/* bounce.c
/*    An example of a dynamic CAVE environment. Two bouncing balls are
/*   drawn. The calculations for their movements are performed in the
/*   main process, and communicated to the drawing processes through
/*   shared memory.
*/

#include <cave.h>
#include <malloc.h>
#include <gl/sphere.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 *);

main(int argc,char **argv)
{
 struct _balldata *ball;
 CAVEConfigure(&argc,argv,NULL);
/* Initialize shared memory */
 ball = init_shmem();
 CAVEInit();
 CAVEInitApplication(init_gl,0);
/* Give the library a pointer to the drawing function, plus one argument */
 CAVEDisplay(draw_balls,1,ball);
 while (!getbutton(ESCKEY))
	{
/* Update the balls' positions */
	compute(ball);
	sginap(1);
	}
 CAVEExit();
}


/* 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;
}


/* init_gl - initialize GL lighting & materials */
void init_gl(void)
{
 float redMaterial[] = { DIFFUSE, 1, 0, 0, LMNULL };
 float blueMaterial[] = { DIFFUSE, 0, 0, 1, LMNULL };
 lmdef(DEFLMODEL,1,0,NULL);
 lmbind(LMODEL,1);
 lmdef(DEFLIGHT,1,0,NULL);
 lmbind(LIGHT0,1);
 lmdef(DEFMATERIAL,1,0,redMaterial);
 lmdef(DEFMATERIAL,2,0,blueMaterial);
}


/* draw_balls - draw the two balls, using the shared data for their
  y coordinates */
void draw_balls(struct _balldata *ball)
{
 float sphereParam0[] = { 2, 4, -5, 1};
 float sphereParam1[] = { -2, 4, -5, 1};

 czclear(0,getgdesc(GD_ZMAX));

 lmbind(MATERIAL,0);
 cpack(0xff088018);
 pushmatrix();
  rot(-90.0,'x');
  rectf(-100.0,-100.0,100.0,100.0);
 popmatrix();

 lmbind(MATERIAL,1);
 sphereParam0[1] = ball[0].y;
 sphdraw(sphereParam0);

 lmbind(MATERIAL,2);
 sphereParam1[1] = ball[1].y;
 sphdraw(sphereParam1);
}