Issue with raster mbtiles with transparency

[serhii-londar]

On latest version of WhirlyGlobe iOS SDK v 3.5 we found issue with raster tiles with transparency. The color looks very different from how it should be, comparing to other mbtiles viewers.
Here is example of what we have in the app vs MapTiler viewer:

The code is from GeographyClassTestCase.
What could be the reasons of that?
Thanks in advance.

[sjg-wdw]

Looks like there's lighting involved in the WhirlyGlobe case. You could try turning that off.
Alpha can also be interpreted differently, depending on how it's being used.

[serhii-londar]

@sjg-wdw How I can turn lighting off?
I've tried globeViewController?.clearLights() - but it doesn't help.

[sjg-wdw]

clearLights should do it, yes. If you're in globe mode it should look different if it's working.

[serhii-londar]

@sjg-wdw The result is the same.

[sjg-wdw]

Strange, that looks like lighting to me.
In any case, I'd try a non-transparent overlay next to see if it matches what you expect. If it does, then the way the transparency is being processed is likely the problem. You might look at the shader (in the .metal file) to see if it's being multiplied through or not.

[serhii-londar]

@sjg-wdw One more question. I found weird behavior when draw motiles with drawpriority > 1000.
Here is example with draw priority <= 400:

Here is with drawpriority > 400:

What can be the reason of black shadow around the images?

Also, it could be fixed by forceMinLevel = false.

[serhii-londar]

@sjg-wdw Any thoughts?

[sjg-wdw]

If you have a layer with transparency, then you can only display one level at once and you want to not force the min level.