To support rotation in DirectX capturer, several other changes are also
required.
1. Removing AddRect in RotateDesktopFrame, this is a performance improvement.
DxgiOutputDuplicator creates a rotated DesktopRegion, which can be directly
add to updated_region.
2. DxgiOutputDuplicator::SourceRect() is not accurate, the rectangle in source
is controlled by |offset| or |rotation_| + |offset|, instead of desktop_rect().
3. The |region| in DxgiTexture::CopyFrom() is not accurate. It needs an
unrotated DesktopRegion which offsets by |offset| instead of desktop_rect(). To
avoid generating both rotated and unrotated updated_region, this parameter has
been removed. This impacts DxgiTextureStagning performance a little bit (1.5ms).
Refer to bug for details.
BUG=webrtc:6646
Review-Url: https://codereview.webrtc.org/2530303002
Cr-Commit-Position: refs/heads/master@{#15308}
This change adds RotateDesktopFrame(), RotateRect(), RotateSize(),
ReverseRotate() functions, so an implementation can use these free functions to
rotate and copy pixels from one DesktopFrame to another at the same time.
This is the first part of the change to support rotation in DirectX capturer. In
a coming change, these functions will be used in DxgiOutputDuplicator to do the
rotation and copying.
Background,
DirectX APIs always return unrotated data buffer, so we need to rotate it to
match the user-selected rotation. What worse is except for the data buffer,
other variables return by these APIs are all rotated, e.g. output size, monitor
position. So we will eventually not be able to capture the rotated monitors,
because we cannot set their position and size correctly. Though
DXGI_OUTDUPL_DESC provides a DXGI_MODE_ROTATION enumeration to indicate the
output rotation, it does not provide a simple way to rotate an IDXGIResource,
which is the only thing we can get from duplication APIs. A typical user case
here is to use a matrix to transform the IDXGIResource and render it to a
surface. But since we do not render the IDXGIResource at all, we need to
manually rotate it.
BUG=314516
Review-Url: https://codereview.webrtc.org/2500883004
Cr-Commit-Position: refs/heads/master@{#15205}
