Samples smooth 2D value noise at (x, z) and returns four independent channels,
each in [0, 1]. Scale coordinates by a noise frequency before passing:
sampleNoise(worldX * 0.05, worldZ * 0.05).
Channels are used separately by the terrain builder for XZ perturbation (channels
0–1), per-cell Y offset (channel 2), and texture blend weights (channel 3).
Samples smooth 2D value noise at (x, z) and returns four independent channels, each in [0, 1]. Scale coordinates by a noise frequency before passing:
sampleNoise(worldX * 0.05, worldZ * 0.05).Channels are used separately by the terrain builder for XZ perturbation (channels 0–1), per-cell Y offset (channel 2), and texture blend weights (channel 3).