BUTR/Bannerlord.BLSE

using Bannerlord.LauncherEx.TPac;

using HarmonyLib.BUTR.Extensions;

using StbSharp;

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Runtime.InteropServices;

using TaleWorlds.TwoDimension.Standalone;

namespace Bannerlord.LauncherEx.Extensions;

internal static class OpenGLTextureExtensions
{
    private enum PixelFormat : uint
    {
        ColorIndex = 6400U,
        StencilIndex,
        DepthComponent,
        Red,
        Green,
        Blue,
        Alpha,
        RGB,
        RGBA,
        Luminance,
        LuminanceAlpha,
        BGR = 32992U,
        BGRA
    }

    private delegate void MakeActiveDelegate(OpenGLTexture texture);
    private static readonly MakeActiveDelegate? _makeActiveDelegate = AccessTools2.GetDelegate<MakeActiveDelegate>(typeof(OpenGLTexture), "MakeActive");

    [DllImport("Opengl32.dll", EntryPoint = "glTexImage2D")]
    private static extern void TexImage2D(uint target, int level, uint pixelInternalformat, int width, int height, int border, PixelFormat format, uint type, byte[] pixels);

    [DllImport("Opengl32.dll", EntryPoint = "glTexImage2D")]
    private static extern void TexImage2D2(uint target, int level, uint pixelInternalformat, int width, int height, int border, PixelFormat format, uint type, IntPtr pixels);

    public static void MakeActive(this OpenGLTexture texture) => _makeActiveDelegate?.Invoke(texture);

    public static bool LoadFromStream(this OpenGLTexture texture, string name, Stream stream)
    {
        if (_makeActiveDelegate is null)
            return false;

        // TODO: For some reason, we need now to pass req_comp as 4, not 0 as previously
        var image = new ImageReader().Read(stream, 4);
        texture.Initialize(name, image.Width, image.Height);
        texture.MakeActive();
        var (error, pixelFormat, pixelInternalformat) = image.Comp switch
        {
            1 => (false, PixelFormat.Red, 0x8229U),
            3 => (false, PixelFormat.RGB, 0x8051U),
            4 => (false, PixelFormat.RGBA, 0x8058U),
            _ => (true, (PixelFormat) 0, 0U),
        };
        if (!error)
        {
            TexImage2D(0x00000DE1, 0, pixelInternalformat, image.Width, image.Height, 0, pixelFormat, 0x00001401, image.Data);
        }

        return true;
    }

    public static bool LoadFromAssetTexture(this OpenGLTexture texture, string name, Texture source)
    {
        if (_makeActiveDelegate is null)
            return false;

        if (source.TexturePixels is null)
            return false;

        var textureData = source.TexturePixels.GetData();
        using var bitmap = TextureUtil.DecodeTextureDataToBitmap(textureData.PrimaryRawImage, (int) source.Width, (int) source.Height, source.Format);
        var data = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);

        texture.Initialize(name, (int) source.Width, (int) source.Height);
        texture.MakeActive();
        TexImage2D2(0x00000DE1, 0, 0x8058U, data.Width, data.Height, 0, PixelFormat.BGRA, 0x00001401, data.Scan0);

        bitmap.UnlockBits(data);

        return true;
    }
}