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FablishRPG/Assets/Synty/SidekickCharacters/Scripts/Runtime/SkinnedMesh/Combiner.cs

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2026-09-28 20:46:57 +01:00
// Copyright (c) 2024 Synty Studios Limited. All rights reserved.
//
// Use of this software is subject to the terms and conditions of the Synty Studios End User Licence Agreement (EULA)
// available at: https://syntystore.com/pages/end-user-licence-agreement
//
// For additional details, see the LICENSE.MD file bundled with this software.
using Synty.SidekickCharacters.Utils;
using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
namespace Synty.SidekickCharacters.SkinnedMesh
{
/// <summary>
/// Combines a set of given SkinnedMeshRenderers into a single SkinnedMEshRenderer.
/// </summary>
public static class Combiner
{
/// <summary>
/// Merges meshes together, including maintaining blend shape data.
/// </summary>
/// <param name="skinnedMeshesToMerge">Meshes to merge.</param>
/// <param name="finalMesh">The mesh to merge everything into.</param>
/// <param name="finalSkinnedMeshRenderer">The SkinnedMeshRenderer to attach the combined mesh to.</param>
public static void MergeAndGetAllBlendShapeDataOfSkinnedMeshRenderers(
SkinnedMeshRenderer[] skinnedMeshesToMerge,
Mesh finalMesh,
SkinnedMeshRenderer finalSkinnedMeshRenderer
)
{
List<BlendShapeData> allBlendShapeData = new List<BlendShapeData>();
//Verify each skinned mesh renderer and get info about all blendshapes of all meshes
int totalVerticesVerifiedAtHereForBlendShapes = 0;
foreach (SkinnedMeshRenderer combine in skinnedMeshesToMerge)
{
// Skip any parts that have not been assigned
if (combine == null)
{
continue;
}
List<BlendShapeData> newData = BlendShapeUtils.GetBlendShapeData(
finalMesh,
combine,
Array.Empty<string>(),
totalVerticesVerifiedAtHereForBlendShapes,
allBlendShapeData
);
//Set vertices verified at here, after processing all blendshapes for this mesh
totalVerticesVerifiedAtHereForBlendShapes += combine.sharedMesh.vertexCount;
}
BlendShapeUtils.RestoreBlendShapeData(allBlendShapeData, finalMesh, finalSkinnedMeshRenderer);
}
/// <summary>
/// Processes the given GameObject and combines the objects contained into combined meshes grouped by their material.
/// Then returns a new GameObject with the combined data.
/// </summary>
/// <param name="skinnedMeshesToCombine">All of the meshes to combine into a single model</param>
/// <param name="baseModel">The base model that has the base rig and where the skinned meshes will be combined to.</param>
/// <param name="baseMaterial">The base material to use for the combined model.</param>
/// <returns>A new GameObject containing all the combined objects, grouped and combined by Material.</returns>
public static GameObject CreateCombinedSkinnedMesh(
List<SkinnedMeshRenderer> skinnedMeshesToCombine,
GameObject baseModel,
Material baseMaterial
)
{
// Create the new base GameObject. This will store all the combined meshes.
GameObject combinedModel = new GameObject("Prefab Character");
GameObject combinedSkinnedMesh = new GameObject("mesh");
combinedSkinnedMesh.transform.parent = combinedModel.transform;
skinnedMeshesToCombine.Sort((a, b) => string.Compare(a.name, b.name));
Material material = null;
Mesh mesh = new Mesh();
GameObject rootBone = BuildSkeleton(skinnedMeshesToCombine, baseModel, combinedModel.transform, out _);
// Build the unique skeleton; one entry per unique bone name, ordered by rig hierarchy traversal.
HashSet<string> usedBoneNames = new HashSet<string>();
foreach (SkinnedMeshRenderer child in skinnedMeshesToCombine)
{
foreach (Transform bone in child.bones)
{
usedBoneNames.Add(bone.name);
}
}
List<Transform> uniqueBoneList = new List<Transform>();
Dictionary<string, int> boneIndexByName = new Dictionary<string, int>();
CollectUsedBonesDepthFirst(rootBone.transform, usedBoneNames, uniqueBoneList, boneIndexByName);
List<CombineInstance> combineInstances = new List<CombineInstance>();
List<BoneWeight> allBoneWeights = new List<BoneWeight>();
// Iterate through the skinned meshes and process them into Material groupings, and remap their bone weights to the unique skeleton.
