I'm trying to use the color matrix input on jit.gl.mesh to control the alpha (which I will happily admit, I barely understand.) In the example below, if I set a mesh using a gridshape, I can pass a matrix with a varying alpha with no problem. If I set the mesh with jit.expr (actually creating a grid), the color matrix no longer has any effect. The only obvious difference seems to me that in the second case, a 5-plane matrix is being passed to the mesh instead of a 3-plane one, but to be honest I don't really understand the arcana of the object well enough to see how that would change things. Can someone have a look at this & set me straight?