Rainline Circuit

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-based Three.js 3D free-roam neon driving game titled “Rainline Circuit.” The game should open directly into a dark futuristic rainy city at night, with a third-person chase camera behind and above a small low-poly hover/sports car. Use a near-black navy background and exponential blue-black fog, a 58-degree perspective camera, and smooth camera follow: the camera stays roughly 8 units behind the car and 4.8 units above it, looking toward the car and slightly ahead in its facing direction.

World and visual style: Build a very large square wet city road/ground, approximately 180 by 180 units, colored glossy dark blue-purple with high metalness and low roughness so it subtly reflects the neon environment. Add two bright cyan longitudinal lane marks on either side of the central driving area. Populate the sides with about 30 dark blocky skyscraper towers arranged along both sides of the city, with varied widths and heights (roughly 10–30 units). Give the buildings deep indigo, violet, and blue-black materials, thin repeating cyan or magenta glowing horizontal window strips, and occasional glowing rectangular holographic advertising panels. Include some larger imported-looking skyscraper silhouettes among them if available, but preserve the simple low-poly/block-built appearance.

Add elevated infrastructure: several long dark elevated highways/bridges spanning across the scene at approximately 2.8 and 6.1 units high, with cyan glowing edge/dash details. Add multiple cross-overpass decks at around 4.45 units high, extending across the road at intervals, with thin magenta glowing edge strips. Light the scene with a cool blue hemisphere/directional light and a strong magenta point light near the player, producing a saturated cyan-and-purple cyberpunk palette. Add a dense rainfall particle field of about 1,200 small pale-blue points distributed through the city; animate the rain falling rapidly and recycle each particle to the top when it reaches the ground. The overall appearance should be sparse, dark, atmospheric, wet, and neon-lit rather than a bright detailed simulation.

Player vehicle: Make a compact futuristic car group centered on the ground, with a dark slate-purple rectangular body about 1.7 wide, 0.42 high, and 3.5 long, a dark glossy raised canopy about 1.2 wide by 0.34 high by 1.4 long, four small black wheels, and a glowing violet-blue underbody bar. The car should have a subtle blue emissive body/canopy treatment. Add two violet translucent rectangular exhaust/trail planes behind the car; they are invisible normally and become visible during a drift. Start the car near the center of the world at z=20, with zero speed and heading facing along positive z.

Driving and controls: Support keyboard WASD and arrow keys. W/up accelerates, S/down brakes or reverses, A/left and D/right steer. Use smooth acceleration and friction: forward target speed is 22, reverse is limited to -10, and speed is clamped to the active target. Steering rotates the heading based on current speed, with stronger steering while drifting. Move the vehicle according to its heading using sine/cosine world motion. When it crosses the ±88 world bounds on either axis, wrap it to the opposite side, creating continuous free roam. Press R to reset the car to x=0, z=20, y slightly above the ground, speed zero, and heading zero.

Drifting: Holding Space enables drift steering and, when the car’s absolute speed is above 7, sets a drift state and shows the two purple trail planes behind the vehicle. While drifting, show the HUD mode text “DRIFT VECTOR.” Releasing Space hides the trails and returns to the normal state unless nitro is active.

Nitro: Holding Shift activates nitro while the meter is above zero, raising the forward target speed from 22 to 34 and draining the meter at 28 units per second. When Shift is not actively consuming nitro, refill it at 10 units per second up to 100. Show “NITRO ACTIVE” while boosting, otherwise “NITRO READY” (unless drifting). Do not add races, opponents, weapons, collisions, missions, lap goals, or a win state; this is explicitly a free-roam driving sandbox.

HUD and interface: Overlay a full-screen HUD without blocking the 3D view. In the upper-left, place a translucent dark glass panel with a thin blue border and soft blue shadow. It must display the cyan title “RAINLINE // FREE ROAM,” then a three-digit speed readout in KM/H calculated as the absolute vehicle speed multiplied by 6 and padded with leading zeroes (for example “000 KM/H”), followed by the current mode text. In the upper-right, display the compact instructions exactly as: “WASD / ARROWS DRIVE” and “SPACE DRIFT · SHIFT NITRO · R RESET.” In the lower-left, display “NITRO” and a horizontal 120-pixel meter with a purple border, violet-to-pink gradient fill, and soft glow whose width reflects the current 0–100 nitro amount. In the lower-right, provide four translucent square touch buttons with cyan borders and arrow glyphs arranged left, up, down, right; pressing and releasing them should control the corresponding steering/throttle keys for mobile play. Add a very subtle full-screen horizontal scanline/repeating-linear-gradient overlay for a futuristic display effect. Keep the interface typography clean, uppercase, compact, and pale blue/cyan, with magenta reserved for nitro and drift effects.”,