omz:forum

    • Register
    • Login
    • Search
    • Recent
    • Popular

    Welcome!

    This is the community forum for my apps Pythonista and Editorial.

    For individual support questions, you can also send an email. If you have a very short question or just want to say hello — I'm @olemoritz on Twitter.


    3D in Pythonista?

    Pythonista
    12
    16
    19141
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • omz
      omz last edited by omz

      If you want to play with SceneKit, here's a starting point (requires beta #160023):

      Screenshot

      Note: You can use gestures (pan/pinch) to control the camera.

      from objc_util import *
      import ui
      import math
      
      load_framework('SceneKit')
      SCNView, SCNScene, SCNBox, SCNText, SCNNode, SCNLight, SCNAction, UIFont = map(ObjCClass, ['SCNView', 'SCNScene', 'SCNBox', 'SCNText', 'SCNNode', 'SCNLight', 'SCNAction', 'UIFont'])
      
      class SCNVector3 (Structure):
      	_fields_ = [('x', c_float), ('y', c_float), ('z', c_float)]
      
      @on_main_thread
      def demo():
      	main_view = ui.View()
      	main_view_objc = ObjCInstance(main_view)
      	scene_view = SCNView.alloc().initWithFrame_options_(((0, 0),(400, 400)), None).autorelease()
      	scene_view.setAutoresizingMask_(18)
      	scene_view.setAllowsCameraControl_(True)
      	scene = SCNScene.scene()
      	root_node = scene.rootNode()
      	text_mesh = SCNText.textWithString_extrusionDepth_('Pythonista', 6.0)
      	text_mesh.setFlatness_(0.2)
      	text_mesh.setChamferRadius_(0.4)
      	text_mesh.setFont_(UIFont.fontWithName_size_('HelveticaNeue-Bold', 18))
      	bbox_min, bbox_max = SCNVector3(), SCNVector3()
      	text_mesh.getBoundingBoxMin_max_(byref(bbox_min), byref(bbox_max), restype=None, argtypes=[POINTER(SCNVector3), POINTER(SCNVector3)])
      	text_width = bbox_max.x - bbox_min.x
      	text_node = SCNNode.nodeWithGeometry_(text_mesh)
      	text_node.setCastsShadow_(True)
      	text_container = SCNNode.node()
      	text_container.addChildNode_(text_node)
      	text_container.setPosition_((0, 40, 0))
      	text_node.setPosition_((-text_width/2, 0, 0))
      	box = SCNBox.boxWithWidth_height_length_chamferRadius_(100, 4, 100, 1)
      	box_node = SCNNode.nodeWithGeometry_(box)
      	root_node.addChildNode_(box_node)
      	rotate_action = SCNAction.repeatActionForever_(SCNAction.rotateByX_y_z_duration_(0, math.pi*2, math.pi*2, 10))
      	text_container.runAction_(rotate_action)
      	root_node.addChildNode_(text_container)
      	light_node = SCNNode.node()
      	light_node.setPosition_((0, 100, 10))
      	light_node.setRotation_((1, 0, 0, -math.pi/2))
      	light = SCNLight.light()
      	light.setType_('spot')
      	light.setCastsShadow_(True)
      	light.setColor_(UIColor.cyanColor().CGColor())
      	light_node.setLight_(light)
      	root_node.addChildNode_(light_node)
      	scene_view.setScene_(scene)
      	main_view_objc.addSubview_(scene_view)
      	main_view.name = 'SceneKit Demo'
      	main_view.present()
      
      demo()
      
      1 Reply Last reply Reply Quote 0
      • Utsira
        Utsira last edited by

        Apologies for bumping a 2-year-old thread. When I try to run the above script in Python 3.5 I get an error at the map command saying:

        no Objective-C class named 'b'SCNView'' found

        Is this some 2.7 -> 3.5 issue? What is the extraneous 'b in the error message referring to?

        thanks in advance.

        1 Reply Last reply Reply Quote 0
        • ccc
          ccc last edited by

          The b'bytes string' is https://docs.python.org/3/reference/lexical_analysis.html#grammar-token-bytesprefix

          SCNView is https://developer.apple.com/reference/scenekit/scnview

          But I know nothing more.

          1 Reply Last reply Reply Quote 0
          • omz
            omz last edited by

            Try adding load_framework('SceneKit') before the line with the error.

            1 Reply Last reply Reply Quote 1
            • abcabc
              abcabc last edited by abcabc

              Thanks Omz . I tried also the basic code from following tutorial using your template and it is working fine.
              https://code.tutsplus.com/tutorials/an-introduction-to-scenekit-fundamentals--cms-23847

              from objc_util import *
              import ui
              import math
              
              load_framework('SceneKit')
              
              SCNView, SCNScene, SCNBox, SCNText, SCNNode, SCNLight, SCNCamera, SCNAction, UIFont = map(ObjCClass, ['SCNView', 'SCNScene', 'SCNBox', 'SCNText', 'SCNNode', 'SCNLight',  'SCNCamera', 'SCNAction', 'UIFont'])
              
              class SCNVector3 (Structure):
                  _fields_ = [('x', c_float), ('y', c_float), ('z', c_float)]
                  
