第一课、OpenGL绘制直线等等

//
//  main.c
//  opengl_ animationRect_0002
//
//  Created by  ch_soft on 12-1-16.
//  Copyright (c) 2012年 __MyCompanyName__. All rights reserved.
//

#include<stdio.h>
#include<GLUT/glut.h>
#include<OpenGL/gl.h> 
#include<OpenGL/glu.h>

//用于绘制窗口需要的图形
void RenderScene()
{

    //清除颜色缓冲区，即窗口的背景色
   glClear(GL_COLOR_BUFFER_BIT);
    

    //设置当前绘图使用的颜色
  glColor3f(0.0f,0.0f,
0.0f);
    

    //使用当前的颜色来绘制一个矩形
//    glRectf(100.0f, 150.0f, 150.0f, 100.0f);
    
//   1.画点
   
GLfloat sizesPoint[2];//保存线宽的尺寸范围
   
GLfloat stepPoint;//保存线宽度尺寸的最小间隔
   
GLfloat curSizePoint;
    
   glGetFloatv(GL_POINT_SIZE_RANGE,sizesPoint);
   glGetFloatv(GL_POINT_SIZE_GRANULARITY,&stepPoint); 
    curSizePoint=sizesPoint[0];
   
for (int i=0;i<25;i++) {
       
glPointSize(curSizePoint); 
       
glBegin(GL_POINTS);
       
glVertex3f(25.0+i*8,200.0f,0.0f); 
       
glEnd();
        curSizePoint +=stepPoint*2;
    }
    
    
//  2. 画直线
    
//    GLfloat sizesLine[2];//保存线宽的尺寸范围
//    GLfloat stepLine;//保存线宽度尺寸的最小间隔
   
GLfloat curSizeLine=5;
//    glGetFloatv(GL_LINE_WIDTH_RANGE,sizesLine);
//    glGetFloatv(GL_LINE_WIDTH_GRANULARITY,&stepLine);
   
glLineWidth(curSizeLine); 
   glBegin(GL_LINES);
   glVertex3f(25.0f,160.0f,0.0f);
   glVertex3f(225.0f,160.0f,0.0f); 
    
   
glEnd();
    
//   3.画连续的直线
   glBegin(GL_LINE_STRIP);
   glVertex3f(25.0f,150.0f,0.0f);
   glVertex3f(100.0f,150.0f,0.0f); 
   glVertex3f(100.0f,130.0f,0.0f);
   
glEnd();
    
   glBegin(GL_LINE_STRIP);
   glVertex3f(0.0f,0.0f,0.0f);
   glVertex3f(10.0f,10.0f,0.0f);
   glVertex3f(20.0f,5.0f,0.0f);
   
glEnd();
    
//   4.画封闭式直线
   glBegin(GL_LINE_LOOP);
   glVertex3f(125.0f,150.0f,0.0f);
   glVertex3f(200.0f,150.0f,0.0f); 
   glVertex3f(200.0f,130.0f,0.0f);
   
glEnd();
    
//   画虚线
   glEnable(GL_LINE_STIPPLE); 

    glLineStipple(1,0x00FF);//第一个参数是倍数，第二个参数是一个十六进制数，用来表示如何显示的
   glBegin(GL_LINES);
   glVertex3f(25.0f,120.0f,0.0f);
   glVertex3f(225.0f,120.0f,0.0f); 
   
glEnd();
    
    
   glLineWidth(3);
   glLineStipple(1,0xFF0C); 
   glBegin(GL_LINES);
   glVertex3f(25.0f,80.0f,0.0f);
   glVertex3f(225.0f,80.0f,0.0f);
   
glEnd();
    
    
   glLineStipple(4,0xFF0C); 
   glBegin(GL_LINES);
   glVertex3f(25.0f,40.0f,0.0f);
   glVertex3f(225.0f,40.0f,0.0f); 
   
glEnd();
   glDisable(GL_LINE_STIPPLE);
   //刷新opengl命令队列
   
glFlush();
}

//改变大小时调用的函数
void ChangeSize(GLsizei w,GLsizei h)
{
   
if (h==0) {
        h=1;
    }
   //设置视区尺寸
   
glViewport(0,
0, w, h);

    //重置坐标系统，使用投影变换复位
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
    
   
if (w<=h) {
       glOrtho (0.0f,250.0f,
0.0f,250.0f*h/w,
1.0f, -1.0f);
    }else
    {
       glOrtho (0.0f,250.0f*w/h,
0.0f,250.0f,
1.0f, -1.0f);
    }
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
}

//用于初始化，常用来设置场景的渲染状态
void SetupRC(void)
{
   glClearColor(1.0f,1.0f,
1.0f,1.0f);
}

int main(int argc,char** argv)
{
   //    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
   //    glutCreateWindow("GLRect");
    
   
glutInit(&argc, argv);
   //初始化GLUT库OpenGL窗口的显示模式
   glutInitDisplayMode (GLUT_SINGLE |GLUT_RGB
|GLUT_DEPTH);
   glutInitWindowSize (500,500); 
   glutInitWindowPosition (100,100);
   glutCreateWindow (argv[0]);
    
    
   glutDisplayFunc(RenderScene);
   glutReshapeFunc(ChangeSize);
    
   
SetupRC();
   glutMainLoop();
    
   
return 0;
}