foreach (SkinnedMeshRenderer child in skinnedMeshesToCombine)
{
material = child.sharedMaterial;
mesh = MeshUtils.CopyMesh(child.sharedMesh);
int[] indexRemap = new int[child.bones.Length];
for (int i = 0; i < indexRemap.Length; i++)
{
if (!boneIndexByName.TryGetValue(child.bones[i].name, out int uniqueIndex))
{
Debug.LogWarning($"Combiner: bone '{child.bones[i].name}' on part '{child.name}' not found in rig; remapping to root.");
uniqueIndex = 0;
}
indexRemap[i] = uniqueIndex;
}
// Collected separately rather than written back to the copied mesh, as CombineMeshes would offset the indices again.
allBoneWeights.AddRange(RemapBoneWeights(mesh.boneWeights, indexRemap));
Matrix4x4 transformMatrix = child.localToWorldMatrix;
CombineInstance combineInstance = new CombineInstance();
combineInstance.mesh = mesh;
combineInstance.transform = transformMatrix;
combineInstances.Add(combineInstance);
}
SkinnedMeshRenderer renderer = combinedSkinnedMesh.AddComponent<SkinnedMeshRenderer>();
Transform[] uniqueBones = uniqueBoneList.ToArray();
renderer.bones = uniqueBones;
renderer.updateWhenOffscreen = true;
Mesh newMesh = new Mesh();
newMesh.CombineMeshes(combineInstances.ToArray(), true, true);
newMesh.RecalculateBounds();
newMesh.name = combinedModel.name;
renderer.rootBone = rootBone.transform;
// Part transforms are baked into the vertices by CombineMeshes, so each bindpose maps from
// the combined renderer's space (identity, at the scene origin) into bone space.
Matrix4x4 rendererLocalToWorld = combinedSkinnedMesh.transform.localToWorldMatrix;
Matrix4x4[] uniqueBindPoses = new Matrix4x4[uniqueBones.Length];
for (int i = 0; i < uniqueBones.Length; i++)
{
uniqueBindPoses[i] = uniqueBones[i].worldToLocalMatrix * rendererLocalToWorld;
}
if (allBoneWeights.Count != newMesh.vertexCount)
{
Debug.LogError($"Combiner: bone weight count {allBoneWeights.Count} != combined vertex count {newMesh.vertexCount}.");
}
// Assign the remapped weights before shrinking the bindposes so no intermediate state has out-of-range bone indices.
newMesh.boneWeights = allBoneWeights.ToArray();
newMesh.bindposes = uniqueBindPoses;
renderer.sharedMesh = newMesh;
renderer.enabled = true;
renderer.sharedMaterial = baseMaterial == null ? material : baseMaterial;
MergeAndGetAllBlendShapeDataOfSkinnedMeshRenderers(skinnedMeshesToCombine.ToArray(), renderer.sharedMesh, renderer);
return combinedModel;
}
/// <summary>
/// Processes the given GameObject and creates a model where each part keeps its own mesh, but all parts share a single
/// merged skeleton hierarchy, built the same way as the combined mesh path.
/// </summary>
/// <param name="partsToAdd">All of the part meshes to add to the model.</param>
/// <param name="baseModel">The base model that has the base rig that the parts will be bound to.</param>
/// <param name="baseMaterial">The base material to use for the model.</param>
/// <returns>A new GameObject containing a renderer per part, all sharing a single skeleton.</returns>
public static GameObject CreateSeparateSkinnedMeshes(
List<SkinnedMeshRenderer> partsToAdd,
GameObject baseModel,
Material baseMaterial
)
{
GameObject partsModel = new GameObject("Prefab Character");
partsToAdd.Sort((a, b) => string.Compare(a.name, b.name));
GameObject rootBone = BuildSkeleton(partsToAdd, baseModel, partsModel.transform, out Hashtable boneNameMap);
foreach (SkinnedMeshRenderer part in partsToAdd)
{
GameObject newPart = new GameObject(part.name);
newPart.transform.parent = partsModel.transform;
SkinnedMeshRenderer renderer = newPart.AddComponent<SkinnedMeshRenderer>();
renderer.updateWhenOffscreen = true;
// Remap the part's bones to the shared skeleton by name, keeping the part's own bone order so the copied
// bone weights and bindposes stay valid without remapping.
Transform[] oldBones = part.bones;
Transform[] newBones = new Transform[oldBones.Length];
for (int i = 0; i < oldBones.Length; i++)
{
Transform newBone = (Transform) boneNameMap[oldBones[i].name];
if (newBone == null)
{
Debug.LogWarning($"Combiner: bone '{oldBones[i].name}' on part '{part.name}' not found in rig; remapping to root.");
newBone = rootBone.transform;
}
newBones[i] = newBone;
}
renderer.sharedMesh = MeshUtils.CopyMesh(part.sharedMesh);
Transform newRootBone = (Transform) boneNameMap[part.rootBone.name];
renderer.rootBone = newRootBone == null ? rootBone.transform : newRootBone;
// CopyMesh does not copy blend shapes, so re-add them from the source part.
