/*
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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

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

#include "client.h"
#include "quakedef.h"
#include "world.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_RegisterVariables()
{
    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));
    Mod_TraceHull(cl.worldmodel->hulls, 0, 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);
}
