object.c

著名物理引擎Hawk的源代码

/* object.c, HAWK game engine
 *
 * Copyright 1997-1998 by Phil Frisbie, Jr.
 * for Hawk Software
 *
 */

#include "hawk.h"
#include "internal.h"

int			nfreeobjects;
OBJECT		*firstobject;
OBJECT		*firstfreeobject;
OBJECT		*objects;
OBJECT		*lastobject;

static BOOL needinit = TRUE;

void objInit(void)
{
	int	i;

	GLevel.nobjects = 0;
	GLevel.objects = TagMalloc(MAX_OBJECTS * sizeof(GLevel.objects[0]), TAG_LEVEL);
	memset(GLevel.objects, 0, MAX_OBJECTS * sizeof(GLevel.objects[0]));
	objects = GLevel.objects;
	for(i=0;i<MAX_OBJECTS;i++)
	{
		if(i != (MAX_OBJECTS - 1))
			objects[i].next = &objects[i+1];
		else
			objects[i].next = NULL;
		if(i != 0)
			objects[i].prev = &objects[i-1];
		else
			objects[i].prev = NULL;
	}
	firstfreeobject = &objects[0];
	firstobject = NULL;
	lastobject = NULL;
	needinit = FALSE;
}

OBJECT *objAdd(void)
{
	int i;

	if(needinit)
		objInit();
	 /* find an unused object */
	if(GLevel.nobjects == 0) /* cannot chain for first object */
	{
		GLevel.objects[0].next = NULL;
		if(!GLevel.objects[0].trace)
			GLevel.objects[0].trace = TagMalloc(sizeof(TRACE), TAG_LEVEL);
		GLevel.objects[0].weapon = NO_MODEL;
		GLevel.nobjects++;
		return &GLevel.objects[0];
	}
	else
	{
		for(i=0;i<MAX_OBJECTS;i++)
		{
			if(GLevel.objects[i].type == O_UNUSED) /* found an unused object */
			{
				int j;
				/* find the last object in the chain */
				for(j=0;j<MAX_OBJECTS;j++)
				{
					if((!GLevel.objects[j].next)
							&& (GLevel.objects[j].type)) /* found the last used object in the chain */					{
						GLevel.objects[j].next = &GLevel.objects[i];
						GLevel.objects[i].next = NULL;
						if(!GLevel.objects[i].trace)
							GLevel.objects[i].trace = TagMalloc(sizeof(TRACE), TAG_LEVEL);
						GLevel.objects[i].weapon = NO_MODEL;
						GLevel.nobjects++;
						return &GLevel.objects[i];
					}
				}
			}
		}
	}
	/* we must be out of objects */
	return NULL;
}

void objDelete(OBJECT *o)
{
	int i;

	 /* find the object */
	for(i=0;i<MAX_OBJECTS;i++)
	{
		if(o == &GLevel.objects[i]) /* found the object */
		{
			int j;
			/* find the previous object in the chain */
			for(j=0;j<MAX_OBJECTS;j++)
			{
				if(o == (OBJECT *)GLevel.objects[j].next) /* found the previous object in the chain */
				{
					GLevel.objects[j].next = o->next;
					o->next = NULL;
					o->type = O_UNUSED;
					GLevel.nobjects--;
				}
			}
		}
	}
}