# Source code for pyqtgraph.opengl.GLViewWidget

    from OpenGL.GL import *  # noqa
    import OpenGL.GL.framebufferobjects as glfbo  # noqa
    import warnings
    from math import cos, radians, sin, tan

    import numpy as np

    from .. import Vector
    from .. import functions as fn
    from .. import getConfigOption
    from ..Qt import QtCore, QtGui, QtWidgets

    ##Vector = QtGui.QVector3D

    class GLViewWidget(QtWidgets.QOpenGLWidget):

        def __init__(self, parent=None, devicePixelRatio=None, rotationMethod='euler'):
            """
            Basic widget for displaying 3D data
              - Rotation/scale controls
              - Axis/grid display
              - Export options

            ================ ==============================================================
            **Arguments:**
            parent           (QObject, optional): Parent QObject. Defaults to None.
            devicePixelRatio No longer in use. High-DPI displays should automatically
                             detect the correct resolution.
            rotationMethod   (str): Mechanimsm to drive the rotation method, options are
                             'euler' and 'quaternion'. Defaults to 'euler'.
            ================ ==============================================================
            """

            QtWidgets.QOpenGLWidget.__init__(self, parent)

            self.setFocusPolicy(QtCore.Qt.FocusPolicy.ClickFocus)

            if rotationMethod not in ["euler", "quaternion"]:
                raise ValueError("Rotation method should be either 'euler' or 'quaternion'")

            self.opts = {
                'center': Vector(0,0,0),  ## will always appear at the center of the widget
                'rotation' : QtGui.QQuaternion(1,0,0,0), ## camera rotation (quaternion:wxyz)
                'distance': 10.0,         ## distance of camera from center
                'fov':  60,               ## horizontal field of view in degrees
                'elevation': 30,          ## camera's angle of elevation in degrees
                'azimuth': 45,            ## camera's azimuthal angle in degrees
                                          ## (rotation around z-axis 0 points along x-axis)
                'viewport': None,         ## glViewport params; None == whole widget
                                          ## note that 'viewport' is in device pixels
                'rotationMethod': rotationMethod
            }
            self.reset()
            self.items = []

            self.noRepeatKeys = [QtCore.Qt.Key.Key_Right, QtCore.Qt.Key.Key_Left, QtCore.Qt.Key.Key_Up, QtCore.Qt.Key.Key_Down, QtCore.Qt.Key.Key_PageUp, QtCore.Qt.Key.Key_PageDown]
            self.keysPressed = {}
            self.keyTimer = QtCore.QTimer()
            self.keyTimer.timeout.connect(self.evalKeyState)

        def _updateScreen(self, screen):
            self._updatePixelRatio()
            if screen is not None:
                screen.physicalDotsPerInchChanged.connect(self._updatePixelRatio)
                screen.logicalDotsPerInchChanged.connect(self._updatePixelRatio)

        def _updatePixelRatio(self):
            event = QtGui.QResizeEvent(self.size(), self.size())
            self.resizeEvent(event)

        def showEvent(self, event):
            window = self.window().windowHandle()
            window.screenChanged.connect(self._updateScreen)
            self._updateScreen(window.screen())

        def deviceWidth(self):
            dpr = self.devicePixelRatioF()
            return int(self.width() * dpr)

        def deviceHeight(self):
            dpr = self.devicePixelRatioF()
            return int(self.height() * dpr)

        def reset(self):
            """
            Initialize the widget state or reset the current state to the original state.
            """
            self.opts['center'] = Vector(0,0,0)  ## will always appear at the center of the widget
            self.opts['distance'] = 10.0         ## distance of camera from center
            self.opts['fov'] = 60                ## horizontal field of view in degrees
            self.opts['elevation'] = 30          ## camera's angle of elevation in degrees
            self.opts['azimuth'] = 45            ## camera's azimuthal angle in degrees
                                                 ## (rotation around z-axis 0 points along x-axis)
            self.opts['viewport'] = None         ## glViewport params; None == whole widget
            self.setBackgroundColor(getConfigOption('background'))

        def addItem(self, item):
            self.items.append(item)

            if self.isValid():
                item.initialize()

            item._setView(self)
            self.update()

        def removeItem(self, item):
            """
            Remove the item from the scene.
            """
            self.items.remove(item)
            item._setView(None)
            self.update()

        def clear(self):
            """
            Remove all items from the scene.
            """
            for item in self.items:
                item._setView(None)
            self.items = []
            self.update()

        def initializeGL(self):
            """
            Initialize items that were not initialized during addItem().
            """
            ctx = self.context()
            fmt = ctx.format()
            if ctx.isOpenGLES() or fmt.version() < (2, 0):
                verString = glGetString(GL_VERSION)
                raise RuntimeError(
                    "pyqtgraph.opengl: Requires >= OpenGL 2.0 (not ES); Found %s" % verString
                )

            for item in self.items:
                if not item.isInitialized():
                    item.initialize()

        def setBackgroundColor(self, *args, **kwds):
            """
            Set the background color of the widget. Accepts the same arguments as
            :func:`~pyqtgraph.mkColor`.
            """
            self.opts['bgcolor'] = fn.mkColor(*args, **kwds).getRgbF()
            self.update()

        def getViewport(self):
            vp = self.opts['viewport']
            if vp is None:
                return (0, 0, self.deviceWidth(), self.deviceHeight())
            else:
                return vp

        def setProjection(self, region=None):
            m = self.projectionMatrix(region)
            glMatrixMode(GL_PROJECTION)
            glLoadMatrixf(np.array(m.data(), dtype=np.float32))

        def projectionMatrix(self, region=None):
            if region is None:
                region = (0, 0, self.deviceWidth(), self.deviceHeight())

            x0, y0, w, h = self.getViewport()
            dist = self.opts['distance']
            fov = self.opts['fov']
            nearClip = dist * 0.001
            farClip = dist * 1000.

