def detect_manual_uv_wrapping(blender_shader_node):
# Detects UV wrapping done using math nodes. This is for emulating wrap
# modes Blender doesn't support. It looks like
#
# next_socket => [Sep XYZ] => [Wrap S] => [Comb XYZ] => blender_shader_node
# => [Wrap T] =>
#
# The [Wrap _] blocks are either math nodes (eg. PINGPONG for mirrored
# repeat), or can be omitted.
#
# Returns None if not detected. Otherwise a dict containing the wrap
# mode in each direction (or None), and next_socket.
result = {}
comb = previous_node(blender_shader_node.inputs['Vector'])
if comb is None or comb.type != 'COMBXYZ': return None
for soc in ['X', 'Y']:
node = previous_node(comb.inputs[soc])
if node is None: return None
if node.type == 'SEPXYZ':
# Passed through without change
wrap = None
prev_socket = previous_socket(comb.inputs[soc])
elif node.type == 'MATH':
# Math node applies a manual wrap
if (node.operation == 'PINGPONG' and get_const_from_socket(
node.inputs[1], kind='VALUE') == 1.0): # scale = 1
wrap = TextureWrap.MirroredRepeat
elif (node.operation == 'WRAP' and get_const_from_socket(
node.inputs[1], kind='VALUE') == 0.0 and # min = 0
get_const_from_socket(node.inputs[2], kind='VALUE')
== 1.0): # max = 1
wrap = TextureWrap.Repeat
else:
return None
prev_socket = previous_socket(node.inputs[0])
else:
return None
if prev_socket is None: return None
prev_node = prev_socket.node
if prev_node.type != 'SEPXYZ': return None
# Make sure X goes to X, etc.
if prev_socket.name != soc: return None
# Make sure both attach to the same SeparateXYZ node
if soc == 'X':
sep = prev_node
else:
if sep != prev_node: return None
result['wrap_s' if soc == 'X' else 'wrap_t'] = wrap
result['next_socket'] = sep.inputs[0]
return result
def __detect_lightpath_trick(socket):
# Detects this (used to prevent casting light on other objects) See ex.
# https://blender.stackexchange.com/a/21535/88681
#
# [ Lightpath ] [ Mix ]
# [ Is Camera Ray] => [Factor ] => socket
# (don't care) => [Shader ]
# next_socket => [ Emission ] => [Shader ]
#
# The Emission node can be omitted.
# Returns None if not detected. Otherwise, a dict containing
# next_socket.
prev = gltf2_blender_get.previous_node(socket)
if prev is None or prev.type != 'MIX_SHADER': return None
in0 = gltf2_blender_get.previous_socket(prev.inputs[0])
if in0 is None or in0.node.type != 'LIGHT_PATH': return None
if in0.name != 'Is Camera Ray': return None
next_socket = prev.inputs[2]
# Detect emission
prev = gltf2_blender_get.previous_node(next_socket)
if prev is not None and prev.type == 'EMISSION':
next_socket = prev.inputs[0]
return {'next_socket': next_socket}
def detect_shadeless_material(blender_material, export_settings):
"""Detect if this material is "shadeless" ie. should be exported
with KHR_materials_unlit. Returns None if not. Otherwise, returns
a dict with info from parsing the node tree.
"""
if not blender_material.use_nodes: return None
# Old Background node detection (unlikely to happen)
bg_socket = gltf2_blender_get.get_socket(blender_material, "Background")
if bg_socket is not None:
return {'rgb_socket': bg_socket}
# Look for
# * any color socket, connected to...
# * optionally, the lightpath trick, connected to...
# * optionally, a mix-with-transparent (for alpha), connected to...
# * the output node
info = {}
for node in blender_material.node_tree.nodes:
if node.type == 'OUTPUT_MATERIAL':
socket = node.inputs[0]
break
else:
return None
# Be careful not to misidentify a lightpath trick as mix-alpha.
result = __detect_lightpath_trick(socket)
if result is not None:
socket = result['next_socket']
else:
result = __detect_mix_alpha(socket)
if result is not None:
socket = result['next_socket']
info['alpha_socket'] = result['alpha_socket']
result = __detect_lightpath_trick(socket)
if result is not None:
socket = result['next_socket']
# Check if a color socket, or connected to a color socket
if socket.type != 'RGBA':
from_socket = gltf2_blender_get.previous_socket(socket)
if from_socket is None: return None
if from_socket.type != 'RGBA': return None
info['rgb_socket'] = socket
return info