⛰ Fractal Mountain Range

This scene uses a technique called 1-D Midpoint Displacement — the same family of algorithms found in video game terrain engines, film visual effects, and geographic simulations.

The Algorithm in Plain English

1. Start with two endpoints at the same height — a flat horizon.
2. Find the midpoint and randomly shift it up or down by some amount (the "scale").
3. You now have three points. Repeat for each of the two sub-segments.
4. Each new pass halves the displacement scale, so finer details are smaller than coarser ones.
5. After N passes you have 2^N + 1 points forming a jagged skyline.

The Hurst Exponent H (Roughness)

The Roughness Bias slider adds to or subtracts from each layer's Hurst exponent H:

• H near 1 → scale halves perfectly → gentle, rolling hills
• H ≈ 0.7 → realistic mountain profiles (used in this sketch)
• H near 0 → scale barely shrinks → extremely jagged, chaotic peaks

Layered Depth (Parallax)

Four independent mountain ranges are generated and drawn back-to-front (the painter's algorithm). Each layer uses different colors and roughness values to simulate atmospheric haze — distant peaks are blue-gray and smooth; nearby ridges are dark green and jagged.

SWTriangle Tessellation

Each terrain layer is a polygon (skyline + flat baseline). Since SWTriangle handles exactly 3 vertices, every "quad" between two consecutive skyline points is split diagonally into two triangles. A brightness tint based on altitude is applied to each triangle pair to suggest topographic shading.

Controls

• Time of Day — changes sky gradient and sun/moon color palette.
• Roughness Bias — globally shifts all layers smoother or rougher.
• New Seed — picks a fresh random seed, producing a completely different landscape.
• Factory Reset — returns to the default scene (seed 42, day, neutral roughness).