Merge initial a3d export support

Initial a3d export support

io_scene_a3d/A3D.py

@@ -20,7 +20,9 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 '''
 
-from .IOTools import unpackStream, readNullTerminatedString, calculatePadding
+from io import BytesIO
+
+from .IOTools import unpackStream, packStream, readNullTerminatedString, calculatePadding
 from . import A3DObjects
 
 '''
@@ -65,6 +67,23 @@ class A3D:
             self.readRootBlock2(stream)
         elif self.version == 3:
             self.readRootBlock3(stream)
+        else:
+            raise RuntimeError(f"Unknown A3D version: {self.version}")
+
+    def write(self, stream, version=2):
+        # Write header data
+        stream.write(A3D_SIGNATURE)
+        packStream("<2H", stream, version, 0)
+        
+        # Write root block
+        if version == 1:
+            self.writeRootBlock1(stream)
+        elif version == 2:
+            self.writeRootBlock2(stream)
+        elif version == 3:
+            self.writeRootBlock3(stream)
+        else:
+            raise RuntimeError(f"Unknown A3D version: {version} whilst writing A3D")
 
     '''
     Root data blocks
@@ -72,6 +91,9 @@ class A3D:
     def readRootBlock1(self, stream):
         raise RuntimeError("Version 1 files are not supported yet")
 
+    def writeRootBlock1(self, stream):
+        raise RuntimeError("Version 1 files are not supported yet")
+
     def readRootBlock2(self, stream):
         # Verify signature
         signature, _ = unpackStream("<2I", stream)
@@ -85,6 +107,21 @@ class A3D:
         self.readTransformBlock2(stream)
         self.readObjectBlock2(stream)
 
+    def writeRootBlock2(self, stream):
+        buffer = BytesIO()
+
+        # Write data to the buffer
+        print("Writing root block")
+        self.writeMaterialBlock2(buffer)
+        self.writeMeshBlock2(buffer)
+        self.writeTransformBlock2(buffer)
+        self.writeObjectBlock2(buffer)
+
+        # Write buffer to stream
+        packStream("<2I", stream, A3D_ROOTBLOCK_SIGNATURE, buffer.tell())
+        buffer.seek(0, 0)
+        stream.write(buffer.read())
+
     def readRootBlock3(self, stream):
         # Verify signature
         signature, length = unpackStream("<2I", stream)
@@ -101,6 +138,21 @@ class A3D:
         padding = calculatePadding(length)
         stream.read(padding)
 
+    def writeRootBlock3(self, stream):
+        buffer = BytesIO()
+
+        # Write data to the buffer
+        print("Writing root block")
+        self.writeMaterialBlock3(buffer)
+        self.writeMeshBlock3(buffer)
+        self.writeTransformBlock3(buffer)
+        self.writeObjectBlock3(buffer)
+
+        # Write buffer to stream
+        packStream("<2I", stream, A3D_ROOTBLOCK_SIGNATURE, buffer.tell())
+        buffer.seek(0, 0)
+        stream.write(buffer.read())
+
     '''
     Material data blocks
     '''
@@ -117,6 +169,20 @@ class A3D:
             material.read2(stream)
             self.materials.append(material)
     
+    def writeMaterialBlock2(self, stream):
+        buffer = BytesIO()
+
+        # Write data to the buffer
+        print("Writing material block")
+        packStream("<I", buffer, len(self.materials))
+        for material in self.materials:
+            material.write2(buffer)
+
+        # Write buffer to stream
+        packStream("<2I", stream, A3D_MATERIALBLOCK_SIGNATURE, buffer.tell())
+        buffer.seek(0, 0)
+        stream.write(buffer.read()) 
+    
     def readMaterialBlock3(self, stream):
         # Verify signature
         signature, length, materialCount = unpackStream("<3I", stream)
@@ -134,6 +200,24 @@ class A3D:
         padding = calculatePadding(length)
         stream.read(padding)
 
