Render to Texture on iOS

Unity Engine
,
1

I am rendering to a texture on iPad3, and the behaviour seems different than on a PC or Mac in editor.
The camera is set to clear the background with a solid color, which is black with 0 alpha.
Then I render an object, and use the texture as a sprite/decal. (with 0 alpha around the edges)
This works great on PC and Mac,
but on iPad, it looks like there is no 0 alpha (like just a solid texture rgb, not rgba) so I see a big black square, instead of transparent border.

Is this a hardware limitation with render to texture, or are there some default settings, that are different on hardware that I may not have considered ?

The shader is a simple one “transparent/diffuse” also tried “unlit/transparent” with same effect
I have iOS pro unity.

cheers in advance
Jon

2

is the texture size a power of two? i think i remember that ios only supports those. not 100% sure thou

3

yes its a power of 2, I think it might be to do with default render texture format. I think the default is different on pc/mac than on actual hardware. for example rgb555 or argb32 argb1555 etc…
(or perhaps different hardware supports different formats, perhaps some without alpha)

going to play around with it now.

4

ok specifically setting the render texture to argb32 seemed to do the trick.