I hope there are some MSX emulator authors reading this :-)

As you can see in the latest version of JEmu2, the sprite colours of Konami MSX2 games are not correct yet. The konami msx2 games' sprites seem to have more colours on the real thing than in JEmu2.
I did emulate the ability to have different colours on each line of the MSX2 sprite, and I think this works correctly (I suppose if I wouldn't emulate that, the effect of character in Firebird running underneath things wouldn't work and in Outrun this seems to work okay too).

I did notice in the portar document the feature about colours of sprite pixels being OR'ed with overlapping sprites when setting some bit. I had a try emulating that feature, but I'm not sure yet if that is in fact the feature Konami used to create those colourful sprites (so far, my attempt in emulating this aspect didn't have the required effect).

Does the V9938 OR the sprite colours, or the RGB values of those colours? (I suppose it just ORs the colour numbers).
Does Konami use this feature in their games?
Any other hints, tips?

Thanks!

OR does the colornumbers..

color 4 OR color 1 gives you the extra color 5 ..

Usas uses it, Vampire Killer uses it, Metal Gear, Space Manbow, heck, everything MSX2'ish

Thanks, I just fixed the sprite colours!

The V9938 can indeed OR the sprite colours, but it only does so under special conditions (CC bit set in consecutive sprites). This is how we do it in openMSX, see "drawMode2" method, under "Calculate colour of pixel to be plotted.".