+    def writeMaterialBlock3(self, stream):
+        buffer = BytesIO()
+
+        # Write data to the buffer
+        print("Writing material block")
+        packStream("<I", buffer, len(self.materials))
+        for material in self.materials:
+            material.write3(buffer)
+
+        # Write buffer to stream
+        packStream("<2I", stream, A3D_MATERIALBLOCK_SIGNATURE, buffer.tell())
+        buffer.seek(0, 0)
+        stream.write(buffer.read())
+
+        # Padding
+        paddingSize = calculatePadding(buffer.tell())
+        stream.write(b"\x00" * paddingSize)
+
     '''
     Mesh data blocks
     '''
@@ -150,6 +234,20 @@ class A3D:
             mesh.read2(stream)
             self.meshes.append(mesh)
 
+    def writeMeshBlock2(self, stream):
+        buffer = BytesIO()
+
+        # Write data to the buffer
+        print("Writing mesh block")
+        packStream("<I", buffer, len(self.meshes))
+        for mesh in self.meshes:
+            mesh.write2(buffer)
+
+        # Write buffer to stream
+        packStream("<2I", stream, A3D_MESHBLOCK_SIGNATURE, buffer.tell())
+        buffer.seek(0, 0)
+        stream.write(buffer.read())
+
     def readMeshBlock3(self, stream):
         # Verify signature
         signature, length, meshCount = unpackStream("<3I", stream)
@@ -167,6 +265,24 @@ class A3D:
         padding = calculatePadding(length)
         stream.read(padding)
 
+    def writeMeshBlock3(self, stream):
+        buffer = BytesIO()
+
+        # Write data to the buffer
+        print("Writing mesh block")
+        packStream("<I", buffer, len(self.meshes))
+        for mesh in self.meshes:
+            mesh.write3(buffer)
+
+        # Write buffer to stream
+        packStream("<2I", stream, A3D_MESHBLOCK_SIGNATURE, buffer.tell())
+        buffer.seek(0, 0)
+        stream.write(buffer.read())
+
+        # Padding
+        paddingSize = calculatePadding(buffer.tell())
+        stream.write(b"\x00" * paddingSize)
+
     '''
     Transform data blocks
     '''
@@ -187,6 +303,22 @@ class A3D:
             parentID, = unpackStream("<i", stream)
             self.transformParentIDs.append(parentID)
 
+    def writeTransformBlock2(self, stream):
+        buffer = BytesIO()
+
+        # Write data to the buffer
+        print("Writing transform block")
+        packStream("<I", buffer, len(self.transforms))
+        for transform in self.transforms:
+            transform.write2(buffer)
+        for parentID in self.transformParentIDs:
+            packStream("<i", buffer, parentID)
+
+        # Write buffer to stream
+        packStream("<2I", stream, A3D_TRANSFORMBLOCK_SIGNATURE, buffer.tell())
+        buffer.seek(0, 0)
+        stream.write(buffer.read())
+
     def readTransformBlock3(self, stream):
         # Verify signature
         signature, length, transformCount = unpackStream("<3I", stream)
@@ -195,7 +327,6 @@ class A3D:
 
         # Read data
         print(f"Reading transform block with {transformCount} transforms and length {length}")
-        transforms = []
         for _ in range(transformCount):
             transform = A3DObjects.A3DTransform()
             transform.read3(stream)
@@ -209,6 +340,26 @@ class A3D:
         padding = calculatePadding(length)
         stream.read(padding)
 
+    def writeTransformBlock3(self, stream):
+        buffer = BytesIO()
+
+        # Write data to the buffer
+        print("Writing transform block")
+        packStream("<I", buffer, len(self.transforms))
+        for transform in self.transforms:
+            transform.write3(buffer)
+        for parentID in self.transformParentIDs:
+            packStream("<i", buffer, parentID)
+
+        # Write buffer to stream
+        packStream("<2I", stream, A3D_TRANSFORMBLOCK_SIGNATURE, buffer.tell())
+        buffer.seek(0, 0)
+        stream.write(buffer.read())
+
+        # Padding
+        paddingSize = calculatePadding(buffer.tell())
+        stream.write(b"\x00" * paddingSize)
+
     '''
     Object data blocks
     '''
@@ -225,6 +376,20 @@ class A3D:
             objec.read2(stream)
             self.objects.append(objec)
 
