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OpenAssetImporter.cs
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// MonoGame - Copyright (C) MonoGame Foundation, Inc
// This file is subject to the terms and conditions defined in
// file 'LICENSE.txt', which is part of this source code package.
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Numerics;
using System.IO;
using System.Linq;
using System.Reflection;
using Assimp;
using Assimp.Unmanaged;
using Microsoft.Xna.Framework.Content.Pipeline.Graphics;
using MonoGame.Framework.Utilities;
namespace Microsoft.Xna.Framework.Content.Pipeline
{
[ContentImporter(
".dae", // Collada
".gltf", "glb", // glTF
".blend", // Blender 3D
".3ds", // 3ds Max 3DS
".ase", // 3ds Max ASE
".obj", // Wavefront Object
".ifc", // Industry Foundation Classes (IFC/Step)
".xgl", ".zgl", // XGL
".ply", // Stanford Polygon Library
".dxf", // AutoCAD DXF
".lwo", // LightWave
".lws", // LightWave Scene
".lxo", // Modo
".stl", // Stereolithography
".ac", // AC3D
".ms3d", // Milkshape 3D
".cob", ".scn", // TrueSpace
".bvh", // Biovision BVH
".csm", // CharacterStudio Motion
".irrmesh", // Irrlicht Mesh
".irr", // Irrlicht Scene
".mdl", // Quake I, 3D GameStudio (3DGS)
".md2", // Quake II
".md3", // Quake III Mesh
".pk3", // Quake III Map/BSP
".mdc", // Return to Castle Wolfenstein
".md5", // Doom 3
".smd", ".vta", // Valve Model
".ogex", // Open Game Engine Exchange
".3d", // Unreal
".b3d", // BlitzBasic 3D
".q3d", ".q3s", // Quick3D
".nff", // Neutral File Format, Sense8 WorldToolKit
".off", // Object File Format
".ter", // Terragen Terrain
".hmp", // 3D GameStudio (3DGS) Terrain
".ndo", // Izware Nendo
DisplayName = "Open Asset Import Library - MonoGame", DefaultProcessor = "ModelProcessor")]
public class OpenAssetImporter : ContentImporter<NodeContent>
{
// Assimp has a few limitations (not all FBX files are supported):
// FBX files reference objects using IDs. Therefore, it is possible to resolve
// bones even if multiple bones/nodes have the same name. But Assimp references
// bones only by name!
// --> Limitation #1: A model cannot have more than one skeleton!
// --> Limitation #2: Bone names need to be unique!
//
// Bones are represented by regular nodes, but there is no flag indicating whether
// a node is a bone. A mesh in Assimp references deformation bones (= bones that
// affect vertices) by name. That means, we can identify the nodes that represent
// deformation bones. But there is no way to identify helper bones (= bones that
// belong to the skeleton, but do not affect vertices). As described in
// http://assimp.sourceforge.net/lib_html/data.html and
// http://gamedev.stackexchange.com/questions/26382/i-cant-figure-out-how-to-animate-my-loaded-model-with-assimp/26442#26442
// we can only guess which nodes belong to a skeleton:
// --> Limitation #3: The skeleton needs to be a direct child of the root node or
// the mesh node!
//
// Node.Transform is irrelevant for bones. This transform is just the pose of the
// bone at the time of the export. This could be one of the animation frames. It
// is not necessarily the bind pose (rest pose)! For example, XNA's Dude.fbx does
// NOT store the skeleton in bind pose.
// The correct transform is stored in Mesh.Bones[i].OffsetMatrix. However, this
// information is only available for deformation bones, not for helper bones.
// --> Limitation #4: The skeleton either must not contain helper bones, or it must
// be guaranteed that the skeleton is exported in bind pose!
//
// An FBX file does not directly store all animation values. In some FBX scene it
// is insufficient to simply read the animation data from the file. Instead, the
// animation properties of all relevant objects in the scene need to be evaluated.
// For example, some animations are the result of the current skeleton pose + the
// current animation. The current skeleton pose is not imported/processed by XNA.
// Assimp does not include an "animation evaluater" that automatically bakes these
// animations.
// --> Limitation #5: All bones included in an animation need to be key framed.
// (There is no automatic evaluation.)
//
// In FBX it is possible to define animations curves for some transform components
// (e.g. translation X and Y) and leave other components (e.g. translation Z) undefined.
// Assimp does not pick the right defaults for undefined components.
// --> Limitation #6: When scale, rotation, or translation is animated, all components
// X, Y, Z need to be key framed.
#region Nested Types
/// <summary>Defines the frame for local scale/rotation/translation of FBX nodes.</summary>
/// <remarks>
/// <para>
/// The transformation pivot defines the frame for local scale/rotation/translation. The
/// local transform of a node is:
/// </para>
/// <para>
/// Local Transform = Translation * RotationOffset * RotationPivot * PreRotation
/// * Rotation * PostRotation * RotationPivotInverse * ScalingOffset
/// * ScalingPivot * Scaling * ScalingPivotInverse
/// </para>
/// <para>
/// where the matrix multiplication order is right-to-left.
