/// <summary>
/// Download Texture data to an Image instance.
/// </summary>
/// <param name="ctx">
/// A <see cref="GraphicsContext"/> used for downloading texture data.
/// </param>
/// <param name="pType">
/// A <see cref="OpenGL.PixelLayout"/> determining the pixel format of the downloaded data.
/// </param>
/// <param name="target">
/// A <see cref="TextureTarget"/> that specify the texture target.
/// </param>
/// <returns>
///
/// </returns>
protected Image[] Get(GraphicsContext ctx, PixelLayout pType, TextureTarget target)
{
// Bind this Texture
ctx.Bind(this);
// Get texture extents
int width, height;
Gl.GetTexLevelParameter(TextureTarget, 0, GetTextureParameter.TextureWidth, out width);
Gl.GetTexLevelParameter(TextureTarget, 0, GetTextureParameter.TextureHeight, out height);
if ((width <= 0) || (height <= 0))
{
throw new InvalidOperationException(String.Format("invalid texture extents {0}x{1}", width, height));
}
// Create image
Image image = new Image(pType, (uint)width, (uint)height);
// Set pixel transfer
foreach (int alignment in new int[] { 8, 4, 2, 1 })
{
if (image.Stride % alignment == 0)
{
Gl.PixelStore(PixelStoreParameter.PackAlignment, alignment);
break;
}
}
// Download texture contents
Gl.GetTexImage(target, 0, Pixel.GetGlFormat(pType), Pixel.GetPixelType(pType), image.ImageBuffer);
// Unbind this texture
ctx.Unbind(this);
return(new Image[] { image });
}
/// <summary>
/// Actually create this BufferObject resources.
/// </summary>
/// <param name="ctx">
/// A <see cref="GraphicsContext"/> used for allocating resources.
/// </param>
/// <exception cref="ArgumentNullException">
/// Exception thrown if <paramref name="ctx"/> is null.
/// </exception>
/// <exception cref="ArgumentException">
/// Exception thrown if <paramref name="ctx"/> is not current on the calling thread.
/// </exception>
/// <exception cref="InvalidOperationException">
/// Exception thrown if this BufferObject has not client memory allocated and the hint is different from
/// <see cref="BufferObjectHint.StaticCpuDraw"/> or <see cref="BufferObjectHint.DynamicCpuDraw"/>.
/// </exception>
/// <exception cref="InvalidOperationException">
/// Exception thrown if this BufferObject is currently mapped.
/// </exception>
protected override void CreateObject(GraphicsContext ctx)
{
CheckCurrentContext(ctx);
if ((ClientBufferAddress == IntPtr.Zero) && ((Hint != BufferObjectHint.StaticCpuDraw) && (Hint != BufferObjectHint.DynamicCpuDraw)))
{
throw new InvalidOperationException("no client buffer");
}
// Determine the client buffer size
uint clientBufferSize = _ClientBufferSize;
if (ClientBufferAddress != IntPtr.Zero)
{
clientBufferSize = ClientBufferSize;
}
Debug.Assert(clientBufferSize > 0);
// Buffer must be bound
ctx.Bind(this);
if (ctx.Caps.GlExtensions.VertexBufferObject_ARB)
{
if (IsMapped)
{
throw new InvalidOperationException("mapped");
}
// Define buffer object (type, size and hints)
AllocateGpuBuffer(clientBufferSize, null);
// Define buffer object contents
if (ClientBufferAddress != IntPtr.Zero)
{
// Provide buffer contents
Gl.BufferSubData(BufferType, IntPtr.Zero, _GpuBufferSize, ClientBufferAddress);
// Release memory, if it is not required anymore
if (_MemoryBufferAutoDispose)
{
ReleaseClientBuffer();
}
}
}
else
{
// Discard previous GPU buffer, if any
if (_GpuBuffer != null)
{
_GpuBuffer.Dispose();
}
if (ClientBufferAddress == IntPtr.Zero)
{
// Note: GPU buffer size specified by _ClientBufferSize
Debug.Assert(_ClientBufferSize > 0);
// Allocate simulated GPU buffer
_GpuBuffer = new AlignedMemoryBuffer(_ClientBufferSize, MinimumBufferAlignment);
}
else
{
// Let a virtual implementation decide how pass information from the client buffer and the "GPU" buffer
UploadClientBuffer();
}
// Store GPU buffer size
_GpuBufferSize = _GpuBuffer.Size;
}
// Reset requested client buffer size
_ClientBufferSize = 0;
}
