Source code for fsleyes.gl.scene3dcanvas

#
# scene3dcanvas.py - The Scene3DCanvas class.
#
# Author: Paul McCarthy <pauldmccarthy@gmail.com>
#
"""This module provides the :class:`.Scene3DCanvas` class, which is used by
FSLeyes for its 3D view.
"""


import logging

import numpy     as np
import OpenGL.GL as gl

import fsl.data.mesh        as fslmesh
import fsl.data.image       as fslimage
import fsl.utils.idle       as idle
import fsl.transform.affine as affine

import fsleyes.gl.routines               as glroutines
import fsleyes.gl.globject               as globject
import fsleyes.gl.text                   as gltext
import fsleyes.displaycontext            as fsldisplay
import fsleyes.displaycontext.canvasopts as canvasopts


log = logging.getLogger(__name__)


[docs]class Scene3DCanvas(object): """The ``Scene3DCanvas`` is an OpenGL canvas used to draw overlays in a 3D view. Currently only ``volume`` and ``mesh`` overlay types are supported. """
[docs] def __init__(self, overlayList, displayCtx): self.__name = '{}_{}'.format(type(self).__name__, id(self)) self.__opts = canvasopts.Scene3DCanvasOpts() self.__overlayList = overlayList self.__displayCtx = displayCtx self.__viewMat = np.eye(4) self.__projMat = np.eye(4) self.__invViewProjMat = np.eye(4) self.__viewport = None self.__resetLightPos = True self.__glObjects = {} # gl.text.Text objects containing anatomical # orientation labels ordered # (xlo, xhi, ylo, yhi, zlo, zhi) where xyz # are the display coordinate system axes. # Created in __refreshLegendLabels self.__legendLabels = None overlayList.addListener('overlays', self.__name, self.__overlayListChanged) displayCtx.addListener('bounds', self.__name, self.__displayBoundsChanged) opts = self.opts opts.addListener('pos', self.__name, self.Refresh) opts.addListener('showCursor', self.__name, self.Refresh) opts.addListener('cursorColour', self.__name, self.Refresh) opts.addListener('bgColour', self.__name, self.Refresh) opts.addListener('showLegend', self.__name, self.Refresh) opts.addListener('legendColour', self.__name, self.__refreshLegendLabels) opts.addListener('labelSize', self.__name, self.__refreshLegendLabels) opts.addListener('occlusion', self.__name, self.Refresh) opts.addListener('zoom', self.__name, self.Refresh) opts.addListener('offset', self.__name, self.Refresh) opts.addListener('rotation', self.__name, self.Refresh) opts.addListener('showLight', self.__name, self.Refresh) opts.addListener('light', self.__name, self.Refresh) opts.addListener('lightPos', self.__name, self.Refresh) opts.addListener('lightDistance', self.__name, self.Refresh) opts.addListener('highDpi', self.__name, self.__highDpiChanged)
[docs] def destroy(self): """Must be called when this Scene3DCanvas is no longer used. """ self.__overlayList.removeListener('overlays', self.__name) self.__displayCtx .removeListener('bounds', self.__name) for ovl in list(self.__glObjects.keys()): self.__deregisterOverlay(ovl) if self.__legendLabels is not None: for lbl in self.__legendLabels: lbl.destroy() self.__opts = None self.__displayCtx = None self.__overlayList = None self.__glObjects = None self.__legendLabels = None
@property def destroyed(self): """Returns ``True`` if :meth:`destroy` has been called. """ return self.__overlayList is None @property def opts(self): """Returns a reference to the :class:`.Scene3DCanvasOpts` instance. """ return self.__opts @property def lightPos(self): """Takes the values of :attr:`.Scene3DOpts.lightPos` and :attr:`.Scene3DOpts.lightDistance`, and converts it to a position in the display coordinate system. The ``Scene3DOpts.lightPos`` property contains rotations about the centre of the display bounding box, and the :attr:`.Scene3DOpts.lightDistance` property specifies the distance of the light from the bounding box centre. """ b = self.