/// </para>
/// <para>
/// 3ds max uses three additional transformations:
/// </para>
/// <para>
/// Local Transform = Translation * Rotation * Scaling
/// * GeometricTranslation * GeometricRotation * GeometricScaling
/// </para>
/// <para>
/// Transformation pivots are stored per FBX node. When Assimp hits an FBX node with
/// a transformation pivot it generates additional nodes named
/// </para>
/// <para>
/// <i>OriginalName</i>_$AssimpFbx$_<i>TransformName</i>
/// </para>
/// <para>
/// where <i>TransformName</i> is one of:
/// </para>
/// <para>
/// Translation, RotationOffset, RotationPivot, PreRotation, Rotation, PostRotation,
/// RotationPivotInverse, ScalingOffset, ScalingPivot, Scaling, ScalingPivotInverse,
/// GeometricTranslation, GeometricRotation, GeometricScaling
/// </para>
/// </remarks>
/// <seealso href="http://download.autodesk.com/us/fbx/20112/FBX_SDK_HELP/index.html?url=WS1a9193826455f5ff1f92379812724681e696651.htm,topicNumber=d0e7429"/>
/// <seealso href="http://area.autodesk.com/forum/autodesk-fbx/fbx-sdk/the-makeup-of-the-local-matrix-of-an-kfbxnode/"/>
private class FbxPivot
{
public static readonly FbxPivot Default = new FbxPivot();
public Matrix? Translation;
public Matrix? RotationOffset;
public Matrix? RotationPivot;
public Matrix? PreRotation;
public Matrix? Rotation;
public Matrix? PostRotation;
public Matrix? RotationPivotInverse;
public Matrix? ScalingOffset;
public Matrix? ScalingPivot;
public Matrix? Scaling;
public Matrix? ScalingPivotInverse;
public Matrix? GeometricTranslation;
public Matrix? GeometricRotation;
public Matrix? GeometricScaling;
public Matrix GetTransform(Vector3? scale, Quaternion? rotation, Vector3? translation)
{
var transform = Matrix.Identity;
if (GeometricScaling.HasValue)
transform *= GeometricScaling.Value;
if (GeometricRotation.HasValue)
transform *= GeometricRotation.Value;
if (GeometricTranslation.HasValue)
transform *= GeometricTranslation.Value;
if (ScalingPivotInverse.HasValue)
transform *= ScalingPivotInverse.Value;
if (scale.HasValue)
transform *= Matrix.CreateScale(scale.Value);
else if (Scaling.HasValue)
transform *= Scaling.Value;
if (ScalingPivot.HasValue)
transform *= ScalingPivot.Value;
if (ScalingOffset.HasValue)
transform *= ScalingOffset.Value;
if (RotationPivotInverse.HasValue)
transform *= RotationPivotInverse.Value;
if (PostRotation.HasValue)
transform *= PostRotation.Value;
if (rotation.HasValue)
transform *= Matrix.CreateFromQuaternion(rotation.Value);
else if (Rotation.HasValue)
transform *= Rotation.Value;
if (PreRotation.HasValue)
transform *= PreRotation.Value;
if (RotationPivot.HasValue)
transform *= RotationPivot.Value;
if (RotationOffset.HasValue)
transform *= RotationOffset.Value;
if (translation.HasValue)
transform *= Matrix.CreateTranslation(translation.Value);
else if (Translation.HasValue)
transform *= Translation.Value;
return transform;
}
}
#endregion
private static readonly List<VectorKey> EmptyVectorKeys = new List<VectorKey>();
private static readonly List<QuaternionKey> EmptyQuaternionKeys = new List<QuaternionKey>();
// XNA Content importer
private ContentImporterContext _context;
private ContentIdentity _identity;
// Assimp scene
private Scene _scene;
private Dictionary<string, Matrix> _deformationBones; // The names and offset matrices of all deformation bones.
private Node _rootBone; // The node that represents the root bone.
private List<Node> _bones = new List<Node>(); // All nodes attached to the root bone.
private Dictionary<string, FbxPivot> _pivots; // The transformation pivots.
// XNA content
private NodeContent _rootNode;
private List<MaterialContent> _materials;
// This is used to enable backwards compatibility with
// XNA providing a model as expected from the original
// FbxImporter and XImporter.
private readonly bool _xnaCompatible;
private readonly string _importerName;
/// <summary>
/// Default constructor.
