DirectLightLayer.cs

using System.Drawing;
using Gondwana.Rendering;
using Gondwana.Scenes;
using SkiaSharp;
 
namespace Gondwana.Drawing.Direct;

public sealed class DirectLightLayer : IDisposable
{
    private readonly List<DirectRadialLight> _lights = [];

    public event Action<DirectRadialLight>? LightAdded;

    public event Action<DirectRadialLight>? LightRemoving;

    public DirectLightLayer(RenderSurfaceHostBase renderSurfaceHost, SceneLayer sceneLayer)
    {
        RenderSurfaceHost = renderSurfaceHost ?? throw new ArgumentNullException(nameof(renderSurfaceHost));
        SceneLayer = sceneLayer ?? throw new ArgumentNullException(nameof(sceneLayer));
    }

    public RenderSurfaceHostBase RenderSurfaceHost { get; }

    public SceneLayer SceneLayer { get; }

    public IReadOnlyList<DirectRadialLight> Lights => _lights;

    public int DefaultZOrder { get; set; } = 10_000;

    public DirectRadialLight AddTorchLight(
        PointF centerWorldPx,
        float radiusWorldPx,
        Color? color = null,
        string? nickname = null)
    {
        var light = new DirectRadialLight(
            color ?? Color.FromArgb(180, 255, 190, 80),
            RenderSurfaceHost,
            SceneLayer,
            centerWorldPx,
            radiusWorldPx,
            nickname)
        {
            ZOrder = DefaultZOrder,
            BlendMode = SKBlendMode.Screen,
            HotspotRadiusRatio = 0.06f,
            MidpointRadiusRatio = 0.55f,
            MidpointIntensityRatio = 0.35f
        };
 
        _lights.Add(light);
        LightAdded?.Invoke(light);
        return light;
    }

    public bool Remove(DirectRadialLight light)
    {
        if (!_lights.Remove(light))
            return false;
 
        LightRemoving?.Invoke(light);
        light.Dispose();
        return true;
    }

    public void Clear()
    {
        foreach (var light in _lights.ToArray())
            Remove(light);
 
        _lights.Clear();
    }

    public void Dispose()
    {
        Clear();
        LightAdded = null;
        LightRemoving = null;
    }
}