Question

The problem is that I can’t select minimalization filter for Texture2D scaling. There is MinFilter

GraphicsDevice.SamplerStates[0].MinFilter

But it’s not working. When I try to assign some filter it just changes back to the Linear.

Is there a way to implement my own filter or how to select one of the available?

Answer 1

I have one answer to my own question and i think it will be better to post a new answer for readability.

    private Texture2D Scale(GraphicsDevice gd, Texture2D texture, float scale)
    {

        int sourceWidth = texture.Width;
        int sourceHeight = texture.Height;

        int destWidth = (int)(sourceWidth * scale);
        int destHeight = (int)(sourceHeight * scale);

        //convert texture into bitmap
        byte[] textureData = new byte[4 * sourceWidth * sourceHeight];
        texture.GetData<byte>(textureData);

        System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(sourceWidth, sourceHeight, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
        System.Drawing.Imaging.BitmapData bmpData = bmp.LockBits(new System.Drawing.Rectangle(0, 0, sourceWidth, sourceHeight), System.Drawing.Imaging.ImageLockMode.WriteOnly,
                       System.Drawing.Imaging.PixelFormat.Format32bppArgb);
        IntPtr safePtr = bmpData.Scan0;
        System.Runtime.InteropServices.Marshal.Copy(textureData, 0, safePtr, textureData.Length);
        bmp.UnlockBits(bmpData);


        //output bitmap
        System.Drawing.Image outputImage = new System.Drawing.Bitmap(destWidth, destHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
        System.Drawing.Graphics grPhoto = System.Drawing.Graphics.FromImage(outputImage);
        grPhoto.InterpolationMode = (System.Drawing.Drawing2D.InterpolationMode)(interpolationMode);


        grPhoto.DrawImage((System.Drawing.Image)bmp, new System.Drawing.Rectangle(0, 0, destWidth, destHeight),
            new System.Drawing.Rectangle(0, 0, sourceWidth, sourceHeight), System.Drawing.GraphicsUnit.Pixel);

        grPhoto.Dispose();

        textureData = new byte[4 * sourceWidth * sourceHeight];

        MemoryStream ms = new MemoryStream();
        ((System.Drawing.Bitmap)outputImage).Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);
        ms.Seek(0, SeekOrigin.Begin);
        Texture2D result = Texture2D.FromFile(gd, ms);
        ms.Dispose();

        return result;
    }

This metod runs in about 20ms – 100ms depending on interpolation mode, maybe someone will find it usefull. Is there a way to optimize it? I dont need 32bit support but there seems to be no way to set it to 24. I found different sizing algorithms
http://www.codeproject.com/KB/GDI-plus/imgresizoutperfgdiplus.aspx
but they are slow.

Is there a way to implement these methods using speed of graphic card?