《计算机图形学》实验一：利用OpenGL实现直线光栅化的DDA算法

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本博客计算机图形学系列文章索引：

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参考教材：《计算机图形学》机械工业出版社，徐文鹏主编。

#include <tchar.h>#include <GL/glut.h>#include <cstdlib>//链接必要的库文件#pragma comment( lib, "opengl32.lib" ) #pragma comment( lib, "glu32.lib" )    #pragma comment( lib, "glut32.lib" ) void LineDDA(int x1,int y1,int x2,int y2){float x, y, dx, dy;int k,i;if(abs(x2-x1)>=abs(y2-y1)){k=abs(x2-x1);}else{k=abs(y2-y1);}dx=(float)(x2-x1)/k;dy=(float)(y2-y1)/k;x=(float)(x1);y=(float)(y1);    for(i=0;i<k; i++)    {glPointSize(2);glBegin (GL_POINTS);glColor3f (1.0f, 0.0f, 0.0f);        glVertex2i ((int)(x+0.5),(int)(y+0.5));glEnd ();        x+=dx;y+=dy;    }  } void RenderScene(void){glClear(GL_COLOR_BUFFER_BIT);//画X轴glBegin(GL_LINES);glColor3f (0.0f, 0.0f, 0.0f);glVertex2f(-50.0f,0.0f);glVertex2f(50.0f,0.0f);glEnd();//画Y轴glBegin(GL_LINES);glColor3f (0.0f, 0.0f, 0.0f);glVertex2f(0.0f,-50.0f);glVertex2f(0.0f,50.0f);glEnd();//用DDA算法画两条线LineDDA(-50,-50,50,50);LineDDA(-50, 50, 50,-50);glFlush();}void ChangeSize(GLsizei w,GLsizei h){if(h==0){h=1;}//定义视口glViewport(0,0,w,h);glMatrixMode(GL_PROJECTION);glLoadIdentity();//定义正交视域体if(w<h){glOrtho(-150,150,-150*h/w,150*h/w,-150,150);}else{glOrtho(-150*w/h,150*w/h,-150,150,-150,150);}}void Init(void){//背景为白色glClearColor(1.0f,1.0f,1.0f,0.0f);}int _tmain(int argc, _TCHAR* argv[]){//设置为RGB颜色模式和单缓存窗口glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);glutCreateWindow("DDA算法画直线");Init();glutDisplayFunc(RenderScene);glutReshapeFunc(ChangeSize);    glutMainLoop();return 0;}

实验结果：