Fix premultiplied alpha issue with color correction
author Casian Andrei
()
committer Casian Andrei
()
commit 6cd210f611b7527922d62bc389dfe38b49566349
tree 88faa60293426b542f8034e29e9d2e6088d4b098
parent 70601dd657efb9066c62e649693f271764523823
Fix premultiplied alpha issue with color correction

When correcting a color that was with premultiplied alpha, the alpha
value was not multiplied back again as a final step. This was breaking
color correction when the blend function was GL_ONE,
GL_ONE_MINUS_SRC_ALPHA. The blend function was changed for normal
windows (a workaround), but not for effect frames, i.e. the effect
frames were broken with color correction enabled.

Removes the blend function workaround.

Removes a useless setupForOutput.

BUG: 311319
REVIEW: 108189
kwin/libkwineffects/kwinglcolorcorrection.cpp
kwin/scene_opengl.cpp