/// </summary>
public OpenAssetImporter()
: this("OpenAssetImporter", false)
{
}
internal OpenAssetImporter(string importerName, bool xnaCompatible)
{
_importerName = importerName;
_xnaCompatible = xnaCompatible;
}
/// <summary>
/// This disables some Assimp model loading features so that
/// the resulting content is the same as what the XNA FbxImporter
/// </summary>
public bool XnaComptatible { get; set; }
public override NodeContent Import(string filename, ContentImporterContext context)
{
if (filename == null)
throw new ArgumentNullException("filename");
if (context == null)
throw new ArgumentNullException("context");
_context = context;
if (CurrentPlatform.OS == OS.Linux)
{
var targetDir = new FileInfo(Assembly.GetExecutingAssembly().Location).Directory.FullName;
try
{
AssimpLibrary.Instance.LoadLibrary(
Path.Combine(targetDir, "libassimp.so"),
Path.Combine(targetDir, "libassimp.so"));
}
catch { }
}
_identity = new ContentIdentity(filename, _importerName);
using (var importer = new AssimpContext())
{
// FBXPreservePivotsConfig(false) can be set to remove transformation
// pivots. However, Assimp does not automatically correct animations!
// --> Leave default settings, handle transformation pivots explicitly.
//importer.SetConfig(new Assimp.Configs.FBXPreservePivotsConfig(false));
// Set flag to remove degenerate faces (points and lines).
// This flag is very important when PostProcessSteps.FindDegenerates is used
// because FindDegenerates converts degenerate triangles to points and lines!
importer.SetConfig(new Assimp.Configs.RemoveDegeneratePrimitivesConfig(true));
// Note about Assimp post-processing:
// Keep post-processing to a minimum. The ModelImporter should import
// the model as is. We don't want to lose any information, i.e. empty
// nodes shoud not be thrown away, meshes/materials should not be merged,
// etc. Custom model processors may depend on this information!
_scene = importer.ImportFile(filename,
PostProcessSteps.FindDegenerates |
PostProcessSteps.FindInvalidData |
PostProcessSteps.FlipUVs | // Required for Direct3D
PostProcessSteps.FlipWindingOrder | // Required for Direct3D
PostProcessSteps.JoinIdenticalVertices |
PostProcessSteps.ImproveCacheLocality |
PostProcessSteps.OptimizeMeshes |
PostProcessSteps.Triangulate
// Unused:
//PostProcessSteps.CalculateTangentSpace
//PostProcessSteps.Debone |
//PostProcessSteps.FindInstances | // No effect + slow?
//PostProcessSteps.FixInFacingNormals |
//PostProcessSteps.GenerateNormals |
//PostProcessSteps.GenerateSmoothNormals |
//PostProcessSteps.GenerateUVCoords | // Might be needed... find test case
//PostProcessSteps.LimitBoneWeights |
//PostProcessSteps.MakeLeftHanded | // Not necessary, XNA is right-handed.
//PostProcessSteps.OptimizeGraph | // Will eliminate helper nodes
//PostProcessSteps.PreTransformVertices |
//PostProcessSteps.RemoveComponent |
//PostProcessSteps.RemoveRedundantMaterials |
//PostProcessSteps.SortByPrimitiveType |
//PostProcessSteps.SplitByBoneCount |
//PostProcessSteps.SplitLargeMeshes |
//PostProcessSteps.TransformUVCoords |
//PostProcessSteps.ValidateDataStructure |
);
FindSkeleton(); // Find _rootBone, _bones, _deformationBones.
// Create _materials.
if (_xnaCompatible)
ImportXnaMaterials();
else
ImportMaterials();
ImportNodes(); // Create _pivots and _rootNode (incl. children).
ImportSkeleton(); // Create skeleton (incl. animations) and add to _rootNode.
// If we have a simple hierarchy with no bones and just the one
// mesh, we can flatten it out so the mesh is the root node.
if (_rootNode.Children.Count == 1 && _rootNode.Children[0] is MeshContent)
{
var absXform = _rootNode.Children[0].AbsoluteTransform;
_rootNode = _rootNode.Children[0];
_rootNode.Identity = _identity;
_rootNode.Transform = absXform;
}
_scene.Clear();
}
return _rootNode;
}
/// <summary>
/// Converts all Assimp <see cref="Material"/>s to standard XNA compatible <see cref="MaterialContent"/>s.
/// </summary>
private void ImportXnaMaterials()
{
_materials = new List<MaterialContent>();
foreach (var aiMaterial in _scene.Materials)
{
// TODO: What about AlphaTestMaterialContent, DualTextureMaterialContent,
// EffectMaterialContent, EnvironmentMapMaterialContent, and SkinnedMaterialContent?