+    def writeObjectBlock2(self, stream):
+        buffer = BytesIO()
+
+        # Write data to the buffer
+        print("Writing object block")
+        packStream("<I", buffer, len(self.objects))
+        for objec in self.objects:
+            objec.write2(buffer)
+
+        # Write buffer to stream
+        packStream("<2I", stream, A3D_OBJECTBLOCK_SIGNATURE, buffer.tell())
+        buffer.seek(0, 0)
+        stream.write(buffer.read())
+
     def readObjectBlock3(self, stream):
         # Verify signature
         signature, length, objectCount = unpackStream("<3I", stream)
@@ -241,3 +406,21 @@ class A3D:
         # Padding
         padding = calculatePadding(length)
         stream.read(padding)
+
+    def writeObjectBlock3(self, stream):
+        buffer = BytesIO()
+
+        # Write data to the buffer
+        print("Writing object block")
+        packStream("<I", buffer, len(self.objects))
+        for objec in self.objects:
+            objec.write3(buffer)
+
+        # Write buffer to stream
+        packStream("<2I", stream, A3D_OBJECTBLOCK_SIGNATURE, buffer.tell())
+        buffer.seek(0, 0)
+        stream.write(buffer.read())
+
+        # Padding
+        paddingSize = calculatePadding(buffer.tell())
+        stream.write(b"\x00" * paddingSize)

