Principal problem with steeper slopes and artifical slopes

[prissi]

During the conversion of pak64 into double slopes I found this visual bug. It is most severe with 16/32 slopes (as of pak64), but anything higher than 8/16 will produce errors too. The problem is that the artificial slopes is always larger than the front slope which must cover it entirely. not sure how to fix this.

(Those house are one row below the peak!)

[Dwachs]

The slope in front needs the draw_as_ding flag set.

[kierongreen]

The problem with that is that with 16/32 the slope in front could be many tiles distant from the tile causing the problem.

[Dwachs]

Here is a patch. It checks up to 5 tiles behind to see whether something might be hidden. Please test. The check stops after 5 tiles, but this might not be enough. Theoretically one has to check up to the border (or at least 255 tiles in the back).

The patch adds a lot more logic to the already bloated calc_back_bild routine. Maybe there is some potential to reduce it.

[prissi]

I seldomly saw more than three double slopes following each other. I think five is quite reasonable, considering that during construction these checks may be triggered on a number of images.

Anyway, this works well it seems. Thank you.

[Dwachs]

in r7002 .

[Dwachs]

This fix was pretty much broken from the beginning. All tiles were set to draw_as_ding ...

Please test again with r7067