/*
  Copyright (C) 2010-2011  Charles Pence <charles@charlespence.net>
  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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include "pch.h"
#include "quakedef.h"

mnode_t    *r_pefragtopnode;


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

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

                    ENTITY FRAGMENT FUNCTIONS

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

efrag_t        **lastlink;

vec3_t        r_emins, r_emaxs;

entity_t    *r_addent;


/*
================
R_RemoveEfrags

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;
}

/*
===================
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 = cl.free_efrags;
        if (!ef)
        {
            Con_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]);
}



/*
===========
R_AddEfrags
===========
*/
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;
}


/*
================
R_StoreEfrags

// FIXME: a lot of this goes away with edge-based
================
*/
void R_StoreEfrags (efrag_t **ppefrag)
{
    entity_t    *pent;
    model_t        *clmodel;
    efrag_t        *pefrag;


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

        switch (clmodel->type)
        {
        case mod_alias:
        case mod_brush:
        case mod_sprite:
            pent = pefrag->entity;

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

            // mark that we've recorded this entity for this frame
                pent->visframe = r_framecount;
            }

            ppefrag = &pefrag->leafnext;
            break;

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


