成果暂存

2026-07-24 16:03:15 +08:00
parent 662f8d908b
commit fb2a36ac7e
32 changed files with 198341 additions and 12 deletions
--- a/blender/export_cesium.py
+++ b/blender/export_cesium.py
@@ -0,0 +1,403 @@
+"""Export the Nantaizi Blender master scene as a Cesium-ready GLB.
+
+The authoring scene intentionally uses a few Blender-only nodes (for example
+the grass tint and procedural tree crown variation).  glTF has a smaller
+material vocabulary, so this exporter creates temporary, export-only PBR
+materials, unwraps the meshes, and embeds all referenced images in the GLB.
+
+The model remains in a local ENU frame: X east, Y north, Z up.  Use the
+companion JSON file to place the GLB with Cesium.Transforms.eastNorthUpToFixedFrame.
+"""
+
+import json
+import os
+import sys
+
+import bpy
+import numpy as np
+
+
+DEFAULT_BLEND = (
+    "/Users/que01/osm2streets-qgis-workflow/outputs/"
+    "nantaizi-lake-innovation-valley/nantaizi_lake_innovation_valley.blend"
+)
+DEFAULT_GLB = (
+    "/Users/que01/osm2streets-qgis-workflow/outputs/"
+    "nantaizi-lake-innovation-valley/nantaizi_lake_innovation_valley_cesium.glb"
+)
+DEFAULT_METADATA = (
+    "/Users/que01/osm2streets-qgis-workflow/outputs/"
+    "nantaizi-lake-innovation-valley/nantaizi_lake_innovation_valley_cesium.json"
+)
+
+# Blender 里使用 MixRGB 在 Poly Haven 贴图上叠加颜色修正。
+# glTF/Cesium 不能稳定保留这类 Blender 专用节点，所以导出前要把
+# 同样的 tint 烘焙到临时图片里，再写入 GLB。
+# 这样 Cesium 预览会尽量接近 Blender 视图，也能避免浅色办公楼外墙、
+# 屋顶在导出后退回偏黑的原始贴图。
+EXPORT_TINTS = {
+    "Grass": ((0.12, 0.48, 0.08), 0.72),
+    "Office White Plaster Facade": ((0.92, 0.94, 0.92), 0.38),
+    # 兼容旧 .blend：普通办公楼从金属板切回灰泥前生成的文件，
+    # 可能还保留这个旧材质名。
+    "Office White Metal Facade": ((0.92, 0.94, 0.92), 0.68),
+    "Office Light Flat Roof": ((0.82, 0.86, 0.88), 0.35),
+    "Industrial White Ribbed Facade": ((0.90, 0.93, 0.91), 0.86),
+    "Factory Blue Metal Roof": ((0.08, 0.50, 0.88), 0.58),
+}
+
+# Cesium 的光照比 Blender 材质预览更“硬”。外墙默认不要保留金属度，
+# 除非确实是工业金属墙面；否则旧金属墙贴图直接导出时容易发黑。
+EXPORT_METALLIC_OVERRIDES = {
+    "Office White Plaster Facade": 0.0,
+    "Office White Metal Facade": 0.0,
+    "Industrial White Ribbed Facade": 0.08,
+}
+
+# 普通办公楼在 Cesium 里使用稳定浅色展示材质。
+# 这些建筑不是工业厂房，导出时如果继续采样原始墙面/屋顶贴图，
+# Cesium 的光照和 mipmap 会把贴图里的暗斑放大，画面就会显得脏黑。
+# 所以这里直接覆盖 Base Color，只保留几何、窗带和必要法线细节。
+EXPORT_BASE_COLOR_OVERRIDES = {
+    "Office White Plaster Facade": (0.93, 0.94, 0.91),
+    "Office White Metal Facade": (0.93, 0.94, 0.91),
+    "Office Light Flat Roof": (0.88, 0.90, 0.88),
+}
+
+# Cesium 是真实 PBR 光照，侧墙和屋顶会比 Blender 材质预览暗很多。
+# 给普通建筑加很弱的 emissive 补光，不是做“发光楼”，只是模拟
+# Blender 预览里的环境光，让浅色办公楼在网页里保持干净明亮。
+EXPORT_EMISSION_OVERRIDES = {
+    "Office White Plaster Facade": ((0.93, 0.94, 0.91), 0.18),
+    "Office White Metal Facade": ((0.93, 0.94, 0.91), 0.18),
+    "Office Light Flat Roof": ((0.88, 0.90, 0.88), 0.14),
+    # 三栋厂房仍保留金属/波纹质感，但 Cesium 里原贴图会偏暗。
+    # 这里加少量补光，让墙面和蓝色屋顶更接近 Blender 预览。
+    "Industrial White Ribbed Facade": ((0.90, 0.93, 0.91), 0.18),
+    "Factory Blue Metal Roof": ((0.08, 0.50, 0.88), 0.12),
+}
+
+
+def cli_args():
+    values = {"blend": DEFAULT_BLEND, "glb": DEFAULT_GLB,
+              "metadata": DEFAULT_METADATA}
+    argv = sys.argv[sys.argv.index("--") + 1:] if "--" in sys.argv else []
+    i = 0
+    while i < len(argv):
+        if argv[i].startswith("--") and i + 1 < len(argv):
+            values[argv[i][2:]] = argv[i + 1]
+            i += 2
+        else:
+            i += 1
+    return values
+
+
+def image_for(material, want_normal=False):
+    """Find a diffuse/normal image from the authoring material nodes."""
