gltfio: allow dynamic attach / detach for bones (#5601)

Sceneform allowed users to attach and detach bones, so this seems like
a useful feature.

Fixes #3075

RELEASE_NOTES.md

@@ -5,6 +5,9 @@ A new header is inserted each time a *tag* is created.
 
 ## main branch
 
+- gltfio: support skinning with bones that do not belong to any scene
+- gltfio: add attachSkin / detachSkin method to FilamentAsset
+
 ## v1.23.0
 
 - Normals on morphed models have been fixed (core Filament change)

android/gltfio-android/src/main/cpp/FilamentAsset.cpp

@@ -340,3 +340,19 @@ Java_com_google_android_filament_gltfio_FilamentAsset_nReleaseSourceData(JNIEnv*
     FilamentAsset* asset = (FilamentAsset*) nativeAsset;
     asset->releaseSourceData();
 }
+
+extern "C" JNIEXPORT void JNICALL
+Java_com_google_android_filament_gltfio_FilamentAsset_nAttachSkin(JNIEnv* env, jclass,
+        jlong nativeAsset, jint skinIndex, jint targetEntity) {
+    FilamentAsset* asset = (FilamentAsset*) nativeAsset;
+    Entity target = Entity::import(targetEntity);
+    asset->attachSkin(skinIndex, target);
+}
+
+extern "C" JNIEXPORT void JNICALL
+Java_com_google_android_filament_gltfio_FilamentAsset_nDetachSkin(JNIEnv* env, jclass,
+        jlong nativeAsset, jint skinIndex, jint targetEntity) {
+    FilamentAsset* asset = (FilamentAsset*) nativeAsset;
+    Entity target = Entity::import(targetEntity);
+    asset->detachSkin(skinIndex, target);
+}

android/gltfio-android/src/main/java/com/google/android/filament/gltfio/FilamentAsset.java

@@ -241,17 +241,37 @@ public class FilamentAsset {
         return result;
     }
 
+    /**
+     * Attaches the given skin to the given node, which must have an associated mesh with
+     * BONE_INDICES and BONE_WEIGHTS attributes.
+     *
+     * This is a no-op if the given skin index or target is invalid.
+     */
+    public void attachSkin(@IntRange(from = 0) int skinIndex, @Entity int target) {
+        nAttachSkin(getNativeObject(), skinIndex, target);
+    }
+
+    /**
+     * Attaches the given skin to the given node, which must have an associated mesh with
+     * BONE_INDICES and BONE_WEIGHTS attributes.
+     *
+     * This is a no-op if the given skin index or target is invalid.
+     */
+    public void detachSkin(@IntRange(from = 0) int skinIndex, @Entity int target) {
+        nDetachSkin(getNativeObject(), skinIndex, target);
+    }
+
     /**
      * Gets the joint count at skin index in this asset.
      */
-    public int getJointCountAt(int skinIndex) {
+    public int getJointCountAt(@IntRange(from = 0) int skinIndex) {
         return nGetJointCountAt(getNativeObject(), skinIndex);
     }
 
     /**
      * Gets joints at skin index in this asset.
      */
-    public @NonNull @Entity int[] getJointsAt(int skinIndex) {
+    public @NonNull @Entity int[] getJointsAt(@IntRange(from = 0) int skinIndex) {
         int[] result = new int[getJointCountAt(skinIndex)];
         nGetJointsAt(getNativeObject(), skinIndex, result);
         return result;
@@ -345,6 +365,9 @@ public class FilamentAsset {
     private static native int nGetMorphTargetCount(long nativeAsset, int entity);
     private static native void nGetMorphTargetNames(long nativeAsset, int entity, String[] result);
 
+    private static native void nAttachSkin(long nativeAsset, int skinIndex, int entity);
+    private static native void nDetachSkin(long nativeAsset, int skinIndex, int entity);
+
     private static native void nGetBoundingBox(long nativeAsset, float[] box);
     private static native String nGetName(long nativeAsset, int entity);
     private static native String nGetExtras(long nativeAsset, int entity);

libs/gltfio/include/gltfio/FilamentAsset.h

@@ -238,6 +238,21 @@ public:
      */
     const Entity* getJointsAt(size_t skinIndex) const noexcept;
 
