/*
	r_alias.c

	Draw Alias Model

	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:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include "QF/sys.h"

#include "r_internal.h"

float r_avertexnormals[NUMVERTEXNORMALS][3] = {
#include "anorms.h"
};

maliasskindesc_t *
R_AliasGetSkindesc (int skinnum, aliashdr_t *ahdr)
{
	maliasskindesc_t *pskindesc;
	maliasskingroup_t *paliasskingroup;

	if ((skinnum >= ahdr->mdl.numskins) || (skinnum < 0)) {
		Sys_MaskPrintf (SYS_dev, "R_AliasSetupSkin: no such skin # %d\n",
						skinnum);
		skinnum = 0;
	}

	pskindesc = ((maliasskindesc_t *)
				 ((byte *) ahdr + ahdr->skindesc)) + skinnum;

	if (pskindesc->type == ALIAS_SKIN_GROUP) {
		int         numskins, i;
		float       fullskininterval, skintargettime, skintime;
		float      *pskinintervals;

		paliasskingroup = (maliasskingroup_t *) ((byte *) ahdr +
												 pskindesc->skin);
		pskinintervals = (float *)
			((byte *) ahdr + paliasskingroup->intervals);
		numskins = paliasskingroup->numskins;
		fullskininterval = pskinintervals[numskins - 1];

		skintime = vr_data.realtime + currententity->animation.syncbase;

		// when loading in Mod_LoadAliasSkinGroup, we guaranteed all interval
		// values are positive, so we don't have to worry about division by 0
		skintargettime = skintime -
			((int) (skintime / fullskininterval)) * fullskininterval;

		for (i = 0; i < (numskins - 1); i++) {
			if (pskinintervals[i] > skintargettime)
				break;
		}
		pskindesc = &paliasskingroup->skindescs[i];
	}

	return pskindesc;
}

static maliasframedesc_t *
alias_get_frame (int framenum, aliashdr_t *hdr, float *frame_interval)
{
	float      *intervals;
	float       fullinterval, time, targettime;
	maliasframedesc_t *frame;
	maliasgroup_t *group;
	int         numframes;
	int         i;

	if ((framenum >= hdr->mdl.numframes) || (framenum < 0)) {
		Sys_MaskPrintf (SYS_dev, "R_AliasSetupFrame: no such frame %d\n",
						framenum);
		framenum = 0;
	}

	frame = &hdr->frames[framenum];
	if (frame->type == ALIAS_SINGLE) {
		if (frame_interval) {
			/*
				One tenth of a second is good for most Quake animations. If
				the nextthink is longer then the animation is usually meant
				to pause (e.g. check out the shambler magic animation in
				shambler.qc).  If its shorter then things will still be
				smoothed partly, and the jumps will be less noticable
				because of the shorter time.  So, this is probably a good
				assumption.
			*/
			*frame_interval = 0.1;
		}
		return frame;
	}

	group = (maliasgroup_t *) ((byte *) hdr + frame->frame);
	intervals = (float *) ((byte *) hdr + group->intervals);
	numframes = group->numframes;
	fullinterval = intervals[numframes - 1];

	time = vr_data.realtime + currententity->animation.syncbase;

	// when loading in Mod_LoadAliasGroup, we guaranteed all interval values
	// are positive, so we don't have to worry about division by 0
	targettime = time - ((int) (time / fullinterval)) * fullinterval;

	for (i = 0; i < (numframes - 1); i++) {
		if (intervals[i] > targettime)
			break;
	}
	if (frame_interval) {
		*frame_interval = intervals[i];
		if (i)
			*frame_interval -= intervals[i - 1];
	}
	return &group->frames[i];
}

maliasframedesc_t *
R_AliasGetFramedesc (int framenum, aliashdr_t *hdr)
{
	return alias_get_frame (framenum, hdr, 0);
}

float
R_AliasGetLerpedFrames (entity_t *ent, aliashdr_t *hdr)
{
	maliasframedesc_t *frame;
	float       interval;

	frame = alias_get_frame (ent->animation.frame, hdr, &interval);
	return R_EntityBlend (ent, frame->firstpose, interval);
}