03447: gauntdl, gauntdl24, gauntleg, gauntleg12: Texture with alpha channel is not drawn properly.

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
03447	Graphics	Minor	Always	Sep 23, 2009, 02:09	Apr 26, 2014, 18:14

Tester	sigmaxix	View Status	Public	Platform	MAMEUI
Assigned To	Phil Bennett	Resolution	Fixed	OS	Windows Vista/7 (64-bit)
Status [?]	Resolved			Driver	midway/vegas.cpp
Version	0.134	Fixed in Version	0.154	Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	03447: gauntdl, gauntdl24, gauntleg, gauntleg12: Texture with alpha channel is not drawn properly.
Description	Rendering problem. Texture with an alpha channel, such as trees, branches, posts, enemy weapons, and walkway rails, hide the objects and items behind them. This does not happen on the arcade. The invisible color often creates a "blurry square" around 2D-props that hides any items or sprites behind them. One example is at the beginning of level 1-3, where the giant tree hides a barrel and "poison food".
Steps To Reproduce	Level 1-3 [Mountain Realm > Cliffs] big tree. Ice Domain > Level 1 behind fences. Forest > Level 1, hanging vines.
Additional Information
Github Commit

Flags	Verified with Original
Regression Version
Affected Sets / Systems	gauntdl, gauntdl24, gauntleg, gauntleg12

Attached Files	Graphical.png (372,419 bytes) Sep 23, 2009, 02:09
Attached Files	Hidden.png (512,608 bytes) Sep 23, 2009, 07:49

No.04974 Fujix Administrator Sep 23, 2009, 07:44 edited on: Sep 23, 2009, 07:51	As stated in 02853, only gauntleg12 works in 0.134. I used it for confirmation. And this is a FAQ, MAME doesn't use Direct3D or any other OS dependent graphic routine. What you select is how Windows draws the final image on the screen by the drawing options (ddraw, gdi, d3d), so it doesn't affect the internal emulation screen created by MAME at all. I fixed the report.
No.04975 Tafoid Administrator Sep 23, 2009, 11:07	I'd like to mention, please, that in the future if posting snapshots to use MAME's mechanism for snapshots (F12). Taking a processed picture like above isn't the proper way to report graphical issues. Thank you.
No.10631 Phil Bennett Developer Apr 26, 2014, 18:14	These 'sprites' are drawn with alpha-testing (passing values > 0) and alpha-blending enabled. The alpha test was not operating on the correct input source, so fully transparent pixels would not be discarded and those passing the depth test would subsequently occlude any geometry rendered behind the sprite. The alpha test is now performed on the output of the alpha combiner and not on the iterated/texture/fixed alpha value (a_other).