gaemstone/src/gaemstone.Client/Systems/Input.cs

using System;
using System.Collections.Generic;
using System.Linq;
using gaemstone.ECS;
using gaemstone.Flecs;
using Silk.NET.Input;
using Silk.NET.Maths;
using static gaemstone.Client.Systems.Windowing;

namespace gaemstone.Client.Systems;

[Module]
[DependsOn<gaemstone.Client.Systems.Windowing>]
public class Input
{
	[Component]
	public class RawInput
	{
		internal IInputContext? Context { get; set; }

		public Dictionary<Key, ButtonState> Keyboard { get; } = new();
		public Dictionary<MouseButton, ButtonState> MouseButtons { get; } = new();
		public Vector2D<float> MousePosition { get; set; }
		public float MouseWheel { get; set; }
		public float MouseWheelDelta { get; set; }

		public bool IsDown(Key key) => Keyboard.GetValueOrDefault(key)?.IsDown == true;
		public bool IsDown(MouseButton button) => MouseButtons.GetValueOrDefault(button)?.IsDown == true;
	}

	public class ButtonState
	{
		public TimeSpan TimePressed;
		public bool IsDown;
		public bool Pressed;
		public bool Released;
	}

	[System<SystemPhase.OnLoad>]
	public static void ProcessInput(TimeSpan delta,
		GameWindow window, RawInput input)
	{
		window.Handle.DoEvents();

		input.Context ??= window.Handle.CreateInput();

		foreach (var state in input.Keyboard.Values.Concat(input.MouseButtons.Values)) {
			if (state.IsDown) state.TimePressed += delta;
			state.Pressed = state.Released = false;
		}

		var keyboard = input.Context.Keyboards[0];
		foreach (var key in keyboard.SupportedKeys) {
			var state = input.Keyboard.GetValueOrDefault(key);
			if (keyboard.IsKeyPressed(key)) {
				if (state == null) input.Keyboard.Add(key, state = new());
				if (!state.IsDown) state.Pressed = true;
				state.IsDown = true;
			} else if (state != null) {
				if (state.IsDown) state.Released = true;
				state.IsDown = false;
			}
		}

		var mouse = input.Context.Mice[0];
		foreach (var button in mouse.SupportedButtons) {
			var state = input.MouseButtons.GetValueOrDefault(button);
			if (mouse.IsButtonPressed(button)) {
				if (state == null) input.MouseButtons.Add(button, state = new());
				if (!state.IsDown) state.Pressed = true;
				state.IsDown = true;
			} else if (state != null) {
				if (state.IsDown) state.Released = true;
				state.IsDown = false;
			}
		}

		input.MousePosition = mouse.Position.ToGeneric();

		input.MouseWheelDelta += mouse.ScrollWheels[0].Y - input.MouseWheel;
		input.MouseWheel = mouse.ScrollWheels[0].Y;
	}
}