var material = new BasicMaterialContent
{
Name = aiMaterial.Name,
Identity = _identity,
};
if (aiMaterial.HasTextureDiffuse)
material.Texture = ImportTextureContentRef(aiMaterial.TextureDiffuse);
if (aiMaterial.HasTextureOpacity)
material.Textures.Add("Transparency", ImportTextureContentRef(aiMaterial.TextureOpacity));
if (aiMaterial.HasTextureSpecular)
material.Textures.Add("Specular", ImportTextureContentRef(aiMaterial.TextureSpecular));
if (aiMaterial.HasTextureHeight)
material.Textures.Add("Bump", ImportTextureContentRef(aiMaterial.TextureHeight));
if (aiMaterial.HasColorDiffuse)
material.DiffuseColor = new Vector3(aiMaterial.ColorDiffuse.X, aiMaterial.ColorDiffuse.Y, aiMaterial.ColorDiffuse.Z);
if (aiMaterial.HasColorEmissive)
material.EmissiveColor = new Vector3(aiMaterial.ColorEmissive.X, aiMaterial.ColorEmissive.Y, aiMaterial.ColorEmissive.Z);
if (aiMaterial.HasOpacity)
material.Alpha = aiMaterial.Opacity;
if (aiMaterial.HasColorSpecular)
material.SpecularColor = new Vector3(aiMaterial.ColorSpecular.X, aiMaterial.ColorSpecular.Y, aiMaterial.ColorSpecular.Z);
if (aiMaterial.HasShininessStrength)
material.SpecularPower = aiMaterial.Shininess;
_materials.Add(material);
}
}
private ExternalReference<TextureContent> ImportTextureContentRef(TextureSlot textureSlot)
{
var texture = new ExternalReference<TextureContent>(textureSlot.FilePath, _identity);
texture.OpaqueData.Add("TextureCoordinate", string.Format("TextureCoordinate{0}", textureSlot.UVIndex));
if (!_xnaCompatible)
{
texture.OpaqueData.Add("Operation", textureSlot.Operation.ToString());
texture.OpaqueData.Add("AddressU", textureSlot.WrapModeU.ToString());
texture.OpaqueData.Add("AddressV", textureSlot.WrapModeU.ToString());
texture.OpaqueData.Add("Mapping", textureSlot.Mapping.ToString());
}
return texture;
}
/// <summary>
/// Returns all the Assimp <see cref="Material"/> features as a <see cref="MaterialContent"/>.
/// </summary>
private void ImportMaterials()
{
_materials = new List<MaterialContent>();
foreach (var aiMaterial in _scene.Materials)
{
// TODO: Should we create a special AssImpMaterial?
var material = new MaterialContent
{
Name = aiMaterial.Name,
Identity = _identity,
};
var slots = aiMaterial.GetAllMaterialTextures();
foreach (var tex in slots)
{
string name;
// Force the XNA naming standard for diffuse textures
// which allows the material to work with the stock
// model processor.
if (tex.TextureType == TextureType.Diffuse)
name = BasicMaterialContent.TextureKey;
else
name = tex.TextureType.ToString();
// We might have multiple textures of the same type so number
// them starting with 2 like in DualTextureMaterialContent.
if (tex.TextureIndex > 0)
name += (tex.TextureIndex + 1);
material.Textures.Add(name, ImportTextureContentRef(tex));
}
if (aiMaterial.HasBlendMode)
material.OpaqueData.Add("BlendMode", aiMaterial.BlendMode.ToString());
if (aiMaterial.HasBumpScaling)
material.OpaqueData.Add("BumpScaling", aiMaterial.BumpScaling);
if (aiMaterial.HasColorAmbient)
material.OpaqueData.Add("AmbientColor", new Vector3(aiMaterial.ColorAmbient.X, aiMaterial.ColorAmbient.Y, aiMaterial.ColorAmbient.Z));
if (aiMaterial.HasColorDiffuse)
material.OpaqueData.Add("DiffuseColor", new Vector3(aiMaterial.ColorDiffuse.X, aiMaterial.ColorDiffuse.Y, aiMaterial.ColorDiffuse.Z));
if (aiMaterial.HasColorEmissive)
material.OpaqueData.Add("EmissiveColor", new Vector3(aiMaterial.ColorEmissive.X, aiMaterial.ColorEmissive.Y, aiMaterial.ColorEmissive.Z));
if (aiMaterial.HasColorReflective)
material.OpaqueData.Add("ReflectiveColor", new Vector3(aiMaterial.ColorReflective.X, aiMaterial.ColorReflective.Y, aiMaterial.ColorReflective.Z));
if (aiMaterial.HasColorSpecular)
material.OpaqueData.Add("SpecularColor", new Vector3(aiMaterial.ColorSpecular.X, aiMaterial.ColorSpecular.Y, aiMaterial.ColorSpecular.Z));
if (aiMaterial.HasColorTransparent)
material.OpaqueData.Add("TransparentColor", new Vector3(aiMaterial.ColorTransparent.X, aiMaterial.ColorTransparent.Y, aiMaterial.ColorTransparent.Z));
if (aiMaterial.HasOpacity)
material.OpaqueData.Add("Opacity", aiMaterial.Opacity);
if (aiMaterial.HasReflectivity)
material.OpaqueData.Add("Reflectivity", aiMaterial.Reflectivity);
if (aiMaterial.HasShadingMode)
material.OpaqueData.Add("ShadingMode", aiMaterial.ShadingMode.ToString());
if (aiMaterial.HasShininess)
material.OpaqueData.Add("Shininess", aiMaterial.Shininess);
if (aiMaterial.HasShininessStrength)
material.OpaqueData.Add("ShininessStrength", aiMaterial.ShininessStrength);
if (aiMaterial.HasTwoSided)
material.OpaqueData.Add("TwoSided", aiMaterial.IsTwoSided);
if (aiMaterial.HasWireFrame)
material.OpaqueData.Add("WireFrame", aiMaterial.IsWireFrameEnabled);
_materials.Add(material);
}
}
/// <summary>
/// Converts all Assimp nodes to XNA nodes. (Nodes representing bones are excluded!)