__displayCtx.bounds centre = np.array([b.xlo + 0.5 * (b.xhi - b.xlo), b.ylo + 0.5 * (b.yhi - b.ylo), b.zlo + 0.5 * (b.zhi - b.zlo)]) yaw, pitch, roll = self.opts.lightPos distance = self.opts.lightDistance yaw = yaw * np.pi / 180 pitch = pitch * np.pi / 180 roll = roll * np.pi / 180 rotmat = affine.axisAnglesToRotMat(pitch, roll, yaw) xform = affine.compose([1, 1, 1], [0, 0, 0], rotmat, origin=centre) lightPos = centre + [0, 0, distance * b.zlen] lightPos = affine.transform(lightPos, xform) return lightPos @property def resetLightPos(self): """By default, the :attr:`lightPos` is updated whenever the :attr:`.DisplayContext.bounds` change. This flag can be used to disable this behaviour. """ return self.__resetLightPos @resetLightPos.setter def resetLightPos(self, reset): """Control whether the :attr:`lightPos` property is reset whenever the :attr:`.DisplayContext.bounds` change. """ self.__resetLightPos = reset
[docs] def defaultLightPos(self): """Resets the :attr:`lightPos` property to a sensible value. """ self.opts.lightPos = [0, 0, 0]
@property def viewMatrix(self): """Returns the view matrix for the current scene - this is an affine matrix which encodes the current :attr:`.Scene3DCanvasOpts.offset`, :attr:`.Scene3DCanvasOpts.zoom`, :attr:`.Scene3DCanvasOpts.rotation` and camera settings. See :meth:`__genViewMatrix`. """ return self.__viewMat @property def viewScale(self): """Returns an affine matrix which encodes the current :attr:`.Scene3DCanvasOpts.zoom` setting. """ return self.__viewScale @property def viewOffset(self): """Returns an affine matrix which encodes the current :attr:`.Scene3DCanvasOpts.offset` setting. """ return self.__viewOffset @property def viewRotation(self): """Returns an affine matrix which encodes the current :attr:`.Scene3DCanvasOpts.rotation` setting. """ return self.__viewRotate @property def viewCamera(self): """Returns an affine matrix which encodes the current camera. transformation. The initial camera orientation in the view shown by a :class:`Scene3DCanvas` is located on the positive Y axis, is oriented towards the positive Z axis, and is pointing towards the centre of the :attr:`.DisplayContext.displayBounds`. """ return self.__viewCamera @property def projectionMatrix(self): """Returns the projection matrix. This is an affine matrix which converts from normalised device coordinates (NDCs, coordinates between -1 and +1) into viewport coordinates. The initial viewport for a :class:`Scene3DCanvas` is configured by the :func:`.routines.ortho` function. See :meth:`__setViewport`. """ return self.__projMat @property def invViewProjectionMatrix(self): """Returns the inverse of the model-view-projection matrix, the equivalent of: ``invert(projectionMatrix * viewMatrix)`` """ return self.__invViewProjMat @property def viewport(self): """Returns a list of three ``(min, max)`` tuples which specify the viewport limits of the currently displayed scene. """ return self.__viewport
[docs] def canvasToWorld(self, xpos, ypos, near=True): """Transform the given x/y canvas coordinates into the display coordinate system. The calculated coordinates will be located on the near clipping plane. :arg near: If ``True`` (the default), the returned coordinate will be located on the near clipping plane. Otherwise, the coordinate will be located on the far clipping plane. """ width, height = self.GetSize() # Normalise pixels to [-1, 1] xp = -1 + 2.0 * xpos / width yp = -1 + 2.0 * ypos / height # We set the Z coord so the resulting # coordinates will be located on either # the near or clipping planes. if near: pos = [xp, yp, -1] else: pos = [xp, yp, 1] # The first step is to convert mouse # coordinates from [-1, 1] to viewport # coodinates via the inverse projection # matrix. # The second step is to transform from # viewport coords into model-view coords. # This is easy - transform by the inverse # MV matrix. # We perform both of these steps in one # by concatenating then inverting the # view/projection matrices. This is # calculated and cached for us in the # __setViewport method. pos = affine.transform(pos, self.__invViewProjMat) return pos
