Gravity Field

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 first-person 3D exploration game titled “Gravity Field.” Use a Three.js-style WebGL scene with a wide 92-degree perspective camera, mouse-look first-person controls after the player clicks the canvas, and a small circular crosshair fixed at the center of the screen. The player is a simple invisible first-person body/camera target, initially positioned near the center of a large outdoor terrain, facing across the landscape. There are no enemies, collectibles, buildings, weapons, score, health, or explicit win condition: the core experience is freely walking and jumping across the terrain while switching the global lighting between day and night.

Build the world as a single large, untextured, gray natural landscape plane roughly 260 by 260 world units. Deform its vertices into gently rolling hills, ridges, two broad mounds, and a shallow valley using smooth layered sine/cosine and Gaussian-like height variations; keep the terrain organic and sparse, with no props or structures. Give it a matte gray material with slight roughness and very low metalness. Add a larger, very dark flat underside far below the terrain so the horizon remains dark and readable. Enable soft shadows and ambient/hemisphere fill.

Day lighting should use a warm, strong directional sun from high to one side, pale blue-gray sky/background, and matching blue-gray fog beginning far out in the landscape. The terrain should be visible as muted gray hills under the sunlight. Night mode should dramatically dim the sun, reduce the sky fill, enable a cool blue directional moon light from the opposite side, change the background and fog to near-black navy (#050817-like), and slightly increase exposure so the moonlit environment remains faintly readable. Start in DAY mode. Switching modes must update the lighting, background, fog, and the HUD label; support both the N key and a bottom-right button whose text alternates between “Switch to night” and “Switch to day.”

Movement must match the on-screen instructions: WASD and arrow keys move, Space jumps, and holding Shift sprints. Use walking speed about 8.5, sprinting faster, jump speed about 10.4, gravity about -25, collision against the terrain, and a slope limit around 48 degrees. Keep the player grounded to the procedurally deformed terrain and show whether the player is grounded or airborne plus current velocity magnitude in meters per second. While moving normally use a 92-degree FOV; while sprinting widen it smoothly to about 104 degrees, then smoothly return it when stopping.

Overlay a minimalist dark sci-fi HUD over the 3D view. At top-left place a translucent near-black rectangular panel with a thin light border, subtle blur/shadow, the uppercase letter-spaced title “GRAVITY FIELD,” and this instruction text: “Click to enter first person. WASD / arrows move, Space jumps, Shift sprints. Press N or use the button to change the global light.” At top-right, right-align a gold uppercase “DAY” or cool pale-blue “NIGHT” label above a small readout such as “grounded · 0.0 m/s” or “airborne · [speed] m/s.” Keep the centered crosshair as a 7-pixel white outlined circle with a faint glow. Add a strong dark vignette around the edges and a subtle blue edge glow, making the scene feel especially dark toward the borders. Place the outlined translucent dark mode button at bottom-right, with approximately 44px minimum height and the mode-switch label. Use a nearly black page background, hide overflow, and make the HUD responsive on narrow screens by reducing the info panel width and instruction font size.