Add support for transparent shaders
chadrik opened this issue · 2 comments
objects should be displaying transparently based on alpha channels, but something is not working... Even if the surfaceShader returns a 0.0 for the alpha value, the pixel shows up black. There might be something fundamental missing from HdStream, or it might be specific to PxrPreviewSurface.
Transparency using the preview surface just works fine in usdview, same goes for the other shaders we use in usdview for displaying image planes (for example). I think it's simply a missing state, that's not set by HdStream and relies on the existing opengl context to set that up.
UsdView enables both blend and sets blend func. (see stageView.py:1503 ) For now I added a simple workaround to setup / restore these values for HdSt, but configuring all the required states in HdSt is the right long term solution.