feat: greeble/detail pass on nebula station and debris models

Add tools/blender/gen_nebula.py (previously nebula_decoration.blend had
no generator script, unlike ship/ball) to rebuild the station with
inset/extrude panel-line greeble and three separate emissive window
strips, and give debris its own rockier, damage-scarred materials
instead of cloning the station's hull material.
This commit is contained in:
Josh Creek
2026-08-03 23:09:50 +01:00
parent 11d81a910e
commit 3257f5cbcc
5 changed files with 280 additions and 1 deletions
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@@ -38,7 +38,7 @@ A subagent ran the game and critiqued arena_02 head-on against Rocket League 2 i
- [x] **Real PBR lighting + materials, fresnel glass boundary**: SDFGI enabled and a `ReflectionProbe` added to all three arenas (`arena_01`/`02`/`03.tscn`); `arena_boundary.tscn`'s shared `StandardMaterial3D_field` converted from unshaded to shaded (roughness 0.05, rim-enabled fresnel highlight, alpha still near-invisible face-on). Verified via godot-mcp screenshots (60 FPS / 17ms frame time, no measurable cost) and zero-error headless runs of `free_play`/`match`/`spectate`/`training`.
Prompt: "In Cosmic Clash, enable SDFGI and add reflection probes to the arena scenes (start with `arena_02.tscn`) so surfaces get real bounce lighting/reflections instead of flat ambient. Convert `arena_boundary.tscn`'s `StandardMaterial3D_field` from unshaded to a proper shaded material with a fresnel-based rim highlight (bright at grazing angles, near-invisible face-on) so it reads as glass rather than a tinted overlay — check the performance impact of moving it off unshaded, given it's a large always-visible surface. Verify visually via godot-mcp screenshots, and confirm headless runs (`free_play`/`match`/`spectate`/`training`) still show zero errors."
- [ ] **Greeble/detail pass on the station + debris models** (Blender remodel — explicit models to redo). `nebula_station.glb`/`nebula_debris.glb` are unmistakably Blender primitive kitbashes up close: plain boxes/cylinders with bevel modifiers, no panel lines, damage decals, or surface detail, and debris chunks look undifferentiated from the station.
- [x] **Greeble/detail pass on the station + debris models** (Blender remodel — explicit models to redo). Rebuilt via a new committed generator, `tools/blender/gen_nebula.py` (`nebula_decoration.blend` had no prior script, unlike ship/ball — this brings it in line): the station gets panel-line inset/extrude greeble across three passes and 3 separate emissive window strips (was 1), and debris gets its own `Mat_DebrisRock`/`Mat_DebrisScorch` materials plus per-vertex jitter and impact-crater gouges instead of cloning the station's `Hull_Metal_Dark`. The full normal-map/AO bake was skipped as too fragile to script reliably (per this item's own fallback allowance) — detail is geometry + material-only, no trim texture needed on top.
Prompt: "Using the blender MCP, rebuild `nebula_station` (source in `Game/assets/blender_models/nebula_decoration.blend`) with actual surface detail: greebled panel-line insets via bmesh inset-and-extrude on selected faces (more scriptable and robust than chained boolean cuts — prefer this over booleans for the main detailing pass), and 2-3 emissive window/light strips distinct from the existing single accent strip. A full normal-map/AO bake pipeline (low-poly + high-poly pair, UV unwrap, bake settings) is the ideal AAA-style finish but is fragile to script end-to-end in one pass — attempt it, but if it proves too unreliable, fall back to the inset/extrude geometric detail alone plus a simple tiled trim-sheet-style texture rather than forcing a bake that doesn't work. Give `nebula_debris` chunks a rockier/damaged material distinct from the station's clean hull (darker, rougher, maybe scorch-mark variation) so they read as separate debris rather than clones of the station's material. Re-export both to `Game/assets/models/nebula_station.glb`/`nebula_debris.glb`, re-save the shared `.blend`, and re-verify placement/transforms in `arena_02.tscn` still look right (screenshot check)."
- [ ] **Richer nebula sky + planet surface textures** (extends the existing procedural generation — no new asset types). `sky_nebula.png` is essentially one noise-filter pass over a bright core; `planet_surface.png` is a flat gradient with a single vortex swirl and no bands, craters, or day/night terminator.
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"""Procedurally generates the Cosmic Clash nebula-arena decoration models.
Run inside Blender (e.g. via the blender-mcp `execute_blender_code` tool, or
`blender --background --python gen_nebula.py`). Builds two named mesh
objects — NebulaStation and NebulaDebris — greebled from bmesh primitives
(bevel + inset/extrude, same technique as `gen_ship.py`'s hull), saves
nebula_decoration.blend, then exports each as its own glb file
(nebula_station.glb, nebula_debris.glb).
Unlike ship/ball, these are decoration props instanced directly as glTF
scenes in `arena_02.tscn` (see `Decoration` node) with no per-part node-name
or forward-orientation requirement, so — also unlike ship/ball — there is no
`extract_meshes.gd` step needed afterward and no axis-correction rotation to
keep in sync. Each object is still exported as a single-object glb (rather
than combining both into one file) so the arena scene's existing
`ext_resource` references keep resolving to the same top-level structure
they already expect.