io_scene_a3d/A3DBlenderExporter.py

@@ -0,0 +1,181 @@
+'''
+Copyright (c) 2025 Pyogenics <https://github.com/Pyogenics>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+'''
+
+from . import A3DObjects
+from .A3DObjects import (
+    A3D_VERTEXTYPE_COORDINATE,
+    A3D_VERTEXTYPE_UV1,
+    A3D_VERTEXTYPE_NORMAL1,
+    A3D_VERTEXTYPE_UV2,
+    A3D_VERTEXTYPE_COLOR,
+    A3D_VERTEXTYPE_NORMAL2
+)
+
+def mirrorUVY(uv):
+    x, y = uv
+    return (x, 1-y)
+
+class A3DBlenderExporter:
+    def __init__(self, modelData, objects, version=2):
+        self.modelData = modelData
+        self.objects = objects
+        self.version = version
+
+    def exportData(self):
+        print("Exporting blender data to A3D")
+
+        # Process objects
+        materials = {}
+        meshes = []
+        transforms = {}
+        objects = []
+        for ob in self.objects:
+            me = ob.data
+            if me == None:
+                # Create a transform for this object without the object itself
+                transform = A3DObjects.A3DTransform()
+                transform.position = ob.location
+                rotationW, rotationX, rotationY, rotationZ = ob.rotation_quaternion
+                transform.rotation = (rotationX, rotationY, rotationZ, rotationW)
+                transform.scale = ob.scale
+                transform.name = ob.name
+                transforms[ob.name] = transform
+                
+                continue
+
+            # Process materials
+            for ma in me.materials:
+                # Make sure we haven't processed this data block already
+                if ma.name in materials:
+                    continue
+
+                materialData = A3DObjects.A3DMaterial()
+                materialData.name = ma.name
+                materialData.diffuseMap = ""
+                colorR, colorG, colorB, _ = ma.diffuse_color
+                materialData.color = (colorR, colorG, colorB)
+
+                materials[ma.name] = materialData
+            # Create mesh
+            mesh = self.buildA3DMesh(me, ob)
+            meshes.append(mesh)
+            # Create transform
+            transform = A3DObjects.A3DTransform()
+            transform.position = ob.location
+            rotationW, rotationX, rotationY, rotationZ = ob.rotation_quaternion
+            transform.rotation = (rotationX, rotationY, rotationZ, rotationW)
+            transform.scale = ob.scale
+            transform.name = ob.name
+            transforms[ob.name] = transform
+            # Create object
+            objec = A3DObjects.A3DObject()
+            objec.name = ob.name
+            objec.meshID = len(meshes) - 1
+            objec.transformID = len(transforms) - 1
+            materialIDs = []
+            for ma in me.materials:
+                materialID = list(materials.keys()).index(ma.name)
+                materialIDs.append(materialID)
+            objec.materialCount = len(materialIDs)
+            objec.materialIDs = materialIDs
+            objects.append(objec)
+        # Create parentIDs
+        transformParentIDs = []
+        for ob in self.objects:
+            parentOB = ob.parent
+            if (parentOB == None) or (parentOB.name not in transforms):
+                if self.version < 3:
+                    transformParentIDs.append(0)
+                else:
+                    transformParentIDs.append(-1)
+            else:
+                parentIndex = list(transforms.keys()).index(parentOB.name)
+                if self.version < 3:
+                    parentIndex += 1 # Version 2 uses 0 to signify empty parent
+                transformParentIDs.append(parentIndex)
+
+        self.modelData.materials = materials.values()
+        self.modelData.meshes = meshes
+        self.modelData.transforms = transforms.values()
+        self.modelData.transformParentIDs = transformParentIDs
+        self.modelData.objects = objects
+
+    def buildA3DMesh(self, me, ob):
+        mesh = A3DObjects.A3DMesh()
+        mesh.name = me.name
+        mesh.vertexCount = len(me.vertices)
+
+        # Create vertex buffers
+        coordinateBuffer = A3DObjects.A3DVertexBuffer()
+        coordinateBuffer.bufferType = A3D_VERTEXTYPE_COORDINATE
+        normal1Buffer = A3DObjects.A3DVertexBuffer()
+        normal1Buffer.bufferType = A3D_VERTEXTYPE_NORMAL1
+        for vertex in me.vertices:
+            coordinateBuffer.data.append(vertex.co)
+            normal1Buffer.data.append(vertex.normal)
+        uv1Buffer = A3DObjects.A3DVertexBuffer()
+        uv1Buffer.bufferType = A3D_VERTEXTYPE_UV1
+        uv1Data = me.uv_layers[0]
+        uv1Vertices = [(0.0, 0.0)] * mesh.vertexCount
+        for polygon in me.polygons:
+            i0, i1, i2 = polygon.vertices
+            uv1Vertices[i0] = mirrorUVY(uv1Data.uv[polygon.loop_start].vector)
+            uv1Vertices[i1] = mirrorUVY(uv1Data.uv[polygon.loop_start+1].vector)
+            uv1Vertices[i2] = mirrorUVY(uv1Data.uv[polygon.loop_start+2].vector)
+        uv1Buffer.data = uv1Vertices
+
+        normal2Buffer = A3DObjects.A3DVertexBuffer()
+        normal2Buffer.bufferType = A3D_VERTEXTYPE_NORMAL2
+        normal2Buffer.data = normal1Buffer.data
+
+        mesh.vertexBufferCount = 3 #XXX: We only do coordinate, normal1 and uv1
+        mesh.vertexBuffers = [coordinateBuffer, uv1Buffer, normal1Buffer]
+
+        # Create submeshes
+        indexArrays = {} # material_index: index array
+        lastMaterialIndex = None
+        for polygon in me.polygons:
+            if polygon.material_index != lastMaterialIndex:
+                indexArrays[polygon.material_index] = []
+            
+            indexArrays[polygon.material_index] += polygon.vertices
+            lastMaterialIndex = polygon.material_index
+        submeshes = []
+        for materialID, indexArray in indexArrays.items():
+            submesh = A3DObjects.A3DSubmesh()
+            submesh.indexCount = len(indexArray)
+            submesh.indices = indexArray
+            submesh.materialID = materialID
+            submesh.smoothingGroups = [0] * (len(indexArray)//3) # Just set all faces to 0
+            submeshes.append(submesh)
+        mesh.submeshCount = len(submeshes)
+        mesh.submeshes = submeshes
+
+        # Bound box data
+        bounds = []
+        for bound in ob.bound_box:
+            x, y, z = bound
+            bounds.append((x, y, z))
+        mesh.bboxMax = max(bounds)
+        mesh.bboxMin = min(bounds)
+
+        return mesh

io_scene_a3d/A3DBlenderImporter.py

@@ -64,21 +64,29 @@ class A3DBlenderImporter:
         
