Engine-Pong/Game/Behaviours/CameraController.cs

using Microsoft.Xna.Framework.Input;

using Syntriax.Engine.Core;
using Syntriax.Engine.Input;

namespace Pong.Behaviours;

public class CameraController : BehaviourOverride
{
    private MonoGameCameraBehaviour cameraBehaviour = null!;
    private IButtonInputs<Keys> buttonInputs = null!;

    private float defaultZoomLevel = 1f;

    protected override void OnFirstActiveFrame()
    {
        if (BehaviourController.TryGetBehaviour(out MonoGameCameraBehaviour? foundCameraBehaviour))
            cameraBehaviour = foundCameraBehaviour;

        cameraBehaviour ??= BehaviourController.AddBehaviour<MonoGameCameraBehaviour>();

        if (BehaviourController.TryGetBehaviour(out IButtonInputs<Keys>? foundButtonInputs))
            buttonInputs = foundButtonInputs;

        buttonInputs ??= BehaviourController.AddBehaviour<KeyboardInputsBehaviour>();
        buttonInputs.RegisterOnPress(Keys.F, SwitchToFullScreen);
        buttonInputs.RegisterOnPress(Keys.R, ResetCamera);
    }

    protected override void OnUpdate()
    {
        if (buttonInputs.IsPressed(Keys.U))
            cameraBehaviour.Zoom += Time.Elapsed.Nanoseconds * 0.00025f;
        if (buttonInputs.IsPressed(Keys.J))
            cameraBehaviour.Zoom -= Time.Elapsed.Nanoseconds * 0.00025f;

        if (buttonInputs.IsPressed(Keys.Q))
            cameraBehaviour.BehaviourController.GameObject.Transform.Rotation += Time.Elapsed.Nanoseconds * 0.000025f;
        if (buttonInputs.IsPressed(Keys.E))
            cameraBehaviour.BehaviourController.GameObject.Transform.Rotation -= Time.Elapsed.Nanoseconds * 0.000025f;
    }

    private void SwitchToFullScreen(IButtonInputs<Keys> inputs, Keys keys)
    {
        if (cameraBehaviour.Graphics.IsFullScreen)
            return;

        cameraBehaviour.Graphics.PreferMultiSampling = false;
        cameraBehaviour.Graphics.PreferredBackBufferWidth = cameraBehaviour.Graphics.GraphicsDevice.Adapter.CurrentDisplayMode.Width;
        cameraBehaviour.Graphics.PreferredBackBufferHeight = cameraBehaviour.Graphics.GraphicsDevice.Adapter.CurrentDisplayMode.Height;
        cameraBehaviour.Graphics.IsFullScreen = true;
        cameraBehaviour.Graphics.ApplyChanges();

        float previousScreenSize = Math.Sqrt(Math.Sqr(cameraBehaviour.Viewport.Width) + Math.Sqr(cameraBehaviour.Viewport.Height));
        float currentScreenSize = Math.Sqrt(Math.Sqr(cameraBehaviour.Graphics.GraphicsDevice.Viewport.Width) + Math.Sqr(cameraBehaviour.Graphics.GraphicsDevice.Viewport.Height));
        defaultZoomLevel /= previousScreenSize / currentScreenSize;
        cameraBehaviour.Zoom /= previousScreenSize / currentScreenSize;
        cameraBehaviour.Viewport = cameraBehaviour.Graphics.GraphicsDevice.Viewport;
    }

    private void ResetCamera(IButtonInputs<Keys> inputs, Keys keys)
    {
        cameraBehaviour.Zoom = defaultZoomLevel;
        Transform.Position = Vector2D.Zero;
        Transform.Rotation = 0f;
    }
}