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UltraStar-Deluxe / USDX

The free and open source karaoke singing game UltraStar Deluxe, inspired by Sony SingStar™
https://usdx.eu
GNU General Public License v2.0
868 stars 162 forks source link

Alpha transparent buttons are not blended properly #94

Open RattleSN4K3 opened 8 years ago

RattleSN4K3 commented 8 years ago

The button images (and likely all other images with an alpha channel). are not properly rendered with correct alpha blending. This can be noticed in the Deluxe theme.

800x600 unbenannt-1

1920x1080 screenshot0045

It could be the alpha blending or the mimap scaling (which is default Linear). Tried somehting but nothing relly worked out (see UTexture.DrawTexture(..).

basisbit commented 8 years ago

this is a known issue which exists since the porting to SDL2. I think this is caused by somewhere in the code having a wrong BGRA / RBGA / BGR / RGB format or wrong endian.

RattleSN4K3 commented 8 years ago

It exists in 1.1 as well. Not related to SDL2 but the used blending code (and all that stuff). I've tested it with a simple image with a round corner without alpha (sharp edges) and a corner with a smooth edge with alpha. I could get the sharp edge fixed with changing the scaling method (from linear to nearest) but the alpha channel problem stays. Haven't investigate into the high mathematical equations blending two images.

basisbit commented 8 years ago

uh, then I was talking of a different issue. never mind then.