d3d11screencapturesrc: Fix mouse cursor blending

Ignore alpha component of source (mouse cursor texture)
when blending alpha channel, otherwise the background area of source
(which has zeros) will be written to render target. Then it will result
in black rectangle if output texture is converted to premultiplied alpha
texture

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5577>

diff --git a/subprojects/gst-plugins-bad/sys/d3d11/gstd3d11screencapturesrc.cpp b/subprojects/gst-plugins-bad/sys/d3d11/gstd3d11screencapturesrc.cpp
index d1f13d6..13ba11b 100644 (file)
--- a/subprojects/gst-plugins-bad/sys/d3d11/gstd3d11screencapturesrc.cpp
+++ b/subprojects/gst-plugins-bad/sys/d3d11/gstd3d11screencapturesrc.cpp
@@ -890,8 +890,8 @@ gst_d3d11_screen_capture_prepare_shader (GstD3D11ScreenCaptureSrc * self)
   blend_desc.RenderTarget[0].SrcBlend = D3D11_BLEND_SRC_ALPHA;
   blend_desc.RenderTarget[0].DestBlend = D3D11_BLEND_INV_SRC_ALPHA;
   blend_desc.RenderTarget[0].BlendOp = D3D11_BLEND_OP_ADD;
-  blend_desc.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND_ONE;
-  blend_desc.RenderTarget[0].DestBlendAlpha = D3D11_BLEND_ZERO;
+  blend_desc.RenderTarget[0].SrcBlendAlpha = D3D11_BLEND_ZERO;
+  blend_desc.RenderTarget[0].DestBlendAlpha = D3D11_BLEND_ONE;
   blend_desc.RenderTarget[0].BlendOpAlpha = D3D11_BLEND_OP_ADD;
   blend_desc.RenderTarget[0].RenderTargetWriteMask =
       D3D11_COLOR_WRITE_ENABLE_ALL;