/// <summary>
/// reduces the amount of movement the camera has to do to capture the
/// rider. It does so predictively
/// </summary>
/// <returns>The reduced position in game coords</returns>
private Vector2d CameraMotionReducer(int frame)
{
const int forwardcount = 40;
EnsureFrame(frame + forwardcount);
Vector2d offset = CalculateOffset(frame);
var box = CameraBoundingBox.Create(Vector2d.Zero, _zoom);
var framebox = CameraBoundingBox.Create(
_frames[frame].RiderCenter,
_zoom);
Vector2d center = Vector2d.Zero;
int math = 0;
for (int i = 0; i < forwardcount; i++)
{
var f = _frames[frame + i];
offset = box.Clamp(offset + f.CameraOffset);
center += framebox.Clamp(f.RiderCenter + offset);
math++;
}
// force the rider to center at the beginning
// it looks awkward to predict heavily at the start.
if (frame < forwardcount)
{
return(Vector2d.Lerp(
_frames[frame].RiderCenter,
center / math,
frame / (float)forwardcount));
}
return(center / math);
}
protected Vector2d CalculateOffset(int frame)
{
var box = CameraBoundingBox.Create(Vector2d.Zero, _zoom);
if (_prevframe != -1 &&
_prevframe <= frame &&
(frame - _prevframe) <= 1)
{
if (frame == _prevframe)
{
return(_prevcamera);
}
if (frame % cacherate != 0)
{
return(box.Clamp(StepCamera(box, ref _prevcamera, frame)));
}
}
int cachepos = Math.Min(frame / cacherate, _framecache.Count - 1);
int framestart = cachepos * cacherate;
Vector2d start = _framecache[cachepos];
for (int i = framestart; i <= frame; i++)
{
if (i % cacherate == 0 && i / cacherate == _framecache.Count)
{
_framecache.Add(start);
}
start = StepCamera(box, ref start, i);
}
// Debug.WriteLine("Calculating " + framestart + "-" + (frame) + " for legacy camera");
return(box.Clamp(start));
}
public override Vector2d GetFrameCamera(int frame)
{
base.GetFrameCamera(frame);
var box = CameraBoundingBox.Create(_frames[frame].RiderCenter, _zoom);
return(box.Clamp(CameraMotionReducer(frame)));
}
