lava_river.flecs

using flecs.script.*
using flecs.components.*
using flecs.game

// "Terraced canyon & lava vein" — stepped mesas + deep cut + glowing lava river

const Resolution: 185
const Scale: 44 / Resolution
const Size: 58
const Height: 2.4
const CellW: Size / Resolution

// canyon direction + width controls
const CanyonAngle: 0.55   // radians-ish feel (just used as a mix axis)
const CanyonWidth: 0.10
const CanyonDepth: 0.75

// terrace controls
const TerraceSteps: 11
const TerraceSharpness: 0.85

for x in 0..Resolution {
  for y in 0..Resolution {
    const xN = x * Scale
    const yN = y * Scale

    // normalized coords (0..1)
    const u = x / Resolution
    const v = y / Resolution

    // rotate-ish axis for canyon: blend u/v into an oblique coordinate
    const s = u * cos(CanyonAngle) + v * sin(CanyonAngle)

    // base terrain: broad + mid + small noise
    const nB = perlin2(xN / 7, yN / 7)
    const nM = perlin2(xN / 3, yN / 3)
    const nS = perlin2(xN, yN)

    // mesa height before terracing
    const mesa =
      0.55 * abs(nB) +
      0.22 * abs(nM) +
      0.10 * abs(nS)

    // terracing: quantize height into steps, then smooth a bit
    const t = clamp(mesa, 0, 1)
    const stepped = floor(t * TerraceSteps) / TerraceSteps
    const terrace = lerp(t, stepped, TerraceSharpness)

    // carve canyon along s axis with a meandering offset
    const meander = 0.06 * perlin2(xN / 4 + 8.2, yN / 4 - 3.1)
    const center = 0.50 + meander
    const dist = abs(s - center)

    const cut = 1 - smoothstep(CanyonWidth, CanyonWidth * 3.5, dist)
    const canyon = -CanyonDepth * cut * (0.7 + 0.3 * abs(perlin2(xN * 1.2, yN * 1.2)))

    // lava: thin core inside canyon, with pulsating emissive ripples
    const lavaCore = smoothstep(CanyonWidth * 0.55, 0.0, dist)
    const lavaNoise = 0.45 + 0.55 * abs(perlin2(xN * 2.6 + 1.7, yN * 2.6 - 0.9))
    const lava = clamp(lavaCore * lavaNoise, 0, 1)

    // final height
    const h = terrace + canyon
    const hN = clamp(h, -0.10, 1)

    // color: sandstone mesas, darker canyon walls, hot lava
    const wall = clamp(cut * 0.8, 0, 1)

    const sandstone = clamp(0.40 + 0.45 * terrace + 0.10 * nB, 0, 1)
    const darken = clamp(1 - 0.65 * wall, 0.2, 1)

    const c1 = sandstone * darken + 0.20 * lava
    const c2 = 0.15 * terrace + 0.85 * lava + 0.25 * wall

    {
      Position3: {x * CellW, hN * Height, y * CellW}
      Box: {CellW, 10, CellW}
      Rgb: {clamp(c1, 0, 1), clamp(c2, 0, 1)}
      Emissive: {0.05 + 2.2 * lava}
      Specular: {clamp(0.28 - 0.18 * lava, 0, 0.3), 2}
    }
  }
}

ground_plane {
  Rgb: {}
}

$ {
  TimeOfDay: {0.78}   // dusk so lava glow pops but terrain still reads
}

camera {
  Position3: {64, 30, 71}
  Rotation3: {-0.55, 3.85, 0}
}