+    candidates = []
+    for node in material.node_tree.nodes:
+        if node.type != "TEX_IMAGE" or not node.image:
+            continue
+        name = os.path.basename(node.image.name).lower()
+        is_normal = "_nor_" in name or "_normal" in name or "_bump" in name
+        if is_normal == want_normal:
+            candidates.append(node.image)
+    return candidates[0] if candidates else None
+
+
+def source_color(material):
+    color = tuple(material.diffuse_color[:3])
+    if len(color) != 3:
+        return (0.5, 0.5, 0.5)
+    return color
+
+
+def source_principled_value(material, input_name, fallback):
+    if not material.use_nodes:
+        return fallback
+    node = material.node_tree.nodes.get("Principled BSDF")
+    if not node or input_name not in node.inputs:
+        return fallback
+    return node.inputs[input_name].default_value
+
+
+def source_texture_scale(material):
+    for node in material.node_tree.nodes:
+        if node.type == "MAPPING":
+            return tuple(node.inputs["Scale"].default_value[:3])
+    return (1.0, 1.0, 1.0)
+
+
+def tinted_image(source, name, tint, factor):
+    """Bake Blender's MixRGB tint into a generated image for glTF."""
+    existing = bpy.data.images.get(name)
+    if existing:
+        return existing
+    width, height = source.size
+    pixels = np.empty(width * height * 4, dtype=np.float32)
+    source.pixels.foreach_get(pixels)
+    rgba = pixels.reshape((-1, 4))
+    rgba[:, :3] = rgba[:, :3] * (1.0 - factor) + np.asarray(
+        tint, dtype=np.float32) * factor
+    result = bpy.data.images.new(name, width=width, height=height, alpha=True)
+    result.file_format = "PNG"
+    result.colorspace_settings.name = "sRGB"
+    result.pixels.foreach_set(pixels)
+    result.pack()
+    return result
+
+
+def cesium_tinted_image(material, source):
+    """Return a baked diffuse image matching the Blender authoring tint."""
+    tint = EXPORT_TINTS.get(material.name)
+    if not tint or not source:
+        return source
+    color, factor = tint
+    safe_name = material.name.replace(" ", "_")
+    return tinted_image(source, f"Cesium {safe_name} Baked", color, factor)
+
+
+def tree_crown_image():
+    """Bake a compact leafy color variation texture for the web material."""
+    name = "Cesium Tree Crown Baked"
+    existing = bpy.data.images.get(name)
+    if existing:
+        return existing
+    size = 256
+    x, y = np.meshgrid(
+        np.linspace(0.0, 1.0, size, dtype=np.float32),
+        np.linspace(0.0, 1.0, size, dtype=np.float32),
+    )
+    noise = (
+        np.sin((x * 17.0 + y * 7.0) * np.pi) * 0.24 +
+        np.sin((x * 43.0 - y * 31.0) * np.pi) * 0.13 +
+        np.sin((x * 89.0 + y * 67.0) * np.pi) * 0.07
+    )
+    noise = np.clip(0.5 + noise, 0.0, 1.0)[..., None]
+    dark = np.asarray((0.035, 0.16, 0.045), dtype=np.float32)
+    light = np.asarray((0.12, 0.42, 0.13), dtype=np.float32)
+    rgb = dark + (light - dark) * noise
+    rgba = np.concatenate(
+        (rgb, np.ones((size, size, 1), dtype=np.float32)), axis=2)
+    result = bpy.data.images.new(name, width=size, height=size, alpha=True)
+    result.file_format = "PNG"
+    result.colorspace_settings.name = "sRGB"
+    result.pixels.foreach_set(rgba.ravel())
+    result.pack()
+    return result
+
+
+def make_export_material(material):
+    """Build a small Principled + Image Texture material understood by glTF."""
