# HG changeset patch
# User Mike Becker <universe@uap-core.de>
# Date 1705841903 -3600
# Node ID 4ccf4703999efd276089ed7cefb072c8b239cdde
# Parent  139dac8ef9ee7bdc0cc89c7826a1bd807c1968ad
improve implementation of scene graph tree

diff -r 139dac8ef9ee -r 4ccf4703999e src/ascension/scene.h
--- a/src/ascension/scene.h	Sun Jan 21 13:34:49 2024 +0100
+++ b/src/ascension/scene.h	Sun Jan 21 13:58:23 2024 +0100
@@ -28,11 +28,11 @@
 #ifndef ASCENSION_SCENE_H
 #define ASCENSION_SCENE_H
 
-#include <cx/list.h>
-
 typedef struct AscSceneNode {
     struct AscSceneNode *parent;
-    CxList *children;
+    struct AscSceneNode *prev;
+    struct AscSceneNode *next;
+    struct AscSceneNode *children;
     // TODO: add node contents
 } AscSceneNode;
 
diff -r 139dac8ef9ee -r 4ccf4703999e src/scene.c
--- a/src/scene.c	Sun Jan 21 13:34:49 2024 +0100
+++ b/src/scene.c	Sun Jan 21 13:58:23 2024 +0100
@@ -28,7 +28,6 @@
 #include "ascension/scene.h"
 #include "ascension/error.h"
 
-#include <cx/linked_list.h>
 #include <assert.h>
 
 void asc_scene_init(AscScene *scene) {
@@ -44,24 +43,25 @@
 }
 
 AscSceneNode *asc_scene_node_create(AscSceneNode *parent) {
-    AscSceneNode *node = malloc(sizeof(AscSceneNode));
+    // TODO: check if this can remain a calloc or if it's too expensive
+    AscSceneNode *node = calloc(1, sizeof(AscSceneNode));
     assert(node != NULL);
-    node->children = cxLinkedListCreateSimple(CX_STORE_POINTERS);
-    assert(node->children != NULL);
-    node->parent = NULL;
     asc_scene_node_link(node, parent);
     return node;
 }
 
 void asc_scene_node_free(AscSceneNode *node) {
     if (node == NULL) return;
-    while (cxListSize(node->children) > 0) {
-        AscSceneNode *child = cxListAt(node->children, 0);
-        asc_scene_node_free(child);
+
+    // free the children recursively
+    while (node->children != NULL) {
+        asc_scene_node_free(node->children);
     }
-    if (node->parent != NULL) {
-        cxListFindRemove(node->parent->children, node);
-    }
+
+    // remove this node from its parent
+    asc_scene_node_unlink(node);
+
+    // free the node
     free(node);
 }
 
@@ -72,13 +72,26 @@
     if (node->parent == parent) return;
     if (node->parent != NULL || parent == NULL) asc_scene_node_unlink(node);
     if (parent != NULL) {
-        cxListAdd(parent->children, node);
+        if (parent->children == NULL) {
+            parent->children = node;
+        } else {
+            parent->children->prev = node;
+            node->next = parent->children;
+        }
         node->parent = parent;
     }
 }
 
 void asc_scene_node_unlink(AscSceneNode *node) {
     if (node->parent == NULL) return;
-    cxListFindRemove(node->parent->children, node);
-    node->parent = NULL;
+    AscSceneNode *left = node->prev;
+    AscSceneNode *right = node->next;
+    assert(left == NULL || node->parent->children != node);
+    if (left != NULL) {
+        left->next = right;
+    } else {
+        node->parent->children = right;
+    }
+    if (right != NULL) right->prev = left;
+    node->parent = node->prev = node->next = NULL;
 }
\ No newline at end of file