动态螺旋线

代码如下：

#include <windows.h>
//#include <GLUT/glut.h>
#include <GL/glut.h>
#include <math.h>
#include <iostream>
using namespace std;

#define GL_PI 3.1415f

void RenderScene()
{
    //glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

    static GLdouble dRadius = 10;
    static GLdouble dAngle = 0.0;

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

    if(dAngle==0.0)
        glClear(GL_COLOR_BUFFER_BIT);
    glPointSize(10.0);
    glBegin(GL_POINTS);
        glVertex2d(dRadius*cos(dAngle),dRadius*sin(dAngle));
    glEnd();

    dRadius *= 1.01;
    dAngle += 0.1;

    if(dAngle > GL_PI)
    {
        dRadius = 10;
        dAngle = 0.0;
    }

    //glutSwapBuffers();
    glFlush();
}

void ChangeSize(GLsizei w,GLsizei h)
{
    if(h==0)
        h = 1;
    //glutPostRedisplay();
    GLfloat aspectRatio = (GLfloat)w/(GLfloat)h;

    glViewport(0,0,w,h);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    if(w<=h)
        glOrtho(-100,100,-100/aspectRatio,100/aspectRatio,100.0,-100.0);
    else
        glOrtho(-100*aspectRatio,100*aspectRatio,-100,100,100.0,-100.0);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

}

void SetupRC()
{
    glClearColor(0.0f,0.0f,1.0f,1.0f);
    glColor3f(1.0f,0.0f,0.0f);
}
void TimerFunction(int value)
{
    glutPostRedisplay();
    glutTimerFunc(33,TimerFunction,1);
}
int main(int argc, char *argv[])
{
   glutInit(&argc,argv);
   glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB|GLUT_DEPTH);
   glutInitWindowSize(800,600);
   glutCreateWindow("Simple");

   glutDisplayFunc(RenderScene);
   glutReshapeFunc(ChangeSize);
   glutTimerFunc(33,TimerFunction,1);

   SetupRC();
   glutMainLoop();
   return 0;
}