+    result = material.copy()
+    result.name = "Cesium " + material.name
+    result.use_nodes = True
+    nodes = result.node_tree.nodes
+    links = result.node_tree.links
+    nodes.clear()
+
+    output = nodes.new("ShaderNodeOutputMaterial")
+    output.location = (520, 0)
+    bsdf = nodes.new("ShaderNodeBsdfPrincipled")
+    bsdf.location = (250, 0)
+    base_color = EXPORT_BASE_COLOR_OVERRIDES.get(
+        material.name, source_color(material))
+    bsdf.inputs["Base Color"].default_value = (*base_color, 1.0)
+    bsdf.inputs["Roughness"].default_value = source_principled_value(
+        material, "Roughness", 0.8)
+    bsdf.inputs["Metallic"].default_value = EXPORT_METALLIC_OVERRIDES.get(
+        material.name, source_principled_value(material, "Metallic", 0.0))
+    emission = EXPORT_EMISSION_OVERRIDES.get(material.name)
+    if emission:
+        emission_color, emission_strength = emission
+        if "Emission Color" in bsdf.inputs:
+            bsdf.inputs["Emission Color"].default_value = (*emission_color, 1.0)
+        elif "Emission" in bsdf.inputs:
+            bsdf.inputs["Emission"].default_value = (*emission_color, 1.0)
+        if "Emission Strength" in bsdf.inputs:
+            bsdf.inputs["Emission Strength"].default_value = emission_strength
+    links.new(bsdf.outputs["BSDF"], output.inputs["Surface"])
+
+    diffuse = image_for(material, want_normal=False)
+    normal = image_for(material, want_normal=True)
+    if material.name == "Tree Crown":
+        diffuse = tree_crown_image()
+    else:
+        diffuse = cesium_tinted_image(material, diffuse)
+    if material.name in EXPORT_BASE_COLOR_OVERRIDES:
+        # 普通办公楼/浅色屋顶使用上面的稳定浅色 Base Color。
+        # 不连接漫反射贴图和法线贴图，避免 Cesium 里重新出现偏黑、
+        # 偏脏的斑驳效果，也避免法线贴图在硬光照下把屋顶压暗。
+        diffuse = None
+        normal = None
+    mapping = None
+    if diffuse or normal:
+        texcoord = nodes.new("ShaderNodeTexCoord")
+        texcoord.location = (-650, 0)
+        mapping = nodes.new("ShaderNodeMapping")
+        mapping.location = (-450, 0)
+        # The authoring materials use Generated coordinates with these scales.
+        # UVs are used here because Generated coordinates are not part of glTF.
+        mapping.inputs["Scale"].default_value = source_texture_scale(material)
+        links.new(texcoord.outputs["UV"], mapping.inputs["Vector"])
+
+    if diffuse:
+        image = nodes.new("ShaderNodeTexImage")
+        image.location = (-200, 80)
+        image.image = diffuse
+        image.extension = "REPEAT"
+        links.new(mapping.outputs["Vector"], image.inputs["Vector"])
+        links.new(image.outputs["Color"], bsdf.inputs["Base Color"])
+
+    if normal:
+        normal_tex = nodes.new("ShaderNodeTexImage")
+        normal_tex.location = (-200, -180)
+        normal_tex.image = normal
+        normal_tex.image.colorspace_settings.name = "Non-Color"
+        normal_tex.extension = "REPEAT"
+        normal_map = nodes.new("ShaderNodeNormalMap")
+        normal_map.location = (20, -160)
+        normal_map.inputs["Strength"].default_value = 0.52
+        links.new(mapping.outputs["Vector"], normal_tex.inputs["Vector"])
+        links.new(normal_tex.outputs["Color"], normal_map.inputs["Color"])
+        links.new(normal_map.outputs["Normal"], bsdf.inputs["Normal"])
+
+    # These values are deliberately conservative for web rendering.  In
+    # particular, avoid transmission/alpha because the source scene has no
+    # transparent geometry and those features are expensive in Cesium.
+    if "Alpha" in bsdf.inputs:
+        bsdf.inputs["Alpha"].default_value = 1.0
+    return result
+
+
+def unwrap_mesh(obj):
+    if obj.type != "MESH" or not obj.data.polygons:
+        return
+    bpy.ops.object.select_all(action="DESELECT")
+    obj.select_set(True)
+    bpy.context.view_layer.objects.active = obj
+    bpy.ops.object.mode_set(mode="EDIT")
+    bpy.ops.mesh.select_all(action="SELECT")
+    try:
+        bpy.ops.uv.smart_project(island_margin=0.025, area_weight=0.0)
+    finally:
+        bpy.ops.object.mode_set(mode="OBJECT")
+
+
+def apply_mesh_modifiers(obj):
+    if obj.type != "MESH":
+        return
+    bpy.ops.object.select_all(action="DESELECT")
+    obj.select_set(True)
+    bpy.context.view_layer.objects.active = obj
+    for modifier in list(obj.modifiers):
+        try:
+            bpy.ops.object.modifier_apply(modifier=modifier.name)
+        except RuntimeError:
+            # A failed nonessential modifier should not prevent the rest of
+            # the park from exporting.