+    /**
+     * Attaches the given skin to the given node, which must have an associated mesh with
+     * BONE_INDICES and BONE_WEIGHTS attributes.
+     *
+     * This is a no-op if the given skin index or target is invalid.
+     */
+    void attachSkin(size_t skinIndex, Entity target) noexcept;
+
+    /**
+     * Detaches the given skin from the given node.
+     *
+     * This is a no-op if the given skin index or target is invalid.
+     */
+    void detachSkin(size_t skinIndex, Entity target) noexcept;
+
     /**
      * Gets the morph target name at the given index in the given entity.
      */

libs/gltfio/src/FFilamentAsset.h

@@ -212,6 +212,10 @@ struct FFilamentAsset : public FilamentAsset {
 
     const utils::Entity* getJointsAt(size_t skinIndex) const noexcept;
 
+    void attachSkin(size_t skinIndex, Entity target) noexcept;
+
+    void detachSkin(size_t skinIndex, Entity target) noexcept;
+
     const char* getMorphTargetNameAt(utils::Entity entity, size_t targetIndex) const noexcept;
 
     size_t getMorphTargetCountAt(utils::Entity entity) const noexcept;

libs/gltfio/src/FilamentAsset.cpp

@@ -120,6 +120,20 @@ const utils::Entity* FFilamentAsset::getJointsAt(size_t skinIndex) const noexcep
     return mSkins[skinIndex].joints.data();
 }
 
+void FFilamentAsset::attachSkin(size_t skinIndex, Entity target) noexcept {
+    if (UTILS_UNLIKELY(mSkins.size() <= skinIndex || target.isNull())) {
+        return;
+    }
+    mSkins[skinIndex].targets.insert(target);
+}
+
+void FFilamentAsset::detachSkin(size_t skinIndex, Entity target) noexcept {
+    if (UTILS_UNLIKELY(mSkins.size() <= skinIndex || target.isNull())) {
+        return;
+    }
+    mSkins[skinIndex].targets.erase(target);
+}
+
 const char* FFilamentAsset::getMorphTargetNameAt(utils::Entity entity,
         size_t targetIndex) const noexcept {
     if (!mResourcesLoaded) {
@@ -381,6 +395,14 @@ const utils::Entity* FilamentAsset::getJointsAt(size_t skinIndex) const noexcept
     return upcast(this)->getJointsAt(skinIndex);
 }
 
+void FilamentAsset::attachSkin(size_t skinIndex, Entity target) noexcept {
+    upcast(this)->attachSkin(skinIndex, target);
+}
+
+void FilamentAsset::detachSkin(size_t skinIndex, Entity target) noexcept {
+    upcast(this)->detachSkin(skinIndex, target);
+}
+
 const char* FilamentAsset::getMorphTargetNameAt(utils::Entity entity,
         size_t targetIndex) const noexcept {
     return upcast(this)->getMorphTargetNameAt(entity, targetIndex);

web/filament-js/filament.d.ts

@@ -584,6 +584,9 @@ export class gltfio$FilamentAsset {
     public popRenderable(): Entity;
     public getMaterialInstances(): Vector<MaterialInstance>;
     public getResourceUris(): Vector<string>;
+    public getSkinNames(): Vector<string>;
+    public attachSkin(skinIndex: number, entity: Entity): void;
+    public detachSkin(skinIndex: number, entity: Entity): void;
     public getBoundingBox(): Aabb;
     public getName(entity: Entity): string;
     public getExtras(entity: Entity): string;

web/filament-js/jsbindings.cpp

@@ -1803,6 +1803,17 @@ class_<FilamentAsset>("gltfio$FilamentAsset")
         return retval;
     }), allow_raw_pointers())
 
+    .function("getSkinNames", EMBIND_LAMBDA(std::vector<std::string>, (FilamentAsset* self), {
+        std::vector<std::string> names(self->getSkinCount());
+        for (size_t i = 0; i < names.size(); ++i) {
+            names[i] = self->getSkinNameAt(i);
+        }
+        return names;
+    }), allow_raw_pointers())
+
+    .function("attachSkin", &FilamentAsset::attachSkin)
+    .function("detachSkin", &FilamentAsset::detachSkin)
+
     .function("getBoundingBox", &FilamentAsset::getBoundingBox)
     .function("getName", EMBIND_LAMBDA(std::string, (FilamentAsset* self, utils::Entity entity), {
         return std::string(self->getName(entity));