MergeAndGetAllBlendShapeDataOfSkinnedMeshRenderers(
new[]
{
part
},
renderer.sharedMesh,
renderer
);
renderer.bones = newBones;
renderer.sharedMaterial = baseMaterial == null ? part.sharedMaterial : baseMaterial;
}
return partsModel;
}
/// <summary>
/// Builds the shared skeleton for a new character model by instantiating the base model's rig and adding any extra
/// bones required by the given parts.
/// </summary>
/// <param name="parts">The part meshes that will be bound to the skeleton.</param>
/// <param name="baseModel">The base model that has the base rig.</param>
/// <param name="characterRoot">The transform of the new character model the skeleton will be parented to.</param>
/// <param name="boneNameMap">The output map between bone names and the bones of the new skeleton.</param>
/// <returns>The root bone GameObject of the new skeleton.</returns>
private static GameObject BuildSkeleton(
List<SkinnedMeshRenderer> parts,
GameObject baseModel,
Transform characterRoot,
out Hashtable boneNameMap
)
{
Transform modelRootBone = baseModel.GetComponentInChildren<SkinnedMeshRenderer>().rootBone;
GameObject rootBone = GameObject.Instantiate(modelRootBone.gameObject, characterRoot, true);
rootBone.name = modelRootBone.name;
boneNameMap = CreateBoneNameMap(rootBone);
Transform[] additionalBones = FindAdditionalBones(boneNameMap, new List<SkinnedMeshRenderer>(parts));
if (additionalBones.Length > 0)
{
JoinAdditionalBonesToBoneArray(Array.Empty<Transform>(), additionalBones, boneNameMap);
// Need to redo the name map now that we have updated the bone array.
boneNameMap = CreateBoneNameMap(rootBone);
}
return rootBone;
}
/// <summary>
/// Collects the bones used by the combined parts in rig hierarchy (pre-order depth-first) order, one entry per unique bone name.
/// Traversal order and first-wins duplicate name handling match <see cref="CreateBoneNameMap" /> so each indexed
/// Transform is the same instance the bone name map resolves to.
/// </summary>
/// <param name="current">The current bone being processed.</param>
/// <param name="usedBoneNames">The names of all bones used by the parts being combined.</param>
/// <param name="orderedBones">The output list of unique bones, in hierarchy order.</param>
/// <param name="boneIndexByName">The output map from bone name to its index in <paramref name="orderedBones" />.</param>
private static void CollectUsedBonesDepthFirst(
Transform current,
HashSet<string> usedBoneNames,
List<Transform> orderedBones,
Dictionary<string, int> boneIndexByName
)
{
if (usedBoneNames.Contains(current.name) && !boneIndexByName.ContainsKey(current.name))
{
boneIndexByName.Add(current.name, orderedBones.Count);
orderedBones.Add(current);
}
// Recurse into all children regardless; a used bone can sit under an unused one.
for (int i = 0; i < current.childCount; i++)
{
CollectUsedBonesDepthFirst(current.GetChild(i), usedBoneNames, orderedBones, boneIndexByName);
}
}
/// <summary>
/// Remaps the bone indices of the given bone weights using the given index remap table.
/// </summary>
/// <param name="weights">The bone weights to remap.</param>
/// <param name="indexRemap">A table mapping old bone indices to new bone indices.</param>
/// <returns>A new array of bone weights with remapped bone indices.</returns>
private static BoneWeight[] RemapBoneWeights(BoneWeight[] weights, int[] indexRemap)
{
BoneWeight[] remappedWeights = new BoneWeight[weights.Length];
for (int i = 0; i < weights.Length; i++)
{
BoneWeight weight = weights[i];
weight.boneIndex0 = indexRemap[weight.boneIndex0];
weight.boneIndex1 = indexRemap[weight.boneIndex1];
weight.boneIndex2 = indexRemap[weight.boneIndex2];
weight.boneIndex3 = indexRemap[weight.boneIndex3];
remappedWeights[i] = weight;
}
return remappedWeights;
}
/// <summary>
/// Processes the movement of bones if required for the given movement dictionary.
