A sandbox 2D physics kinematics engine that simulates gravity, momentum, and collisions in real-time. Built with OCaml using the Core and Async libraries, with graphics rendering via OCaml Graphics.

The engine uses a timestep system that advances the simulation in discrete steps (default: 0.001s). Each timestep processes collision reactions, updates object velocities based on forces, and then updates positions. User interactions are handled through event-driven input listeners that asynchronously wait for mouse clicks and button events, allowing seamless object creation, dragging, and UI control without blocking the physics simulation loop.

Core Physics

• vector.mli - 2D vector operations and transformations
• units.mli - conversions between pixel coordinates and physics units
• objects.mli - object types (Ball, Box, Line, Cup) with position, velocity, and physics properties
• force.mli - force representation for applying physics effects to objects
• collisions.mli - collision detection between objects (ball-ball, ball-line, ball-cup, etc.)
• reactions.mli - collision response handling and reaction effects
• step.mli - physics simulation time step execution

User Interface

• click_state.mli - tracks user interaction state (creating objects, dragging, selecting)
• click_interactions.mli - handles mouse click events and user input
• panel.mli - UI components (buttons and text boxes)
• canvas.mli - bounded area for managing and rendering physics objects
• interface.mli - combines panel and canvas into a unified interface

Simulation Runtime

• world_state.mli - simulation status tracking (In_progress, Paused, Clear, Failure)
• world_graphics.mli - graphics initialization and rendering system
• world.mli - main world container combining state, interface, and interaction handling
• run.mli - main entry point that starts the simulation