         # Create objects
         objects = []
-        for objectData in self.modelData.objects:
+        for transformID, transformData in enumerate(self.modelData.transforms):
-            ob = self.buildBlenderObject(objectData)
+            # Find out if this transform is used by an object
+            ob = None
+            for objectData in self.modelData.objects:
+                if objectData.transformID == transformID:
+                    ob = self.buildBlenderObject(objectData)
+                    break
+            
+            # Empty transform, create an empty object to represent it
+            if ob == None:
+                ob = self.buildBlenderEmptyObject(transformData)
+
             objects.append(ob)
-        # Assign object parents and link to collection
+
-        for obI, ob in enumerate(objects):
+        # Assign parents
-            # Assign parents
+        for objectID, parentID in enumerate(self.modelData.transformParentIDs):
-            parentID = self.modelData.transformParentIDs[obI]
+            if self.modelData.version < 3:
-            if parentID == 0 and self.modelData.version < 3:
+                # version 2 models use 0 to signify empty parent so everything is shifted up
-                # version 2 models use 0 to signify empty parent
+                parentID -= 1
+            if parentID == -1:
                 continue
-            elif parentID == -1:
+            ob = objects[objectID]
-                # version 3 models use -1 to signify empty parent
+            ob.parent = objects[parentID]
-                continue
-            parentOB = objects[parentID]
-            ob.parent = parentOB
 
         return objects
 
@@ -237,3 +245,20 @@ class A3DBlenderImporter:
                 addImageTextureToMaterial(image, ma.node_tree)
 
         return ob
+
+    def buildBlenderEmptyObject(self, transformData):
+        # Create the object
+        ob = bpy.data.objects.new(transformData.name, None)
+        ob.empty_display_size = 10 # Assume that the model is in alternativa scale (x100)
+
+        # Set transform
+        ob.location = transformData.position
+        ob.scale = transformData.scale
+        ob.rotation_mode = "QUATERNION"
+        x, y, z, w = transformData.rotation
+        ob.rotation_quaternion = (w, x, y, z)
+        if self.reset_empty_transform:
+            if transformData.scale == (0.0, 0.0, 0.0): ob.scale = (1.0, 1.0, 1.0)
+            if transformData.rotation == (0.0, 0.0, 0.0, 0.0): ob.rotation_quaternion = (1.0, 0.0, 0.0, 0.0)
+
+        return ob

io_scene_a3d/A3DObjects.py

@@ -20,7 +20,7 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 '''
 
-from .IOTools import unpackStream, readNullTerminatedString, readLengthPrefixedString, calculatePadding
+from .IOTools import unpackStream, packStream, readNullTerminatedString, writeNullTerminatedString, readLengthPrefixedString, writeLengthPrefixedString, calculatePadding
 
 class A3DMaterial:
     def __init__(self):
@@ -35,6 +35,12 @@ class A3DMaterial:
 
         print(f"[A3DMaterial name: {self.name} color: {self.color} diffuse map: {self.diffuseMap}]")
 
+    def write2(self, stream):
+        writeNullTerminatedString(stream, self.name)
+        colorR, colorG, colorB = self.color
+        packStream("<3f", stream, colorR, colorG, colorB)
+        writeNullTerminatedString(stream, self.diffuseMap)
+
     def read3(self, stream):
         self.name = readLengthPrefixedString(stream)
         self.color = unpackStream("<3f", stream)
@@ -42,6 +48,12 @@ class A3DMaterial:
 
         print(f"[A3DMaterial name: {self.name} color: {self.color} diffuse map: {self.diffuseMap}]")
 
+    def write3(self, stream):
+        writeLengthPrefixedString(stream, self.name)
+        colorR, colorG, colorB = self.color
+        packStream("<3f", stream, colorR, colorG, colorB)
+        writeLengthPrefixedString(stream, self.diffuseMap)
+
 class A3DMesh:
     def __init__(self):
         self.name = ""
@@ -71,6 +83,15 @@ class A3DMesh:
         
         print(f"[A3DMesh name: {self.name} bbox max: {self.bboxMax} bbox min: {self.bboxMin} vertex buffers: {len(self.vertexBuffers)} submeshes: {len(self.submeshes)}]")
 
