Add new queries to TransformManager and Scene.

filament/include/filament/Scene.h

@@ -63,7 +63,7 @@ class UTILS_PUBLIC Scene : public FilamentAPI {
 public:
 
     /**
-     * Set the SkyBox,
+     * Sets the SkyBox.
      *
      * The Skybox is drawn last and covers all pixels not touched by geometry.
      *
@@ -122,6 +122,13 @@ public:
      * @return The total number of Light objects in the Scene.
      */
     size_t getLightCount() const noexcept;
+
+    /**
+     * Returns true if the given entity is in the Scene.
+     *
+     * @return Whether the given entity is in the Scene.
+     */
+    bool hasEntity(utils::Entity entity) const noexcept;
 };
 
 } // namespace filament

filament/include/filament/TransformManager.h

@@ -105,7 +105,7 @@ public:
     void destroy(utils::Entity e) noexcept;
 
     /**
-     * Re-parent an entity to a new one.
+     * Re-parents an entity to a new one.
      * @param i             The instance of the transform component to re-parent
      * @param newParent     The instance of the new parent transform
      * @attention It is an error to re-parent an entity to a descendant and will cause undefined behaviour.
@@ -114,7 +114,30 @@ public:
     void setParent(Instance i, Instance newParent) noexcept;
 
     /**
-     * Set a local transform of a transform component.
+     * Returns the parent of a transform component, or the null entity if it is a root.
+     * @param i The instance of the transform component to query.
+     */
+    utils::Entity getParent(Instance i) const noexcept;
+
+    /**
+     * Returns the number of children of a transform component.
+     * @param i The instance of the transform component to query.
+     * @return The number of children of the queried component.
+     */
+    size_t getChildCount(Instance i) const noexcept;
+
+    /**
+     * Gets a list of children for a transform component.
+     *
+     * @param i The instance of the transform component to query.
+     * @param chidren Pointer to array-of-Entity. The array must have at least "count" elements.
+     * @param count The maximum number of children to retrieve.
+     * @return The number of children written to the pointer.
+     */
+    size_t getChildren(Instance i, utils::Entity* children, size_t count) const noexcept;
+
+    /**
+     * Sets a local transform of a transform component.
      * @param ci              The instance of the transform component to set the local transform to.
      * @param localTransform  The local transform (i.e. relative to the parent).
      * @see getTransform()

filament/src/Scene.cpp

@@ -349,6 +349,10 @@ size_t FScene::getLightCount() const noexcept {
     return count;
 }
 
+bool FScene::hasEntity(Entity entity) const noexcept {
+    return mEntities.find(entity) != mEntities.end();
+}
+
 void FScene::setSkybox(FSkybox const* skybox) noexcept {
     std::swap(mSkybox, skybox);
     if (skybox) {
@@ -424,4 +428,8 @@ size_t Scene::getLightCount() const noexcept {
     return upcast(this)->getLightCount();
 }
 
+bool Scene::hasEntity(Entity entity) const noexcept {
+    return upcast(this)->hasEntity(entity);
+}
+
 } // namespace filament

filament/src/components/TransformManager.cpp

@@ -69,6 +69,28 @@ void FTransformManager::setParent(Instance i, Instance parent) noexcept {
     }
 }
 
+Entity FTransformManager::getParent(Instance i) const noexcept {
+    i = mManager[i].parent;
+    return i ? mManager.getEntity(i) : Entity();
+}
+
+size_t FTransformManager::getChildCount(Instance i) const noexcept {
+    size_t count = 0;
+    for (Instance ci = mManager[i].firstChild; ci; ci = mManager[ci].next, ++count);
+    return count;
+}
+
+size_t FTransformManager::getChildren(Instance i, utils::Entity* children,
+        size_t count) const noexcept {
+    Instance ci = mManager[i].firstChild;
+    size_t numWritten = 0;
+    while (ci && numWritten < count) {
+        children[numWritten++] = mManager.getEntity(ci);
+        ci = mManager[ci].next;
+    }
+    return numWritten;
+}
+
 void FTransformManager::destroy(Entity e) noexcept {
     // update the reference of the element we're removing
     auto& manager = mManager;
@@ -392,6 +414,19 @@ void TransformManager::setParent(Instance i, Instance newParent) noexcept {
     upcast(this)->setParent(i, newParent);
 }
 
+utils::Entity TransformManager::getParent(Instance i) const noexcept {
+    return upcast(this)->getParent(i);
+}
+
+size_t TransformManager::getChildCount(Instance i) const noexcept {
+    return upcast(this)->getChildCount(i);
+}
+
+size_t TransformManager::getChildren(Instance i, utils::Entity* children,
+        size_t count) const noexcept {
+    return upcast(this)->getChildren(i, children, count);
+}
+
 void TransformManager::openLocalTransformTransaction() noexcept {
     upcast(this)->openLocalTransformTransaction();
 }

filament/src/components/TransformManager.h

@@ -62,6 +62,12 @@ public:
 
     void setParent(Instance i, Instance newParent) noexcept;
 
+    utils::Entity getParent(Instance i) const noexcept;
+
+    size_t getChildCount(Instance i) const noexcept;
+
+    size_t getChildren(Instance i, utils::Entity* children, size_t count) const noexcept;
+
     void openLocalTransformTransaction() noexcept;
 
     void commitLocalTransformTransaction() noexcept;

filament/src/details/Scene.h

@@ -67,6 +67,7 @@ public:
 
     size_t getRenderableCount() const noexcept;
     size_t getLightCount() const noexcept;
+    bool hasEntity(utils::Entity entity) const noexcept;
 
 public:
     /*