/*
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.

*/
// chase.c -- chase camera code

#include "q_defs.h"

cvar_t  chase_back = {"chase_back", "100", CVAR_NONE};
cvar_t  chase_up = {"chase_up", "16", CVAR_NONE};
cvar_t  chase_right = {"chase_right", "0", CVAR_NONE};
cvar_t  chase_active = {"chase_active", "0", CVAR_NONE};

/*
==============
Chase_Init
==============
*/
void Chase_Init(void)
{
	Cvar_RegisterVariable(&chase_back);
	Cvar_RegisterVariable(&chase_up);
	Cvar_RegisterVariable(&chase_right);
	Cvar_RegisterVariable(&chase_active);
}

/*
==============
TraceLine

TODO: impact on bmodels, monsters
==============
*/
void TraceLine(vec3_t start, vec3_t end, vec3_t impact)
{
	trace_t trace;

	memset(&trace, 0, sizeof(trace));
	SV_RecursiveHullCheck(cl.worldmodel->hulls, 0, 0, 1, start, end, &trace);

	VectorCopy(trace.endpos, impact);
}

/*
==============
Chase_UpdateForClient -- johnfitz -- orient client based on camera. called after input
==============
*/
void Chase_UpdateForClient(void)
{
	//place camera

	//assign client angles to camera

	//see where camera points

	//adjust client angles to point at the same place
}

/*
==============
Chase_UpdateForDrawing -- johnfitz -- orient camera based on client. called before drawing

TODO: stay at least 8 units away from all walls in this leaf
==============
*/
void Chase_UpdateForDrawing(void)
{
	int32_t         i;
	vec3_t  forward, up, right;
	vec3_t  ideal, crosshair, temp;

	AngleVectors(cl.viewangles, forward, right, up);

	// calc ideal camera location before checking for walls
	for(i = 0 ; i < 3 ; i++)
		ideal[i] = cl.viewent.origin[i]
		           - forward[i] * chase_back.value
		           + right[i] * chase_right.value;
	//+ up[i]*chase_up.value;
	ideal[2] = cl.viewent.origin[2] + chase_up.value;

	// make sure camera is not in or behind a wall
	TraceLine(r_refdef.vieworg, ideal, temp);
	if(VectorLength(temp) != 0)
		VectorCopy(temp, ideal);

	// place camera
	VectorCopy(ideal, r_refdef.vieworg);

	// find the spot the player is looking at
	VectorMA(cl.viewent.origin, 4096, forward, temp);
	TraceLine(cl.viewent.origin, temp, crosshair);

	// calculate camera angles to look at the same spot
	VectorSubtract(crosshair, r_refdef.vieworg, temp);
	VectorAngles(temp, r_refdef.viewangles);
	if(r_refdef.viewangles[PITCH] == 90 || r_refdef.viewangles[PITCH] == -90)
		r_refdef.viewangles[YAW] = cl.viewangles[YAW];
}