OpenGL step to step(1)

在窗体上绘制一个矩形，just a demo

#include <GLUT/GLUT.h>

void init()

{

    glClearColor(0.0,0.0,0.0,0.0);

    glShadeModel(GL_FLAT);

}

void display()

{

    glClear(GL_COLOR_BUFFER_BIT);

    glColor3f(1.0,1.0,1.0);

    glLoadIdentity();

    gluLookAt(0.0,0.0, 5.0, 0.0,0.0,0.0,0.0,1.0,0.0);

    glScalef(1.0,2.0,1.0);

    glutWireCube(1.0);

    glFlush();

}

void reshape(int w,int h)

{

    glViewport(0, 0, (GLsizei)w, (GLsizei)h);

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    glFrustum(-1, 1.0, -1, 1.0, 1.5, 20.0);

    glMatrixMode(GL_MODELVIEW);

}

int main(int argc, char ** argv)

{

    glutInit(&argc, argv);

    glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);

    glutInitWindowSize(500, 500);

    glutInitWindowPosition(100,100);

    glutCreateWindow("Xcode Glut Demo");

    init();

    glutDisplayFunc(display);

    glutReshapeFunc(reshape);

    glutMainLoop();

    return 0;

}