/*
	chasecam.c
	
	Chase camera code for UQuake
	
	Copyright (C) 1996-1997 Id Software, Inc.
	Copyright (C) 1999-2000 The QuakeForge Project.
	Portions Copyright their respective authors.

	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.
*/

#include "quakedef.h"

cvar_t	cl_chasecam 		= {"cl_chasecam", "0", true};
cvar_t	cl_chasecam_up		= {"cl_chasecam_up", "16", true};
cvar_t	cl_chasecam_back	= {"cl_chasecam_back", "100", true};
cvar_t	cl_chasecam_right = {"cl_chasecam_right", "0", true};

vec3_t	chase_pos;
vec3_t	chase_angles;

vec3_t	chase_dest;
vec3_t	chase_dest_angles;

void Chase_Init (void) {
	Cvar_RegisterVariable (&cl_chasecam);
	Cvar_RegisterVariable (&cl_chasecam_up);
	Cvar_RegisterVariable (&cl_chasecam_back);
	Cvar_RegisterVariable (&cl_chasecam_right);
}

void Chase_Reset (void) {
	// for respawning and teleporting
	//	start position 12 units behind head
}

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);
}

void Chase_Update (void) {

	int		i;
	float	dist;
	vec3_t	forward, up, right;
	vec3_t	dest, stop;

	// if can't see player, reset
	AngleVectors (cl.viewangles, forward, right, up);

	// calc exact destination
	for (i=0 ; i<3 ; i++)
		chase_dest[i] = r_refdef.vieworg[i]
			- forward[i] * cl_chasecam_back.value
			- right[i] * cl_chasecam_right.value;
	chase_dest[2] = r_refdef.vieworg[2] + cl_chasecam_up.value;

	// find the spot the player is looking at
	VectorMA (r_refdef.vieworg, 4096, forward, dest);
	TraceLine (r_refdef.vieworg, dest, stop);

	// calculate pitch to look at the same spot from camera
	VectorSubtract (stop, r_refdef.vieworg, stop);
	dist = DotProduct (stop, forward);
	if (dist < 1)
		dist = 1;
	r_refdef.viewangles[PITCH] = -atan(stop[2] / dist) / M_PI * 180;

	// move towards destination
	VectorCopy (chase_dest, r_refdef.vieworg);
}