hyper-tps / scenes / test / gate_dc_vs_lookdev.gd

extends SceneTree
## Does dc-terrain's field agree with the lookdev's?
##
## This is the check that did not exist while every other gate was green, and
## its absence is why "the shader is correct" and "the shader never ran" looked
## the same from here. Everything else either ran OUTSIDE Godot (the standalone
## harness) or ran inside Godot and only inspected GLSL text.
##
## It walks DCTerrain.sample_density down a set of columns and writes the surface
## it finds. gate_dc_vs_lookdev.py then renders the SAME columns with
## erosion_render -- the harness that is itself gated against the parity oracle
## -- and compares. Two independent implementations of the same field, so an
## agreement means something.
##
## It works because ProcNodesBridge::evaluate now reads the heightfield too. It
## could not exist before that: sample_density answered from the fBm world the
## field replaced, and would have "agreed" with nothing.
##
##   "$HYPER_TPS_GODOT" --headless --path . --script res://scenes/test/gate_dc_vs_lookdev.gd

const OX := 52800.0
const OZ := 37440.0
const N := 16
const MPP := 120.0
const OUT := "/tmp/dc_surface.txt"

var _m: Node = null


func _init() -> void:
	var packed := load("res://scenes/maps/map_dc_diffusion.tscn") as PackedScene
	if packed == null:
		print("FAIL — map_dc_diffusion.tscn did not load"); quit(2); return
	_m = packed.instantiate()
	root.add_child(_m)


func _process(_dt: float) -> bool:
	var terrain = _m.get_node_or_null("DCTerrain")
	if terrain == null:
		print("FAIL — no DCTerrain"); quit(1); return true

	# PROVE THE GENERATOR IS OURS. If the resource never got assigned, DCTerrain
	# silently falls back to its built-in noise -- which is what "I turned
	# use_noise off and it changed" was telling us, and nothing downstream of
	# that fallback is worth comparing.
	var gen = terrain.get("generator")
	if gen == null:
		print("FAIL — DCTerrain has NO generator; it is drawing built-in noise")
		quit(1); return true
	print("  generator: ", gen.get_class(), "  heightfield: ", gen.get("heightfield_path"))

	var f := FileAccess.open(OUT, FileAccess.WRITE)
	f.store_line("# x z surface_y   (from DCTerrain.sample_density)")
	var found := 0
	for jz in range(N):
		for ix in range(N):
			var x := OX + ix * MPP
			var z := OZ + jz * MPP
			var y: float = _m.call("_surface_y", terrain, x, z)
			if y > -999998.0:
				found += 1
			f.store_line("%.1f %.1f %.4f" % [x, z, y])
	f.close()
	print("  wrote %s — %d of %d columns had a surface" % [OUT, found, N * N])
	if found != N * N:
		print("FAIL — some columns have no surface at all")
		quit(1); return true
	print("  now run: python3 terrain-lookdev/gate_dc_vs_lookdev.py")
	quit(0)
	return true