thief-mission-viewer/project/code/TMV/TextureLoader.cs

using System.Collections.Generic;
using System.Linq;
using Godot;
using KeepersCompound.LGS;

namespace KeepersCompound.TMV;

public partial class TextureLoader
{
    private readonly string _fmName;
    private readonly List<Texture2D> _textureCache = new();
    private readonly Dictionary<int, int> _idMap = new();
    private readonly Dictionary<int, string> _idPathMap = new();
    private readonly Dictionary<string, int> _pathMap = new();

    public TextureLoader(string fmName)
    {
        _fmName = fmName;
        LoadDefaultTexture();
    }

    private void LoadDefaultTexture()
    {
        const string path = "res://project/jorge.png";
        var texture = ResourceLoader.Load<CompressedTexture2D>(path);
        _textureCache.Add(texture);
    }

    public bool Register(int id, string path)
    {
        return _idPathMap.TryAdd(id, path);
    }

    private bool Load(int id, string path)
    {
        var loaded = false;
        var pathManager = Context.Instance.PathManager;
        var (_, texPath) = pathManager.GetResourcePath(ResourceType.Texture, _fmName, path);

        if (texPath != null)
        {
            var texture = LoadTexture(texPath);
            if (texture != null)
            {
                _textureCache.Add(texture);
                loaded = true;
            }
        }

        var index = loaded ? _textureCache.Count - 1 : 0;
        _idMap.TryAdd(id, index);
        _pathMap.TryAdd(path, index);
        return loaded;
    }

    public static ImageTexture LoadTexture(string path)
    {
        var ext = path.GetExtension().ToLower();
        string[] validExtensions = { "png", "tga", "pcx", "gif" };
        if (validExtensions.Contains(ext))
        {
            var texture = ext switch
            {
                "pcx" => LoadPcx(path),
                "gif" => LoadGif(path),
                _ => ImageTexture.CreateFromImage(Image.LoadFromFile(path)),
            };
            return texture;
        }
        return null;
    }

    // TODO: We should report load failures
    public Texture2D Get(int id)
    {
        if (_idMap.TryGetValue(id, out int value))
        {
            return _textureCache[value];
        }

        if (_idPathMap.TryGetValue(id, out var path) && Load(id, path))
        {
            return _textureCache[_idMap[id]];
        }

        return _textureCache[0];
    }

    // TODO: Load by path :)
    public Texture2D Get(string path)
    {
        if (!_pathMap.ContainsKey(path))
        {
            return _textureCache[0];
        }
        return _textureCache[_pathMap[path]];
    }
}