Question

I’m trying to use SharpDX to create a simple maze-like 2D program using DirectX.

To that end I want to create bitmaps that I can render on-screen for the walls, hallways, outside of the maze, etc.

However, I can’t seem to figure out how to either load an existing image file into the Bitmap class in the SharpDX library, or how to create a new such Bitmap class from scratch.

Since all the classes are said to be mapped directly to DirectX types, I guess this just means I need to learn more DirectX, but I was hoping there was a simple example somewhere that could show me what I need to do.

If I have to construct a new Bitmap from scratch and draw to it, I can do that, it’s not difficult getting the pixels I need right, however I can’t even seem to figure out that part.

Does anyone have any experience with the SharpDX library and can give me some pointers?

Answer 1

You should ask directly this question to the “Issue” tab on Sharpdx project, as I would be able to give you a quick response from there (you are lucky that I’m sometimes checking its usage from the net 😉 ). If you were asking this officially, I could make an improvement to the library and keep a record of your request in the issue database.

Concerning your particular issue, it’s not clear what kind of DirectX API you are using. I assume that you are using Direct2D?

If yes, there is no API to load directly a SharpDX.Direct2D1.Bitmap from a file (I will add this method to the API). I have just uploaded a bitmap sample that is performing this.

/// <summary>
/// Loads a Direct2D Bitmap from a file using System.Drawing.Image.FromFile(...)
/// </summary>
/// <param name="renderTarget">The render target.</param>
/// <param name="file">The file.</param>
/// <returns>A D2D1 Bitmap</returns>
public static Bitmap LoadFromFile(RenderTarget renderTarget, string file)
{
    // Loads from file using System.Drawing.Image
    using (var bitmap = (System.Drawing.Bitmap)System.Drawing.Image.FromFile(file))
    {
        var sourceArea = new System.Drawing.Rectangle(0, 0, bitmap.Width, bitmap.Height);
        var bitmapProperties = new BitmapProperties(new PixelFormat(Format.R8G8B8A8_UNorm, AlphaMode.Premultiplied));
        var size = new System.Drawing.Size(bitmap.Width, bitmap.Height);

        // Transform pixels from BGRA to RGBA
        int stride = bitmap.Width * sizeof(int);
        using (var tempStream = new DataStream(bitmap.Height * stride, true, true))
        {
            // Lock System.Drawing.Bitmap
            var bitmapData = bitmap.LockBits(sourceArea, ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppPArgb);

            // Convert all pixels 
            for (int y = 0; y < bitmap.Height; y++)
            {
                int offset = bitmapData.Stride*y;
                for (int x = 0; x < bitmap.Width; x++)
                {
                    // Not optimized 
                    byte B = Marshal.ReadByte(bitmapData.Scan0, offset++);
                    byte G = Marshal.ReadByte(bitmapData.Scan0, offset++);
                    byte R = Marshal.ReadByte(bitmapData.Scan0, offset++);
                    byte A = Marshal.ReadByte(bitmapData.Scan0, offset++);
                    int rgba = R | (G << 8) | (B << 16) | (A << 24);
                    tempStream.Write(rgba);
                }

            }
            bitmap.UnlockBits(bitmapData);
            tempStream.Position = 0;

            return new Bitmap(renderTarget, size, tempStream, stride, bitmapProperties);
        }
    }
}

As you said, SharpDX is giving access to the raw-low-level DirectX API (unlike for example XNA that is giving a higher level API), so you definitely need to understand how program raw DirectX in order to use SharpDX.