+    def write2(self, stream):
+        packStream("<2I", stream, self.vertexCount, self.vertexBufferCount)
+        for vertexBuffer in self.vertexBuffers:
+            vertexBuffer.write2(stream)
+        
+        packStream("<I", stream, self.submeshCount)
+        for submesh in self.submeshes:
+            submesh.write2(stream)
+
     def read3(self, stream):
         # Read mesh info
         self.name = readLengthPrefixedString(stream)
@@ -95,6 +116,24 @@ class A3DMesh:
         
         print(f"[A3DMesh name: {self.name} bbox max: {self.bboxMax} bbox min: {self.bboxMin} vertex buffers: {len(self.vertexBuffers)} submeshes: {len(self.submeshes)}]")
 
+    def write3(self, stream):
+        writeLengthPrefixedString(stream, self.name)
+        bboxMaxX, bboxMaxY, bboxMaxZ = self.bboxMax
+        packStream("<3f", stream, bboxMaxX, bboxMaxY, bboxMaxZ)
+        bboxMinX, bboxMinY, bboxMinZ = self.bboxMin
+        packStream("<3f", stream, bboxMinX, bboxMinY, bboxMinZ)
+        packStream("<f", stream, 0.0) # XXX: Unknown float value!
+
+        # Write vertex buffers
+        packStream("<2I", stream, self.vertexCount, self.vertexBufferCount)
+        for vertexBuffer in self.vertexBuffers:
+            vertexBuffer.write2(stream)
+        
+        # Write submeshes
+        packStream("<I", stream, self.submeshCount)
+        for submesh in self.submeshes:
+            submesh.write3(stream)
+
 A3D_VERTEXTYPE_COORDINATE = 1
 A3D_VERTEXTYPE_UV1 = 2
 A3D_VERTEXTYPE_NORMAL1 = 3
@@ -126,6 +165,12 @@ class A3DVertexBuffer:
         
         print(f"[A3DVertexBuffer data: {len(self.data)} buffer type: {self.bufferType}]")
 
+    def write2(self, stream):
+        packStream("<I", stream, self.bufferType)
+        for vertex in self.data:
+            for vertexElement in vertex:
+                packStream("<f", stream, vertexElement)
+
 class A3DSubmesh:
     def __init__(self):
         self.indices = []
@@ -135,25 +180,43 @@ class A3DSubmesh:
         self.indexCount = 0
 
     def read2(self, stream):
-        self.indexCount, = unpackStream("<I", stream) # This is just the face count so multiply it by 3
+        faceCount, = unpackStream("<I", stream)
-        self.indexCount *= 3
+        self.indexCount = faceCount * 3
         self.indices = list(unpackStream(f"<{self.indexCount}H", stream))
         self.smoothingGroups = list(unpackStream(f"<{self.indexCount//3}I", stream))
         self.materialID, = unpackStream("<H", stream)
 
         print(f"[A3DSubmesh indices: {len(self.indices)} smoothing groups: {len(self.smoothingGroups)} materialID: {self.materialID}]")
 
+    def write2(self, stream):
+        faceCount = self.indexCount // 3
+        packStream("<I", stream, faceCount)
+        for index in self.indices:
+            packStream("<H", stream, index)
+        for smoothingGroup in self.smoothingGroups:
+            packStream("<I", stream, smoothingGroup)
+        packStream("<H", stream, self.materialID)
+
     def read3(self, stream):
         # Read indices
         self.indexCount, = unpackStream("<I", stream)
         self.indices = list(unpackStream(f"<{self.indexCount}H", stream))
         
         # Padding
-        padding = calculatePadding(self.indexCount*2) # Each index is 2 bytes
+        paddingSize = calculatePadding(self.indexCount*2) # Each index is 2 bytes
-        stream.read(padding)
+        stream.read(paddingSize)
 
         print(f"[A3DSubmesh indices: {len(self.indices)} smoothing groups: {len(self.smoothingGroups)} materialID: {self.materialID}]")
 
+    def write3(self, stream):
+        packStream("<I", stream, self.indexCount)
+        for index in self.indices:
+            packStream("<H", stream, index)
+        
+        # Padding
+        paddingSize = calculatePadding(self.indexCount*2) # Each index is 2 bytes
+        stream.write(b"\x00" * paddingSize)
+
 class A3DTransform:
     def __init__(self):
         self.name = ""
@@ -168,6 +231,14 @@ class A3DTransform:
 
         print(f"[A3DTransform position: {self.position} rotation: {self.rotation} scale: {self.scale}]")
 
