All four road tiers now carve into the 3D world. Rugged and Trail were
generated, exported and parsed all along, but nothing ever consumed them —
which is why county roads visible on the 2D map did not exist in 3D.
Tier identity is now carried into the carve via a RoadSegment struct, so each
tier gets its own width, shoulder and grade-smoothing from one tunable block in
Constants: highways widest and holding a grade, trails narrow and hugging the
land. Rugged and Trail surface as dirt rather than asphalt.
Because tiers now have different reach, nearest-by-distance was no longer a
sound way to pick the governing road — a nearby footpath could shadow a highway
whose shoulder still covered the column. The carve now considers only roads
whose shoulder actually reaches, and takes the closest of those.
The per-chunk cull pad is derived from the widest shoulder plus a margin, so
widening a road cannot silently truncate it at chunk edges.
Untouched: density field, Marching Cubes interpolation/welding, chunk dims,
the .dat contract, the 2D A* generation, and mesher normals.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
HeightAtPixel read a single heightmap cell after truncating the coordinate with
(int). Road path points are fractional and spaced under a metre apart, so
consecutive points truncated into the same cell (flat), then tipped into the
next one (a full inter-cell jump) — a metre-scale staircase under F2's fix.
It now reads the four surrounding cells and blends them bilinearly using the
fractional part of the coordinate, so height varies continuously with position.
Edge clamping is preserved: at the map border the second cell clamps back onto
the first, making the blend a no-op rather than an out-of-range read.
Only the sampling helper changed. Signature and both callers are untouched.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Road elevation is now sampled at the point on the road segment nearest the
column being carved, instead of at the segment's midpoint. The old behaviour
gave every column near a segment that segment's single midpoint height, so each
stretch of road was one flat plank and consecutive planks stepped like a
staircase wherever the road crossed a gradient.
Elevation now varies continuously along the segment, and because neighbouring
segments share an end point the height matches exactly at the joins. A new
ROAD_GRADE_SMOOTHING constant dials between holding a straight grade
(cut-and-fill) and hugging the land, per D-021.
Untouched: density field, Marching Cubes, chunk dimensions, the .dat contract,
and the 2D A* road network itself. Only how existing paths are carved into 3D.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Vertex colour is now chosen from the true, unrounded surface height and faded
between adjacent materials across a tunable band, instead of switching at one
rounded integer depth. This removes the horizontal contour banding.
Colour path only: density field, Marching Cubes interpolation/welding, chunk
dimensions, the .dat contract and all road logic are untouched. BlockID
classification is unchanged and still drives non-visual use.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