/// </summary>
private void ImportNodes()
{
_pivots = new Dictionary<string, FbxPivot>();
_rootNode = ImportNodes(_scene.RootNode, null, null);
}
/// <summary>
/// Converts the specified node and all descendant nodes.
/// </summary>
/// <param name="aiNode">The node.</param>
/// <param name="aiParent">The parent node. Can be <see langword="null"/>.</param>
/// <param name="parent">The <paramref name="aiParent"/> node converted to XNA.</param>
/// <returns>The XNA <see cref="NodeContent"/>.</returns>
/// <remarks>
/// It may be necessary to skip certain "preserve pivot" nodes in the hierarchy. The
/// converted node needs to be relative to <paramref name="aiParent"/>, not <c>node.Parent</c>.
/// </remarks>
private NodeContent ImportNodes(Node aiNode, Node aiParent, NodeContent parent)
{
Debug.Assert(aiNode != null);
NodeContent node = null;
if (aiNode.HasMeshes)
{
var mesh = new MeshContent
{
Name = aiNode.Name,
Identity = _identity,
Transform = GetRelativeTransform(aiNode, aiParent)
};
foreach (var meshIndex in aiNode.MeshIndices)
{
var aiMesh = _scene.Meshes[meshIndex];
if (!aiMesh.HasVertices)
continue;
var geom = CreateGeometry(mesh, aiMesh);
mesh.Geometry.Add(geom);
}
node = mesh;
}
else if (aiNode.Name.Contains("_$AssimpFbx$"))
{
// This is a transformation pivot.
// <OriginalName>_$AssimpFbx$_<TransformName>
// where <TransformName> is one of
// Translation, RotationOffset, RotationPivot, PreRotation, Rotation,
// PostRotation, RotationPivotInverse, ScalingOffset, ScalingPivot,
// Scaling, ScalingPivotInverse
string originalName = GetNodeName(aiNode.Name);
FbxPivot pivot;
if (!_pivots.TryGetValue(originalName, out pivot))
{
pivot = new FbxPivot();
_pivots.Add(originalName, pivot);
}
Matrix transform = aiNode.Transform;
if (aiNode.Name.EndsWith("_Translation"))
pivot.Translation = transform;
else if (aiNode.Name.EndsWith("_RotationOffset"))
pivot.RotationOffset = transform;
else if (aiNode.Name.EndsWith("_RotationPivot"))
pivot.RotationPivot = transform;
else if (aiNode.Name.EndsWith("_PreRotation"))
pivot.PreRotation = transform;
else if (aiNode.Name.EndsWith("_Rotation"))
pivot.Rotation = transform;
else if (aiNode.Name.EndsWith("_PostRotation"))
pivot.PostRotation = transform;
else if (aiNode.Name.EndsWith("_RotationPivotInverse"))
pivot.RotationPivotInverse = transform;
else if (aiNode.Name.EndsWith("_ScalingOffset"))
pivot.ScalingOffset = transform;
else if (aiNode.Name.EndsWith("_ScalingPivot"))
pivot.ScalingPivot = transform;
else if (aiNode.Name.EndsWith("_Scaling"))
pivot.Scaling = transform;
else if (aiNode.Name.EndsWith("_ScalingPivotInverse"))
pivot.ScalingPivotInverse = transform;
else if (aiNode.Name.EndsWith("_GeometricTranslation"))
pivot.GeometricTranslation = transform;
else if (aiNode.Name.EndsWith("_GeometricRotation"))
pivot.GeometricRotation = transform;
else if (aiNode.Name.EndsWith("_GeometricScaling"))
pivot.GeometricScaling = transform;
else
throw new InvalidContentException(string.Format("Unknown $AssimpFbx$ node: \"{0}\"", aiNode.Name), _identity);
}
else if (!_bones.Contains(aiNode)) // Ignore bones.
