/*
Copyright (C) 1996-2001 Id Software, Inc.
Copyright (C) 2002-2009 John Fitzgibbons and others
Copyright (C) 2010-2014 QuakeSpasm developers

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
// r_efrag.c

#include "quakedef.h"

mnode_t	*r_pefragtopnode;


//===========================================================================

/*
===============================================================================

					ENTITY FRAGMENT FUNCTIONS

ericw -- GLQuake only uses efrags for static entities, and they're never
removed, so I trimmed out unused functionality and fields in efrag_t.

Now, efrags are just a linked list for each leaf of the static
entities that touch that leaf. The efrags are hunk-allocated so there is no
fixed limit.
 
This is inspired by MH's tutorial, and code from RMQEngine.
http://forums.insideqc.com/viewtopic.php?t=1930
 
===============================================================================
*/

vec3_t		r_emins, r_emaxs;

entity_t	*r_addent;


#define EXTRA_EFRAGS	128

// based on RMQEngine
static efrag_t *R_GetEfrag (void)
{
	// we could just Hunk_Alloc a single efrag_t and return it, but since
	// the struct is so small (2 pointers) allocate groups of them
	// to avoid wasting too much space on the hunk allocation headers.
	
	if (cl.free_efrags)
	{
		efrag_t *ef = cl.free_efrags;
		cl.free_efrags = ef->leafnext;
		ef->leafnext = NULL;
		
		cl.num_efrags++;
		
		return ef;
	}
	else
	{
		int i;
		
		cl.free_efrags = (efrag_t *) Hunk_AllocName (EXTRA_EFRAGS * sizeof (efrag_t), "efrags");
		
		for (i = 0; i < EXTRA_EFRAGS - 1; i++)
			cl.free_efrags[i].leafnext = &cl.free_efrags[i + 1];
		
		cl.free_efrags[i].leafnext = NULL;
		
		// call recursively to get a newly allocated free efrag
		return R_GetEfrag ();
	}
}

/*
===================
R_SplitEntityOnNode
===================
*/
void R_SplitEntityOnNode (mnode_t *node)
{
	efrag_t		*ef;
	mplane_t	*splitplane;
	mleaf_t		*leaf;
	int			sides;

	if (node->contents == CONTENTS_SOLID)
	{
		return;
	}

// add an efrag if the node is a leaf

	if ( node->contents < 0)
	{
		if (!r_pefragtopnode)
			r_pefragtopnode = node;

		leaf = (mleaf_t *)node;

// grab an efrag off the free list
		ef = R_GetEfrag();
		ef->entity = r_addent;

// set the leaf links
		ef->leafnext = leaf->efrags;
		leaf->efrags = ef;

		return;
	}

// NODE_MIXED

	splitplane = node->plane;
	sides = BOX_ON_PLANE_SIDE(r_emins, r_emaxs, splitplane);

	if (sides == 3)
	{
	// split on this plane
	// if this is the first splitter of this bmodel, remember it
		if (!r_pefragtopnode)
			r_pefragtopnode = node;
	}

// recurse down the contacted sides
	if (sides & 1)
		R_SplitEntityOnNode (node->children[0]);

	if (sides & 2)
		R_SplitEntityOnNode (node->children[1]);
}

/*
===========
R_CheckEfrags -- johnfitz -- check for excessive efrag count
===========
*/
void R_CheckEfrags (void)
{
	if (cls.signon < 2)
		return; //don't spam when still parsing signon packet full of static ents

	if (cl.num_efrags > 640 && dev_peakstats.efrags <= 640)
		Con_DWarning ("%i efrags exceeds standard limit of 640.\n", cl.num_efrags);

	dev_stats.efrags = cl.num_efrags;
	dev_peakstats.efrags = q_max(cl.num_efrags, dev_peakstats.efrags);
}

/*
===========
R_AddEfrags
===========
*/
void R_AddEfrags (entity_t *ent)
{
	qmodel_t	*entmodel;
	int			i;

	if (!ent->model)
		return;

	r_addent = ent;

	r_pefragtopnode = NULL;

	entmodel = ent->model;

	for (i=0 ; i<3 ; i++)
	{
		r_emins[i] = ent->origin[i] + entmodel->mins[i];
		r_emaxs[i] = ent->origin[i] + entmodel->maxs[i];
	}

	R_SplitEntityOnNode (cl.worldmodel->nodes);

	ent->topnode = r_pefragtopnode;

	R_CheckEfrags (); //johnfitz
}


/*
================
R_StoreEfrags -- johnfitz -- pointless switch statement removed.
================
*/
void R_StoreEfrags (efrag_t **ppefrag)
{
	entity_t	*pent;
	efrag_t		*pefrag;

	while ((pefrag = *ppefrag) != NULL)
	{
		pent = pefrag->entity;

		if ((pent->visframe != r_framecount) && (cl_numvisedicts < MAX_VISEDICTS))
		{
			cl_visedicts[cl_numvisedicts++] = pent;
			pent->visframe = r_framecount;
		}

		ppefrag = &pefrag->leafnext;
	}
}