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

using System.Collections.Generic;
using System.IO;
using System.Linq;
using Godot;

namespace KeepersCompound.TMV;

public partial class TextureLoader
{
    private readonly string _rootPath; // TODO: Load from installation resources
    private readonly string _fmPath;
    private readonly Dictionary<string, string> _fmTexturePaths = new();

    private readonly List<ImageTexture> _textureCache = new();
    private readonly Dictionary<int, int> _idMap = new();
    private readonly Dictionary<string, int> _pathMap = new();

    public TextureLoader(string rootPath, string fmPath)
    {
        _rootPath = rootPath;
        _fmPath = fmPath;

        LoadDefaultTexture();
        RegisterFmTexturePaths();
    }

    private void LoadDefaultTexture()
    {
        // TODO: This should be a resource loaded from RES
        const string path = "user://textures/jorge.png";
        var texture = ImageTexture.CreateFromImage(Image.LoadFromFile(path));
        _textureCache.Add(texture);
    }

    private void RegisterFmTexturePaths()
    {
        // TODO: Load DDS BMP GIF CEL
        string[] validExtensions = { "png", "tga", "pcx" };

        var famOptions = new EnumerationOptions { MatchCasing = MatchCasing.CaseInsensitive };
        var textureOptions = new EnumerationOptions
        {
            MatchCasing = MatchCasing.CaseInsensitive,
            RecurseSubdirectories = true,
        };

        foreach (var dirPath in Directory.EnumerateDirectories(_fmPath, "fam", famOptions))
        {
            foreach (var path in Directory.EnumerateFiles(dirPath, "*", textureOptions))
            {
                if (validExtensions.Contains(path.GetExtension().ToLower()))
                {
                    // TODO: This only adds the first one found rather than the highest priority
                    var key = path.TrimPrefix(_fmPath).GetBaseName().ToLower();
                    _fmTexturePaths.TryAdd(key, path);
                }
            }
        }
    }

    public bool Load(int id, string path)
    {
        var userTexturesPath = ProjectSettings.GlobalizePath($"user://textures{path}.PCX");

        var loaded = false;
        if (_fmTexturePaths.TryGetValue(path.ToLower(), out var filePath))
        {
            _textureCache.Add(LoadTexture(filePath));
            loaded = true;
        }
        else if (File.Exists(userTexturesPath))
        {
            _textureCache.Add(LoadTexture(userTexturesPath));
            loaded = true;
        }

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

    private static ImageTexture LoadTexture(string path)
    {
        var ext = path.GetExtension().ToLower();
        var texture = ext switch
        {
            "pcx" => LoadPcx(path),
            _ => ImageTexture.CreateFromImage(Image.LoadFromFile(path)),
        };
        return texture;
    }

    public ImageTexture Get(int id)
    {
        if (!_idMap.ContainsKey(id))
        {
            return _textureCache[0];
        }
        return _textureCache[_idMap[id]];
    }

    public ImageTexture Get(string path)
    {
        if (!_pathMap.ContainsKey(path))
        {
            return _textureCache[0];
        }
        return _textureCache[_pathMap[path]];
    }
}