5d768ee · terrain-lookdev

Changed files (4) +182 -1

erosion_render.cpp +18 -0

…	…	@@ -246,6 +246,24 @@ static void set_param(ErosionWrapperParams& p, const char* k, const char* v) {
246	246	else if (!strcmp(k, "en_gain")) p.en_gain = f;
247	247	else if (!strcmp(k, "en_octaves")) p.en_octaves = i;
248	248	else if (!strcmp(k, "en_erosion_scale")) p.en_erosion_scale = f;
	249	else if (!strcmp(k, "en_fade_div")) p.en_fade_div = f;
	250	else if (!strcmp(k, "en_height_amp")) p.en_height_amp = f;
	251	else if (!strcmp(k, "en_erosion_lac")) p.en_erosion_lac = f;
	252	else if (!strcmp(k, "en_gully_weight")) p.en_gully_weight = f;
	253	else if (!strcmp(k, "en_detail")) p.en_detail = f;
	254	else if (!strcmp(k, "en_normalization")) p.en_normalization = f;
	255	else if (!strcmp(k, "en_height_offset_a")) p.en_height_offset_a = f;
	256	else if (!strcmp(k, "en_height_offset_b")) p.en_height_offset_b = f;
	257	else if (!strcmp(k, "rounding_ridges")) p.rounding_ridges = f;
	258	else if (!strcmp(k, "rounding_creases")) p.rounding_creases = f;
	259	else if (!strcmp(k, "rounding_input")) p.rounding_input = f;
	260	else if (!strcmp(k, "rounding_per_oct")) p.rounding_per_oct = f;
	261	else if (!strcmp(k, "onset_input")) p.onset_input = f;
	262	else if (!strcmp(k, "onset_per_oct")) p.onset_per_oct = f;
	263	else if (!strcmp(k, "onset_ridge_input")) p.onset_ridge_input = f;
	264	else if (!strcmp(k, "onset_ridge_oct")) p.onset_ridge_oct = f;
	265	else if (!strcmp(k, "assumed_slope_mag")) p.assumed_slope_mag = f;
	266	else if (!strcmp(k, "assumed_slope_mix")) p.assumed_slope_mix = f;
249	267	else { fprintf(stderr, "unknown parameter '%s'\n", k); exit(2); }
250	268	}
251	269

index.html +30 -1

…	…	@@ -106,6 +106,17 @@ kbd{font-family:"IBM Plex Mono",monospace;background:#0e1216;border:1px solid va
106	106	<fieldset><legend>Detail + base noise</legend>
107	107	<div id="grp_detail"></div>
108	108	</fieldset>
	109	<fieldset><legend>Filter shape · baked in the engine</legend>
	110	<p class="note" style="margin:0 0 4px;border:0;padding:0">These are constants on
	111	the engine path — <code>GpuCompiler</code>'s push-constant block is seven floats
	112	and rounding plus onset need eight. This path emits GLSL text, so it has no such
	113	cap. <b>rounding input</b> is runevision's input-feature-size control: <i>"the
	114	erosion function doesn't know about the sizes of the terrain features coming
	115	from [the input height function], so an input value is provided for tweaking
	116	the rounding of those."</i> It has been pinned at 0.1 while terrain_height went
	117	20 km → 60 km.</p>
	118	<div id="grp_shape"></div>
	119	</fieldset>
109	120
110	121	<p class="note">Both panels are shaded by the same code, so a difference on
111	122	screen is a difference in the terrain and not in the renderer.
…	…	@@ -162,7 +173,25 @@ const GROUPS = {
162	173	["detail_gain",0.5,0.2,0.9,0.01],["detail_octaves",4,1,10,1],
163	174	["noise_lacunarity",1.87,1.2,3,0.01],["gn_scale",3,0.1,40,0.1],
164	175	["gn_gain",0.1,0,0.9,0.01],["gn_detail",3,1,8,1],
165		["voxel_size",1,0.25,512,0.25]]
	176	["voxel_size",1,0.25,512,0.25]],
	177	shape: [["en_fade_div",4.8,0.5,40.0,0.1],
	178	["en_height_amp",0.25,0.02,2.0,0.01],
	179	["en_erosion_lac",2.0,1.2,4.0,0.01],
	180	["en_gully_weight",0.5,0.0,2.0,0.01],
	181	["en_detail",1.5,0.2,5.0,0.05],
	182	["en_normalization",0.5,0.0,1.0,0.01],
	183	["en_height_offset_a",-0.65,-2.0,1.0,0.01],
	184	["en_height_offset_b",0.0,0.0,1.0,0.01],
	185	["rounding_ridges",0.1,0.0,2.0,0.005],
	186	["rounding_creases",0.0,0.0,2.0,0.005],
	187	["rounding_input",0.1,0.005,4.0,0.005],
	188	["rounding_per_oct",2.0,0.25,6.0,0.05],
	189	["onset_input",1.25,0.0,6.0,0.05],
	190	["onset_per_oct",1.25,0.0,6.0,0.05],
	191	["onset_ridge_input",2.8,0.0,8.0,0.05],
	192	["onset_ridge_oct",1.5,0.0,6.0,0.05],
	193	["assumed_slope_mag",0.7,0.0,3.0,0.01],
	194	["assumed_slope_mix",1.0,0.0,1.0,0.01]]
166	195	};
167	196	const $ = id => document.getElementById(id);
168	197	let view = "shaded-height";

