max-effort/Code/Systems/TunnelSystem.cs

using Godot;
using MaxEffort.Code.Core;
using MaxEffort.Code.Data;

namespace MaxEffort.Code.Systems;

[GlobalClass]
public partial class TunnelSystem : Node
{
    [Export] private TunnelConfig _config;
    [Export] private ColorRect _vignetteOverlay;
    
    private float _currentFocus = 0f;
    private bool _isEfforting = false;
    
    public override void _Ready()
    {
        EventBus.OnLiftEffortApplied += HandleEffort;
        EventBus.OnFocusRelease += HandleRelease;
    }

    public override void _ExitTree()
    {
        EventBus.OnLiftEffortApplied -= HandleEffort;
        EventBus.OnFocusRelease -= HandleRelease;
    }

    public override void _Process(double delta)
    {
        var dt = (float)delta;
        
        if (_isEfforting)
        {
            _currentFocus += _config.VisionNarrowRate * dt;
        }
        else
        {
            _currentFocus -= _config.VisionRecoverRate * dt;
        }
        
        _currentFocus = Mathf.Clamp(_currentFocus, 0f, _config.MaxTunnelIntensity);

        var visualValue = _config.VisionCurve?.Sample(_currentFocus) ?? _currentFocus;

        if (_vignetteOverlay != null)
        {
            var mat = _vignetteOverlay.Material as ShaderMaterial;
            mat?.SetShaderParameter("vignette_intensity", visualValue);
        }
        
        EventBus.PublishFocusChanged(_currentFocus);

        _isEfforting = false;
    }

    private void HandleRelease()
    {
     _isEfforting = false;
    }

    private void HandleEffort(float effortDelta)
    {
        _isEfforting = true;
    }
}