用OpenGL绘制图形

用OpenGL绘制图形

结果

代码

/*

* File: main.c

* Author: leo

*

* Drawing a simple 3D rectangle program with GLUT

* OpenGL ~~

*/

#include <stdio.h>

#include <stdlib.h>

#include <GL/gl.h>

#include <GL/glu.h>

#include <GL/glut.h>

//called to draw scene

void RenderScene(void)

{

//clear the window with current clearing color

glClear(GL_COLOR_BUFFER_BIT);

//set current drawing color to read

glColor3f(1.0f,0.0f,0.0f); //设置以后绘制操作所用的颜色

//draw a filled rectangle with current color

glRectf(100.f,150.0f,150.0f,100.0f); //绘制一个填充的矩形

//flush drawing commands

glFlush();

}

//set up the rendering state

void SetupRC(void)

{

glClearColor(0.0f,0.0f,1.0f,1.0f);

}

//called by GLUT library when the window has changed size

void ChangeSize(GLsizei w, GLsizei h)

{

//prevent a divide by zero

if(h == 0)

h = 1;

//set viewport to window dimensions

glViewport(0,0,w,h);

//reset coordinate system

glMatrixMode(GL_PROJECTION);

glLoadIdentity();//在每次进行任何矩阵处理之前都“复位”坐标系

//establish clipping volumn(left,right,bottom,top,near,far)

if(w <= h)

glOrtho(0.0f,250.0f,0.0f,250.0f*h/w,1.0,-1.0);

else

glOrtho(0.0f,250.0f*w/h,0.0f,250.0f,1.0,-1.0);

glMatrixMode(GL_MODELVIEW);

glLoadIdentity();

}

int main(int argc, char** argv) {

glutInit(&argc,argv);

glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);

glutCreateWindow("Plot Rect. using GLUT");

glutDisplayFunc(RenderScene);

glutReshapeFunc(ChangeSize);//窗口大小发生变化，就重新设置坐标系

SetupRC();

glutMainLoop();

return (EXIT_SUCCESS);

}