1 files changed, 82 insertions, 0 deletions
diff --git a/io_scene_gltf2/blender/imp/gltf2_blender_KHR_materials_volume.py b/io_scene_gltf2/blender/imp/gltf2_blender_KHR_materials_volume.py
new file mode 100644
index 00000000..f909c7f6
--- /dev/null
+++ b/io_scene_gltf2/blender/imp/gltf2_blender_KHR_materials_volume.py
@@ -0,0 +1,82 @@
+# SPDX-License-Identifier: Apache-2.0
+# Copyright 2018-2021 The glTF-Blender-IO authors.
+
+from ...io.com.gltf2_io import TextureInfo, MaterialNormalTextureInfoClass
+from .gltf2_blender_texture import texture
+
+def volume(mh, location, volume_socket, thickness_socket):
+    # implementation based on https://github.com/KhronosGroup/glTF-Blender-IO/issues/1454#issuecomment-928319444
+    try:
+        ext = mh.pymat.extensions['KHR_materials_volume']
+    except Exception:
+        return
+
+    # Attenuation Color
+    attenuationColor = \
+            mh.pymat.extensions['KHR_materials_volume'] \
+            .get('attenuationColor')
+    # glTF is color3, Blender adds alpha
+    if attenuationColor is None:
+        attenuationColor = [1.0, 1.0, 1.0, 1.0]
+    else:
+        attenuationColor.extend([1.0])
+    volume_socket.node.inputs[0].default_value = attenuationColor
+
+    # Attenuation Distance / Density
+    attenuationDistance = mh.pymat.extensions['KHR_materials_volume'].get('attenuationDistance')
+    if attenuationDistance is None:
+        density = 0
+    else:
+        density = 1.0 / attenuationDistance
+    volume_socket.node.inputs[1].default_value = density
+
+    # thicknessFactor / thicknessTexture
+    x, y = location
+    try:
+        ext = mh.pymat.extensions['KHR_materials_volume']
+    except Exception:
+        return
+    thickness_factor = ext.get('thicknessFactor', 0)
+    tex_info = ext.get('thicknessTexture')
+    if tex_info is not None:
+        tex_info = TextureInfo.from_dict(tex_info)
+
+    if thickness_socket is None:
+        return
+
+    if tex_info is None:
+        thickness_socket.default_value = thickness_factor
+        return
+
+    # Mix thickness factor
+    if thickness_factor != 1:
+        node = mh.node_tree.nodes.new('ShaderNodeMath')
+        node.label = 'Thickness Factor'
+        node.location = x - 140, y
+        node.operation = 'MULTIPLY'
+        # Outputs
+        mh.node_tree.links.new(thickness_socket, node.outputs[0])
+        # Inputs
+        thickness_socket = node.inputs[0]
+        node.inputs[1].default_value = thickness_factor
+
+        x -= 200
+
+    # Separate RGB
+    node = mh.node_tree.nodes.new('ShaderNodeSeparateColor')
+    node.location = x - 150, y - 75
+    # Outputs
+    mh.node_tree.links.new(thickness_socket, node.outputs['Green'])
+    # Inputs
+    thickness_socket = node.inputs[0]
+
+    x -= 200
+
+    texture(
+        mh,
+        tex_info=tex_info,
+        label='THICKNESS',
+        location=(x, y),
+        is_data=True,
+        color_socket=thickness_socket,
+    )