diff -r 84472fb3adbd -r cfa1d05754ac src/scene.c
--- a/src/scene.c	Thu Aug 15 17:33:42 2024 +0200
+++ b/src/scene.c	Sun Oct 06 19:43:08 2024 +0200
@@ -32,7 +32,6 @@
 
 #include <cx/linked_list.h>
 #include <cx/array_list.h>
-#include <cx/tree.h>
 #include <cx/utils.h>
 
 #include "ascension/shader.h"
@@ -40,24 +39,7 @@
 
 #include <assert.h>
 
-static CxTreeIterator asc_scene_node_iterator(
-        AscSceneNode *node,
-        bool visit_on_exit
-) {
-    return cx_tree_iterator(
-            node, visit_on_exit,
-            offsetof(AscSceneNode, children),
-            offsetof(AscSceneNode, next)
-    );
-}
-
-static CxTreeVisitor asc_scene_node_visitor(AscSceneNode *node) {
-    return cx_tree_visitor(node,
-            offsetof(AscSceneNode, children),
-            offsetof(AscSceneNode, next)
-    );
-}
-
+// TODO: move to a sprite.c
 static void asc_sprite_draw(AscSprite const *node) {
     // Obtain shader
     AscShaderSprite *shader = ASC_SHADER_SPRITE;
@@ -76,7 +58,7 @@
     asc_primitives_draw_plane();
 }
 
-void asc_scene_draw(AscSceneNode *root, asc_recti viewport, AscCamera *camera) {
+void asc_scene_draw(AscScene scene, asc_recti viewport, AscCamera *camera) {
     // create render groups
     CxList *render_group[ASC_RENDER_GROUP_COUNT];
     cx_for_n(i, ASC_RENDER_GROUP_COUNT) {
@@ -84,7 +66,7 @@
     }
 
     // skip the root node deliberately, we know it's just the container
-    CxTreeVisitor iter = asc_scene_node_visitor(root);
+    CxTreeVisitor iter = cxTreeVisit(scene);
     cxIteratorNext(iter);
 
     // update the children and add them to the render groups
@@ -128,7 +110,7 @@
             asc_mat4f_mulst(
                     node->world_transform,
                     node->transform,
-                    node->parent->world_transform
+                    asc_scene_node_parent(node)->world_transform
             );
         }
 
@@ -186,52 +168,55 @@
 
 AscSceneNode *asc_scene_node_empty(void) {
     AscSceneNode *node = calloc(1, sizeof(AscSceneNode));
-    node->free_func = (asc_scene_free_func) free;
     node->scale.x = node->scale.y = node->scale.z = 1;
     asc_transform_identity(node->transform);
     asc_transform_identity(node->world_transform);
     return node;
 }
 
-void asc_scene_node_free(AscSceneNode *node) {
-    if (node == NULL) return;
-
-    // remove this node from its parent
-    asc_scene_node_unlink(node);
-
-    // free the entire subtree
-    CxTreeIterator iter = asc_scene_node_iterator(node, true);
-    cx_foreach(AscSceneNode*, child, iter) {
-        if (!iter.exiting) continue;
-        if (child->behaviors != NULL) {
-            cxListDestroy(child->behaviors);
-        }
-        if (child->free_func != NULL) {
-            child->free_func(child);
-        } else {
-            free(child);
-        }
+void asc_scene_node_destructor(AscSceneNode *node) {
+    if (node->behaviors != NULL) {
+        cxListDestroy(node->behaviors);
+    }
+    if (node->free_func != NULL) {
+        node->free_func(node);
+    } else {
+        free(node);
     }
 }
 
-void asc_scene_node_link(AscSceneNode * restrict parent, AscSceneNode * restrict node) {
-    cx_tree_link(
-            parent, node,
-            offsetof(AscSceneNode, parent),
-            offsetof(AscSceneNode, children),
-            offsetof(AscSceneNode, prev),
-            offsetof(AscSceneNode, next)
+AscScene asc_scene_create(void) {
+    AscSceneNode *root = asc_scene_node_empty();
+    AscScene scene = cxTreeCreateWrapped(
+            cxDefaultAllocator, root,
+            cx_tree_node_base_layout
     );
+    root->scene = scene;
+    scene->simple_destructor = (cx_destructor_func) asc_scene_node_destructor;
+    return scene;
+}
+
+void asc_scene_destroy(AscScene scene) {
+    cxTreeDestroy(scene);
 }
 
-void asc_scene_node_unlink(AscSceneNode *node) {
-    cx_tree_unlink(
-            node,
-            offsetof(AscSceneNode, parent),
-            offsetof(AscSceneNode, children),
-            offsetof(AscSceneNode, prev),
-            offsetof(AscSceneNode, next)
-    );
+void asc_scene_node_add(AscSceneNode * restrict parent, AscSceneNode * restrict node) {
+    assert(node->scene == NULL || node->scene == parent->scene);
+    cxTreeSetParent(parent->scene, parent, node);
+    CxTreeVisitor visitor = cxTreeVisitSubtree(parent->scene, node);
+    cx_foreach(AscSceneNode *, n, visitor) {
+        n->scene = parent->scene;
+    }
+    asc_node_update_transform(node);
+}
+
+void asc_scene_node_remove(AscSceneNode *node) {
+    if (node->scene == NULL) return;
+    cxTreeRemoveSubtree(node->scene, node);
+    CxTreeVisitor visitor = cxTreeVisitSubtree(node->scene, node);
+    cx_foreach(AscSceneNode *, n, visitor) {
+        n->scene = NULL;
+    }
 }
 
 void asc_scene_add_behavior(
@@ -263,7 +248,14 @@
         return;
     }
 
-    CxTreeIterator iter = asc_scene_node_iterator(node, false);
+    // if node is not part of a scene, just mark it and return
+    if (node->scene == NULL) {
+        asc_set_flag(node->flags, ASC_SCENE_NODE_UPDATE_TRANSFORM);
+        return;
+    }
+
+    // creating the iterator this way saves us from needing scene as parameter
+    CxTreeIterator iter = cxTreeIterateSubtree(node->scene, node, false);
     cx_foreach(AscSceneNode*, n, iter) {
         if (asc_test_flag(n->flags, ASC_SCENE_NODE_UPDATE_TRANSFORM)) {
             cxTreeIteratorContinue(iter);