{
node = new NodeContent
{
Name = aiNode.Name,
Identity = _identity,
Transform = GetRelativeTransform(aiNode, aiParent)
};
}
if (node != null)
{
if (parent != null)
parent.Children.Add(node);
// For the children, this is the new parent.
aiParent = aiNode;
parent = node;
if (_scene.HasAnimations)
{
foreach (var animation in _scene.Animations)
{
var animationContent = ImportAnimation(animation, node.Name);
if (animationContent.Channels.Count > 0)
node.Animations.Add(animationContent.Name, animationContent);
}
}
}
Debug.Assert(parent != null);
foreach (var child in aiNode.Children)
ImportNodes(child, aiParent, parent);
return node;
}
private GeometryContent CreateGeometry(MeshContent mesh, Mesh aiMesh)
{
var geom = new GeometryContent
{
Identity = _identity,
Material = _materials[aiMesh.MaterialIndex]
};
// Vertices
var baseVertex = mesh.Positions.Count;
foreach (var vert in aiMesh.Vertices)
mesh.Positions.Add((Vector3)vert);
geom.Vertices.AddRange(Enumerable.Range(baseVertex, aiMesh.VertexCount));
geom.Indices.AddRange(aiMesh.GetIndices());
if (aiMesh.HasBones)
{
var xnaWeights = new List<BoneWeightCollection>();
var vertexCount = geom.Vertices.VertexCount;
bool missingBoneWeights = false;
for (var i = 0; i < vertexCount; i++)
{
var list = new BoneWeightCollection();
for (var boneIndex = 0; boneIndex < aiMesh.BoneCount; boneIndex++)
{
var bone = aiMesh.Bones[boneIndex];
foreach (var weight in bone.VertexWeights)
{
if (weight.VertexID != i)
continue;
list.Add(new BoneWeight(bone.Name, weight.Weight));
}
}
if (list.Count == 0)
{
// No bone weights found for vertex. Use bone 0 as fallback.
missingBoneWeights = true;
list.Add(new BoneWeight(aiMesh.Bones[0].Name, 1));
}
xnaWeights.Add(list);
}
if (missingBoneWeights)
{
_context.Logger.LogWarning(
string.Empty,
_identity,
"No bone weights found for one or more vertices of skinned mesh '{0}'.",
aiMesh.Name);
}
geom.Vertices.Channels.Add(VertexChannelNames.Weights(0), xnaWeights);
}
// Individual channels go here
if (aiMesh.HasNormals)
geom.Vertices.Channels.Add(VertexChannelNames.Normal(), aiMesh.Normals.Select(s => (Vector3)s));
for (var i = 0; i < aiMesh.TextureCoordinateChannelCount; i++)
geom.Vertices.Channels.Add(VertexChannelNames.TextureCoordinate(i), aiMesh.TextureCoordinateChannels[i].Select(s => new Vector2(s.X, s.Y)));
for (var i = 0; i < aiMesh.VertexColorChannelCount; i++)
geom.Vertices.Channels.Add(VertexChannelNames.Color(i), aiMesh.VertexColorChannels[i].Select(s => (Color)s));
return geom;
}
/// <summary>
/// Identifies the nodes that represent bones and stores the bone offset matrices.
/// </summary>
private void FindSkeleton()
{
// See http://assimp.sourceforge.net/lib_html/data.html, section "Bones"
// and notes above.
// First, identify all deformation bones.
_deformationBones = FindDeformationBones(_scene);
if (_deformationBones.Count == 0)
return;
// Walk the tree upwards to find the root bones.
var rootBones = new HashSet<Node>();
foreach (var boneName in _deformationBones.Keys)
rootBones.Add(FindRootBone(_scene, boneName));
if (rootBones.Count > 1)
throw new InvalidContentException("Multiple skeletons found. Please ensure that the model does not contain more that one skeleton.", _identity);
_rootBone = rootBones.First();
// Add all nodes below root bone to skeleton.
GetSubtree(_rootBone, _bones);
}
/// <summary>
/// Finds the deformation bones (= bones attached to meshes).
/// </summary>
/// <param name="scene">The scene.</param>
/// <returns>A dictionary of all deformation bones and their offset matrices.</returns>
private static Dictionary<string, Matrix> FindDeformationBones(Scene scene)
{
Debug.Assert(scene != null);
var offsetMatrices = new Dictionary<string, Matrix>();
if (scene.HasMeshes)
foreach (var mesh in scene.Meshes)
if (mesh.HasBones)
foreach (var bone in mesh.Bones)
if (!offsetMatrices.ContainsKey(bone.Name))
offsetMatrices[bone.Name] = bone.OffsetMatrix;
return offsetMatrices;
}
/// <summary>
/// Finds the root bone of a specific bone in the skeleton.
/// </summary>
/// <param name="scene">The scene.</param>
/// <param name="boneName">The name of a bone in the skeleton.</param>
/// <returns>The root bone.</returns>
private static Node FindRootBone(Scene scene, string boneName)
{
Debug.Assert(scene != null);
Debug.Assert(!string.IsNullOrEmpty(boneName));
// Start with the specified bone.
Node node = scene.RootNode.FindNode(boneName);
Debug.Assert(node != null, "Node referenced by mesh not found in model.");
// Walk all the way up to the scene root or the mesh node.