[docs] def getGLObject(self, overlay): """Returns the :class:`.GLObject` associated with the given overlay, or ``None`` if there is not one. """ return self.__glObjects.get(overlay, None)
[docs] def getGLObjects(self): """Returns two lists: - A list of overlays to be drawn - A list of corresponding :class:`GLObject` instances The lists are in the order that they should be drawn. This method also creates ``GLObject`` instances for any overlays in the :class:`.OverlayList` that do not have one. """ overlays = self.__displayCtx.getOrderedOverlays() surfs = [o for o in overlays if isinstance(o, fslmesh.Mesh)] vols = [o for o in overlays if isinstance(o, fslimage.Image)] other = [o for o in overlays if o not in surfs and o not in vols] overlays = [] globjs = [] # If occlusion is on, we draw all surfaces first, # so they are on the scene regardless of volume # opacity. # # If occlusion is off, we draw all volumes # (without depth testing) first, and draw all # surfaces (with depth testing) afterwards. # In this way, the surfaces will be occluded # by the last drawn volume. I figure that this # is better than being occluded by *all* volumes, # regardless of depth or camera orientation. # # The one downside to this is that if a # transparent volume is in front of a surface, # the surface won't be shown. # # The only way to overcome this would be to # sort by depth on every render which, given # the possibility of volume clipping planes, # is a bit too complicated for my liking. if self.opts.occlusion: ovlOrder = surfs + vols + other else: ovlOrder = vols + surfs + other for ovl in ovlOrder: globj = self.getGLObject(ovl) # If there is no GLObject for this # overlay, create one, but don't # add it to the list (as creation # is done asynchronously). if globj is None: self.__registerOverlay(ovl) # Otherwise, if the value for this # overlay evaluates to False, that # means that it has been scheduled # for creation, but is not ready # yet. elif globj: overlays.append(ovl) globjs .append(globj) return overlays, globjs
[docs] def _initGL(self): """Called when the canvas is ready to be drawn on. """ self.__overlayListChanged() self.__displayBoundsChanged()
def __overlayListChanged(self, *a): """Called when the :class:`.OverlayList` changes. Destroys/creates :class:`.GLObject` instances as necessary. """ # Destroy any GL objects for overlays # which are no longer in the list for ovl, globj in list(self.__glObjects.items()): if ovl not in self.__overlayList: self.__deregisterOverlay(ovl) # Create GLObjects for any # newly added overlays for ovl in self.__overlayList: if ovl not in self.__glObjects: self.__registerOverlay(ovl) self.__refreshLegendLabels(refresh=False) def __refreshLegendLabels(self, *a, refresh=True): """Called when the legend labels (anatomical orientations) need to be refreshed - when the selected overlay changes, or when the :attr:`.Scene3DCanvasOpts.legendColour` is changed. """ # Update legend labels. Figure out the # anatomical labels for each axis. overlay = self.__displayCtx.getSelectedOverlay() if overlay is None: return if self.__legendLabels is None: self.__legendLabels = [gltext.Text(coordinates='pixels') for _ in range(6)] dopts = self.