/* navigate1.c
/*    An example of navigating in a CAVE environment. The world is that
/*  of bounce.c. The user navigates using the wand joystick - JOYSTICK_Y
/*  controls the forward/back motion; JOYSTICK_X controls turning.
*/

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

/* The data that will be shared between processes */
struct _balldata
	{
	float y;
	};

void init_gl(void),draw_balls(struct _balldata *);
struct _balldata *init_shmem(void);
void compute(struct _balldata *);
void navigate(void);

main(int argc,char **argv)
{
 struct _balldata *ball;
 CAVEConfigure(&argc,argv,NULL);
 ball = init_shmem();
 CAVEInit();
 CAVEInitApplication(init_gl,0);
 CAVEDisplay(draw_balls,1,ball);
 while (!CAVEgetbutton(CAVE_ESCKEY))
	{
	navigate();
	compute(ball);
	sginap(1);
	}
 CAVEExit();
}


#define SPEED 5.0f  /* Max navigation speed in feet per second */

/* navigate - perform the navigation calculations. This checks the joystick
  state and uses that to move and rotate. The Y position of the joystick
  determines the speed of motion in the direction of the wand. The X position
  of the joystick determines the speed of rotation about the CAVE's Y axis.
  Joystick values in the range -.2 to .2 are ignored; this provides a dead
  zone to eliminate noise. The motion is scaled by dt, the time passed since
  the last call to navigate(), in order to maintain a smooth speed. */
void navigate(void)
{
 float jx=CAVE_JOYSTICK_X,jy=CAVE_JOYSTICK_Y,dt,t;
 static float prevtime = 0;
 t = CAVEGetTime();
 dt = t - prevtime;
 prevtime = t;
 if (fabs(jy)>0.2)
	{
	float wandFront[3];
	CAVEGetVector(CAVE_WAND_FRONT,wandFront);
	CAVENavTranslate(wandFront[0]*jy*SPEED*dt, wandFront[1]*jy*SPEED*dt,
			wandFront[2]*jy*SPEED*dt);
	}
 if (fabs(jx)>0.2)
	CAVENavRot(-jx*90.0f*dt,'y');
}


/* init_shmem - initializes shared memory. The data is allocated from a
  shared memory arena, and so will be common to all processes forked after
  this is called. */
struct _balldata *init_shmem(void)
{
 struct _balldata *ball;
 ball = CAVEMalloc(2*sizeof(struct _balldata));
 bzero(ball,2*sizeof(struct _balldata));
 return ball;
}


/* compute - compute new positions for the balls. The height of the balls
  is a function of the current CAVE time. */
void compute(struct _balldata *ball)
{
 float t = CAVEGetTime();
 ball[0].y = fabs(sin(t)) * 6 + 1;
 ball[1].y = fabs(sin(t*1.2)) * 4 + 1;
}




static GLuint greenMat, blueMat; 
static GLUquadricObj *sphereObj;

/* init_gl - initialize GL lighting & materials */
void init_gl(void)
{
 float greenMaterial[] = { 0, 1, 0, 1 };
 float blueMaterial[] = { 0, 0, 1, 1 };
 glEnable(GL_LIGHT0);
 greenMat = glGenLists(1);
 glNewList(greenMat, GL_COMPILE);
 glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, greenMaterial);
 glEndList();
 blueMat = glGenLists(1);
 glNewList(blueMat, GL_COMPILE);
 glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, blueMaterial);
 glEndList();
 sphereObj = gluNewQuadric();
}


/* draw_balls - draw the two balls, using the shared data for their
  y coordinates */
void draw_balls(struct _balldata *ball)
{
 glClearColor(0., 0., 0., 0.);
 glClear(GL_DEPTH_BUFFER_BIT|GL_COLOR_BUFFER_BIT);
 glEnable(GL_LIGHTING);

/* Apply the navigation transformation */
 CAVENavTransform();

 glCallList(greenMat);
 glPushMatrix();
 glTranslatef(2.0, ball[0].y, -5.0);
 gluSphere(sphereObj, 1.0, 8, 8);
 glPopMatrix();

 glCallList(blueMat);
 glPushMatrix();
 glTranslatef(-2.0, ball[1].y, -5.0);
 gluSphere(sphereObj, 1.0, 8, 8);
 glPopMatrix();

 glDisable(GL_LIGHTING);
}