private void PlatformGetData <T>(int level, int arraySlice, Rectangle rect, T[] data, int startIndex, int elementCount) where T : struct
{
Threading.EnsureUIThread();
#if GLES
// TODO: check for for non renderable formats (formats that can't be attached to FBO)
var framebufferId = 0;
GL.GenFramebuffers(1, out framebufferId);
GraphicsExtensions.CheckGLError();
GL.BindFramebuffer(FramebufferTarget.Framebuffer, framebufferId);
GraphicsExtensions.CheckGLError();
GL.FramebufferTexture2D(FramebufferTarget.Framebuffer, FramebufferAttachment.ColorAttachment0, TextureTarget.Texture2D, this.glTexture, 0);
GraphicsExtensions.CheckGLError();
GL.ReadPixels(rect.X, rect.Y, rect.Width, rect.Height, this.glFormat, this.glType, data);
GraphicsExtensions.CheckGLError();
GraphicsDevice.DisposeFramebuffer(framebufferId);
#else
var tSizeInByte = ReflectionHelpers.SizeOf <T> .Get();
GL.BindTexture(TextureTarget.Texture2D, this.glTexture);
GL.PixelStore(PixelStoreParameter.PackAlignment, Math.Min(tSizeInByte, 8));
if (glFormat == (PixelFormat)GLPixelFormat.CompressedTextureFormats)
{
// Note: for compressed format Format.GetSize() returns the size of a 4x4 block
var pixelToT = Format.GetSize() / tSizeInByte;
var tFullWidth = Math.Max(this.width >> level, 1) / 4 * pixelToT;
var temp = new T[Math.Max(this.height >> level, 1) / 4 * tFullWidth];
GL.GetCompressedTexImage(TextureTarget.Texture2D, level, temp);
GraphicsExtensions.CheckGLError();
var rowCount = rect.Height / 4;
var tRectWidth = rect.Width / 4 * Format.GetSize() / tSizeInByte;
for (var r = 0; r < rowCount; r++)
{
var tempStart = rect.X / 4 * pixelToT + (rect.Top / 4 + r) * tFullWidth;
var dataStart = startIndex + r * tRectWidth;
Array.Copy(temp, tempStart, data, dataStart, tRectWidth);
}
}
else
{
// we need to convert from our format size to the size of T here
var tFullWidth = Math.Max(this.width >> level, 1) * Format.GetSize() / tSizeInByte;
var temp = new T[Math.Max(this.height >> level, 1) * tFullWidth];
GL.GetTexImage(TextureTarget.Texture2D, level, glFormat, glType, temp);
GraphicsExtensions.CheckGLError();
var pixelToT = Format.GetSize() / tSizeInByte;
var rowCount = rect.Height;
var tRectWidth = rect.Width * pixelToT;
for (var r = 0; r < rowCount; r++)
{
var tempStart = rect.X * pixelToT + (r + rect.Top) * tFullWidth;
var dataStart = startIndex + r * tRectWidth;
Array.Copy(temp, tempStart, data, dataStart, tRectWidth);
}
}
#endif
}
