#include <cave_ogl.h>
#include <GL/glu.h>

void init_shared_data(),gl_init_fn(),draw_fn();

/* Shared data */
float *x,*y,*z;

main(int argc,char **argv)
{
 float vx,vy,vz;
 CAVEConfigure(&argc,argv,NULL);
 init_shared_data();
 vx = (drand48()-0.5)/10.0;
 vy = (drand48()-0.5)/10.0;
 vz = (drand48()-0.5)/10.0;
 CAVEInit();
 CAVEInitApplication(gl_init_fn,0);
 CAVEDisplay(draw_fn,0);
 while (!CAVEgetbutton(CAVE_ESCKEY))
        {       /* Bounce the ball around */
        if (*x < -5) vx = fabs(vx);
        else if (*x > 5) vx = -fabs(vx);
        if (*y < 0) vy = fabs(vy);
        else if (*y > 10) vy = -fabs(vy);
        if (*z < -5) vz = fabs(vz);
        else if (*z > 5) vz = -fabs(vz);
        *x += vx;
        *y += vy;
        *z += vz;
        sginap(1);  /* Make this loop run about 100 iterations/second */
        }
 CAVEExit();
}

/* Get a shared arena, amalloc the shared variables, & initialize them */
void init_shared_data()
{
 x = (float *) CAVEMalloc(sizeof(float));
 y = (float *) CAVEMalloc(sizeof(float));
 z = (float *) CAVEMalloc(sizeof(float));
 *x = 0;
 *y = 5;
 *z = 0;
}

static GLUquadricObj *sphereObj;

/* initialize the graphics - define the lighting data */
void gl_init_fn()
{
 float light_pos[] = { -5, 10, 5, 0 };
 float mat_diffuse[] = { 0.6, 0.5, 0.1, 1 };
 glLightfv(GL_LIGHT0, GL_POSITION, light_pos);
 glEnable(GL_LIGHT0);
 glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, mat_diffuse);
 sphereObj = gluNewQuadric();
}

/* draw the scene - draw a ball at (*x,*y,*z), and, if button 1 is pressed,
 draw a smaller ball in front of the wand */
void draw_fn()
{
 glClearColor(0.5, 1., 1., 0.);
 glClear(GL_DEPTH_BUFFER_BIT|GL_COLOR_BUFFER_BIT);
 glEnable(GL_LIGHTING);
 glPushMatrix();
   glTranslatef(*x,*y,*z);
   gluSphere(sphereObj, 1.0, 8, 8);
 glPopMatrix();
 if (CAVEBUTTON1)
        {
        float wandPos[3],wandFront[3];
        CAVEGetPosition(CAVE_WAND,wandPos);
        CAVEGetVector(CAVE_WAND_FRONT,wandFront);
        glPushMatrix();
          glTranslatef(wandPos[0]+wandFront[0]*2,wandPos[1]+wandFront[1]*2,
                        wandPos[2]+wandFront[2]*2);
          gluSphere(sphereObj, .25, 8, 8);
        glPopMatrix();
        }
 glDisable(GL_LIGHTING);
}