server.py +21 -0

…	…	@@ -59,6 +59,27 @@ KNOBS = {
59	59	"en_gain": ("f", 0.2, 0.9),
60	60	"en_octaves": ("i", 1, 12),
61	61	"en_erosion_scale": ("f", 0.002, 0.5),
	62	# Baked on the engine path (7-float push-constant cap); reachable here
	63	# because this path emits GLSL text. rounding_input is runevision's
	64	# input-feature-size control.
	65	"en_fade_div": ("f", 0.5, 40.0),
	66	"en_height_amp": ("f", 0.02, 2.0),
	67	"en_erosion_lac": ("f", 1.2, 4.0),
	68	"en_gully_weight": ("f", 0.0, 2.0),
	69	"en_detail": ("f", 0.2, 5.0),
	70	"en_normalization": ("f", 0.0, 1.0),
	71	"en_height_offset_a": ("f", -2.0, 1.0),
	72	"en_height_offset_b": ("f", 0.0, 1.0),
	73	"rounding_ridges": ("f", 0.0, 2.0),
	74	"rounding_creases": ("f", 0.0, 2.0),
	75	"rounding_input": ("f", 0.005, 4.0),
	76	"rounding_per_oct": ("f", 0.25, 6.0),
	77	"onset_input": ("f", 0.0, 6.0),
	78	"onset_per_oct": ("f", 0.0, 6.0),
	79	"onset_ridge_input": ("f", 0.0, 8.0),
	80	"onset_ridge_oct": ("f", 0.0, 6.0),
	81	"assumed_slope_mag": ("f", 0.0, 3.0),
	82	"assumed_slope_mix": ("f", 0.0, 1.0),
62	83	}
63	84
64	85	NO_SURFACE = -3.0e38

