This sets up a basic 2-player racing game on an oval track.

How to Play:

1. Player 1: Use W (accelerate), S (brake/reverse), A (turn left), D (turn right).
2. Player 2: Use ArrowUp (accelerate), ArrowDown (brake/reverse), ArrowLeft (turn left), ArrowRight (turn right).
3. Press Enter to start the game from the initial screen.
4. Complete 3 laps by passing through the checkpoints in order (Finish Line -> Top -> Left -> Bottom -> Finish Line). The finish line is checkered.
5. The first player to complete 3 laps wins.
6. After the game ends, press Enter to return to the start screen.

Key Features Implemented:

• Two players controlled by WASD and Arrow Keys.
• Simultaneous input handling.
• Basic car physics (acceleration, friction, turning).
• A predefined oval track with visual representation.
• Pixel-based collision detection with track boundaries using an offscreen canvas.
• Lap counting using checkpoints.
• Game states (start, playing, game over) with basic UI.
• Modular code structure (main.js, game.js, car.js, track.js, input.js, ui.js).

Potential Improvements (Beyond Scope of Initial Request):

• Random Track Generation: Implement algorithms (e.g., using Perlin noise or path generation) in track.js. This would significantly increase complexity, especially for collision detection and checkpoint placement.
• Better Collision Response: Instead of just stopping/bouncing back, calculate collision normals for more realistic physics.
• Power-ups: Add items on the track.
• Sound Effects: Add engine sounds, collisions, lap completion sounds.
• More Sophisticated UI: Menus with buttons, better visual feedback.
• AI Opponent: Add a computer-controlled car.
• Camera: Implement a camera that follows the player(s) or shows the whole track strategically.
• Sprites: Use images for cars instead of simple rectangles.

Key Changes:

1. Track.js - Random Generation:

   • generateTrack() now creates random controlPoints within the canvas bounds.
   • It uses a new helper file js/spline.js containing Catmull-Rom spline functions (generateSplinePoints) to create a smooth, closed-loop centerLine based on these control points.
   • generateCheckpoints() places checkpoints along the generated centerLine.
     • It calculates the tangent angle of the track at the checkpoint location.
     • The normalAngle (perpendicular) is calculated (tangentAngle + Math.PI / 2).
     • Checkpoints are stored with their center x, y, width (track width), height (thickness), and the calculated angle (the normal angle).
     • The first checkpoint (i === 0) is always marked as the isFinishLine.
   • getStartPosition() now calculates the start position and the initial car angle based on the position and angle of the finish line checkpoint.
   • draw() is updated to draw checkpoints rotated according to their angle.
   • getCheckpointIndex() now performs a rotated bounding box check. It transforms the car's coordinates into the checkpoint's local (rotated) coordinate system before checking if the point falls within the checkpoint's dimensions.

2. spline.js (New File):

   • Contains helper functions catmullRomPoint and generateSplinePoints to calculate points along a Catmull-Rom spline. This creates smoother, more natural-looking random tracks than just connecting random points with straight lines.
   • Includes getPointOnSpline (though not currently used) which could be useful for placing objects precisely along the track later.

3. Car.js:

   • Constructor now takes a startAngle argument.
   • reset() method updated to also reset the car's angle.
   • handleTrackCollisionAndLaps() now passes the midpoint between the previous and current frame's position to track.getCheckpointIndex() for more reliable detection of crossing the thin checkpoint lines. Added a basic off-track speed penalty.

4. Game.js:

   • When creating cars, it now gets the startInfo (including position and angle) from track.getStartPosition().
   • It slightly offsets the two cars perpendicular to the starting angle so they don't start exactly on top of each other.
   • When restarting (Enter pressed on game over screen), it now sets this.needsReset = true.
   • The main loop in main.js checks game.needsReset and completely recreates the Game object if true, ensuring a new random track is generated.

5. main.js:

   • Modified the game loop to check game.needsReset and recreate the Game instance when necessary.

Now, each time you finish a race and press Enter, a new, randomly generated track with correctly oriented checkpoints will be created.

Okay, let's increase the complexity of the randomly generated tracks and ensure the checkpoint/finish line visualization is clearly perpendicular (crossing the track width).

It seems there might be a misunderstanding in the request "чтобы они были не вдоль трассы" (so they are not along the track). Checkpoints in racing typically cross the track perpendicularly, they don't run parallel to the direction of travel for a long distance. The previous implementation already aimed for this perpendicular orientation.

I will enhance the track generation to be more complex and double-check the drawing logic to make the perpendicular nature of the checkpoints visually clearer.

Changes:

1. track.js:
   • Increased numControlPoints in generateTrack for potentially more turns and complexity.
   • Slightly increased the randomness factor for control point placement.
   • Increased the visual thickness (height) of the checkpoint lines in draw to make their orientation across the track more apparent.
   • Added comments to clarify the rotation logic for drawing checkpoints.

Here are the updated files:

The tracks should now feel a bit more varied and complex due to more control points and slightly higher randomness. The checkpoint lines are thicker, which should help visualize that they are indeed oriented across the track (perpendicular to the direction of travel), fulfilling the standard requirement for racing checkpoints.

You are right! My apologies, the previous drawing logic for checkpoints might have been confusing, and the placement could definitely lead to overlaps on complex tracks.

Let's fix this:

1. Increase Visual Thickness: We'll make the checkpoint lines significantly thicker (cp.height) so their orientation across the track is unmistakable.
2. Prevent Overlapping: We'll implement a smarter checkpoint placement strategy in generateCheckpoints. Instead of placing them at fixed intervals based on control points, we'll iterate along the calculated centerLine and place checkpoints only when a minimum distance along the track has been covered since the last one. This prevents them from bunching up on tight corners.
3. Clarify Drawing: I'll add comments to the drawing code to be crystal clear about how the rotation and rectangle dimensions create the perpendicular line.

Here are the updated files, focusing on track.js:

Now the checkpoints should be visually thicker (making their perpendicular orientation clearer) and spaced out along the track to prevent overlapping, even on complex curves.

Okay, let's start fresh and build the 2-player racing game with random tracks, menus, and simultaneous controls.

This setup provides:

1. Clearer Structure: Code is organized into modules (Game, Car, Track, InputHandler, UI, spline).
2. Game States: Manages startMenu, playing, and gameOver states.
3. Random Tracks: Uses the improved spline and checkpoint generation logic from our previous discussion.
4. Simultaneous Input: InputHandler correctly handles multiple key presses.
5. 2-Axis Control: Cars accelerate, brake/reverse, and turn.
6. Basic Menu/UI: Text-based start menu and game over screen drawn on the canvas.
7. Improved Visuals: Slightly nicer colors, car drawing, and track rendering settings.
8. Reset Logic: Pressing Enter after game over triggers a full game reset with a new track.

This forms a solid foundation for the game you described.