+    def write2(self, stream):
+        positionX, positionY, positionZ = self.position
+        packStream("<3f", stream, positionX, positionY, positionZ)
+        rotationX, rotationY, rotationZ, rotationW = self.rotation
+        packStream("<4f", stream, rotationX, rotationY, rotationZ, rotationW)
+        scaleX, scaleY, scaleZ = self.scale
+        packStream("<3f", stream, scaleX, scaleY, scaleZ)
+
     def read3(self, stream):
         self.name = readLengthPrefixedString(stream)
         self.position = unpackStream("<3f", stream)
@@ -176,6 +247,15 @@ class A3DTransform:
 
         print(f"[A3DTransform name: {self.name} position: {self.position} rotation: {self.rotation} scale: {self.scale}]")
 
+    def write3(self, stream):
+        writeLengthPrefixedString(stream, self.name)
+        positionX, positionY, positionZ = self.position
+        packStream("<3f", stream, positionX, positionY, positionZ)
+        rotationX, rotationY, rotationZ, rotationW = self.rotation
+        packStream("<4f", stream, rotationX, rotationY, rotationZ, rotationW)
+        scaleX, scaleY, scaleZ = self.scale
+        packStream("<3f", stream, scaleX, scaleY, scaleZ)
+
 class A3DObject:
     def __init__(self):
         self.name = ""
@@ -191,6 +271,10 @@ class A3DObject:
 
         print(f"[A3DObject name: {self.name} meshID: {self.meshID} transformID: {self.transformID} materialIDs: {len(self.materialIDs)}]")
 
+    def write2(self, stream):
+        writeNullTerminatedString(stream, self.name)
+        packStream("<2I", stream, self.meshID, self.transformID)
+
     def read3(self, stream):
         self.meshID, self.transformID, self.materialCount = unpackStream("<3I", stream)
 
@@ -200,3 +284,8 @@ class A3DObject:
             self.materialIDs.append(materialID)
 
         print(f"[A3DObject name: {self.name} meshID: {self.meshID} transformID: {self.transformID} materialIDs: {len(self.materialIDs)}]")
+
+    def write3(self, stream):
+        packStream("<3I", stream, self.meshID, self.transformID, self.materialCount)
+        for materialID in self.materialIDs:
+            packStream("<i", stream, materialID)

io_scene_a3d/IOTools.py

@@ -20,20 +20,29 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 '''
 
-from struct import unpack, calcsize
+from struct import unpack, pack, calcsize
 
 def unpackStream(format, stream):
     size = calcsize(format)
     data = stream.read(size)
     return unpack(format, data)
 
+def packStream(format, stream, *data):
+    packedData = pack(format, *data)
+    stream.write(packedData)
+
 def readNullTerminatedString(stream):
     string = b""
     char = stream.read(1)
     while char != b"\x00":
         string += char
         char = stream.read(1)
-    return string.decode("utf8", errors="ignore")
+    return string.decode("utf-8", errors="ignore")
+
+def writeNullTerminatedString(stream, string):
+    string = string.encode("utf-8")
+    stream.write(string)
+    stream.write(b"\x00")
 
 def calculatePadding(length):
     # (it basically works with rounding)
@@ -48,3 +57,12 @@ def readLengthPrefixedString(stream):
     stream.read(paddingSize)
 
     return string.decode("utf8", errors="ignore")
+
+def writeLengthPrefixedString(stream, string):
+    string = string.encode("utf-8")
+
+    packStream("<I", stream, len(string))
+    stream.write(string)
+
+    paddingSize = calculatePadding(len(string))
+    stream.write(b"\x00" * paddingSize)

io_scene_a3d/__init__.py

@@ -22,11 +22,12 @@ SOFTWARE.
 
