CharacterBody2D Implementation

Expert CharacterBody2D feel systems — not beginner moveandslide tutorials.

NEVER Do

• NEVER use RigidBody2D for standard player controllers — RigidBody is for physics-simulated objects. For responsive, feel-driven player movement, always use CharacterBody2D.
• NEVER multiply velocity by delta before moveandslide() — moveandslide() handles delta internally. Manual multiplication makes movement framerate-dependent.
• NEVER use globalposition updates for gameplay movement — Use velocity + moveand_slide(). Direct position hacks bypass collision, floor snap, and one-way rules.
• NEVER "fall through" one-ways by nudging position.y — Use one-way collision shapes + layer/mask (and temporary mask disable / collide-with-areas patterns). See godot-2d-physics.
• NEVER ignore floor/wall/ceiling state right after moveandslide() — isonfloor(), isonwall(), isonceiling(), and slide collisions drive coyote, wall jump, and bonk logic.
• NEVER rely on default floorsnaplength for fast stair-climbing — Default snapping is too small for high-velocity characters. Use custom raycast-based stair logic.
• NEVER apply gravity while isonfloor() is true — Constant downward force causes micro-jitter and fights floor-snap. Reset velocity.y on land.
• NEVER use Area2D as primary ground detection — Prefer isonfloor() / shapecasts; Areas are for triggers, not floor truth.
• NEVER forget ceiling bonk — Reset velocity.y when isonceiling() or the player floats into the ceiling until gravity wins.
• NEVER round physics positions for pixel art — Keep physics high-precision; round sprite positions in process only ([subpixelmovementrounding.gd](scripts/subpixelmovement_rounding.gd)).
• NEVER spam queuefree() for hordes — Pool bullets/enemies when spawn/despawn is frequent ([performancecharacterpooling.gd](scripts/performancecharacter_pooling.gd)).

When to Use CharacterBody2D

Decision Tree → MANDATORY Scripts

Golden path: Read expertphysics2d.gd first. Add dash/wall/jump scripts only after that controller is in place. Do not re-inline coyote/buffer/accel loops in the scene when the script already owns them.

One-Way Platforms (correct recipe)

1. Author one-way on the platform collider (CollisionShape2D one-way / TileSet physics one-way), not by teleporting the player.
2. Put platforms and player on explicit collision layers/masks so drop-through can temporarily clear the platform bit (or disable collide-with) while holding down + jump — then restore next physics frames.
3. Keep drop-through on the physics tick; never bypass moveandslide with position nudges.
4. For tile one-ways, align TileSet physics layers with CharacterBody masks — see godot-tilemap-mastery + godot-2d-physics.

Expert Character Architectures

1. Wall Cling (Variable Friction)

Monitor isonwall() while falling; scale velocity.y by a friction factor (optionally from tile custom data) instead of a binary wall-slide bool. Prefer [wallslidejumprefined.gd](scripts/wallslidejumprefined.gd) over a bespoke cling fork.

2. Animation-Driven Movement (Root Motion)

Pull AnimationTree.getrootmotionposition(), convert to 2D, assign velocity = motion / delta, then moveand_slide(). Keeps feet locked to authored clips; pair with godot-2d-animation.

3. Game-Feel Profiler (Jump Arcs)

Debug-draw historical positions + current velocity in draw() to visualize apex, coyote, and buffer windows while tuning exports on expertphysics2d.gd — [gamefeelprofiler.gd](scripts/gamefeel_profiler.gd).

MANDATORY for top-down/tank recipes, moving platforms, slide-collision response, and gotcha tables: [movement-recipes.md](references/movement-recipes.md). Do NOT Load when expertphysics2d.gd already covers your platformer scope.

Reference

Progressive disclosure: open Official Documentation links only when researching a specific API;
load Related Skills when routing work to a peer domain — do not preload the whole lattice.

Official Documentation

• Using CharacterBody2D — Canonical moveand_slide / floor-wall-ceiling contracts; do not set position for gameplay motion.
• CharacterBody2D — API for velocity, snap, ison_floor / wall / ceiling, and slide-collision accessors.
• Physics introduction — Why CharacterBody vs RigidBody/StaticBody, and how layers/masks gate every contact.
• Collision shapes (2D) — Capsule/box sizing and why scaled CollisionShape2D nodes corrupt normals and floor detect.
• 2D movement — Input axes into velocity for top-down and platformer starters before juice systems.
• Kinematic character (2D) — Classic slide/collision loop patterns that still inform custom stair and slope handling.
• Troubleshooting physics issues — One-way platforms, tunneling, and jitter diagnoses that show up in CharacterBody feel bugs.
• Ray-casting — Direct-space rays for stair snaps, ledge checks, and ground probes beyond isonfloor().
• KinematicCollision2D — Per-slide normals/remainders from getslide_collision for wall jumps and ceiling bonks.
• Physics interpolation introduction — Smooth visuals at high refresh while keeping jump/coyote logic on the physics tick.
• InputEvent — Action just-pressed timing that jump buffers and coyote windows depend on.

Related Skills

Prerequisites

• godot-project-foundations — Default gravity, physics tick rate, and 2D layer names must be set before coyote/jump feel is tunable.
• godot-gdscript-mastery — Typed physicsprocess, timers, and move_toward discipline underpin every movement script here.
• godot-2d-physics — Collision layer/mask matrices, one-way shapes, and query hygiene CharacterBody motion sits on.
• godot-input-handling — Physics-step action sampling so jump buffer / coyote windows stay frame-stable.

Complements

• godot-raycasting-queries — Stair snaps, wall cling probes, and ledge rays that extend beyond ison* helpers.
• godot-tilemap-mastery — One-way tiles and tile physics layers must match CharacterBody masks for platforms.
• godot-2d-animation — Drive walk/jump/fall clips from floor/air/dash state without fighting moveandslide.
• godot-state-machine-advanced — Dash, wall-slide, and airborne states scale cleaner than giant physicsprocess switches.
• godot-camera-systems — Follow/look-ahead cameras couple tightly to CharacterBody velocity and landing snaps.
• godot-signal-architecture — Landed/dashed/wall-jumped events need clean ownership so UI/VFX listeners do not spam.

Downstream / consumers

• godot-genre-platformer — Genre-level platformer feel consumes coyote, buffer, slopes, and one-ways from this skill.
• godot-genre-metroidvania — Ability-gated movement (wall jump, dash) builds on the controllers defined here.
• godot-combat-system — Knockback and hitstun apply impulses through the same velocity + slide loop.
• godot-monte-carlo-balancer — Coyote frames, jump height, dash cooldown, and air accel are balance knobs — simulate them instead of guessing.

Master

• godot-master — Library router and mirrored entry point for CharacterBody2D alongside sibling domains.