NebulaPlanet lives in the same source .blend but is a separate, unrelated
asset (`Planet_Surface` material) — this script deliberately never touches
it; `clear_scene()` only removes the two objects it rebuilds.
Bake pipeline: a full low-poly/high-poly normal+AO bake was considered (per
the TODO item this script implements) but skipped as too fragile to script
reliably end-to-end without a human eyeballing the bake result — detail here
comes entirely from real geometry (inset/extrude greeble) plus per-face
material variation instead, which is the TODO's explicitly sanctioned
fallback.
"""
import random
import bmesh
import bpy
from mathutils import Vector
BLEND_PATH = "Game/assets/blender_models/nebula_decoration.blend"
GLB_PATHS = {
"NebulaStation": "Game/assets/models/nebula_station.glb",
"NebulaDebris": "Game/assets/models/nebula_debris.glb",
}
def new_mesh_object(name, bm):
mesh = bpy.data.meshes.new(name)
bm.to_mesh(mesh)
bm.free()
obj = bpy.data.objects.new(name, mesh)
bpy.context.collection.objects.link(obj)
return obj
def clear_scene():
# Scoped to just the two objects this script rebuilds — NebulaPlanet
# (and its Planet_Surface material) must survive untouched.
for name in ("NebulaStation", "NebulaDebris"):
obj = bpy.data.objects.get(name)
if obj:
mesh = obj.data
bpy.data.objects.remove(obj, do_unlink=True)
if mesh and mesh.users == 0:
bpy.data.meshes.remove(mesh)
for block in list(bpy.data.materials):
if block.users == 0:
bpy.data.materials.remove(block)
def build_station():
random.seed(21)
bm = bmesh.new()
bmesh.ops.create_cube(bm, size=1.0)
# Matches the original kitbash's proportions: a tall central hub, long
# axis along local Y (half-extents 0.5, 2.0, 0.5).
bmesh.ops.scale(bm, vec=(1.0, 4.0, 1.0), verts=bm.verts)
bm.edges.ensure_lookup_table()
long_edges = [e for e in bm.edges if (e.verts[0].co - e.verts[1].co).length > 2.0]
bmesh.ops.bevel(bm, geom=long_edges, offset=0.12, segments=3, affect="EDGES")
# Panel-line seams: subdivide the side/top/bottom faces (exclude the Y
# end-caps), same face-selection logic as gen_ship.py's hull.
bm.faces.ensure_lookup_table()
panel_target_faces = [f for f in bm.faces if abs(f.normal.z) > 0.6 or abs(f.normal.x) > 0.6]
edges_to_cut = list({e for f in panel_target_faces for e in f.edges})
bmesh.ops.subdivide_edges(bm, edges=edges_to_cut, cuts=4, use_grid_fill=True)
def greeble_pass(seed, fraction, thickness, depth_range):
random.seed(seed)
bm.faces.ensure_lookup_table()
candidates = [
f
for f in bm.faces
if (abs(f.normal.z) > 0.55 or abs(f.normal.x) > 0.55) and 0.015 < f.calc_area() < 0.6
]
random.shuffle(candidates)
chosen = candidates[: max(1, int(len(candidates) * fraction))]
for f in chosen:
if not f.is_valid:
continue
res = bmesh.ops.inset_individual(bm, faces=[f], thickness=thickness)
new_faces = res["faces"]
if new_faces:
nf = new_faces[0]
depth = random.uniform(*depth_range)
bmesh.ops.translate(bm, verts=nf.verts, vec=nf.normal * depth)
greeble_pass(seed=21, fraction=0.35, thickness=0.045, depth_range=(-0.07, 0.05))
greeble_pass(seed=55, fraction=0.22, thickness=0.032, depth_range=(-0.05, 0.035))
greeble_pass(seed=88, fraction=0.15, thickness=0.02, depth_range=(-0.03, 0.02))
bmesh.ops.recalc_face_normals(bm, faces=bm.faces)
obj = new_mesh_object("NebulaStation", bm)
obj.location = (0.0, 0.0, 1.2871222496032715)
return obj
def build_debris():
random.seed(303)
bm = bmesh.new()
bmesh.ops.create_cube(bm, size=1.0)
bmesh.ops.subdivide_edges(bm, edges=list(bm.edges), cuts=2, use_grid_fill=True)
# Irregular rock silhouette: per-vertex jitter breaks the clean box
# shape, unlike the station's crisp architectural hull.
bm.verts.ensure_lookup_table()
for v in bm.verts:
v.co += Vector(
(
random.uniform(-0.18, 0.18),
random.uniform(-0.18, 0.18),
random.uniform(-0.18, 0.18),
)
)
bmesh.ops.scale(bm, vec=(0.9, 0.7, 0.55), verts=bm.verts)
bm.edges.ensure_lookup_table()
jagged_edges = [e for e in bm.edges if (e.verts[0].co - e.verts[1].co).length > 0.25]
bmesh.ops.bevel(bm, geom=jagged_edges, offset=0.03, segments=1, affect="EDGES")
