/*
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.

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

#include "quakedef.h"

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

vec3_t  chase_pos;
vec3_t  chase_angles;

vec3_t  chase_dest;
vec3_t  chase_dest_angles;


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

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]*chase_back.value
    - right[i]*chase_right.value;
  chase_dest[2] = r_refdef.vieworg[2] + chase_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);
}