Problem with RenderTexture with transparent background when running on iOS

Questions & Answers
1

The project I’m working on has a sort of 3D model viewer that has been made using a second camera that renders onto a RenderTexture which is in turn applied to a Quad which is in the main camera’s scene. This second camera has it’s Clear Flag set to Solid Color as a fully transparent black color (rgba[0,0,0,0]). The quad’s shader is set to Unlit/Transparent.

The RenderTexture is created with no problems, and it’s background alpha value is 0, meaning the Quad does have a transparent background, which is what I see in the editor window, but when running on an iPad the RenderTexture background is completely opaque and does not blend with the objects behind the quad, leaving a big black rectangle in the scene instead of a cutout of the model like we want.

Is this a bug on iOS or is there something I can do? It works fine on Android.

2

On iOS, render texture with transparency seems to require 24bit depth and format ARGB32, e.g.

this.camera.targetTexture = new RenderTexture(256, 256, 24, RenderTextureFormat.ARGB32);