Using allow_uav_condition loop attribute in HLSL

Reference URL

• RWTexture2D - read and write @ GameDev.net
  • http://www.gamedev.net/topic/620793-rwtexture2d-read-and-write/
• HLSL flow control @ msdn
  • http://msdn.microsoft.com/en-us/library/windows/desktop/bb509602%28v=vs.85%29.aspx
• [Dx11] InterlockedAdd on floats in Pixel Shader - Workaround? @ GameDev.net
  • http://www.gamedev.net/topic/613648-dx11-interlockedadd-on-floats-in-pixel-shader-workaround/
• "Counting Quads" @ Self Shadow
  • http://blog.selfshadow.com/2012/11/12/counting-quads/
• A Digression on Divergence
  • http://tangentvector.wordpress.com/2013/04/12/a-digression-on-divergence/
• About [allow_uav_condition] in Twitter
  • https://twitter.com/marcosalvi/status/322221622989819904

Memo

• When I tried to set the loop termination condition based on UAV, the following HLSL shader error occured.

HLSL Error message:
Loop termination conditions in varying flow control
cannot depend on data read from a UAV

• If you want to determine the loop termination condition based on UAV read, you have to set [allow_uav_condition] as a loop attribute.
• But I cannot use flow control with UAV at my notebook PC with NVidia driver. So, I used some workaround based on this article. ( "Counting Quads @ Self Shadow" )

• In Japanese: UAV の値に応じて HLSL の制御ループの停止条件を書こうとしたら, シェーダのコンパイルエラーが出ました. その際, 制御ループの属性に [allow_uav_condition] を指定する必要がありました
• (追記) しかし僕のノート PC の NVidia ドライバだと, どうも UAV を使ったフロー制御ができなかったので 上の記事に載っていた一時対応で対処しました.