Tells the delegate that the renderer has cleared the viewport and is about to render the scene.
- iOS 8.0+
- macOS 10.8+
- tvOS 9.0+
- watchOS 3.0+
The SceneKit object responsible for rendering the scene. Examine this object’s
contextproperty if you need to reference the OpenGL context that your custom rendering code draws into.
SCNSceneobject to be rendered.
The current system time, in seconds. If your custom rendering involves animation, use this parameter to compute your own animation state.
Implement this method to perform custom drawing before SceneKit renders a scene—for example, to draw backdrop content underneath SceneKit content. You should only execute Metal or OpenGL drawing commands (and any setup required to perform them) in this method—the results of modifying SceneKit objects during this method are undefined.
To render using Metal, use the
rendererparameter to retrieve the scene renderer’s
currentobject and encode your own drawing commands. If you need to reference other Metal state, see the properties listed in
Render Command Encoder
To render using OpenGL, simply call the relevant OpenGL drawing commands—SceneKit automatically makes its OpenGL context the current context before calling this method. If you need to reference the OpenGL context being rendered into, examine the
contextproperty of the
You must draw using the appropriate graphics technology for the view currently being rendered. Use the
rendering property of the
renderer object to determine whether Metal or OpenGL is in use.