public unsafe void GetTextureData(int mipLevel, IntPtr destination, int storageSizeInBytes)
{
int width = MipmapHelper.GetDimension(Width, mipLevel);
int height = MipmapHelper.GetDimension(Height, mipLevel);
Bind();
GL.GetTexImage(TextureTarget.Texture2D, mipLevel, OpenTK.Graphics.OpenGL.PixelFormat.Alpha, _pixelType, destination);
GL.BindTexture(TextureTarget.Texture2D, 0);
GL.PixelStore(PixelStoreParameter.PackAlignment, 1);
// Need to reverse the rows vertically.
int pixelSizeInBytes = FormatHelpers.GetPixelSizeInBytes(_veldridFormat);
int rowBytes = width * pixelSizeInBytes;
IntPtr stagingRow = Marshal.AllocHGlobal(rowBytes);
byte * stagingPtr = (byte *)stagingRow.ToPointer();
byte * sourcePtr = (byte *)destination.ToPointer();
for (int y = height - 1, destY = 0; y > (height / 2); y--)
{
Buffer.MemoryCopy(sourcePtr + (y * rowBytes), stagingPtr, rowBytes, rowBytes);
Buffer.MemoryCopy(sourcePtr + (destY * rowBytes), sourcePtr + (y * rowBytes), rowBytes, rowBytes);
Buffer.MemoryCopy(stagingPtr, sourcePtr + (destY * rowBytes), rowBytes, rowBytes);
destY++;
}
// Reset to default value.
GL.PixelStore(PixelStoreParameter.PackAlignment, 4);
}
public void GetTextureData(int mipLevel, IntPtr destination, int storageSizeInBytes)
{
int width = MipmapHelper.GetDimension(Width, mipLevel);
int height = MipmapHelper.GetDimension(Height, mipLevel);
D3DTexture2D stagingTexture = new D3DTexture2D(_device, new Texture2DDescription()
{
Width = width,
Height = height,
Usage = ResourceUsage.Staging,
BindFlags = BindFlags.None,
CpuAccessFlags = CpuAccessFlags.Read,
OptionFlags = ResourceOptionFlags.None,
MipLevels = 1,
ArraySize = 1,
SampleDescription = new SharpDX.DXGI.SampleDescription(1, 0),
Format = DeviceTexture.Description.Format
});
// Copy the data from the GPU to the staging texture.
_device.ImmediateContext.CopySubresourceRegion(DeviceTexture, mipLevel, null, stagingTexture.DeviceTexture, 0);
int elementCount = width * height;
// Copy the data to the array.
DataBox db = _device.ImmediateContext.MapSubresource(
stagingTexture.DeviceTexture,
0,
MapMode.Read,
MapFlags.None,
out DataStream ds);
int pixelSizeInBytes = D3DFormats.GetPixelSize(DeviceTexture.Description.Format);
int rowSize = pixelSizeInBytes * width;
// If the pitch exactly matches the row size, we can simply copy all the data.
if (rowSize == db.RowPitch)
{
SharpDX.Utilities.CopyMemory(destination, db.DataPointer, elementCount * pixelSizeInBytes);
}
else
{
// The texture data may not have a pitch exactly equal to the row width.
// This means that the pixel data is not "tightly packed" into the buffer given
// to us, and has empty data at the end of each row.
for (int rowNumber = 0; rowNumber < height; rowNumber++)
{
int rowStartOffsetInBytes = rowNumber * width * pixelSizeInBytes;
ds.Read(destination, rowStartOffsetInBytes, width * pixelSizeInBytes);
// At the end of the row, seek the stream to skip the extra filler data,
// which is equal to (RowPitch - RowSize) bytes.
ds.Seek(db.RowPitch - rowSize, SeekOrigin.Current);
}
}
stagingTexture.Dispose();
}