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Votes
1
Found in
4.3.1f1
Issue ID
582978
Regression
No
Background sprite can be visible when it shouldn't (due to alpha)
To reproduce:
1. Open attached project
2. Open scene "Game". It contains three sprites - a flower with alpha on it's edges, a grass sprite and a background sprite with white edges
3. In play mode, notice how the white edges of the "BG" sprite are visible on the shadow parts of the flower (alpha) even though there is a sprite covering the "BG"
4. Move the flower away - the lines are no longer visible
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TomasJ
Mar 26, 2014 10:46
The alpha issue isn't exactly a bug, but a way Unity does blending. This happens because textures are not with premultiplied alpha.
You can work around in one of the following ways:
- Duplicate the desired shader and change blending to "Blend SrcAlpha OneMinusSrcAlpha, One OneMinusSrcAlpha" - this will set different blending mode for alpha, but might not be supported on some mobile GPUs.
- Duplicate the desired shader and emulate premultiplied alpha:
-- Set blending to "Blend One OneMinusSrcAlpha"
-- Multiply RGB by alpha in the pixel shader (final.rgb *= final.a)