For the fun, a Photos cube

abcabc

Nice. The following two lines could be added after cubenode definition if someone wants to animate the cube. (Also need to include SCNAction in the list defined after load_framework)

rotate_action = SCNAction.repeatActionForever_(SCNAction.rotateByX_y_z_duration_(0, math.pi*2, math.pi*2, 10))
cube_node.runAction_(rotate_action)

cvp

Thanks

I still try to define a shape like a tetrahedron (4 triangular faces) using SCNGeometrySource but I've problems with array of vertices.
I try to convert this code in Pythonista, I'm sure @JonB could do it in two minutes and I'm fighting against errors for hours.
My dream is to be able, one day in a very far future, to help JonB in something 🙄

SCNVector3 verts[] = { SCNVector3Make(0, 0, 0), SCNVector3Make(1, 0, 0), SCNVector3Make(0, 1, 0) };
SCNGeometrySource *src = [SCNGeometrySource geometrySourceWithVertices:verts count:3];
int indexes[] = { 0, 1, 2 };
NSData *datIndexes = [NSData dataWithBytes:indexes length:sizeof(indexes)];
SCNGeometryElement *ele = [SCNGeometryElement geometryElementWithData:datIndexes primitiveType:SCNGeometryPrimitiveTypeTriangles primitiveCount:1 bytesPerIndex:sizeof(int)];
SCNGeometry *geo = [SCNGeometry geometryWithSources:@[src] elements:@[ele]];

scj643

I actually need people to help make an API for scenekit so we can do this type of stuff with a python AI

cvp

I would like to help but I think I know not enough objective c for that...
When I program in objc, I spend hours before it works.

scj643

https://github.com/scj643/objc_tools is my repo

cvp

I know your repo, often checked...

momorprods

hey, digging out this old topic - did you have chance into the triangle mesh generation?

I have started converting the Obj-c snippet above, but it crashes Pythonista at the geometrySourceWithVertices call. Probably my bad, but I’m clueless about how to fiw this:

verts=[SCNVector3(0, 0, 0), SCNVector3(1, 0, 0), SCNVector3(0, 1, 0)]

src = SCNGeometrySource.geometrySourceWithVertices_count_(POINTER(verts),3)

cvp

@momorprods No, sorry, I didn't success...

JonB

It wouldn't be POINTER here. Try byref.

JonB

Actually, verts must be a ctypes array, not a python list.

momorprods

oh ok thanks, going to try that and keep you posted!

momorprods

Made this, but still crashing. Am I making another noob mistake?

verts=[0.0,0.0,0.0 , 1.0,0.0,0.0 , 0.0,1.0,0.0]
arr = (ctypes.c_float * len(verts))(*verts)
src = SCNGeometrySource.geometrySourceWithVertices_count_(byref(arr),3)

cvp

@momorprods Perhaps this (at least, no crash 😀)

class SCNVector3(Structure):
	_fields_ = [('x', c_double), ('y', c_double), ('z', c_double)]

And

    verts=[SCNVector3(0, 0, 0), SCNVector3(1, 0, 0), SCNVector3(0, 1, 0)]
    verts_array = (SCNVector3 * len(verts))(*verts)
    SCNGeometrySource = ObjCClass('SCNGeometrySource').geometrySourceWithVertices_count_(
    verts_array,len(verts),
    restype=c_void_p,
    argtypes=[POINTER(SCNVector3), c_ulong],)

momorprods

wooohoooo thanks!!

momorprods

Making some good progress thanks to your help. But I’m getting a last crash on the very last instruction - any idea?

#triangle generation
verts=[SCNVector3(0, 0, 0), SCNVector3(1, 0, 0), SCNVector3(0, 1, 0)]
verts_array = (SCNVector3 * len(verts))(*verts)

src = ObjCClass('SCNGeometrySource').geometrySourceWithVertices_count_(
    verts_array,len(verts),
    restype=c_void_p,
    argtypes=[POINTER(SCNVector3), c_ulong],)
    
indexes=[0,1,2]
indexes_array = (c_ulong*len(indexes))(*indexes)
datIndexes = ObjCClass('NSData').dataWithBytes_length_(indexes_array,len(indexes_array))
 
ele=ObjCClass('SCNGeometryElement').geometryElementWithData_primitiveType_primitiveCount_bytesPerIndex_(datIndexes,SCNGeometryPrimitiveTypeTriangles,1,4)
   
# CRASH Here: 
geo = ObjCClass('SCNGeometry').geometryWithSources_elements_(src,ele)

cvp

@momorprods I've read that indices must contain a first element with the number of points but I don't know if it is true.
sources and elements must be arrays
But I have also a crash with my code
See faultlog below but I can't solve the problem, sorry

    verts = [SCNVector3(0, 0, 0), SCNVector3(1, 0, 0), SCNVector3(0, 1, 0)]
    verts_array = (SCNVector3 * len(verts))(*verts)
    SCNGeometrySource = ObjCClass('SCNGeometrySource').geometrySourceWithVertices_count_(
    verts_array,len(verts),
    restype=c_void_p,
    argtypes=[POINTER(SCNVector3), c_ulong],)
    sources = NSArray([SCNGeometrySource])
    
    indices = [3,0,1,2]	# number points and their indices
    indices_data = ns(indices)
    # primitiveType = 0 for triangle
    # primitiveCount = 1
    SCNGeometryElement = ObjCClass('SCNGeometryElement').geometryElementWithData_primitiveType_primitiveCount_bytesPerIndex_(indices_data,0,1,4)
    elements = NSArray([SCNGeometryElement])
    
    geometry = ObjCClass('SCNGeometry').geometryWithSources_elements_(sources, elements)