+            pass
+
+
+def export(args):
+    if not os.path.exists(args["blend"]):
+        raise FileNotFoundError(args["blend"])
+    bpy.ops.wm.open_mainfile(filepath=args["blend"])
+
+    # Build one export material per source material and assign it in memory.
+    material_map = {}
+    meshes = []
+    for obj in bpy.context.scene.objects:
+        if obj.type != "MESH":
+            continue
+        # Cesium supplies the ellipsoid/globe surface. The authoring ground
+        # plane is deliberately omitted so it cannot appear as a large flat
+        # rectangle over the basemap.
+        if obj.name == "Ground Plane":
+            continue
+        meshes.append(obj)
+        apply_mesh_modifiers(obj)
+        unwrap_mesh(obj)
+        for slot in obj.material_slots:
+            if not slot.material:
+                continue
+            source = slot.material
+            if source.name not in material_map:
+                material_map[source.name] = make_export_material(source)
+            slot.material = material_map[source.name]
+
+    bpy.ops.object.select_all(action="DESELECT")
+    for obj in meshes:
+        obj.select_set(True)
+    bpy.context.view_layer.objects.active = meshes[0] if meshes else None
+
+    os.makedirs(os.path.dirname(args["glb"]), exist_ok=True)
+    bpy.ops.export_scene.gltf(
+        filepath=args["glb"],
+        export_format="GLB",
+        use_selection=True,
+        export_apply=False,
+        export_texcoords=True,
+        export_normals=True,
+        export_materials="EXPORT",
+        export_image_format="AUTO",
+        export_extras=True,
+        export_cameras=False,
+        export_lights=False,
+    )
+
+    scene = bpy.context.scene
+    try:
+        bounds = json.loads(scene.get("osm_bounds", "{}"))
+    except (TypeError, ValueError):
+        bounds = {}
+    if bounds:
+        center_lon = (bounds["min_lon"] + bounds["max_lon"]) / 2.0
+        center_lat = (bounds["min_lat"] + bounds["max_lat"]) / 2.0
+    else:
+        center_lon = center_lat = 0.0
+    metadata = {
+        "asset": os.path.basename(args["glb"]),
+        "coordinate_system": "local ENU meters (X east, Y north, Z up)",
+        "heading_correction_degrees": -90.0,
+        # A small offset prevents centimeter-high road markings and grass from
+        # fighting with the globe depth buffer at overview distances.
+        "anchor": {"longitude": center_lon, "latitude": center_lat, "height": 0.35},
+        "bounds": bounds,
+        "source_osm": scene.get("source_osm", ""),
+        "source_geojson": scene.get("source_geojson", ""),
+        "scene_stats": {
+            "buildings": scene.get("building_count", 0),
+            "industrial_buildings": scene.get("industrial_building_count", 0),
+            "lake_polygons": scene.get("lake_count", 0),
+            "trees": scene.get("tree_count", 0),
+            "grass_polygons": scene.get("grass_count", 0),
+            "scrub_polygons": scene.get("scrub_count", 0),
+            "fountains": scene.get("fountain_count", 0),
+        },
+        "cesium_js": (
+            "const p = Cesium.Cartesian3.fromDegrees(" +
+            f"{center_lon:.8f}, {center_lat:.8f}, 0.35);\n" +
+            "const enu = Cesium.Transforms.eastNorthUpToFixedFrame(p);\n" +
+            "const correction = Cesium.Matrix3.fromRotationZ(Cesium.Math.toRadians(-90.0));\n" +
+            "const modelMatrix = Cesium.Matrix4.multiplyByMatrix3(enu, correction, new Cesium.Matrix4());\n" +
+            "Cesium.Model.fromGltfAsync({ url: '" + os.path.basename(args["glb"]) +
+            "', modelMatrix }).then(model => viewer.scene.primitives.add(model));"
+        ),
+    }
+    os.makedirs(os.path.dirname(args["metadata"]), exist_ok=True)
+    with open(args["metadata"], "w", encoding="utf-8") as handle:
+        json.dump(metadata, handle, ensure_ascii=False, indent=2)
+        handle.write("\n")
+
+    # Keep the authoring blend untouched. The temporary export materials are
+    # only present in this Blender process and are not saved.
+    print("CESIUM_EXPORT_DONE", json.dumps({
+        "glb": args["glb"], "metadata": args["metadata"],
+        "meshes": len(meshes), "materials": len(material_map),
+        "anchor": [center_lon, center_lat],
+    }, ensure_ascii=True))
+
+
+if __name__ == "__main__":
+    export(cli_args())