sweep_mountain.py +113 -0

…	…	@@ -0,0 +1,113 @@
	1	#!/usr/bin/env python3
	2	"""
	3	MOUNTAIN-LAYER SWEEP — what gain and octave count let the erosion filter work?
	4
	5	hyper-games #46. The filter is a faithful port of runevision's, and the
	6	reference feeds it ONE near-smooth fBm: freq 3, 3 octaves, gain 0.1, lac 2.0,
	7	amplitude 0.125 (lpmitchell/AdvancedTerrainErosion README, and the same config
	8	in the Shadertoy lineage). dc-terrain adds a mountain layer on top of that at
	9	8 octaves, gain 0.68, lacunarity 1.87 -- gain*lac = 1.27, so the input's slope
	10	GROWS 27% per octave and the finest octave dominates it. The filter then puts
	11	gullies on every bump at every scale.
	12
	13	CRITERION, so this is not eyeballing:
	14
	15	1. gain * lacunarity, which must be <= 1 for the input's slope not to grow
	16	with frequency. Arithmetic, not opinion.
	17	2. the per-octave local power-law exponent beta of the RESULT, measured by
	18	the #46 §4 instrument. A generator with a drainage hierarchy STEEPENS
	19	down the column (terrain-diffusion does: 4.18 -> 4.69 -> 5.10). One that
	20	is texture at every scale stays flat (ours shipped at 3.58/3.44/3.78).
	21
	22	Both baselines are rendered here too, so the column is read against something
	23	rather than in the abstract.
	24	"""
	25	import sys, urllib.parse, urllib.request
	26	import numpy as np
	27	sys.path.insert(0, "/storage/projects/code/godot/terrain-lookdev")
	28	from spectrum_probe import radial_power_spectrum, selftest
	29
	30	LOOKDEV = "http://127.0.0.1:8818"
	31	N, MPP = 512, 30.0
	32	GEOM = dict(n=N, mpp=MPP, ox=120000, oz=40000, steps=256, voxel_size=2 * MPP)
	33	OCTAVE_BANDS = [(64, 128), (128, 256)] # 120-240 m, 60-120 m at this geometry
	34	FIT = (16, 64)
	35
	36
	37	def fetch(kind, **kw):
	38	q = urllib.parse.urlencode(kw)
	39	with urllib.request.urlopen(f"{LOOKDEV}/api/{kind}.bin?{q}", timeout=900) as r:
	40	n = int(r.headers["X-N"]); mpp = float(r.headers["X-Mpp"])
	41	buf = r.read()
	42	return np.frombuffer(buf, dtype="<f4").reshape(n, n).astype(np.float64), mpp
	43
	44
	45	def betas(h, mpp):
	46	"""Local beta per octave, plus the sd of the field. No extrapolation."""
	47	k, p = radial_power_spectrum(h)
	48	out = []
	49	for lo, hi in [FIT] + OCTAVE_BANDS:
	50	m = (k > lo) & (k <= hi) & (p > 0)
	51	if m.sum() < 4:
	52	out.append(float("nan")); continue
	53	s, _ = np.polyfit(np.log10(k[m]), np.log10(p[m]), 1)
	54	out.append(-s)
	55	return out
	56
	57
	58	def row(label, h, mpp, note=""):
	59	b = betas(h, mpp)
	60	trend = b[2] - b[1] # positive = steepens toward fine = hierarchy
	61	print(f" {label:<26} {h.std():7.0f} {b[0]:7.2f} {b[1]:7.2f} {b[2]:7.2f} "
	62	f"{trend:+7.2f} {note}")
	63	return b, trend
	64
	65
	66	def main():
	67	print("INSTRUMENT SELF-TEST")
	68	if not selftest(verbose=False):
	69	print(" FAILED"); return 2
	70	print(" all pass\n")
	71
	72	print(f"{N}x{N} @ {MPP:g} m/px = {N*MPP/1000:.2f} km, voxel {GEOM['voxel_size']:g} m "
	73	f"(band-limited to the sampling)")
	74	print(f"beta measured locally inside each band. 'trend' = beta(60-120m) - beta(120-240m);")
	75	print(f"POSITIVE means it steepens toward fine scales, i.e. large forms dominate.\n")
	76	hdr = f" {'config':<26} {'sd m':>7} {'0.24-1km':>7} {'120-240':>7} {'60-120':>7} {'trend':>7}"
	77	print(hdr); print(" " + "-" * (len(hdr) - 2))
	78
	79	# --- baselines ---------------------------------------------------------
	80	hd, _ = fetch("diffusion", n=N, i1=0, j1=2048)
	81	row("terrain-diffusion", hd, 30.0, "<- the target character")
	82	hr, _ = fetch("erosion", **GEOM, mountain_height=0)
	83	row("erosion, NO mountain", hr, MPP, "<- ~runevision's own config")
	84	hs, _ = fetch("erosion", **GEOM)
	85	row("SHIPPING (gain .68, oct 8)", hs, MPP, "<- gain*lac = 1.27")
	86	print()
	87
	88	# --- gain sweep at 8 octaves ------------------------------------------
	89	print(" gain sweep, mountain_octaves = 8")
	90	best = None
	91	for g in (0.60, 0.5348, 0.45, 0.35, 0.25, 0.15, 0.10):
	92	h, _ = fetch("erosion", **GEOM, mountain_gain=g)
	93	b, t = row(f" gain {g:.4f}", h, MPP, f"gainlac {g1.87:.2f}")
	94	if best is None or t > best[1]:
	95	best = (g, t)
	96	print(f"\n best trend at gain {best[0]:.4f} ({best[1]:+.2f})\n")
	97
	98	# --- octave sweep at that gain ----------------------------------------
	99	print(f" octave sweep, mountain_gain = {best[0]:.4f}")
	100	for o in (8, 6, 5, 4, 3):
	101	h, _ = fetch("erosion", **GEOM, mountain_gain=best[0], mountain_octaves=o)
	102	row(f" octaves {o}", h, MPP)
	103
	104	# --- the reference shape, transplanted --------------------------------
	105	print("\n runevision's own input shape on our mountain layer")
	106	for g, o in ((0.10, 3), (0.15, 3), (0.25, 3), (0.25, 4), (0.35, 4)):
	107	h, _ = fetch("erosion", **GEOM, mountain_gain=g, mountain_octaves=o)
	108	row(f" gain {g:.2f} oct {o}", h, MPP, f"gainlac {g1.87:.2f}")
	109	return 0
	110
	111
	112	if __name__ == "__main__":
	113	sys.exit(main())

terrain-lookdev commits / 5d768ee

Changed files (4) +182 -1