Crash when automatic shadows and multithreading are both enabled

[Tober]

Panda3d version: 1.9.0 devel
OS: Windows 7 64 bit

I've set up shadows using light.setShadowCaster(), but when I turn on multithreading with threading-model Cull/Draw in the config, panda3d freezes up before it draws anything to the screen.

I've narrowed it down to a simple example. If both the commented first line and second line exist, it doesn't work for me.

from panda3d.core import loadPrcFileData
#First line
loadPrcFileData('', 'threading-model Cull/Draw')

from panda3d.core import *

from direct.showbase.ShowBase import ShowBase

class Engine(ShowBase):
      def __init__(self):
            ShowBase.__init__(self)
            base.setBackgroundColor(1,0,0,1)

            model = loader.loadModel("models/environment")
            model.reparentTo(render)
            model.setScale(0.1)
            box = loader.loadModel("models/box")
            box.reparentTo(render)
            box.setZ(1)

            light=DirectionalLight("test")
            light.setColor((1,1,1,1))
            light.setSpecularColor((1,1,1,1))
            #Second line
            light.setShadowCaster(True, 1024, 1024)
            light.getLens().setFilmSize(20)

            base.disableMouse()
            base.camera.setPos(10,0,10)
            base.camera.lookAt(render)

            node = render.attachNewNode(light)
            node.setPos(-2,-2,2)
            node.lookAt(render)

            render.setLight(node)
            render.setShaderAuto()

            self.open = True
            while self.open:
                  print "updating..."
                  taskMgr.step()

Engine()

[rdb (rdb)]

Problem is that the shader generator calls GraphicsEngine::make_output on the draw thread even though it's only supposed to be called on the app thread.

[rdb (rdb)]

I'm afraid there may not be an easy way to solve this problem right now. However, I have plans to change the architecture of buffers so that they can live in the scene graph; that would alleviate the need for them to be registered with the GraphicsEngine.

A terrible, terrible hack around this problem would be to set the threading model only after a few frames of rendering, after the shadow buffers have been created.

[rdb (rdb)]

Fixed in https://github.com/panda3d/panda3d/commit/7ee9467f8da4211b82e9f40dd194f8204271cf78

See corresponding issue in GitHub: https://github.com/panda3d/panda3d/issues/162