[mono-android] Deleting textures to free up resources

[Kestutis Tauckela]

Hi,

I'm having problems deleting old textures via OpenGL ES. To test that, I was
using modified TexturedCube example. You can find original example here:
https://github.com/mono/monodroid-samples/tree/master/TexturedCube.
The only difference I made was loading (creating) textured and destroying
them each time the cube was rendered. It was working slower (as expected),
but if the texture would be destroyed properly - the exmaple would still run
indefinitelly. Currently while using 256x256 texture it crashes after
exactly 130 successful creations and destructions of said textures (on
GalaxyS phone). Further tests shown that texture destruction code can be
skipped entirely and still produce same results. Which makes me think that
there might be some issues in destruction of the textures.

Am I missing some destruction call to clean-up properly? Or is it a bug?

BTW, the crash happens in the "bitmap.Recycle();" call. It looks like bitmap
object is not null, but not valid either. Is it another bug in
BitmapFactory.DecodeResource?

Thank you,
Kestutis Tauckela.
http://www.outlanderstudios.com/

Here are main functions from the code I was using:
        protected int LoadTexture (Context context, int resourceId)
        {
            int nTextureId = 0;

            // create texture
            GL.Enable(All.Texture2D);
            GL.GenTextures(1, ref nTextureId);
            GL.BindTexture(All.Texture2D, nTextureId);

            // setup texture parameters
            GL.TexParameterx(All.Texture2D, All.TextureMagFilter,
(int)All.Linear);
            GL.TexParameterx(All.Texture2D, All.TextureMinFilter,
(int)All.Linear);
            GL.TexParameterx(All.Texture2D, All.TextureWrapS,
(int)All.ClampToEdge);
            GL.TexParameterx(All.Texture2D, All.TextureWrapT,
(int)All.ClampToEdge);

            int ww, hh;
            int [] pixels = GetTextureFromBitmapResource (context,
resourceId, out ww, out hh);

            GL.TexImage2D (All.Texture2D, 0, (int)All.Rgba, ww, hh, 0,
All.Rgba, All.UnsignedByte, pixels);

            return nTextureId;
        }

        protected void DestroyTexture(ref int nTextureID)
        {
            GL.DeleteTextures(1, ref nTextureID);
        }

        static int[] GetTextureFromBitmapResource(Context context, int
resourceId, out int width, out int height)
        {
            Bitmap bitmap = null;
            try {
                bitmap = BitmapFactory.DecodeResource(context.Resources,
resourceId);

                width = bitmap.Width;
                height = bitmap.Height;

                int [] pixels = new int [width * height];

                // Start writing from bottom row, to effectively flip it in
Y-axis
                bitmap.GetPixels  (pixels, pixels.Length - width, -width, 0,
0, width, height);
                return pixels;
            }
            finally    {
                if (bitmap != null) {
                    bitmap.Recycle();
                }
            }
        }
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