__displayCtx.getOpts(overlay) labels = dopts.getLabels()[0] # getLabels returns (xlo, ylo, zlo, xhi, yhi, zhi) - # - rearrange them to (xlo, xhi, ylo, yhi, zlo, zhi) labels = [labels[0], labels[3], labels[1], labels[4], labels[2], labels[5]] for label, text in zip(labels, self.__legendLabels): text.text = label text.colour = self.opts.legendColour text.fontSize = self.opts.labelSize text.halign = 'centre' text.valign = 'centre' if refresh: self.Refresh() def __highDpiChanged(self, *a): """Called when the :attr:`.Scene3DCanvasOpts.highDpi` property changes. Calls the :meth:`.GLCanvasTarget.EnableHighDPI` method. """ self.EnableHighDPI(self.opts.highDpi) def __displayBoundsChanged(self, *a): """Called when the :attr:`.DisplayContext.bounds` change. Resets the :attr:`.Scene3DCanvasOpts.lightPos` property. """ if self.resetLightPos: self.defaultLightPos() self.Refresh() def __registerOverlay(self, overlay): """Called when a new overlay has been added to the overlay list. Creates a ``GLObject`` for it, and registers property listeners. """ if not isinstance(overlay, (fslmesh.Mesh, fslimage.Image)): return log.debug('Registering overlay {}'.format(overlay)) display = self.__displayCtx.getDisplay(overlay) if not self.__genGLObject(overlay): return display.addListener('enabled', self.__name, self.Refresh) display.addListener('overlayType', self.__name, self.__overlayTypeChanged) def __deregisterOverlay(self, overlay): """Called when an overlay has been removed from the overlay list. Dstroys the ``GLObject`` for it, and de-registers property listeners. """ log.debug('Deregistering overlay {}'.format(overlay)) try: display = self.__displayCtx.getDisplay(overlay) display.removeListener('overlayType', self.__name) display.removeListener('enabled', self.__name) except fsldisplay.InvalidOverlayError: pass globj = self.__glObjects.pop(overlay, None) if globj is not None: globj.deregister(self.__name) globj.destroy() def __genGLObject(self, overlay): """Create a ``GLObject`` for the given overlay, if one doesn't already exist. """ if overlay in self.__glObjects: return False display = self.__displayCtx.getDisplay(overlay) if display.overlayType not in ('volume', 'mesh'): return False self.__glObjects[overlay] = False def create(): if not self or self.destroyed: return if overlay not in self.__glObjects: return if not self._setGLContext(): self.__glObjects.pop(overlay) return log.debug('Creating GLObject for {}'.format(overlay)) globj = globject.createGLObject(overlay, self.__overlayList, self.__displayCtx, self, True) if globj is not None: globj.register(self.__name, self.Refresh) self.__glObjects[overlay] = globj idle.idle(create) return True def __overlayTypeChanged(self, value, valid, display, name): """Called when the :attr:`.Display.overlayType` of an overlay has changed. Re-generates a :class:`.GLObject` for it. """ overlay = display.overlay globj = self.__glObjects.pop(overlay, None) if globj is not None: globj.deregister(self.__name) globj.destroy() self.__genGLObject(overlay) self.Refresh() def __genViewMatrix(self, w, h): """Generate and return a transformation matrix to be used as the model-view matrix. This includes applying the current :attr:`zoom`, :attr:`rotation` and :attr:`offset` settings, and configuring the camera. This method is called by :meth:`__setViewport`. :arg w: Canvas width in pixels :arg h: Canvas height in pixels """ opts = self.opts b = self.