blitCopyMask() support for wDstX < wSrcX

[approxit]

It finally happened. After around 7 years, we just got use case for blitting with wDstX < wSrcX, which currently is not implemented.

In Last-Minute-Creations/villages@77b6cd0 I've prepared bugged version of blitting (hit space to actually render bitmap). In this use case, I'm trying to slide a bitmap from offscreen left side to center. Because we don't want to blit outside of buffer, we need to draw smaller chunks of bitmap. Details shown in below picture, made with such a professional tool:

[tehKaiN]

This requires blitting in descending mode so that pixels are blitted from bottom-right corner instead of top-left one as well as it will reverse the pixel shifting direction from right to left.

[Vairn]

Did I fix this. or is this something different?

[tehKaiN]

afaik it's still there - and the title is slightly wrong, because only blitCopyMask() has this shortcoming, blitCopy() is fine. It was more or less intentional to make it so in order for that function to be a bit faster calculation-wise.

Now that we have dedicated bob system, this shortcoming can be fixed since it's no longer the fastest way to draw masked objects and could be more universal.

[tehKaiN]

Yeah, my memory tricked me, apparently it's fixed in c6824b2

it would be nice to test the mentioned code though, will try to do it today.