AchMover

AchMover is a 2D character movement component that works the moment you attach it. It does not use Rigidbody2D — collision resolution (move-and-slide), gravity, slopes, stairs, and ground snapping are all handled internally. The only required component is CapsuleCollider2D, which is added automatically.

Usage

Add the Ach Mover component to your character GameObject. That's it.

Mode	Controls
Platformer	A / D to move, Space / W / ↑ to jump
TopDown	WASD / arrow keys to move in all directions

New Input System supported — switching Player Settings to Input System Package automatically routes input through Keyboard.current / Gamepad.current.

If a Rigidbody2D exists on the same GameObject, AchMover sets simulated = false automatically to prevent it from fighting transform-based movement.

Inspector

Movement

Field	Default	Description
MoveSpeed	5	Movement speed in Units/sec
JumpForce	12	Jump impulse force (UseGravity = true only)
Mode	Platformer	Platformer or TopDown

Physics

Field	Default	Description
UseGravity	true	Enables gravity and ground detection
GravityScale	3	Gravity multiplier
FallMultiplier	2	Extra gravity while falling — higher = heavier feel
MaxFallSpeed	20	Terminal fall speed cap

Slopes & Stairs

Field	Default	Description
MaxSlopeAngle	50°	Maximum walkable slope angle. Anything steeper is treated as a wall
StepHeight	0.3	Maximum step / ledge height the character will auto-climb (Units)

Control

Field	Default	Description
Movable	true	false disables input — control via code only
FlipSprite	true	Mirrors transform.localScale.x based on movement direction — children (weapons, effects, hitboxes) flip together

Built-in Collision System

Each FixedUpdate, AchMover runs the following pipeline:

1. Velocity — combines input, gravity, and queued jumps into the per-frame velocity.
2. Move-and-slide — CapsuleCollider2D.Cast along the motion direction; on hit, slides along the surface. Up to 4 iterations to handle corners and multiple contacts.
3. Stair stepping — when blocked by a wall, attempts to lift over a ledge ≤ StepHeight (lift up → move forward → drop down).
4. Ground probe — capsule cast downward; grounded if surface angle ≤ MaxSlopeAngle.
5. Ground snap — pulls the character back to the slope surface when descending so it stays glued.
6. Depenetration — a final overlap check pushes out of any residual penetration.

State Properties

bool    isGrounded   = mover.IsGrounded;    // On the ground? (UseGravity = true only)
bool    isMoving     = mover.IsMoving;      // Actively moving? (based on input)
Vector2 velocity     = mover.Velocity;      // Current velocity
Vector2 groundNormal = mover.GroundNormal;  // Surface normal under the feet (Vector2.up if airborne)

Joystick / Custom Input

// Connect an on-screen joystick
mover.InputProvider = () => joystick.Direction;

// Disconnect (returns to keyboard input)
mover.InputProvider = null;

Code Control API

These methods work regardless of the Movable flag.

mover.Jump();                                   // Jump (UseGravity = true only)
mover.Teleport(new Vector2(10f, 0f));           // Instant position warp
mover.SetVelocity(new Vector2(-5f, 4f));        // Override velocity (knockback, etc.)
mover.AddForce(Vector2.left * 10f);             // Add to velocity as an impulse
mover.Stop();                                   // Stop immediately

Without a Rigidbody2D, AddForce always behaves like an impulse (added directly to velocity). The forceMode argument is kept for source compatibility but is ignored.

Knockback example

mover.Movable = false;
mover.SetVelocity(new Vector2(-6f, 5f));
await Task.Delay(400);
mover.Movable = true;

UseGravity combinations

Mode	UseGravity	Behaviour
Platformer	true	Gravity + jump + slopes + stairs, horizontal movement
Platformer	false	No gravity, horizontal movement only (vertical free)
TopDown	false	No gravity, free 4-direction movement
TopDown	true	4-direction movement + free fall (special cases)

AchFollower — AI Chasing

AchFollower is a standalone component that chases a target. It has no relation to AchMover and can be used on any GameObject independently.

Field	Default	Description
Target	null	The Transform to follow
MoveSpeed	5	Movement speed (Units/sec)
StopDistance	0.5	Stops moving when closer than this distance

// Set target
follower.SetTarget(player.transform);

// Clear target
follower.ClearTarget();

Moves by setting transform.position directly.

For advanced movement along an A* path, see the A* Pathfinding guide.

AchProjectile — Projectiles

Manages all projectile types (straight, homing, and more) in a single component. Select the Type in the Inspector — only the relevant fields are shown.

Common Fields

Field	Default	Description
Type	Straight	Projectile movement mode
MoveSpeed	10	Movement speed (Units/sec)

Per-Type Fields

Type	Field	Default	Description
Straight	Direction	Vector2.right	Initial movement direction
Homing	Target	null	Transform to track
Homing	TurnSpeed	180	Max turn angle per second (degrees)

// Set launch direction (Straight & Homing)
projectile.Launch(Vector2.right);

// Set / clear tracking target (Homing)
projectile.SetTarget(enemy.transform);
projectile.ClearTarget();

A Homing projectile that loses its target continues in its last direction.

Trigger / Collision Events

Because there's no Rigidbody2D, this GameObject does not raise OnCollisionEnter2D directly. OnTriggerEnter2D still fires when the other trigger has a Rigidbody2D — set up trigger zones as Kinematic Rigidbody2D + Trigger Collider and they'll work as expected.