__displayCtx.bounds centre = [b.xlo + 0.5 * b.xlen, b.ylo + 0.5 * b.ylen, b.zlo + 0.5 * b.zlen] # The MV matrix comprises (in this order): # # - A rotation (the rotation property) # # - Camera configuration. With no rotation, the # camera will be looking towards the positive # Y axis (i.e. +y is forwards), and oriented # towards the positive Z axis (i.e. +z is up) # # - A translation (the offset property) # - A scaling (the zoom property) # Scaling and rotation matrices. Rotation # is always around the centre of the # displaycontext bounds (the bounding # box which contains all loaded overlays). scale = opts.zoom / 100.0 scale = affine.scaleOffsetXform([scale] * 3, 0) rotate = affine.rotMatToAffine(opts.rotation, centre) # The offset property is defined in x/y # pixels, normalised to [-1, 1]. We need # to convert them into viewport space, # where the horizontal axis maps to # (-xhalf, xhalf), and the vertical axis # maps to (-yhalf, yhalf). See # gl.routines.ortho. offset = np.array(opts.offset[:] + [0]) xlen, ylen = glroutines.adjust(b.xlen, b.ylen, w, h) offset[0] = xlen * offset[0] / 2 offset[1] = ylen * offset[1] / 2 offset = affine.scaleOffsetXform(1, offset) # And finally the camera. eye = list(centre) eye[1] += 1 up = [0, 0, 1] camera = glroutines.lookAt(eye, centre, up) # Order is very important! xform = affine.concat(offset, scale, camera, rotate) np.array(xform, dtype=np.float32) self.__viewOffset = offset self.__viewScale = scale self.__viewRotate = rotate self.__viewCamera = camera self.__viewMat = xform def __setViewport(self): """Called by :meth:`_draw`. Configures the viewport and calculates the model-view trasformation matrix. :returns: ``True`` if the viewport was successfully configured, ``False`` otherwise. """ width, height = self.GetScaledSize() b = self.__displayCtx.bounds blo = [b.xlo, b.ylo, b.zlo] bhi = [b.xhi, b.yhi, b.zhi] zoom = self.opts.zoom / 100.0 if width == 0 or height == 0: return False # We allow one dimension to be # flat, so we can display 2D # meshes (e.g. flattened surfaces) if np.sum(np.isclose(blo, bhi)) > 1: return False # Generate the view and projection matrices self.__genViewMatrix(width, height) projmat, viewport = glroutines.ortho(blo, bhi, width, height, zoom) self.__projMat = projmat self.__viewport = viewport self.__invViewProjMat = affine.concat(self.__projMat, self.__viewMat) self.__invViewProjMat = affine.invert(self.__invViewProjMat) gl.glViewport(0, 0, width, height) gl.glMatrixMode(gl.GL_PROJECTION) gl.glLoadMatrixf(self.__projMat.ravel('F')) gl.glMatrixMode(gl.GL_MODELVIEW) gl.glLoadIdentity() return True
[docs] def _draw(self): """Draws the scene to the canvas. """ if self.destroyed: return if not self._setGLContext(): return opts = self.opts glroutines.clear(opts.bgColour) if not self.__setViewport(): return overlays, globjs = self.getGLObjects() if len(overlays) == 0: return # If occlusion is on, we offset the # depth of each overlay so that, where # a depth collision occurs, overlays # which are higher in the list will get # drawn above (closer to the screen) # than lower ones. depthOffset = affine.scaleOffsetXform(1, [0, 0, 0.1]) depthOffset = np.array(depthOffset, dtype=np.float32, copy=False) xform = np.array(self.__viewMat, dtype=np.float32, copy=False) for ovl, globj in zip(overlays, globjs): display = self.__displayCtx.getDisplay(ovl) if not globj.ready(): continue if not display.enabled: continue if opts.occlusion: xform = affine.concat(depthOffset, xform) elif isinstance(ovl, fslimage.Image): gl.glClear(gl.GL_DEPTH_BUFFER_BIT) log.debug('Drawing {} [{}]'.format(ovl, globj)) globj.preDraw( xform=xform) globj.draw3D( xform=xform) globj.postDraw(xform=xform) if opts.showCursor: with glroutines.enabled((gl.GL_DEPTH_TEST)): self.__drawCursor() if opts.showLegend: self.__drawLegend() if opts.showLight: self.__drawLight() # Testing click-to-near/far clipping plane transformation if hasattr(self, 'points'): colours = [(1, 0, 0, 1), (0, 0, 1, 1)] gl.glPointSize(5) gl.glBegin(gl.GL_LINES) for i, p in enumerate(self.points): gl.glColor4f(*colours[i % 2]) p = affine.transform(p, self.viewMatrix) gl.glVertex3f(*p) gl.glEnd()
