《電腦圖形學》實驗一：利用OpenGL實現直線光柵化的DDA演算法

本部落格電腦圖形學系列文章索引：

地址：《電腦圖形學系列相關文章索引（持續更新）》

參考教材：《電腦圖形學》 機械工業出版社 ，徐文鵬主編。

 

#include <tchar.h>#include <GL/glut.h>#include <cstdlib>//連結必要的庫檔案#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);//畫X軸glBegin(GL_LINES);glColor3f (0.0f, 0.0f, 0.0f);glVertex2f(-50.0f,0.0f);glVertex2f(50.0f,0.0f);glEnd();//畫Y軸glBegin(GL_LINES);glColor3f (0.0f, 0.0f, 0.0f);glVertex2f(0.0f,-50.0f);glVertex2f(0.0f,50.0f);glEnd();//用DDA演算法畫兩條線LineDDA(-50,-50,50,50);LineDDA(-50, 50, 50,-50);glFlush();}void ChangeSize(GLsizei w,GLsizei h){if(h==0){h=1;}//定義視口glViewport(0,0,w,h);glMatrixMode(GL_PROJECTION);glLoadIdentity();//定義正交視域體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){//背景為白色glClearColor(1.0f,1.0f,1.0f,0.0f);}int _tmain(int argc, _TCHAR* argv[]){//設定為RGB顏色模式和單緩衝視窗glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);glutCreateWindow("DDA演算法畫直線");Init();glutDisplayFunc(RenderScene);glutReshapeFunc(ChangeSize);    glutMainLoop();return 0;}

實驗結果：