added collada_factory.py

Author: Roberto De Ioris

tutorials/WritingAColladaFactoryWithPython_Assets/collada_factory.py

@@ -0,0 +1,142 @@
+from unreal_engine.classes import PyFactory, StaticMesh, Object, Class
+
+import unreal_engine as ue
+
+from collada import Collada
+
+from unreal_engine.structs import StaticMeshSourceModel, MeshBuildSettings
+from unreal_engine import FRawMesh
+import numpy
+
+from unreal_engine import FVector, FRotator
+from unreal_engine import SWindow, SVerticalBox, SHorizontalBox, SButton, SRotatorInputBox
+from unreal_engine.enums import EHorizontalAlignment
+
+from unreal_engine.classes import Material
+from unreal_engine.structs import Rotator, StaticMaterial
+
+class ColladaImportOptions(Object):
+
+    DefaultRotation = Rotator
+    DefaultMaterial = Material
+
+class ColladaFactory(PyFactory):
+
+    ImportOptions = ColladaImportOptions()
+
+    def __init__(self):
+        # inform the editor that this class is able to import assets
+        self.bEditorImport = True
+        # register the .dae extension as supported
+        self.Formats = ['dae;Collada']
+        # set the UClass this UFactory will generate
+        self.SupportedClass = StaticMesh
+        ue.log(dir(self))
+
+    
+    def open_collada_wizard(self):
+
+        def cancel_import():
+            self.wizard.request_destroy()
+
+        def confirm_import():
+            self.do_import = True
+            self.wizard.request_destroy()
+
+        self.wizard = SWindow(title='Collada Import Options', modal=True, sizing_rule=1)(
+                          SVerticalBox()
+                          (
+                              ue.create_detail_view(self.ImportOptions),
+                              auto_height=True,
+                              padding = 10
+                          )
+                          (
+                              SHorizontalBox()
+                              (
+                                  SButton(text='Cancel', on_clicked=cancel_import, h_align = EHorizontalAlignment.HAlign_Center)
+                              )
+                              (
+                                  SButton(text='Import', on_clicked=confirm_import, h_align = EHorizontalAlignment.HAlign_Center)
+                              ),
+                              auto_height=True,
+                              padding = 4,
+                          ),
+                          
+                      )
+        self.wizard.add_modal()
+
+
+    # this functions starts with an uppercase letter, so it will be visible to the UE system
+    # not required obviously, but it will be a good example
+    def FixMeshData(self):
+        # move from collada system (y on top) to ue4 one (z on top, forward decreases over viewer)
+        for i in range(0, len(self.vertices), 3):
+           xv, yv, zv = self.vertices[i], self.vertices[i+1], self.vertices[i+2]
+           # invert forward
+           vec = FVector(zv * -1, xv, yv) * self.ImportOptions.DefaultRotation
+           self.vertices[i] = vec.x
+           self.vertices[i+1] = vec.y
+           self.vertices[i+2] = vec.z
+           xn, yn, zn = self.normals[i], self.normals[i+1], self.normals[i+2]
+           nor = FVector(zn * -1, xn, yn) * self.ImportOptions.DefaultRotation
+           # invert forward
+           self.normals[i] = nor.x
+           self.normals[i+1] = nor.y
+           self.normals[i+2] = nor.z
+        
+        # fix uvs from 0 on bottom to 0 on top
+        for i, uv in enumerate(self.uvs):
+            if i % 2 != 0:
+                self.uvs[i] = 1 - uv
+
+    def PyFactoryCreateFile(self, uclass: Class, parent: Object, name: str, filename: str) -> Object:
+        # load the collada file
+        dae = Collada(filename)
+        ue.log_warning(dae)
+
+        self.do_import = False
+        self.open_collada_wizard()
+
+        if not self.do_import:
+            return None
+
+
+        # create a new UStaticMesh with the specified name and parent
+        static_mesh = StaticMesh(name, parent)
+
+        # prepare a new model with the specified build settings
+        source_model = StaticMeshSourceModel(BuildSettings=MeshBuildSettings(bRecomputeNormals=False, bRecomputeTangents=True, bUseMikkTSpace=True, bBuildAdjacencyBuffer=True, bRemoveDegenerates=True))
+
+        # extract vertices, uvs and normals from the da file (numpy.ravel will flatten the arrays to simple array of floats)
+        triset = dae.geometries[0].primitives[0]
+        self.vertices = numpy.ravel(triset.vertex[triset.vertex_index])
+        # take the first uv channel (there could be multiple channels, like the one for lightmapping)
+        self.uvs = numpy.ravel(triset.texcoordset[0][triset.texcoord_indexset[0]])
+        self.normals = numpy.ravel(triset.normal[triset.normal_index])
+
+        # fix mesh data
+        self.FixMeshData()
+        
+        # create a new mesh, FRawMesh is an ptopmized wrapper exposed by the python plugin. read: no reflection involved
+        mesh = FRawMesh()
+        # assign vertices
+        mesh.set_vertex_positions(self.vertices)
+        # uvs are required
+        mesh.set_wedge_tex_coords(self.uvs)
+        # normals are optionals
+        mesh.set_wedge_tangent_z(self.normals)
+        
+        # assign indices (not optimized, just return the list of triangles * 3...)
+        mesh.set_wedge_indices(numpy.arange(0, len(triset) * 3))
+
+        # assign the FRawMesh to the LOD0 (the model we created before)
+        mesh.save_to_static_mesh_source_model(source_model)
+
+        # assign LOD0 to the SataticMesh and build it
+        static_mesh.SourceModels = [source_model]
+        static_mesh.static_mesh_build()
+        static_mesh.static_mesh_create_body_setup()
+
+        static_mesh.StaticMaterials = [StaticMaterial(MaterialInterface=self.ImportOptions.DefaultMaterial, MaterialSlotName='Main')]
+
+        return static_mesh