I asked this question on stackoverflow but assumed this might be a better area to ask it as well for a more informed answer.
My problem is that I am trying to create a camera class and have it so that my camera follows the proper RHS, however the Y axis seems to be inverted since on the screen the 0 starts at the top.
Here is my Camera2D Class:
class Camera2D
{
private Vector2 _position;
private float _zoom;
private float _rotation;
private float _cameraSpeed;
private Viewport _viewport;
private Matrix _viewMatrix;
private Matrix _viewMatrixIverse;
public static float MinZoom = float.Epsilon;
public static float MaxZoom = float.MaxValue;
public Camera2D(Viewport viewport)
{
_viewMatrix = Matrix.Identity;
_viewport = viewport;
_cameraSpeed = 4.0f;
_zoom = 1.0f;
_rotation = 0.0f;
_position = Vector2.Zero;
}
public void Move(Vector2 amount)
{
_position += amount;
}
public void Zoom(float amount)
{
_zoom += amount;
_zoom = MathHelper.Clamp(_zoom, MaxZoom, MinZoom);
UpdateViewTransform();
}
public Vector2 Position
{
get { return _position; }
set { _position = value; UpdateViewTransform(); }
}
public Matrix ViewMatrix
{
get { return _viewMatrix; }
}
private void UpdateViewTransform()
{
Matrix proj = Matrix.CreateTranslation(new Vector3(_viewport.Width * 0.5f, _viewport.Height * 0.5f, 0)) *
Matrix.CreateScale(new Vector3(1f, 1f, 1f));
_viewMatrix = Matrix.CreateRotationZ(_rotation) *
Matrix.CreateScale(new Vector3(_zoom, _zoom, 1.0f)) *
Matrix.CreateTranslation(_position.X, _position.Y, 0.0f);
_viewMatrix = proj * _viewMatrix;
}
}
I test it using SpriteBatch in the following way:
protected override void Draw(GameTime gameTime)
{
GraphicsDevice.Clear(Color.CornflowerBlue);
Vector2 position = new Vector2(0, 0);
// TODO: Add your drawing code here
spriteBatch.Begin(SpriteSortMode.Immediate,
BlendState.AlphaBlend,
null,
null,
null,
null,
camera.ViewMatrix);
Texture2D circle = CreateCircle(100);
spriteBatch.Draw(circle, position, Color.Red);
spriteBatch.End();
base.Draw(gameTime);
}