def __drawCursor(self): """Draws three lines at the current :attr:`.DisplayContext.location`. """ opts = self.opts b = self.__displayCtx.bounds pos = opts.pos points = np.array([ [pos.x, pos.y, b.zlo], [pos.x, pos.y, b.zhi], [pos.x, b.ylo, pos.z], [pos.x, b.yhi, pos.z], [b.xlo, pos.y, pos.z], [b.xhi, pos.y, pos.z], ], dtype=np.float32) points = affine.transform(points, self.__viewMat) gl.glLineWidth(1) r, g, b = opts.cursorColour[:3] gl.glColor4f(r, g, b, 1) gl.glBegin(gl.GL_LINES) for p in points: gl.glVertex3f(*p) gl.glEnd() def __drawLegend(self): """Draws a legend in the bottom left corner of the screen, showing anatomical orientation. """ copts = self.opts b = self.__displayCtx.bounds w, h = self.GetSize() xlen, ylen = glroutines.adjust(b.xlen, b.ylen, w, h) # A line for each axis vertices = np.zeros((6, 3), dtype=np.float32) vertices[0, :] = [-1, 0, 0] vertices[1, :] = [ 1, 0, 0] vertices[2, :] = [ 0, -1, 0] vertices[3, :] = [ 0, 1, 0] vertices[4, :] = [ 0, 0, -1] vertices[5, :] = [ 0, 0, 1] # Each axis line is scaled to # 60 pixels, and the legend is # offset from the bottom-left # corner by twice this amount. scale = [xlen * 30.0 / w] * 3 offset = [-0.5 * xlen + 2.0 * scale[0], -0.5 * ylen + 2.0 * scale[1], 0] # Apply the current camera # angle and rotation settings # to the legend vertices. Offset # anatomical labels off each # axis line by a small amount. rotation = affine.decompose(self.__viewMat)[2] xform = affine.compose(scale, offset, rotation) labelPoses = affine.transform(vertices * 1.2, xform) vertices = affine.transform(vertices, xform) # Draw the legend lines gl.glDisable(gl.GL_DEPTH_TEST) gl.glColor3f(*copts.cursorColour[:3]) gl.glLineWidth(2) gl.glBegin(gl.GL_LINES) gl.glVertex3f(*vertices[0]) gl.glVertex3f(*vertices[1]) gl.glVertex3f(*vertices[2]) gl.glVertex3f(*vertices[3]) gl.glVertex3f(*vertices[4]) gl.glVertex3f(*vertices[5]) gl.glEnd() canvas = np.array([w, h]) view = np.array([xlen, ylen]) # Draw each label for i, label in enumerate(self.__legendLabels): # Calculate pixel x/y # location for this label xx, xy = canvas * (labelPoses[i, :2] + 0.5 * view) / view label.pos = (xx, xy) label.draw(w, h) def __drawLight(self): """Draws a representation of the light source. """ lightPos = self.lightPos bounds = self.__displayCtx.bounds centre = np.array([bounds.xlo + 0.5 * (bounds.xhi - bounds.xlo), bounds.ylo + 0.5 * (bounds.yhi - bounds.ylo), bounds.zlo + 0.5 * (bounds.zhi - bounds.zlo)]) lightPos = affine.transform(lightPos, self.__viewMat) centre = affine.transform(centre, self.__viewMat) # draw the light as a point gl.glColor4f(1, 1, 0, 1) gl.glPointSize(10) gl.glBegin(gl.GL_POINTS) gl.glVertex3f(*lightPos) gl.glEnd() # draw a line from the light to the # centre of the display bounding box gl.glBegin(gl.GL_LINES) gl.glVertex3f(*lightPos) gl.glVertex3f(*centre) gl.glEnd() def __drawBoundingBox(self): """Draws a bounding box around all overlays. Used for debugging. """ b = self.__displayCtx.bounds xlo, xhi = b.x ylo, yhi = b.y zlo, zhi = b.z xlo += 0.1 xhi -= 0.1 vertices = np.array([ [xlo, ylo, zlo], [xlo, ylo, zhi], [xlo, yhi, zlo], [xlo, yhi, zhi], [xhi, ylo, zlo], [xhi, ylo, zhi], [xhi, yhi, zlo], [xhi, yhi, zhi], [xlo, ylo, zlo], [xlo, yhi, zlo], [xhi, ylo, zlo], [xhi, yhi, zlo], [xlo, ylo, zhi], [xlo, yhi, zhi], [xhi, ylo, zhi], [xhi, yhi, zhi], [xlo, ylo, zlo], [xhi, ylo, zlo], [xlo, ylo, zhi], [xhi, ylo, zhi], [xlo, yhi, zlo], [xhi, yhi, zlo], [xlo, yhi, zhi], [xhi, yhi, zhi], ]) vertices = affine.transform(vertices, self.__viewMat) gl.glLineWidth(2) gl.glColor3f(0.5, 0, 0) gl.glBegin(gl.GL_LINES) for v in vertices: gl.glVertex3f(*v) gl.glEnd()