platformer-movement

Platformer Movement

Overview

Platformer movement is provided by two classes in FlatRedBall2.Movement:

• PlatformerValues — a plain data class holding movement parameters for one movement mode (Ground, Air, etc.)
• PlatformerBehavior — a component added to an entity that reads input, drives the state machine, and applies velocity/acceleration each frame

Minimal Setup

Movement coefficients are recommended in a JSON file for fast tuning and hot-reload. Copy the template from .claude/templates/PlatformerConfig/player.platformer.json into the project's Content/ folder, adjust values, and add <Content Include="Content/*.json" CopyToOutputDirectory="PreserveNewest" /> to the .csproj. For prototypes/tests, equivalent hardcoded values in C# are valid.

public class Player : Entity
{
    private readonly PlatformerBehavior _platformer = new();

    public override void CustomInitialize()
    {
        PlatformerConfig.FromJson("Content/player.platformer.json").ApplyTo(_platformer);

        var keyboard = Engine.Input.Keyboard;
        // Use .Or() to accept multiple key combos (e.g. Space or Up for jump, Arrows or WASD for move):
        _platformer.JumpInput     = new KeyboardPressableInput(keyboard, Keys.Space)
                                        .Or(new KeyboardPressableInput(keyboard, Keys.Up));
        _platformer.MovementInput = new KeyboardInput2D(keyboard, Keys.Left, Keys.Right, Keys.Up, Keys.Down)
                                        .Or(new KeyboardInput2D(keyboard, Keys.A, Keys.D, Keys.W, Keys.S));
    }

    public override void CustomActivity(FrameTime time)
    {
        _platformer.Update(this, time);  // call AFTER collisions are resolved
    }
}

PlatformerConfig JSON

PlatformerConfig.FromJson(path) deserializes a JSON file into a pure data model; the ApplyTo extension method pushes it onto a PlatformerBehavior. The config is a model — it does not reference the behavior; ApplyTo lives in PlatformerConfigExtensions.