Fatal Python error: Aborted

Current thread 0x0000000100d62b80 (most recent call first):
File "/var/containers/Bundle/Application/E4751F4F-64A4-4BE6-AB9D-9C9564715002/Pythonista3.app/Frameworks/Py3Kit.framework/pylib/site-packages/objc_util.py", line 773 in call
File "/private/var/mobile/Containers/Shared/AppGroup/668A7D98-7216-47ED-917D-AA0B6173167E/Pythonista3/Documents/test6.py", line 51 in demo
File "/var/containers/Bundle/Application/E4751F4F-64A4-4BE6-AB9D-9C9564715002/Pythonista3.app/Frameworks/Py3Kit.framework/pylib/site-packages/objc_util.py", line 1066 in OMMainThreadDispatcher_invoke_imp

Thread 0x000000016fa5f000 (most recent call first):
File "/var/containers/Bundle/Application/E4751F4F-64A4-4BE6-AB9D-9C9564715002/Pythonista3.app/Frameworks/Py3Kit.framework/pylib/site-packages/objc_util.py", line 898 in call
File "/var/containers/Bundle/Application/E4751F4F-64A4-4BE6-AB9D-9C9564715002/Pythonista3.app/Frameworks/Py3Kit.framework/pylib/site-packages/objc_util.py", line 1095 in new_func
File "/private/var/mobile/Containers/Shared/AppGroup/668A7D98-7216-47ED-917D-AA0B6173167E/Pythonista3/Documents/test6.py", line 76 in <module>

Objective-C exception details:

NSInvalidArgumentException: -[SCNGeometrySource count]: unrecognized selector sent to instance 0x283276100

JonB

this works

from ctypes import *
from objc_util import *

class SCNVector3(Structure):
    _fields_ = [('x', c_double), ('y', c_double), ('z', c_double)]

verts=[SCNVector3(0, 0, 0), SCNVector3(1, 0, 0), SCNVector3(0, 1, 0)]

SCNVector3Array3=SCNVector3 * len(verts)
verts_array=SCNVector3Array3(*verts)
SCNGeometrySource = ObjCClass('SCNGeometrySource')

s=SCNGeometrySource.geometrySourceWithVertices_count_(byref(verts_array),len(verts),restype=c_void_p,argtypes=[POINTER(SCNVector3Array3), c_ulong],)

cvp

@JonB Yes, but in my code,,the crash was in

    geometry = ObjCClass('SCNGeometry').geometryWithSources_elements_(sources, elements)

cvp

@momorprods @JonB No crash with

    verts = [SCNVector3(0, 0, 0), SCNVector3(1, 0, 0), SCNVector3(0, 1, 0)]     
    SCNVector3Array3=SCNVector3 * len(verts)
    verts_array=SCNVector3Array3(*verts)
    SCNGeometrySource = ObjCClass('SCNGeometrySource')
    s = SCNGeometrySource.geometrySourceWithVertices_count_(byref(verts_array),len(verts),restype=c_void_p,argtypes=[POINTER(SCNVector3Array3), c_ulong],)
   
    indexes=[0,1,2]
    indexes_array = (c_ulong*len(indexes))(*indexes)
    datIndexes = ObjCClass('NSData').dataWithBytes_length_(indexes_array,len(indexes_array))
    # primitiveType = 0 for triangle
    # primitiveCount = 1  
    e = ObjCClass('SCNGeometryElement').geometryElementWithData_primitiveType_primitiveCount_bytesPerIndex_(datIndexes,0,1,4)
    
    geometry = ObjCClass('SCNGeometry').geometryWithSources_elements_([s],[e])
	```

Edit: but nothing visible

cvp

@momorprods I'm not sure if you should take in account the length of c_ulong
Just an idea, rally not sure.
Anyway, Scene stays blank 😢

    #indexes=[0,1,2]
    indexes = [c_ulong(0),c_ulong(1),c_ulong(2)]
    indexes_array = (c_ulong*len(indexes))(*indexes)
    #datIndexes = ObjCClass('NSData').dataWithBytes_length_(indexes_array, len(indexes_array))
    datIndexes = ObjCClass('NSData').dataWithBytes_length_(indexes_array, len(indexes_array)*sizeof(c_ulong))
    # primitiveType = 0 for triangle
    # primitiveCount = 1  
    #e = ObjCClass('SCNGeometryElement').geometryElementWithData_primitiveType_primitiveCount_bytesPerIndex_(datIndexes,0,1,4)
    e = ObjCClass('SCNGeometryElement').geometryElementWithData_primitiveType_primitiveCount_bytesPerIndex_(datIndexes,0,1,sizeof(c_ulong))