/// </summary>
/// <param name="boneNameMap">The bone name map that has all the bones of the rig.</param>
/// <param name="movementDictionary">The dictionary of bones to process the movement from.</param>
/// <param name="rotationDictionary">The dictionary of bone rotations to process.</param>
public static void ProcessBoneMovement(Hashtable boneNameMap, Dictionary<string, Vector3> movementDictionary, Dictionary<string, Quaternion> rotationDictionary)
{
Dictionary<string, Vector3> bonePositionDictionary = new Dictionary<string, Vector3>();
Dictionary<string, Quaternion> boneRotationDictionary = new Dictionary<string, Quaternion>();
Dictionary<string, Vector3> boneMovementDictionary = new Dictionary<string, Vector3>();
foreach (Transform currentBone in boneNameMap.Values)
{
// Store bone positions from rig before processing joints.
bonePositionDictionary.TryAdd(currentBone.name, currentBone.transform.localPosition);
boneRotationDictionary.TryAdd(currentBone.name, currentBone.transform.localRotation);
if (movementDictionary.ContainsKey(currentBone.name))
{
float jointDistance = Vector3.Distance(bonePositionDictionary[currentBone.name], movementDictionary[currentBone.name]);
float rotationDistance = Quaternion.Angle(boneRotationDictionary[currentBone.name], rotationDictionary[currentBone.name]);
// If the bone in the new part is at a different location, move the actual bone to the same position.
if (jointDistance > 0.0001)
{
Vector3 rigMovement = movementDictionary[currentBone.name];
// If an existing joint movement exists, and is further from the standard joint position, use that instead.
if (boneMovementDictionary.TryGetValue(currentBone.name, out Vector3 existingMovement)
&& Math.Abs(Vector3.Distance(bonePositionDictionary[currentBone.name], existingMovement)) > Math.Abs(jointDistance))
{
rigMovement = existingMovement;
}
currentBone.transform.localPosition = rigMovement;
boneMovementDictionary[currentBone.name] = rigMovement;
}
if (rotationDistance > 0.01)
{
Quaternion rigRotation = rotationDictionary[currentBone.name];
if (boneRotationDictionary.TryGetValue(currentBone.name, out Quaternion existingRotation)
&& Math.Abs(Quaternion.Angle(boneRotationDictionary[currentBone.name], existingRotation)) > Math.Abs(rotationDistance))
{
rigRotation = existingRotation;
}
currentBone.transform.localRotation = rigRotation;
boneRotationDictionary[currentBone.name] = rigRotation;
}
}
}
}
/// <summary>
/// Creates a map between bones and their names.
/// </summary>
/// <param name="currentBone">The Current bone being mapped.</param>
/// <returns>A hashmap between bone names and bones.</returns>
public static Hashtable CreateBoneNameMap(GameObject currentBone)
{
Hashtable boneNameMap = new Hashtable();
boneNameMap.Add(currentBone.name, currentBone.transform);
for (int i = 0; i < currentBone.transform.childCount; i++)
{
Hashtable childBoneMap = CreateBoneNameMap(currentBone.transform.GetChild(i).gameObject);
foreach (DictionaryEntry entry in childBoneMap)
{
if (!boneNameMap.ContainsKey(entry.Key))
{
boneNameMap.Add(entry.Key, (Transform) entry.Value);
}
}
}
return boneNameMap;
}
/// <summary>
/// Finds any bones in a given list of SkinnedMeshRenderers that aren't in the given bone map.
/// </summary>
/// <param name="boneMap">The bone map to check for the existence of bones.</param>
/// <param name="meshes">The list of SkinnedMeshRenderers to check for additional bones.</param>
/// <returns>An array of all additional bones.</returns>
public static Transform[] FindAdditionalBones(Hashtable boneMap, List<SkinnedMeshRenderer> meshes)
{
List<Transform> newBones = new List<Transform>();
foreach (SkinnedMeshRenderer mesh in meshes)
{
foreach (Transform bone in mesh.bones)
{
if (!boneMap.ContainsKey(bone.name))
{
newBones.Add(bone);
}
}
}
return newBones.ToArray();
}
/// <summary>
/// Adds additional bones to the current bone array.
/// </summary>
/// <param name="bones">The current bone array.</param>
/// <param name="additionBones">The new bones to add.</param>
/// <param name="boneMap">The current bone name map.</param>
/// <returns>The new bone array.</returns>
public static Transform[] JoinAdditionalBonesToBoneArray(Transform[] bones, Transform[] additionBones, Hashtable boneMap)
{
List<Transform> fullBones = new List<Transform>();
fullBones.AddRange(bones);
foreach (Transform bone in additionBones)
{
Transform newParent = (Transform) boneMap[bone.parent.name];
if (newParent != null && !newParent.Find(bone.name))
{
GameObject newBone = GameObject.Instantiate(bone.gameObject, newParent);
newBone.name = newBone.name.Replace("(Clone)", "");
fullBones.Add(newBone.transform);
if (!boneMap.ContainsKey(bone.name))
{
boneMap.Add(bone.name, newBone.transform);
}
}
}
return fullBones.ToArray();
}
}
}