160 lines
6.1 KiB
Python
160 lines
6.1 KiB
Python
"""Run inside Unreal (Python console / Execute Python Script).
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Reads terrain_config.json (next to this script) and:
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1. builds a heightfield mesh with GeometryScript (fractal value noise),
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bakes it to a StaticMesh, and drops it into the level;
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2. scatters tree/rock StaticMeshActors across it per "scatter_layers",
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using the same noise field so foliage height always matches the
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ground beneath it (no raycasting needed).
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Run import_environment_assets.py first so the mesh paths referenced in
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terrain_config.json actually exist.
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Set the TERRAIN_CONFIG env var to point at a different config file, e.g. to
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run terrain_config_variants_demo.json without touching the default config.
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See generate_terrain_from_heightmap.py for the same pipeline driven by a real
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heightmap image instead of procedural noise - both share terrain_common.py.
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"""
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import os, json, math, random, unreal
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import terrain_common as tc
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CONFIG_PATH = os.environ.get(
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"TERRAIN_CONFIG",
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os.path.join(os.path.dirname(os.path.abspath(__file__)), "terrain_config_variants_demo.json"),
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)
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# ---------------------------------------------------------------------------
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# Fractal value noise (pure Python, no engine dependency) -------------------
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# ---------------------------------------------------------------------------
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class ValueNoise2D:
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"""Seeded, smooth, tileable-enough value noise for terrain-style height fields."""
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def __init__(self, seed):
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rng = random.Random(seed)
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table = list(range(256))
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rng.shuffle(table)
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self._perm = table + table # avoid overflow when indexing i+1
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@staticmethod
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def _fade(t):
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return t * t * t * (t * (t * 6 - 15) + 10)
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@staticmethod
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def _lerp(a, b, t):
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return a + t * (b - a)
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def _gradient(self, ix, iy):
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h = self._perm[(self._perm[ix & 255] + iy) & 255]
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angle = (h / 255.0) * 2.0 * math.pi
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return math.cos(angle), math.sin(angle)
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def sample(self, x, y):
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x0, y0 = math.floor(x), math.floor(y)
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x1, y1 = x0 + 1, y0 + 1
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sx, sy = x - x0, y - y0
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def dot_grid(ix, iy, px, py):
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gx, gy = self._gradient(ix, iy)
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return gx * (px - ix) + gy * (py - iy)
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n00 = dot_grid(x0, y0, x, y)
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n10 = dot_grid(x1, y0, x, y)
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n01 = dot_grid(x0, y1, x, y)
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n11 = dot_grid(x1, y1, x, y)
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u, v = self._fade(sx), self._fade(sy)
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return self._lerp(self._lerp(n00, n10, u), self._lerp(n01, n11, u), v)
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class FractalHeightField:
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def __init__(self, noise_cfg, height_scale):
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self.height_scale = height_scale
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self.frequency = noise_cfg["frequency"]
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self.octaves = noise_cfg["octaves"]
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self.lacunarity = noise_cfg["lacunarity"]
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self.gain = noise_cfg["gain"]
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self.noise = ValueNoise2D(noise_cfg["seed"])
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def height(self, x, y):
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amplitude, frequency, total, max_amp = 1.0, self.frequency, 0.0, 0.0
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for _ in range(self.octaves):
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total += amplitude * self.noise.sample(x * frequency, y * frequency)
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max_amp += amplitude
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amplitude *= self.gain
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frequency *= self.lacunarity
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return (total / max_amp) * self.height_scale
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def normal(self, x, y, step=200.0):
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return tc.finite_difference_normal(self.height, x, y, step)
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# ---------------------------------------------------------------------------
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def generate_tile(config, terrain_cfg, tile_label):
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"""Builds one terrain + its scatter layers + its explicit placements, all
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under a dedicated Outliner folder so multiple tiles can coexist in one level.
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"""
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field = FractalHeightField(terrain_cfg["noise"], terrain_cfg["height_scale"])
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base_folder = f"ProceduralTerrain/{tile_label}"
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print(f"[{tile_label}] building terrain mesh (seed={terrain_cfg['noise']['seed']})...")
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static_mesh, bounds = tc.build_terrain_mesh(terrain_cfg, field)
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loc = terrain_cfg["location"]
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origin = unreal.Vector(loc[0], loc[1], loc[2])
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tc.spawn_terrain_actor(static_mesh, origin, base_folder, f"Terrain_{tile_label}")
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for layer_cfg in config.get("scatter_layers", []):
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tc.scatter_layer(layer_cfg, field, bounds, origin, base_folder)
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explicit_entries = config.get("explicit_placements", [])
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if explicit_entries:
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tc.place_explicit(explicit_entries, field, origin, base_folder)
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def main():
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with open(CONFIG_PATH, "r") as f:
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config = json.load(f)
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base_terrain_cfg = config["terrain"]
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variants = config.get("variants")
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if not variants:
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# Single-tile mode: unchanged behavior for existing configs.
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generate_tile(config, base_terrain_cfg, "Main")
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print("Done.")
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return
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# Variant mode: one JSON list of seeds becomes N independent, deterministic
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# tiles laid out side by side in a single run - each a full reproducible
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# world driven by nothing but that seed. There's no "batch-produce N baked,
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# comparable layouts from one data file" workflow in the Foliage tool or a
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# PCG graph; you'd re-author or re-seed each one by hand, one at a time.
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gap = base_terrain_cfg["size_x"] * 1.2
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base_seed = base_terrain_cfg["noise"]["seed"]
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base_layer_seeds = {layer["name"]: layer.get("seed", 0) for layer in config.get("scatter_layers", [])}
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for i, seed_offset in enumerate(variants):
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tile_label = f"Variant_{seed_offset}"
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terrain_cfg = json.loads(json.dumps(base_terrain_cfg)) # cheap deep copy
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terrain_cfg["noise"]["seed"] = base_seed + seed_offset
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terrain_cfg["asset_name"] = f"{base_terrain_cfg['asset_name']}_{tile_label}"
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terrain_cfg["location"] = [
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base_terrain_cfg["location"][0] + i * gap,
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base_terrain_cfg["location"][1],
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base_terrain_cfg["location"][2],
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]
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tile_config = json.loads(json.dumps(config))
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tile_config["terrain"] = terrain_cfg
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for layer_cfg in tile_config.get("scatter_layers", []):
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layer_cfg["seed"] = base_layer_seeds.get(layer_cfg["name"], 0) + seed_offset
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generate_tile(tile_config, terrain_cfg, tile_label)
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print(f"Done: {len(variants)} variant(s) generated side by side.")
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main()
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