/*
Copyright (C) 1996-1997 Id Software, Inc.

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.

*/
// gl_refrag.c

#include "quakedef.h"
#include "gl_local.h"

mnode_t	*r_pefragtopnode;


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

/*
===============================================================================
					ENTITY FRAGMENT FUNCTIONS
===============================================================================
*/

efrag_t		**lastlink;
vec3_t		r_emins, r_emaxs;
entity_t	*r_addent;

//Call when removing an object from the world or moving it to another position
void R_RemoveEfrags (entity_t *ent) {
	efrag_t *ef, *old, *walk, **prev;

	ef = ent->efrag;

	while (ef) {
		prev = &ef->leaf->efrags;
		while (1) {
			walk = *prev;
			if (!walk)
				break;
			if (walk == ef) {	
				// remove this fragment
				*prev = ef->leafnext;
				break;
			} else {
				prev = &walk->leafnext;
			}
		}

		old = ef;
		ef = ef->entnext;

		// put it on the free list
		old->entnext = cl.free_efrags;
		cl.free_efrags = old;
	}

	ent->efrag = NULL; 
}

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
		if (!(ef = cl.free_efrags)) {
			Com_Printf ("Too many efrags!\n");
			return;		// no free fragments...
		}
		cl.free_efrags = cl.free_efrags->entnext;

		ef->entity = r_addent;

		// add the entity link	
		*lastlink = ef;
		lastlink = &ef->entnext;
		ef->entnext = NULL;

		// set the leaf links
		ef->leaf = leaf;
		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]);
}

void R_AddEfrags (entity_t *ent) {
	model_t *entmodel;
	int i;

	if (!ent->model)
		return;

	r_addent = ent;

	lastlink = &ent->efrag;
	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;
}

void R_StoreEfrags (efrag_t **ppefrag) {
	entity_t *pent;
	model_t *model;
	efrag_t *pefrag;

	for (pefrag = *ppefrag; pefrag; pefrag = pefrag->leafnext) {
		pent = pefrag->entity;
		model = pent->model;

		if (model->modhint == MOD_FLAME && !r_drawflame.value)
			continue;

		switch (model->type) {
		case mod_alias:
		case mod_brush:
		case mod_sprite:
			if (pent->visframe != r_framecount) {
				CL_AddEntity (pent);				
				pent->visframe = r_framecount;	// mark that we've recorded this entity for this frame
			}
			break;

		default:	
			Sys_Error ("R_StoreEfrags: Bad entity type %d", model->type);
		}
	}
}
