"""Bake a low-frequency wearer lighting atlas for the diffuse study.""" from __future__ import annotations import argparse import sys from pathlib import Path import bpy def math_value(nodes, links, operation, source, value): node = nodes.new("ShaderNodeMath") node.operation = operation links.new(source, node.inputs[0]) node.inputs[1].default_value = value return node.outputs[0] def math_pair(nodes, links, operation, first, second): node = nodes.new("ShaderNodeMath") node.operation = operation links.new(first, node.inputs[0]) links.new(second, node.inputs[1]) return node.outputs[0] def add_constant(nodes, links, source, value): node = nodes.new("ShaderNodeMath") node.operation = "ADD" links.new(source, node.inputs[0]) node.inputs[1].default_value = value return node.outputs[0] def smooth_spot(nodes, links, x_socket, z_socket, center_x, center_z, radius): dx = add_constant(nodes, links, x_socket, -center_x) dz = add_constant(nodes, links, z_socket, -center_z) dx_squared = math_pair(nodes, links, "MULTIPLY", dx, dx) dz_squared = math_pair(nodes, links, "MULTIPLY", dz, dz) distance_squared = math_pair(nodes, links, "ADD", dx_squared, dz_squared) distance = nodes.new("ShaderNodeMath") distance.operation = "SQRT" links.new(distance_squared, distance.inputs[0]) falloff = nodes.new("ShaderNodeMapRange") falloff.clamp = True falloff.interpolation_type = "SMOOTHERSTEP" falloff.inputs[1].default_value = 0.0 falloff.inputs[2].default_value = radius falloff.inputs[3].default_value = 1.0 falloff.inputs[4].default_value = 0.0 links.new(distance.outputs[0], falloff.inputs[0]) return falloff.outputs[0] def main() -> None: parser = argparse.ArgumentParser() parser.add_argument("--model", required=True, type=Path) parser.add_argument("--output", required=True, type=Path) parser.add_argument("--size", type=int, default=2048) argv = sys.argv[sys.argv.index("--") + 1 :] if "--" in sys.argv else [] args = parser.parse_args(argv) bpy.ops.wm.read_factory_settings(use_empty=True) bpy.ops.import_scene.gltf(filepath=str(args.model)) meshes = [obj for obj in bpy.context.scene.objects if obj.type == "MESH"] if len(meshes) != 1: raise RuntimeError(f"Expected one mesh, found {len(meshes)}") wearer = meshes[0] bpy.ops.object.select_all(action="DESELECT") wearer.select_set(True) bpy.context.view_layer.objects.active = wearer bpy.ops.object.transform_apply(location=False, rotation=True, scale=True) if not wearer.data.uv_layers: raise RuntimeError("The wearer GLB has no UV map") wearer.data.uv_layers.active_index = 0 source_images = [ node.image for material in wearer.data.materials if material and material.use_nodes for node in material.node_tree.nodes if node.type == "TEX_IMAGE" and node.image is not None ] if not source_images: raise RuntimeError("The wearer GLB has no embedded base-color texture") source = max(source_images, key=lambda image: image.size[0] * image.size[1]) source.colorspace_settings.name = "sRGB" baked = bpy.data.images.new( "WearerLighting", width=args.size, height=args.size, alpha=True, float_buffer=False, ) baked.colorspace_settings.name = "sRGB" baked.generated_color = (0.0, 0.0, 0.0, 1.0) material = bpy.data.materials.new("Wearer lighting bake") material.use_nodes = True nodes = material.node_tree.nodes links = material.node_tree.links nodes.clear() output = nodes.new("ShaderNodeOutputMaterial") emission = nodes.new("ShaderNodeEmission") source_texture = nodes.new("ShaderNodeTexImage") source_texture.image = source source_texture.interpolation = "Linear" source_texture.extension = "EXTEND" target_texture = nodes.new("ShaderNodeTexImage") target_texture.image = baked target_texture.select = True nodes.active = target_texture luminance = nodes.new("ShaderNodeRGBToBW") links.new(source_texture.outputs["Color"], luminance.inputs["Color"]) hsv = nodes.new("ShaderNodeSeparateColor") hsv.mode = "HSV" links.new(source_texture.outputs["Color"], hsv.inputs["Color"]) saturation = hsv.outputs[1] # The source texture contributes only broad semantic separation: dark hair, # mid-tone skin and restrained light clothing. Fine albedo detail is not # emitted directly into the final web composite. luma_term = math_value(nodes, links, "MULTIPLY", luminance.outputs["Val"], 0.12) saturation_term = math_value(nodes, links, "MULTIPLY", saturation, 0.60) semantic = math_pair(nodes, links, "ADD", luma_term, saturation_term) semantic = add_constant(nodes, links, semantic, 0.08) geometry = nodes.new("ShaderNodeNewGeometry") position = nodes.new("ShaderNodeSeparateXYZ") links.new(geometry.outputs["Position"], position.inputs["Vector"]) # Object-space emphasis follows the approved order: # raised hand/ring, face, clothing, hair. hand_spot = smooth_spot( nodes, links, position.outputs["X"], position.outputs["Z"], center_x=-0.26, center_z=0.15, radius=0.34, ) face_spot = smooth_spot( nodes, links, position.outputs["X"], position.outputs["Z"], center_x=-0.05, center_z=0.50, radius=0.43, ) hand_spot = math_value(nodes, links, "MULTIPLY", hand_spot, 0.70) face_spot = math_value(nodes, links, "MULTIPLY", face_spot, 0.42) focus = math_pair(nodes, links, "ADD", hand_spot, face_spot) focus_gate = math_value(nodes, links, "MULTIPLY", semantic, 1.40) focus_gate = add_constant(nodes, links, focus_gate, 0.12) focus = math_pair(nodes, links, "MULTIPLY", focus, focus_gate) normal_dot = nodes.new("ShaderNodeVectorMath") normal_dot.operation = "DOT_PRODUCT" normal_dot.inputs[1].default_value = (0.0, -1.0, 0.0) links.new(geometry.outputs["Normal"], normal_dot.inputs[0]) front = nodes.new("ShaderNodeMath") front.operation = "MAXIMUM" front.inputs[1].default_value = 0.0 links.new(normal_dot.outputs["Value"], front.inputs[0]) front_term = math_value(nodes, links, "MULTIPLY", front.outputs[0], 0.10) semantic_term = math_value(nodes, links, "MULTIPLY", semantic, 0.65) focus_term = math_value(nodes, links, "MULTIPLY", focus, 0.75) lighting = math_pair(nodes, links, "ADD", semantic_term, focus_term) lighting = math_pair(nodes, links, "ADD", lighting, front_term) # Suppress dark hair without carrying its fine texture into the result. luma_gate = math_value(nodes, links, "MULTIPLY", luminance.outputs["Val"], 0.65) luma_gate = add_constant(nodes, links, luma_gate, 0.35) lighting = math_pair(nodes, links, "MULTIPLY", lighting, luma_gate) lighting = math_value(nodes, links, "MULTIPLY", lighting, 0.32) clamp = nodes.new("ShaderNodeClamp") clamp.inputs[1].default_value = 0.0 clamp.inputs[2].default_value = 1.0 links.new(lighting, clamp.inputs[0]) links.new(clamp.outputs[0], emission.inputs["Color"]) links.new(emission.outputs["Emission"], output.inputs["Surface"]) wearer.data.materials.clear() wearer.data.materials.append(material) scene = bpy.context.scene scene.render.engine = "CYCLES" scene.cycles.device = "CPU" scene.cycles.samples = 1 scene.render.image_settings.file_format = "PNG" scene.render.image_settings.color_mode = "RGBA" scene.render.image_settings.color_depth = "8" scene.render.film_transparent = True bpy.ops.object.bake(type="EMIT", margin=32, use_clear=True) args.output.parent.mkdir(parents=True, exist_ok=True) baked.filepath_raw = str(args.output) baked.file_format = "PNG" baked.save() print(f"saved={args.output} source={source.name} size={args.size}x{args.size}") if __name__ == "__main__": main()