static bool BackgroundLargerThanScreen(SpriteMover mover, CameraWorldWrapper camera)
{
float cameraArea = camera.GetScreenDimsInWorldCoords().magnitude;
var backgroundDims = mover.Dimentions;
return(backgroundDims.magnitude > cameraArea);
}
public HorizontalTilingBackground(Camera camera, SpriteMover spriteMover, SpriteMover spriteCopyMover)
{
if (!SpriteMoverDimsEqual(spriteMover, spriteCopyMover))
{
throw new ArgumentException("backgrounds must have equal sizes");
}
_cameraWorldWrapper = new CameraWorldWrapper(camera);
if (!BackgroundLargerThanScreen(spriteMover, _cameraWorldWrapper))
{
throw new ArgumentException("background must be larger than screen (in world units)");
}
_bgMover = spriteMover;
_copyBgMover = spriteCopyMover;
// place the one copy of bg at the center of the camera, the other tiled to the left
_bgMover.MoveCenter(_cameraWorldWrapper.Position);
TileSpriteToTheLeft(_bgMover, _copyBgMover);
}
SpriteMover GetOtherBackground(SpriteMover thisSprite)
{
return(thisSprite == _bgMover ?
_copyBgMover : _bgMover);
}
bool CameraOutOfLeftBound(SpriteMover sprite)
{
return(_cameraWorldWrapper.LeftBound - BgChangeTolerance <= sprite.LeftBound);
}
bool CameraOutOfRightBound(SpriteMover sprite)
{
return(_cameraWorldWrapper.RightBound + BgChangeTolerance >= sprite.RightBound);
}
/// <summary>
/// tiles one sprite to the left of another:
/// places the <paramref name="movingSprite"/> so that it's top right corner
/// is at the <paramref name="staticSprite"/>'s top left corner,
/// making a seemless connection
/// </summary>
static void TileSpriteToTheLeft(SpriteMover staticSprite, SpriteMover movingSprite)
{
movingSprite.MoveTopRightCorner(staticSprite.TopLeft);
}
static bool SpriteMoverDimsEqual(SpriteMover mover, SpriteMover otherMover)
{
return(Math.Abs(
(mover.Dimentions - otherMover.Dimentions).magnitude) < 0.02);
}