import vtk
from vtk.util import numpy_support
from fury import enable_warnings
VTK_9_PLUS = vtk.vtkVersion.GetVTKMajorVersion() >= 9
SHADERS_TYPE = {"vertex": vtk.vtkShader.Vertex,
"geometry": vtk.vtkShader.Geometry,
"fragment": vtk.vtkShader.Fragment,
}
SHADERS_BLOCK = {
"position": "//VTK::PositionVC", # frag position in VC
"normal": "//VTK::Normal", # optional normal declaration
"light": "//VTK::Light", # extra lighting parameters
"tcoord": "//VTK::TCoord", # Texture coordinates
"color": "//VTK::Color", # material property values
"clip": "//VTK::Clip", # clipping plane vars
"camera": "//VTK::Camera", # camera and actor matrix values
"prim_id": "//VTK::PrimID", # Apple Bug
"valuepass": "//VTK::ValuePass", # Value raster
"output": "//VTK::Output", # only for geometry shader
}
[docs]def shader_to_actor(actor, shader_type, impl_code="", decl_code="",
block="valuepass", keep_default=True,
replace_first=True, replace_all=False, debug=False):
"""Apply your own substitutions to the shader creation process.
A bunch of string replacements is applied to a shader template. Using this
function you can apply your own string replacements to add features you
desire
Parameters
----------
actor : vtkActor
Object where you want to add the shader code.
shader_type : str
Shader type: vertex, geometry, fragment
impl_code : str, optional
shader implementation code, should be a string or filename
decl_code : str, optional
shader declaration code, should be a string or filename
by default None
block : str, optional
section name to be replaced. vtk use of heavy string replacments to
to insert shader and make it flexible. Each section of the shader
template have a specific name. For more informations:
https://vtk.org/Wiki/Shaders_In_VTK. The possible values are:
position, normal, light, tcoord, color, clip, camera, prim_id,
valuepass. by default valuepass
keep_default : bool, optional
keep the default block tag to let VTK replace it with its default
behavior. By default True
replace_first : bool, optional
If True, apply this change before the standard VTK replacements
by default True
replace_all : bool, optional
[description], by default False
debug : bool, optional
introduce a small error to debug shader code.
by default False
"""
shader_type = shader_type.lower()
shader_type = SHADERS_TYPE.get(shader_type, None)
if shader_type is None:
msg = "Invalid Shader Type. Please choose between "
msg += ', '.join(SHADERS_TYPE.keys())
raise ValueError(msg)
block = block.lower()
block = SHADERS_BLOCK.get(block, None)
if block is None:
msg = "Invalid Shader Type. Please choose between "
msg += ', '.join(SHADERS_BLOCK.keys())
raise ValueError(msg)
block_dec = block + "::Dec"
block_impl = block + "::Impl"
if keep_default:
decl_code = block_dec + "\n" + decl_code
impl_code = block_impl + "\n" + impl_code
if debug:
enable_warnings()
error_msg = "\n\n--- DEBUG: THIS LINE GENERATES AN ERROR ---\n\n"
impl_code += error_msg
sp = actor.GetShaderProperty() if VTK_9_PLUS else actor.GetMapper()
sp.AddShaderReplacement(shader_type, block_dec, replace_first,
decl_code, replace_all)
sp.AddShaderReplacement(shader_type, block_impl, replace_first,
impl_code, replace_all)
[docs]def replace_shader_in_actor(actor, shader_type, code):
"""Set and Replace the shader template with a new one.
Parameters
----------
actor : vtkActor
Object where you want to set the shader code.
shader_type : str
Shader type: vertex, geometry, fragment
code : str
new shader template code
"""
function_name = {
"vertex": "SetVertexShaderCode",
"fragment": "SetFragmentShaderCode",
"geometry": "SetGeometryShaderCode"
}
shader_type = shader_type.lower()
function = function_name.get(shader_type, None)
if function is None:
msg = "Invalid Shader Type. Please choose between "
msg += ', '.join(function_name.keys())
raise ValueError(msg)
sp = actor.GetShaderProperty() if VTK_9_PLUS else actor.GetMapper()
getattr(sp, function)(code)
[docs]def add_shader_callback(actor, callback):
"""Add a shader callback to the actor.
Parameters
----------
actor : vtkActor
Rendered Object
callback : callable
function or class that contains 3 parameters: caller, event, calldata.
This callback will be trigger at each `UpdateShaderEvent` event.
"""
@vtk.calldata_type(vtk.VTK_OBJECT)
def cbk(caller, event, calldata=None):
callback(caller, event, calldata)
mapper = actor.GetMapper()
mapper.AddObserver(vtk.vtkCommand.UpdateShaderEvent, cbk)
[docs]def attribute_to_actor(actor, arr, attr_name, deep=True):
"""Link a numpy array with vertex attribute.
Parameters
----------
actor : vtkActor
Rendered Object
arr : ndarray
array to link to vertices
attr_name : str
vertex attribute name. the vtk array will take the same name as the
attribute.
deep : bool, optional
If True a deep copy is applied. Otherwise a shallow copy is applied,
by default True
"""
nb_components = arr.shape[1] if arr.ndim > 1 else arr.ndim
vtk_array = numpy_support.numpy_to_vtk(arr, deep=deep)
vtk_array.SetNumberOfComponents(nb_components)
vtk_array.SetName(attr_name)
actor.GetMapper().GetInput().GetPointData().AddArray(vtk_array)
mapper = actor.GetMapper()
mapper.MapDataArrayToVertexAttribute(
attr_name, attr_name, vtk.vtkDataObject.FIELD_ASSOCIATION_POINTS, -1)