gistfile1.cpp

#include <stdio.h>
#include <stdlib.h>
#include "glut.h"

void WindowSize(int , int );            //負責視窗及繪圖內容的比例
void Keyboard(unsigned char ,int, int );   //獲取鍵盤輸入
void Display(void);                     //描繪

int main(int argc, char** argv)
{
   glutInit(&argc, argv);
   glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
   glutInitWindowSize(400,400);         //視窗長寬
   glutInitWindowPosition(600,80);         //視窗左上角的位置
   glutCreateWindow("這裡是視窗標題");      //建立視窗
   
   //下面三個是用來指定Callback函數
   glutReshapeFunc(WindowSize);
   glutKeyboardFunc(Keyboard);
   glutDisplayFunc(Display);
   glutMainLoop();
   return 0;
}

void Display(void)
{
	glClearColor(1, 1, 1, 1.0);   //用白色塗背景
	glClear(GL_COLOR_BUFFER_BIT| GL_DEPTH_BUFFER_BIT);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	gluLookAt(10,10,10,0,0,0,0,1,0);   //視線的座標及方向
	
	glPointSize(10);
	glBegin(GL_POINTS);
	glColor3f( 1, 0, 0);
	glVertex3f(0,0,0);
	glEnd();

	glBegin(GL_LINES);
	glColor3f( 1, 0, 0);
	glVertex3f(-100,0,0);
	glVertex3f(100,0,0);
	glColor3f( 1, 0, 0);
	glVertex3f(0,-100,0);
	glVertex3f(0,100,0);
	glColor3f( 1, 0, 0);
	glVertex3f(0,0,-100);
	glVertex3f(0,0,100);
	glEnd();
	
	glutSwapBuffers();
}

void Keyboard(unsigned char key, int x, int y)
{
   printf("你所按按鍵的碼是%x\t此時視窗內的滑鼠座標是(%d,%d)\n", key, x, y);
}

void WindowSize(int w, int h)
{
   printf("目前視窗大小為%dX%d\n",w,h);
   glViewport(0, 0, w, h);            //當視窗長寬改變時，畫面也跟著變
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   glOrtho(-10,10,-10,10,-10,10);      //正交投影
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
}