This is a binding map problem in ImpellerC. See comment: https://github.com/flutter/flutter/issues/105156#issuecomment-1150232082 ~Should be `glUniformMatrix4fv`. Here's the `glUniform4f` call with the first 4 items in the matrix:~  ~Output positions of vertex shader ending up with all 0s:~ -