 import bpy
 from bpy.types import Operator, OperatorFileListElement, AddonPreferences
-from bpy.props import StringProperty, BoolProperty, CollectionProperty, FloatProperty
+from bpy.props import StringProperty, BoolProperty, CollectionProperty, FloatProperty, EnumProperty
-from bpy_extras.io_utils import ImportHelper
+from bpy_extras.io_utils import ImportHelper, ExportHelper
 
 from .A3D import A3D
 from .A3DBlenderImporter import A3DBlenderImporter
+from .A3DBlenderExporter import A3DBlenderExporter
 from .BattleMap import BattleMap
 from .BattleMapBlenderImporter import BattleMapBlenderImporter
 from .LightmapData import LightmapData
@@ -99,6 +100,44 @@ class ImportA3D(Operator, ImportHelper):
 
         return {"FINISHED"}
 
+class ExportA3D(Operator, ExportHelper):
+    bl_idname = "export_scene.alternativa"
+    bl_label = "Export A3D"
+    bl_description = "Export an A3D model"
+    bl_options = {'PRESET', 'UNDO'}
+
+    filter_glob: StringProperty(default="*.a3d", options={'HIDDEN'})
+    filename_ext: StringProperty(default=".a3d", options={'HIDDEN'})
+
+    a3d_version: EnumProperty(
+        items=(
+            ("2", "A3D2", "Version 2 files are used to store map geometry like props and simple models like drones and particle effects"),
+            ("3", "A3D3", "Version 3 files are used to store tank turret and hull models")
+        ),
+        description="A3D file version",
+        default="2",
+        name="version"
+    )
+
+    def draw(self, context):
+        export_panel_options_a3d(self.layout, self)
+
+    def invoke(self, context, event):
+        return ExportHelper.invoke(self, context, event)
+    
+    def execute(self, context):
+        print(f"Exporting blender data to {self.filepath}")
+
+        modelData = A3D()
+        modelExporter = A3DBlenderExporter(modelData, bpy.context.selected_objects, version=int(self.a3d_version))
+        modelExporter.exportData()
+
+        # Write file
+        with open(self.filepath, "wb") as file:
+            modelData.write(file, version=int(self.a3d_version))
+
+        return {"FINISHED"}
+
 class ImportBattleMap(Operator, ImportHelper):
     bl_idname = "import_scene.tanki_battlemap"
     bl_label = "Import map"
@@ -167,6 +206,12 @@ def import_panel_options_a3d(layout, operator):
         body.prop(operator, "try_import_textures")
         body.prop(operator, "reset_empty_transform")
 
+def export_panel_options_a3d(layout, operator):
+    header, body = layout.panel("alternativa_import_options", default_closed=False)
+    header.label(text="Options")
+    if body:
+        body.prop(operator, "a3d_version")
+
 def import_panel_options_battlemap(layout, operator):
     header, body = layout.panel("tanki_battlemap_import_options", default_closed=False)
     header.label(text="Options")
@@ -180,6 +225,9 @@ def import_panel_options_battlemap(layout, operator):
 def menu_func_import_a3d(self, context):
     self.layout.operator(ImportA3D.bl_idname, text="Alternativa3D HTML5 (.a3d)")
 
+def menu_func_export_a3d(self, context):
+    self.layout.operator(ExportA3D.bl_idname, text="Alternativa3D HTML5 (.a3d)")
+
 def menu_func_import_battlemap(self, context):
     self.layout.operator(ImportBattleMap.bl_idname, text="Tanki Online BattleMap (.bin)")
 
@@ -189,6 +237,7 @@ Registration
 classes = [
     Preferences,
     ImportA3D,
+    ExportA3D,
     ImportBattleMap
 ]
 
@@ -196,12 +245,14 @@ def register():
     for c in classes:
         bpy.utils.register_class(c)
     bpy.types.TOPBAR_MT_file_import.append(menu_func_import_a3d)
+    bpy.types.TOPBAR_MT_file_export.append(menu_func_export_a3d)
     bpy.types.TOPBAR_MT_file_import.append(menu_func_import_battlemap)
 
 def unregister():
     for c in classes:
         bpy.utils.unregister_class(c)
     bpy.types.TOPBAR_MT_file_import.remove(menu_func_import_a3d)
+    bpy.types.TOPBAR_MT_file_export.remove(menu_func_export_a3d)
     bpy.types.TOPBAR_MT_file_import.remove(menu_func_import_battlemap)
 
 if __name__ == "__main__":