Node rootBone = node;
while (node != scene.RootNode && !node.HasMeshes)
{
// Only when FBXPreservePivotsConfig(true):
// The FBX path likes to put these extra preserve pivot nodes in here.
if (!node.Name.Contains("$AssimpFbx$"))
rootBone = node;
node = node.Parent;
}
return rootBone;
}
/// <summary>
/// Imports the skeleton including all skeletal animations.
/// </summary>
private void ImportSkeleton()
{
if (_rootBone == null)
return;
// Convert nodes to bones and attach to root node.
var rootBoneContent = (BoneContent)ImportBones(_rootBone, _rootBone.Parent, null);
_rootNode.Children.Add(rootBoneContent);
if (!_scene.HasAnimations)
return;
// Convert animations and add to root bone.
foreach (var animation in _scene.Animations)
{
var animationContent = ImportAnimation(animation);
rootBoneContent.Animations.Add(animationContent.Name, animationContent);
}
}
/// <summary>
/// Converts the specified node and all descendant nodes to XNA bones.
/// </summary>
/// <param name="aiNode">The node.</param>
/// <param name="aiParent">The parent node.</param>
/// <param name="parent">The <paramref name="aiParent"/> node converted to XNA.</param>
/// <returns>The XNA <see cref="NodeContent"/>.</returns>
private NodeContent ImportBones(Node aiNode, Node aiParent, NodeContent parent)
{
Debug.Assert(aiNode != null);
Debug.Assert(aiParent != null);
NodeContent node = null;
if (!aiNode.Name.Contains("_$AssimpFbx$")) // Ignore pivot nodes
{
const string mangling = "_$AssimpFbxNull$"; // Null leaf nodes are helpers
if (aiNode.Name.Contains(mangling))
{
// Null leaf node
node = new NodeContent
{
Name = aiNode.Name.Replace(mangling, string.Empty),
Identity = _identity,
Transform = GetRelativeTransform(aiNode, aiParent)
};
}
else if (_bones.Contains(aiNode))
{
// Bone
node = new BoneContent
{
Name = aiNode.Name,
Identity = _identity
};
// node.Transform is irrelevant for bones. This transform is just the
// pose of the node at the time of the export. This could, for example,
// be one of the animation frames. It is not necessarily the bind pose
// (rest pose)!
// In XNA BoneContent.Transform needs to be set to the relative bind pose
// matrix. The relative bind pose matrix can be derived from the OffsetMatrix
// which is stored in aiMesh.Bones.
//
// offsetMatrix ... Offset matrix. Transforms the mesh from local space to bone space in bind pose.
// bindPoseRel ... Relative bind pose matrix. Defines the transform of a bone relative to its parent bone.
// bindPoseAbs ... Absolute bind pose matrix. Defines the transform of a bone relative to world space.
//
// The offset matrix is the inverse of the absolute bind pose matrix.
// offsetMatrix = inverse(bindPoseAbs)
//
// bindPoseAbs = bindPoseRel * parentBindPoseAbs
// => bindPoseRel = bindPoseAbs * inverse(parentBindPoseAbs)
// = inverse(offsetMatrix) * parentOffsetMatrix
Matrix offsetMatrix;
Matrix parentOffsetMatrix;
bool isOffsetMatrixValid = _deformationBones.TryGetValue(aiNode.Name, out offsetMatrix);
bool isParentOffsetMatrixValid = _deformationBones.TryGetValue(aiParent.Name, out parentOffsetMatrix);
if (isOffsetMatrixValid && isParentOffsetMatrixValid)
{
node.Transform = Matrix.Invert(offsetMatrix) * parentOffsetMatrix;
}
else if (isOffsetMatrixValid && aiNode == _rootBone)
{
// The current bone is the first in the chain.
// The parent offset matrix is missing. :(
FbxPivot pivot;
if (_pivots.TryGetValue(node.Name, out pivot))
{
// --> Use transformation pivot.
node.Transform = pivot.GetTransform(null, null, null);
}
else
{
// --> Let's assume that parent's transform is Identity.
node.Transform = Matrix.Invert(offsetMatrix);
}
}
else if (isOffsetMatrixValid && aiParent == _rootBone)
{
// The current bone is the second bone in the chain.
// The parent offset matrix is missing. :(
// --> Derive matrix from parent bone, which is the root bone.
parentOffsetMatrix = Matrix.Invert(parent.Transform);
node.Transform = Matrix.Invert(offsetMatrix) * parentOffsetMatrix;
}
else
{
// Offset matrices are not provided by Assimp. :(
// Let's hope that the skeleton was exported in bind pose.
// (Otherwise we are just importing garbage.)
node.Transform = GetRelativeTransform(aiNode, aiParent);
}
}
}
if (node != null)
{
if (parent != null)
parent.Children.Add(node);
// For the children, this is the new parent.
aiParent = aiNode;
parent = node;
}
foreach (var child in aiNode.Children)
ImportBones(child, aiParent, parent);
return node;
}
/// <summary>
/// Converts the specified animation to XNA.