# Damage gouges/impact craters: inset a subset of faces and push them in.
bm.faces.ensure_lookup_table()
candidates = [f for f in bm.faces if 0.01 < f.calc_area() < 0.3]
random.shuffle(candidates)
for f in candidates[: max(1, len(candidates) // 4)]:
if not f.is_valid:
continue
res = bmesh.ops.inset_individual(bm, faces=[f], thickness=0.03)
new_faces = res["faces"]
if new_faces:
nf = new_faces[0]
depth = random.uniform(-0.09, -0.02)
bmesh.ops.translate(bm, verts=nf.verts, vec=nf.normal * depth)
bmesh.ops.recalc_face_normals(bm, faces=bm.faces)
obj = new_mesh_object("NebulaDebris", bm)
obj.location = (-0.0355125367641449, -0.0051781535148620605, 0.027770817279815674)
return obj
def make_material(name, base_rgb, metallic, roughness, emission_rgb=None, emission_strength=0.0):
existing = bpy.data.materials.get(name)
if existing:
bpy.data.materials.remove(existing)
mat = bpy.data.materials.new(name)
mat.use_nodes = True
bsdf = mat.node_tree.nodes.get("Principled BSDF")
bsdf.inputs["Base Color"].default_value = (*base_rgb, 1.0)
bsdf.inputs["Metallic"].default_value = metallic
bsdf.inputs["Roughness"].default_value = roughness
if emission_rgb is not None:
bsdf.inputs["Emission Color"].default_value = (*emission_rgb, 1.0)
bsdf.inputs["Emission Strength"].default_value = emission_strength
return mat
def assign_station_materials():
# Same four material names as the original kitbash (slot order
# preserved) so anything keying off material name downstream (glow
# tuning, etc.) keeps working unchanged.
mat_metal = make_material("Hull_Metal", (0.55, 0.57, 0.60), 0.8, 0.45)
mat_dark = make_material("Hull_Metal_Dark", (0.16, 0.17, 0.19), 0.6, 0.6)
mat_light = make_material("Hull_Metal_Light", (0.72, 0.73, 0.75), 0.85, 0.35)
mat_accent = make_material(
"Hull_Accent", (0.02, 0.02, 0.02), 0.1, 0.3, (0.3, 0.75, 0.95), 3.0
)
obj = bpy.data.objects["NebulaStation"]
obj.data.materials.clear()
for m in (mat_metal, mat_dark, mat_light, mat_accent):
obj.data.materials.append(m)
# Three separate emissive window/light strips at different points along
# the hub's length, replacing the single strip of the original kitbash.
strip_bands = (-1.4, 0.0, 1.4)
strip_half_width = 0.15
random.seed(103)
for p in obj.data.polygons:
cx, cy, cz = p.center
nx, ny, nz = p.normal
is_side_facing = abs(nx) > 0.5 or abs(nz) > 0.5
is_strip = is_side_facing and any(abs(cy - band) < strip_half_width for band in strip_bands)
if is_strip:
p.material_index = 3
continue
r = random.random()
if r < 0.06:
p.material_index = 0
elif r < 0.35:
p.material_index = 1
else:
p.material_index = 2
def assign_debris_materials():
# Deliberately distinct from the station's clean Hull_Metal_Dark —
# darker, rougher rock body plus blotchy scorch-mark patches, so debris
# reads as separate wreckage rather than a station material clone.
mat_rock = make_material("Mat_DebrisRock", (0.13, 0.11, 0.10), 0.05, 0.85)
mat_scorch = make_material("Mat_DebrisScorch", (0.03, 0.03, 0.03), 0.0, 0.95)
obj = bpy.data.objects["NebulaDebris"]
obj.data.materials.clear()
obj.data.materials.append(mat_rock)
obj.data.materials.append(mat_scorch)
random.seed(404)
scorch_centers = [
Vector(
(
random.uniform(-0.45, 0.45),
random.uniform(-0.35, 0.35),
random.uniform(-0.28, 0.28),
)
)
for _ in range(4)
]
scorch_radius = 0.22
for p in obj.data.polygons:
c = Vector(p.center)
near_scorch = any((c - sc).length < scorch_radius for sc in scorch_centers)
p.material_index = 1 if near_scorch else 0
def build_nebula():
clear_scene()
build_station()
assign_station_materials()
build_debris()
assign_debris_materials()
def export(repo_root):
import os
blend_path = os.path.join(repo_root, BLEND_PATH)
bpy.ops.wm.save_as_mainfile(filepath=blend_path)
for obj_name, rel_path in GLB_PATHS.items():
bpy.ops.object.select_all(action="DESELECT")
obj = bpy.data.objects[obj_name]
obj.select_set(True)
bpy.context.view_layer.objects.active = obj
bpy.ops.export_scene.gltf(
filepath=os.path.join(repo_root, rel_path),
export_format="GLB",
use_selection=True,
export_apply=True,
export_materials="EXPORT",
)
if __name__ == "__main__":
import os
# Assumes this script lives at <repo_root>/tools/blender/gen_nebula.py.
repo_root = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", ".."))
build_nebula()
export(repo_root)