/*
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 "q_defs.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 stuff 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 allocate 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
	{
		int32_t 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;
	int32_t                 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("%" PRIi32 " 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;
	int32_t                 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;
	}
}