iOS GLES2 Material with VideoRam texture leeds to black screen

[Tobi-La]

Godot version:
3.1.2 stable
OS/device including version:
iPhone 6s, iOS 13.3.1
Issue description:
When you have a scene with a material, that uses a texture which is imported in Video Ram mode, the game does not render the scene and shows only a black screen.
Steps to reproduce:

• Create a GLES2 scene with a mesh
• Assign a material to the mesh
• Set an png as the texture with was imported in mode "Video Ram"

Minimal reproduction project:
ioSGLES2.zip

[Calinou]

Do iPhones support ETC1 texture compression? If not, you'll have to generate PVRTC-compressed textures using an external tool. Unfortunately, this process is undocumented.

[Tobi-La]

I tried checking pvrtc here, but it unfortunately didn't work:

Can you give me some more hints to get started? Or is there any other workaround? When using lossy textures I get crashes, it seems to me when I render multiple objects. Single objects seem to work fine.

[Calinou]

@Tobi-La The built-in PVRTC encoder option is broken according to #28669. This is why you'll have to call the encoder manually and store the resulting files somewhere in the project folder.

[Tobi-La]

How do I know where to store them? And do you knwo a tool that can do that?

[Calinou]

How do I know where to store them? And do you knwo a tool that can do that?

You can place them anywhere. Placing them in the same directory as the uncompressed images makes sense. You'll just have to specify the path to the compressed image in the MeshInstance's material. However, this will most likely cause the texture to stop displaying on desktop (as PVRTC is only supported on iOS).

As for obtaining PVRTexToolCLI, it seems it's now part of the PowerVR SDK available here. (Unfortunately, there's no minimal installation that contains just the required executable.)

[Tobi-La]

I have the following options to encode:

I tried the first and load it as a texture, but it doesn't load:

modules/pvr/texture_loader_pvr.cpp:73 - Condition "hsize != 52" is true. Returned: RES()
Failed loading resource: res://textures/myTexture.pvr.

Which mode do I have to use?

[Tobi-La]

@Calinou I tried all available options, but all of them generate the same error. I set this as the texture albedo directly, may that be wrong?