              '''
              https://code.tutsplus.com/tutorials/an-introduction-to-scenekit-fundamentals--cms-23847
              '''
              '''
              override func viewDidLoad() {
                  super.viewDidLoad()
                   
                  let sceneView = SCNView(frame: self.view.frame)
                  self.view.addSubview(sceneView)
                       
                  let scene = SCNScene()
                  sceneView.scene = scene
               
                  let camera = SCNCamera()
                  let cameraNode = SCNNode()
                  cameraNode.camera = camera
                  cameraNode.position = SCNVector3(x: 0.0, y: 0.0, z: 3.0)
               
                  let light = SCNLight()
                  light.type = SCNLightTypeOmni
                  let lightNode = SCNNode()
                  lightNode.light = light
                  lightNode.position = SCNVector3(x: 1.5, y: 1.5, z: 1.5)
               
                  let cubeGeometry = SCNBox(width: 1.0, height: 1.0, length: 1.0, chamferRadius: 0.0)
                  let cubeNode = SCNNode(geometry: cubeGeometry)
               
                  scene.rootNode.addChildNode(lightNode)
                  scene.rootNode.addChildNode(cameraNode)
                  scene.rootNode.addChildNode(cubeNode)
              }
              '''
              
              @on_main_thread
              def demo():
                  main_view = ui.View()
                  main_view_objc = ObjCInstance(main_view)
                  scene_view = SCNView.alloc().initWithFrame_options_(((0, 0),(400, 400)), None).autorelease()
                  scene_view.setAutoresizingMask_(18)
                  scene_view.setAllowsCameraControl_(True)
                  main_view_objc.addSubview_(scene_view)
                  main_view.name = 'SceneKit Demo'
                  
                  scene = SCNScene.scene()
                  scene_view.setScene_(scene)
                  
                  root_node = scene.rootNode()
                  
                  camera = SCNCamera.camera()
                  camera_node = SCNNode.node()
                  camera_node.setCamera(camera)
                  camera_node.setPosition((0.0, 0.0, 3.0))
              
                  light = SCNLight.light()
                  light.setType_('omni')
                  light_node = SCNNode.node()
                  light_node.setLight_(light)
                  light_node.setPosition((1.5, 1.5, 1.5))
                  
                  cube_geometry = SCNBox.boxWithWidth_height_length_chamferRadius_(1, 1, 1, 0)
                  cube_node = SCNNode.nodeWithGeometry_(cube_geometry)
                  
                  root_node.addChildNode_(light_node)
                  root_node.addChildNode_(camera_node)        
                  root_node.addChildNode_(cube_node)
                  
                  main_view.present()
              
              demo()
              
              
              
              

              Full example here
              https://gist.github.com/balachandrana/644840a223b636ecd84d14a595dad33b

              1 Reply Last reply Reply Quote 0
              • Utsira
                Utsira last edited by

                @omz thanks, it works now, that's awesome. I've used SceneKit quite a lot with Swift, but I'm still new to Python/ Pythonista. One question, how come you implement SCNVector3 as a Python class, rather than importing it with the other ObjC classes? Just trying to understand the implications of working with ObjC libraries in Pythonista. thanks.

                1 Reply Last reply Reply Quote 0
                • dgelessus
                  dgelessus last edited by

                  SCNVector3 is a C struct, not an Objective-C class. Objective-C classes carry lots of information at runtime (their name, superclass, protocols, methods, etc.), and all Objective-C objects contain a pointer to their class. All of this information can be looked up via APIs provided by the Objective-C runtime library. That's what makes objc_util possible.

                  C structs, on the other hand, carry no runtime info at all. If you look at some struct data, you cannot see what its type is. For all you know, it might not even be a struct. It could also be an int, or an array of bytes. There is also no way to see what struct types there are, or what fields a certain struct type has.

                  So to be able to work with struct data, you first need to describe its type. In ctypes, you do that by creating a subclass of the ctypes.Structure class. Your subclass's _fields_ attribute lists the name and type of every field in the struct. Once you've done that, you can allocate instances of your struct in memory, and you can tell ctypes that a function takes or returns struct data of that type.

                  In this specific case, I don't think the declaration of SCNVector3 is actually needed. In the above code, you can see that all places where a SCNVector3 would be used in Swift, the Python/objc_util version simply uses a tuple. This is only possible because Objective-C is involved. All Objective-C methods have a type signature, which describes the types of their return value and all arguments, including structs. This allows objc_util to get some basic info about a method's struct arguments, which is enough to convert a Python tuple into correctly formated C struct data. This only works with Objective-C method arguments though, and not anywhere else. For plain C functions and variables, you still need to declare the struct type by hand.

                  1 Reply Last reply Reply Quote 1
                  • Utsira
                    Utsira last edited by

                    Thank you for your answer @dgelessus , really interesting.

                    1 Reply Last reply Reply Quote 0
                    • bcraig_6973
                      bcraig_6973 @JadedTuna last edited by

                      @JadedTuna
                      I am new to this
                      Have you got a better Handel on how to do this
                      All I want to do is just using 3 Python learn to how create a 2d flat grid in 3d space
                      What are the step by steps to do this kind of thing ?

                      1 Reply Last reply Reply Quote 0
                      • Brun0oO
                        Brun0oO last edited by Brun0oO

                        Hi,

                        I got, from a swift project, some SceneKit assets (files with ‘.scn’ extension). I put them in a ###.scnassets directory and try to load them using the SCNScene.sceneNamed_ method.
                        This call fails, i got None as result.
                        Do you know if I need to make a kind of initialization for the SceneKit resources mechanism ?

                        Thanks for your help...

                        1 Reply Last reply Reply Quote 0
                        • First post
                          Last post
                        Powered by NodeBB Forums | Contributors