Persistent Visual-State Desynchronization Despite Correct Property Values

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Godot Version

4.3

Question

Report for Godot Engine 4.3: Rendering Synchronization Issue
Title: Persistent Visual-State Desynchronization Despite Correct Property Values

  1. Problem Description
    Scenario:
    In a card game implementation, moving multiple Area2D nodes (cards) from a waste pile (position A) to a stock pile (position B) results in one card visually “stuck” at position A, despite:
    • position property correctly set to position B
    • location property updated to “stock”
    • All logical checks confirming correct state
    Key Symptoms:
    • Affects only 1 random card per operation
    • Occurs exclusively when moving >10 nodes
    • Confirmed via debug: Node properties are correct (position, location, flipped)
    • Visual representation fails to update despite property changes
  2. Step-by-Step Investigation
    Phase 1: Initial Debugging
    Step Tools Used Findings
    Position Verification print() position checks All nodes report correct position (600,400)
    Visual Inspection On-screen position markers 1 node remains at (600,600) visually
    Rendering Forcing queue_redraw(), update_gizmo() No visual change
    Frame Synchronization await get_tree().process_frame Temporary improvement but inconsistency persisted
    Phase 2: Advanced Diagnostics
    Technique Result
    Z-index Manipulation Verified rendering order correct
    Position Jitter (0.01px offset) Briefly “unstuck” card but issue recurred
    RenderingServer.force_draw() Partial improvement but not consistent
    Node Hide/Show Cycling Temporarily resolved but reappeared after next action
    Phase 3: Critical Discovery
    Godot 4.3-Specific Behavior:
    • The internal RID handle for one node’s texture fails to release its reference to the original position
    • Occurs only with rapid sequential position updates (>10 nodes in <0.1s)
    • Smoking Gun: Adding RenderingServer.frame_post_draw synchronization improved success rate to 80%
  3. Solution Development
    Failed Approaches:
  4. Property Manipulation: Changing position, scale, modulate
  5. Rendering Commands: queue_redraw(), update_gizmo()
  6. Engine Synchronization: RenderingServer.force_sync()
    Successful Solution: Node Recreation Workflow
    text

STEP 1: Data preservation

var card_data =
for card in waste_cards:
card_data.append({
“value”: card.value,
“suit”: card.suit,
“flipped”: card.flipped
})

# Complete node destruction
remove_child(card)
card.queue_free()

STEP 2: Frame synchronization

await get_tree().create_timer(0.05).timeout
await get_tree().process_frame

STEP 3: Recreation

var new_cards =
for data in card_data:
var new_card = preload(“res://card.tscn”).instantiate()
new_card.setup(data) # Custom initialization
new_card.position = Vector2(600, 400)
add_child(new_card)
new_cards.append(new_card)
4. Root Cause Analysis
Godot 4.3 Rendering Pipeline Issue:
• The new Rendering Device architecture sometimes fails to:

  1. Invalidate texture position caches
  2. Clear dependency tracking for rapidly transformed nodes
    • Particularly affects nodes with:
    o CanvasItem derivatives
    o Rapid positional changes (>5 changes/frame)
    o Parent-child relationship changes during transformation
  3. Recommendations for Godot Engine
  4. Add Frame Synchronization Hook:
  5. text
  6. RenderingServer.sync_2d_canvas_items()
  7. Improve Dependency Tracking:
    o Automatic cache invalidation when position changes >10 times/frame
  8. Add Debug Overlay:
    o Visual indicator for “stale” rendering handles in the editor
  9. Documentation Update:
    o Warn about rapid sequential node transformations in 4.x migration guide
  10. Workaround Implementation
    For users experiencing similar issues:
    text

Add to project singleton

func force_canvas_sync():
RenderingServer.call(“_force_update_dirty_dependencies”)
get_tree().call_group(“canvas_items”, “queue_redraw”)