

 
 glVertex2i(60, 40);
 glVertex2i(100, 40);
 glEnd();

 glFlush();

}

int main(int argc, char** argv)
{
 glutInit(&argc, argv);
 glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
 glutInitWindowPosition(50, 100);
 glutInitWindowSize(640, 480);
 glutCreateWindow("LINE DARW");
 init();
 glutDisplayFunc(display);
 glutMainLoop();
 return 0;
}