OpenGLES3 Error when rendering Cesium Tiles on Quest Devic

[csciguy8]

Reported from the community here,

We started getting this error when we switched to OpenGLES3 from Vulcan. Google seems to point to single pass/double pass issues with the shader.

AndroidPlayer "Oculus_Quest Pro@ADB:230YC01DB200SQ:0" Assertion failed: OPENGL NATIVE PLUG-IN ERROR: GL_INVALID_OPERATION: Operation illegal in current state

You can easily reproduce this in the sample cesium projects if you run them on Quest. The errors only appear when a cesium tile is rendering on Android.

We believe the shader is Cesium_RoundPolygonMask

If we put that in the scene on something unrelated to cesium tiles it doesn’t throw the error. So we assume its a specific pass being used within that shader.