Sketch Sprint

Cinevva's analyzer read this game's design doc and its source, then wrote the brief below. "Make your own" hands it to the game creator as your opening message, so you start from a real spec rather than a one-line idea.

Create a browser game titled “Sketch Sprint” called a playful 3D sketch-wheel racing game. Use a full-screen responsive layout split into two horizontal regions: the upper ~58% is a Three.js 3D race scene and the lower ~42% is a dark purple drawing pad. Keep the visual style bright, toy-like, rounded, and arcade-oriented, with a deep purple background, hot pink accents, mint green, yellow, lavender, and white.

In the 3D scene, use a third-person perspective camera positioned behind and slightly to the right/above the player, looking down a long track toward the finish. The world has a lavender-purple sky/background with matching fog, strong soft shadows, and colorful standard-material toy geometry. Build a segmented narrow race course extending along the negative Z axis, starting around z=6 and finishing at z=-124. Use broad rectangular track platforms, alternating purple and green sections, with slight offsets and rotations between segments to give the course a winding toy-track feel. Add repeated small black/dark and white checkered tiles across the track. Add pink crumbling tile sections around z=-34 and z=-75, leaving some gaps; these tiles gently wobble when the player is near them. Place alternating pink and yellow rectangular pylons along both sides of the course. At the end, create a finish gate with two tall pink posts, a yellow horizontal top beam, and a white strip across the track. Include a toy-style ramp near z=-27 if possible.

The player is a small cart centered near the start. Make it from simple low-poly/block parts: a hot-pink rectangular body, lavender raised seat, yellow axle, and two bright mint-green custom-shaped extruded wheels mounted on either side. The wheel silhouette must be generated from the user’s drawing rather than being a fixed circle. Add a second yellow-wheeled rival cart slightly to the player’s right and behind at the start. Both carts move automatically forward down the track (decreasing Z); the player’s speed should respond to the custom wheel shape, while the rival travels at a steady faster-looking pace with slight bobbing. Animate wheel rotation, subtle cart bobbing, and small rotations while racing.

The central mechanic is drawing your own wheel/legs. The bottom panel must display the title “DRAW YOUR LEGS” and subtitle “Sketch a shape, release, then watch it spin,” plus the hint “Drag in the pad to invent your wheel.” Let the player draw with pointer/mouse/touch input on a full-panel canvas. Render the stroke in thick rounded yellow lines. On pointer release, sample the drawn stroke into a polygon (up to roughly 14 points), center and normalize it, rebuild both extruded 3D wheel meshes from that polygon, and calculate a wheel power/speed factor from stroke length and size, clamped approximately between 0.55 and 2.4. A reasonable, more substantial/wider/more complex drawing should produce stronger wheel power and higher acceleration. Ignore strokes that are too short. The default wheel before drawing should be an irregular six-point mint-green sketch-like shape. The Clear button in the upper-right of the drawing pad should erase the canvas, restore that default wheel shape, and rebuild the wheels.

The player should continuously accelerate/decelerate according to wheel power, with a capped speed around 8.5 m/s, some drag, and occasional course/slope or gap penalties so the race has changing motion. Show the player’s current speed in a yellow rounded badge at the upper-right, formatted like “0.0 m/s.” Track progress from start to finish and show a centered top HUD label such as “CHECKPOINT 1 / 6,” updating through six checkpoints, with a rounded progress bar beneath it that fills using a green-to-yellow-to-pink gradient and a small checkered-flag icon at its right end. Add a white rounded “↻ Restart” button in the upper-left. Put a dark translucent hint badge beneath the progress bar.

When the player reaches the finish gate, stop the race and show a centered dark translucent overlay with a white rounded card, pink “Finish!” heading, result text that says either “You beat the rival!” if the rival is ahead/behind according to the race comparison or “You made it to the flag.”, a small instruction like “Redraw a wilder wheel and race again.”, and a “Race again” button. Restart should reset both carts, progress, speed, finish state, and hide the overlay. Make the scene responsive for desktop and mobile; preserve pointer/touch drawing behavior without scrolling. If WebGL is unavailable, provide a simple 2D fallback preview with a purple track, pink cart body, lavender seat, green wheels, and “3D preview fallback” text.