Wireframe shader causes error on Android player build

[FejZa]

XRTK - Mixed Reality Toolkit Bug Report

Describe the bug

When targeting the Android platform and XR Setting is enabled building the Player will fail because of the Mixed Reality Toolkit/Wireframe shader.

Shader error in 'Mixed Reality Toolkit/Wireframe': unrecognized identifier 'DEFAULT_UNITY_VERTEX_OUTPUT_STEREO_EYE_INDEX' at line 47 (on gles3)

Compiling Vertex program with STEREO_MULTIVIEW_ON
Platform defines: UNITY_NO_DXT5nm UNITY_NO_RGBM UNITY_ENABLE_REFLECTION_BUFFERS UNITY_FRAMEBUFFER_FETCH_AVAILABLE UNITY_NO_CUBEMAP_ARRAY UNITY_NO_SCREENSPACE_SHADOWS UNITY_PBS_USE_BRDF2 SHADER_API_MOBILE UNITY_HARDWARE_TIER3 UNITY_COLORSPACE_GAMMA UNITY_LIGHTMAP_DLDR_ENCODING

To Reproduce

• Create Unity Project
• Import XRTK
• Switch to Android platform
• Build

Expected behavior

The Android Player can be built.

Actual behavior

Build Fails.

Your Setup (please complete the following information)

• Unity 2019.1.2f1
• XRTK development branch

Target Platform (please complete the following information)

• Android

[FejZa]

Happens only if target is Android and XR Settings enabled

[StephenHodgson]

Strange cause this is pretty much lifted from Unity's built in wire frame shader (which I thought was cross platform)

[FejZa]

Ah forgot About this one. I wasn't able to reproduce it anymore. Probably some hickups Unity had. Closing it.

[SimonDarksideJ]

The issue is real (unlike the cake which is a lie)
Shader needs updating or exclusions adding for Android. Currently, have to remove the shader to run on Android

[SimonDarksideJ]

I did see Cameron did some updates to the Standard shader to include Wireframe support. Maybe we could do a refresh from the MRTK for the standard shader and deprecate this one.

According to Ronald at MR dev summit, it's because there is a property that Unity does not expose for the Android platform and it's a known issue.

[FejZa]

We should take a look at the updated shaders. Now that XRTK almost has Oculus Quest support it's important people are able to build to Android without having to delete a shader.

[SimonDarksideJ]

Quest Support is now live in Dev, so we really should look for a way to resolve this issue.
Either by fixing this shader or updating to the latest MRTK standard shader (which now has wireframe support)

One snag is that (apparently) the Quest does not have geom fragment shader support, which is needed? for wireframe.

Supposedly this version of the MRTK standard shader does work?
https://github.com/microsoft/MixedRealityToolkit-Unity/pull/4993/files/493ddac1a19a15c20795016a8f7a361ff1dc72a6#diff-55fa8fd379bc8ffc69911bd63bbc37a3

[StephenHodgson]

Fix the shader

[SimonDarksideJ]

I will look to porting the updated MRTK standard shader which supposedly has wireframe support then we can remove the non-functioning one

[StephenHodgson]

The latest code is pretty much the port from mrtk

[SimonDarksideJ]

Will double-check, if so we only need test that the wireframe logic is working. Will pull up a test scene

[SimonDarksideJ]

Resolved Build issue through PR #254. This resolves the build issue, however, the shader causes the screen to go black on Android, likely due to incompatibility.