/* navigate2.c
/*    An example of a navigation and interaction. Navigation is added
/*   to interact.c (without the joystick control of scaling). The positions
/*   and vectors used for interaction must be converted to world coordinates.
*/

#include <cave.h>
#include <malloc.h>
#include <gl/sphere.h>

/* The data that will be shared between processes */
struct _balldata
	{
	float x,y,z;
	float radius;
	int grabbed;
	struct _balldata *next;
	};

void init_gl(void),draw_balls(struct _balldata **);
void check_add(struct _balldata **list);
struct _balldata * update_held(struct _balldata *ball);
struct _balldata * check_grab(struct _balldata **list);
void navigate(void);

main(int argc,char **argv)
{
 struct _balldata **ballList,*heldBall=NULL;
 CAVEConfigure(&argc,argv,NULL);
 ballList = (struct _balldata **) CAVEMalloc(sizeof(struct _balldata *));
 *ballList = NULL;
 CAVEInit();
 CAVEInitApplication(init_gl,0);
 CAVEDisplay(draw_balls,1,ballList);
 while (!getbutton(ESCKEY))
	{
	navigate();
	check_add(ballList);
	if (heldBall)
		heldBall = update_held(heldBall);
	else
		heldBall = check_grab(ballList);
	sginap(1);
	}
 CAVEExit();
}


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

/* navigate - perform the navigation calculations. */
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');
}


void check_add(struct _balldata **list)
{
 if (CAVEButtonChange(3) == -1)
	{
	struct _balldata *ball;
	float wandPos[3],wandFront[3];
	ball = (struct _balldata *) CAVEMalloc(sizeof(struct _balldata));
	if (!ball)
		{
		fprintf(stderr,"OUT OF MEMORY!\n");
		return;
		}
	CAVEGetPosition(CAVE_WAND_NAV,wandPos);
	CAVEGetVector(CAVE_WAND_FRONT_NAV,wandFront);
	ball->x = wandPos[0] + wandFront[0]*2;
	ball->y = wandPos[1] + wandFront[1]*2;
	ball->z = wandPos[2] + wandFront[2]*2;
	ball->radius = 1;
	ball->grabbed = 0;
	ball->next = *list;
	*list = ball;
	}
}


struct _balldata * update_held(struct _balldata *ball)
{
 if (!CAVEBUTTON1)
	{
	float wandPos[3];
	CAVEGetPosition(CAVE_WAND_NAV,wandPos);
	ball->x = wandPos[0];
	ball->y = wandPos[1];
	ball->z = wandPos[2];
	ball->grabbed = 0;
	return NULL;
	}
 return ball;
}


struct _balldata * check_grab(struct _balldata **list)
{
 if (CAVEButtonChange(1) == 1)
	{
	struct _balldata *ball;
	float wandPos[3];
	CAVEGetPosition(CAVE_WAND_NAV,wandPos);
	for (ball = *list; ball; ball = ball->next)
		{
		float dist;
#define SQR(x) ((x)*(x))
		dist = SQR(ball->x - wandPos[0]) +
			SQR(ball->y - wandPos[1]) + 
			SQR(ball->z - wandPos[2]);
		if (dist < SQR(ball->radius))
			{
			ball->grabbed = 1;
			return ball;
			}
		}
	}
 return NULL;
}


/* init_gl - initialize GL lighting & materials */
void init_gl(void)
{
 float redMaterial[] = { DIFFUSE, 1, 0, 0, LMNULL };
 lmdef(DEFLMODEL,1,0,NULL);
 lmbind(LMODEL,1);
 lmdef(DEFLIGHT,1,0,NULL);
 lmbind(LIGHT0,1);
 lmdef(DEFMATERIAL,1,0,redMaterial);
}


/* draw_balls - draw the balls, using the shared data for their positions
  & sizes */
void draw_balls(struct _balldata **ballList)
{
 struct _balldata *ball;
 float sphereParam[4];

 czclear(0,getgdesc(GD_ZMAX));

 lmbind(MATERIAL,1);

 for (ball = *ballList; ball; ball = ball->next)
/* Draw the grabbed ball in CAVE coordinates */
	if (ball->grabbed)
		{
		sphereParam[0] = sphereParam[1] = sphereParam[2] = 0;
		sphereParam[3] = ball->radius;
		pushmatrix();
		 CAVEWandTransform();
		 sphdraw(sphereParam);
		popmatrix();
		}
/* Draw all the other balls in world coordinates */
	else
		{
		sphereParam[0] = ball->x;
		sphereParam[1] = ball->y;
		sphereParam[2] = ball->z;
		sphereParam[3] = ball->radius;
		pushmatrix();
		 CAVENavTransform();
		 sphdraw(sphereParam);
		popmatrix();
		}
}