Make a new scene graph.

Scripting Issues
1

On the road to grokking cameras, I am trying to make a fresh SG, attach a Camera and see a box. Could anyone help repair the code below, which just shows nothing at all right now. I guess there’s some voodoo I need to make ‘render2’ an actual visible SG.

import direct.directbase.DirectStart
from pandac.PandaModules import *

camNode = Camera('cam')
camNP = NodePath(camNode)

render2 = NodePath('render2')
camNP.reparentTo(render2)
camNP.setPos(0,-10,2)

box = loader.loadModel('box.egg')
box.reparentTo(render2)
box.setPos(0,0,0)

camNP.lookAt(box)

box.place()
run()

\d

2

Python is not my thing, but I think this is what going on:

You are loading the box, wich will be placed in its local space ( I guess centered in your model )
Then you reparent it to the camera node.

So in ‘world’ space, the box is now at 0,-10,2 wich is the position of your camera.
So the camera must be inside the box, and it will be fairly hard for the camera to look at its own position :wink:

Try this: (parent the box after positioning)

box = loader.loadModel(‘box.egg’)
box.setPos(0,0,0)
box.reparentTo(render2)

3

First of all, you need to tell the Camera what it should render. Do:

camNode.setScene(render2d)

Secondly, you need to tell the Camera where it should render into. A buffer, a window, or a part of the window, …?
So, you need to create a DisplayRegion by calling makeMonoDisplayRegion() on the buffer or window. Then call setCamera and pass it your camera NodePath.

Or you could just attach an existing display region to the camera.

4

Thanks rdb. I will stick to ‘render’ for now. I was only looking for an example of making a new Camera() for use in the diagrams. I got it working now.

\d

5

For the record, note that camNode.setScene() is no longer the preferred way to tell a camera what it should be rendering. The preferred way is simply the parent the camera into the scene graph you desire.

But, yeah, a camera requires a DisplayRegion in order to render anything. It’s really the DisplayRegion that’s doing the rendering; the camera just sets up the view properties for the DisplayRegion.

David