ball bouncing in 3d

#include <iostream>
#include <math.h>
#include <stdlib.h>

#ifdef __APPLE__
#include <OpenGL/OpenGL.h>
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif

using namespace std;

#include <GL/glut.h>

// this is a simple example of a 3D interactive program

float rx,ry, rw, rh;

float bx, by;
float dx, dy;

float winWid, winHeight;



void redraw( void )
{
int i;
float px, py;

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

// here is the floor
glColor3f(0.6,0.6,0.0);
glPushMatrix();
glTranslatef(0.0,-10.0,-10.0);
glRotatef(90.0,1.0,0.0,0.0);
for(i=0;i<10;++i)
{
glRectf(-10.0, float(i)*2.0, 10.0, float(i)*2.0 + 1.0);
}

glColor3f(1.0,0.0,0.0);

px = rx/20.0-10.0;
py = 10.0-ry/20.0;
glTranslatef(0.0,0.0,-0.003);
glRectf(px - 2.0,py -2.0, px + 2.0, py + 2.0);

glPopMatrix();

// the ball
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glPushMatrix();
glTranslatef(bx,by,-0.150);
glRotatef(90.0,0.0,1.0,0.0);
glutSolidSphere( 2.0,10,10);
glPopMatrix();
glDisable(GL_LIGHTING);

// the shadow
glColor3f(0.4,0.4,0.0);
glPushMatrix();
glTranslatef(bx,-10.0,-0.0150);
glScalef(1.0,0.001,1.0);
glutSolidSphere( 2.0,10,10);
glPopMatrix();

glutSwapBuffers();

bx += dx;
by += dy;

if (by > 10.0) dy = -dy;
if (bx > 10.0) dx = -dx;

if (by < -8.0) dy = -dy; // floor + radius
if (bx < -10.0) dx = -dx;

dy = dy - 0.003; // this is gravity
}

void mousebutton(int button, int state, int x, int y)
{
if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN)
{
rx = x; ry = winHeight - y;
}
}

void motion(int x, int y)
// called when a mouse is in motion with a button down
{

rx = x; ry = winHeight - y;
}

void keyboard(unsigned char key, int x, int y) // x and y give the mouse pos
{
cerr << "Key " << key << " int " << int(key) << "\n";
}

void reshape(int w, int h)
{

winWid = w, winHeight = h;
glViewport(0.0,0.0,winWid,winHeight);

glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-10.0,10.0,-10.0,10.0, 20.0, 2000.0);
glTranslatef(0.0,0.0,-25.0);

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}

int main(int argc, char *argv[])
{
cerr << "hello world\n";

rx = 100; ry = 200; rw = 30; rh = 15;

bx = 0; by = 0;
dx = 0.06; dy = 0.08;
winWid = 500; winHeight = 500;

glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH);
glutCreateWindow("Mouse example");
glutPositionWindow(200,100);
glutReshapeWindow(winWid,winHeight);

glClearColor(0.5,0.5,0.5,1.0);

float light_position[] = {-10.0,20.0,20.0,1.0};
glLightfv(GL_LIGHT0,GL_POSITION, light_position);

glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-10.0,10.0,-10.0,10.0, 20.0, 2000.0);
glTranslatef(0.0,0.0,-25.0);

glMatrixMode(GL_MODELVIEW);;
glLoadIdentity();

glEnable(GL_DEPTH_TEST);

glutDisplayFunc(redraw);
glutReshapeFunc(reshape);
glutIdleFunc(redraw);
glutMouseFunc( mousebutton);
glutKeyboardFunc(keyboard);
glutMotionFunc( motion);

glutMainLoop();

return 0;
}