/// </summary>
/// <param name="aiAnimation">The animation.</param>
/// <param name="nodeName">An optional filter.</param>
/// <returns>The animation converted to XNA.</returns>
private AnimationContent ImportAnimation(Animation aiAnimation, string nodeName = null)
{
var animation = new AnimationContent
{
Name = GetAnimationName(aiAnimation.Name),
Identity = _identity,
Duration = TimeSpan.FromSeconds(aiAnimation.DurationInTicks / aiAnimation.TicksPerSecond)
};
// In Assimp animation channels may be split into separate channels.
// "nodeXyz" --> "nodeXyz_$AssimpFbx$_Translation",
// "nodeXyz_$AssimpFbx$_Rotation",
// "nodeXyz_$AssimpFbx$_Scaling"
// Group animation channels by name (strip the "_$AssimpFbx$" part).
IEnumerable < IGrouping < string,NodeAnimationChannel >> channelGroups;
if (nodeName != null)
{
channelGroups = aiAnimation.NodeAnimationChannels
.Where(channel => nodeName == GetNodeName(channel.NodeName))
.GroupBy(channel => GetNodeName(channel.NodeName));
}
else
{
channelGroups = aiAnimation.NodeAnimationChannels
.GroupBy(channel => GetNodeName(channel.NodeName));
}
foreach (var channelGroup in channelGroups)
{
var boneName = channelGroup.Key;
var channel = new AnimationChannel();
// Get transformation pivot for current bone.
FbxPivot pivot;
if (!_pivots.TryGetValue(boneName, out pivot))
pivot = FbxPivot.Default;
var scaleKeys = EmptyVectorKeys;
var rotationKeys = EmptyQuaternionKeys;
var translationKeys = EmptyVectorKeys;
foreach (var aiChannel in channelGroup)
{
if (aiChannel.NodeName.EndsWith("_$AssimpFbx$_Scaling"))
{
scaleKeys = aiChannel.ScalingKeys;
Debug.Assert(pivot.Scaling.HasValue);
Debug.Assert(!aiChannel.HasRotationKeys || (aiChannel.RotationKeyCount == 1 && (aiChannel.RotationKeys[0].Value == new Quaternion(1, 0, 0, 0) || aiChannel.RotationKeys[0].Value == new Quaternion(0, 0, 0, 0))));
Debug.Assert(!aiChannel.HasPositionKeys || (aiChannel.PositionKeyCount == 1 && aiChannel.PositionKeys[0].Value == new Vector3(0, 0, 0)));
}
else if (aiChannel.NodeName.EndsWith("_$AssimpFbx$_Rotation"))
{
rotationKeys = aiChannel.RotationKeys;
Debug.Assert(pivot.Rotation.HasValue);
Debug.Assert(!aiChannel.HasScalingKeys || (aiChannel.ScalingKeyCount == 1 && aiChannel.ScalingKeys[0].Value == new Vector3(1, 1, 1)));
Debug.Assert(!aiChannel.HasPositionKeys || (aiChannel.PositionKeyCount == 1 && aiChannel.PositionKeys[0].Value == new Vector3(0, 0, 0)));
}
else if (aiChannel.NodeName.EndsWith("_$AssimpFbx$_Translation"))
{
translationKeys = aiChannel.PositionKeys;
Debug.Assert(pivot.Translation.HasValue);
Debug.Assert(!aiChannel.HasScalingKeys || (aiChannel.ScalingKeyCount == 1 && aiChannel.ScalingKeys[0].Value == new Vector3(1, 1, 1)));
Debug.Assert(!aiChannel.HasRotationKeys || (aiChannel.RotationKeyCount == 1 && (aiChannel.RotationKeys[0].Value == new Quaternion(1, 0, 0, 0) || aiChannel.RotationKeys[0].Value == new Quaternion(0, 0, 0, 0))));
}
else
{
scaleKeys = aiChannel.ScalingKeys;
rotationKeys = aiChannel.RotationKeys;
translationKeys = aiChannel.PositionKeys;
}
}
// Get all unique keyframe times. (Assuming that no two key frames
// have the same time, which is usually a safe assumption.)
var times = scaleKeys.Select(k => k.Time)
.Union(rotationKeys.Select(k => k.Time))
.Union(translationKeys.Select(k => k.Time))
.OrderBy(t => t)
.ToList();
Debug.Assert(times.Count == times.Distinct().Count(), "Sequences combined with Union() should not have duplicates.");
int prevScaleIndex = -1;
int prevRotationIndex = -1;
int prevTranslationIndex = -1;
double prevScaleTime = 0.0;
double prevRotationTime = 0.0;
double prevTranslationTime = 0.0;
Vector3? prevScale = null;
Quaternion? prevRotation = null;
Vector3? prevTranslation = null;