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# -*- coding: utf-8 -*-
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
from abc import ABCMeta, abstractmethod
import numpy as np
from vispy.gloo import VertexBuffer
from ..shaders import Function
class BaseFilter(object):
"""Superclass for all filters."""
def _attach(self, visual):
"""Called when a filter should be attached to a visual.
Parameters
----------
visual : instance of BaseVisual
The visual that called this.
"""
raise NotImplementedError(self)
def _detach(self, visual):
"""Called when a filter should be detached from a visual.
Parameters
----------
visual : instance of BaseVisual
The visual that called this.
"""
raise NotImplementedError(self)
class Filter(BaseFilter):
"""Base class for all filters that use fragment and/or vertex shaders.
Parameters
----------
vcode : str | Function | None
Vertex shader code. If None, ``vhook`` and ``vpos`` will
be ignored.
vhook : {'pre', 'post'}
Hook name to attach the vertex shader to.
vpos : int
Position in the hook to attach the vertex shader.
fcode : str | Function | None
Fragment shader code. If None, ``fhook`` and ``fpos`` will
be ignored.
fhook : {'pre', 'post'}
Hook name to attach the fragment shader to.
fpos : int
Position in the hook to attach the fragment shader.
Attributes
----------
vshader : Function | None
Vertex shader.
fshader : Function | None
Fragment shader.
"""
def __init__(self, vcode=None, vhook='post', vpos=5,
fcode=None, fhook='post', fpos=5):
super(Filter, self).__init__()
if vcode is not None:
self.vshader = Function(vcode) if isinstance(vcode, str) else vcode
self._vexpr = self.vshader()
self._vhook = vhook
self._vpos = vpos
else:
self.vshader = None
if fcode is not None:
self.fshader = Function(fcode) if isinstance(fcode, str) else fcode
self._fexpr = self.fshader()
self._fhook = fhook
self._fpos = fpos
else:
self.fshader = None
self._attached = False
@property
def attached(self):
return self._attached
def _attach(self, visual):
"""Called when a filter should be attached to a visual.
Parameters
----------
visual : instance of Visual
The visual that called this.
"""
if self.vshader:
hook = visual._get_hook('vert', self._vhook)
hook.add(self._vexpr, position=self._vpos)
if self.fshader:
hook = visual._get_hook('frag', self._fhook)
hook.add(self._fexpr, position=self._fpos)
self._attached = True
self._visual = visual
def _detach(self, visual):
"""Called when a filter should be detached from a visual.
Parameters
----------
visual : instance of Visual
The visual that called this.
"""
if self.vshader:
hook = visual._get_hook('vert', self._vhook)
hook.remove(self._vexpr)
if self.fshader:
hook = visual._get_hook('frag', self._fhook)
hook.remove(self._fexpr)
self._attached = False
self._visual = None
class PrimitivePickingFilter(Filter, metaclass=ABCMeta):
"""Abstract base class for Visual-specific filters to implement a
primitive-picking mode.
Subclasses must (and usually only need to) implement
:py:meth:`_get_picking_ids`.
"""
def __init__(self, fpos=9, *, discard_transparent=False):
# fpos is set to 9 by default to put it near the end, but before the
# default PickingFilter
vfunc = Function("""\
varying vec4 v_marker_picking_color;
void prepare_marker_picking() {
v_marker_picking_color = $ids;
}
""")
ffunc = Function("""\
varying vec4 v_marker_picking_color;
void marker_picking_filter() {
if ( $enabled != 1 ) {
return;
}
if ( $discard_transparent == 1 && gl_FragColor.a == 0.0 ) {
discard;
}
gl_FragColor = v_marker_picking_color;
}
""")
self._id_colors = VertexBuffer(np.zeros((0, 4), dtype=np.float32))
vfunc['ids'] = self._id_colors
self._n_primitives = 0
super().__init__(vcode=vfunc, fcode=ffunc, fpos=fpos)
self.enabled = False
self.discard_transparent = discard_transparent
@abstractmethod
def _get_picking_ids(self):
"""Return a 1D array of picking IDs for the vertices in the visual.
Generally, this method should be implemented to:
1. Calculate the number of primitives in the visual (may be
persisted in `self._n_primitives`).
2. Calculate a range of picking ids for each primitive in the
visual. IDs should start from 1, reserving 0 for the background. If
primitives comprise multiple vertices (triangles), ids may need to
be repeated.
The return value should be an array of uint32 with shape
(num_vertices,).
If no change to the picking IDs is needed (for example, the number of
primitives has not changed), this method should return `None`.
"""
raise NotImplementedError(self)
def _update_id_colors(self):
"""Calculate the colors encoding the picking IDs for the visual.
For performance, this method will not update the id colors VertexBuffer
if :py:meth:`_get_picking_ids` returns `None`.
"""
# this should remain untouched
ids = self._get_picking_ids()
if ids is not None:
id_colors = self._pack_ids_into_rgba(ids)
self._id_colors.set_data(id_colors)
@staticmethod
def _pack_ids_into_rgba(ids):
"""Pack an array of uint32 primitive ids into float32 RGBA colors."""
if ids.dtype != np.uint32:
raise ValueError(f"ids must be uint32, got {ids.dtype}")
return np.divide(
ids.view(np.uint8).reshape(-1, 4),
255,
dtype=np.float32
)
def _on_data_updated(self, event=None):
if not self.attached:
return
self._update_id_colors()
@property
def enabled(self):
return self._enabled
@enabled.setter
def enabled(self, e):
self._enabled = bool(e)
self.fshader['enabled'] = int(self._enabled)
self._on_data_updated()
@property
def discard_transparent(self):
return self._discard_transparent
@discard_transparent.setter
def discard_transparent(self, d):
self._discard_transparent = bool(d)
self.fshader['discard_transparent'] = int(self._discard_transparent)
def _attach(self, visual):
super()._attach(visual)
visual.events.data_updated.connect(self._on_data_updated)
self._on_data_updated()
def _detach(self, visual):
visual.events.data_updated.disconnect(self._on_data_updated)
super()._detach(visual)
|