            r = nearClip * tan(0.5 * radians(fov))
            t = r * h / w

            ## Note that X0 and width in these equations must be the values used in viewport
            left  = r * ((region[0]-x0) * (2.0/w) - 1)
            right = r * ((region[0]+region[2]-x0) * (2.0/w) - 1)
            bottom = t * ((region[1]-y0) * (2.0/h) - 1)
            top    = t * ((region[1]+region[3]-y0) * (2.0/h) - 1)

            tr = QtGui.QMatrix4x4()
            tr.frustum(left, right, bottom, top, nearClip, farClip)
            return tr

        def setModelview(self):
            m = self.viewMatrix()
            glMatrixMode(GL_MODELVIEW)
            glLoadMatrixf(np.array(m.data(), dtype=np.float32))

        def viewMatrix(self):
            tr = QtGui.QMatrix4x4()
            tr.translate( 0.0, 0.0, -self.opts['distance'])
            if self.opts['rotationMethod'] == 'quaternion':
                tr.rotate(self.opts['rotation'])
            else:
                # default rotation method
                tr.rotate(self.opts['elevation']-90, 1, 0, 0)
                tr.rotate(self.opts['azimuth']+90, 0, 0, -1)
            center = self.opts['center']
            tr.translate(-center.x(), -center.y(), -center.z())
            return tr

        def itemsAt(self, region=None):
            """
            Return a list of the items displayed in the region (x, y, w, h)
            relative to the widget.
            """
            region = (region[0], self.deviceHeight()-(region[1]+region[3]), region[2], region[3])

            #buf = np.zeros(100000, dtype=np.uint)
            buf = glSelectBuffer(100000)
            try:
                glRenderMode(GL_SELECT)
                glInitNames()
                glPushName(0)
                self._itemNames = {}
                self.paintGL(region=region, useItemNames=True)

            finally:
                hits = glRenderMode(GL_RENDER)

            items = [(h.near, h.names[0]) for h in hits]
            items.sort(key=lambda i: i[0])
            return [self._itemNames[i[1]] for i in items]

        def paintGL(self, region=None, viewport=None, useItemNames=False):
            """
            viewport specifies the arguments to glViewport. If None, then we use self.opts['viewport']
            region specifies the sub-region of self.opts['viewport'] that should be rendered.
            Note that we may use viewport != self.opts['viewport'] when exporting.
            """
            if viewport is None:
                glViewport(*self.getViewport())
            else:
                glViewport(*viewport)
            self.setProjection(region=region)
            self.setModelview()
            bgcolor = self.opts['bgcolor']
            glClearColor(*bgcolor)
            glClear( GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT )
            self.drawItemTree(useItemNames=useItemNames)

        def drawItemTree(self, item=None, useItemNames=False):
            if item is None:
                items = [x for x in self.items if x.parentItem() is None]
            else:
                items = item.childItems()
                items.append(item)
            items.sort(key=lambda a: a.depthValue())
            for i in items:
                if not i.visible():
                    continue
                if i is item:
                    try:
                        glPushAttrib(GL_ALL_ATTRIB_BITS)
                        if useItemNames:
                            glLoadName(i._id)
                            self._itemNames[i._id] = i
                        i.paint()
                    except:
                        from .. import debug
                        debug.printExc()
                        print("Error while drawing item %s." % str(item))

                    finally:
                        glPopAttrib()
                else:
                    glMatrixMode(GL_MODELVIEW)
                    glPushMatrix()
                    try:
                        tr = i.transform()
                        glMultMatrixf(np.array(tr.data(), dtype=np.float32))
                        self.drawItemTree(i, useItemNames=useItemNames)
                    finally:
                        glMatrixMode(GL_MODELVIEW)
                        glPopMatrix()

        def setCameraPosition(self, pos=None, distance=None, elevation=None, azimuth=None, rotation=None):
            if rotation is not None:
                # Alternatively, we could define that rotation overrides elevation and azimuth
                if elevation is not None:
                    raise ValueError("cannot set both rotation and elevation")
                if azimuth is not None:
                    raise ValueError("cannot set both rotation and azimuth")

            if pos is not None:
                self.opts['center'] = pos
            if distance is not None:
                self.opts['distance'] = distance

            if self.opts['rotationMethod'] == "quaternion":
                # note that "quaternion" mode modifies only opts['rotation']
                if elevation is not None or azimuth is not None:
                    eu = self.opts['rotation'].toEulerAngles()
                    if azimuth is not None:
                        eu.setZ(-azimuth-90)
                    if elevation is not None:
                        eu.setX(elevation-90)
                    self.opts['rotation'] = QtGui.QQuaternion.fromEulerAngles(eu)
                if rotation is not None:
                    self.opts['rotation'] = rotation
            else:
                # note that "euler" mode modifies only opts['elevation'] and opts['azimuth']
                if elevation is not None:
                    self.opts['elevation'] = elevation
                if azimuth is not None:
                    self.opts['azimuth'] = azimuth
                if rotation is not None:
                    eu = rotation.toEulerAngles()
                    self.opts['elevation'] = eu.x() + 90
                    self.opts['azimuth'] = -eu.z() - 90

            self.update()

        def cameraPosition(self):
            """Return current position of camera based on center, dist, elevation, and azimuth"""
            center = self.opts['center']
            dist = self.opts['distance']
            if self.opts['rotationMethod'] == "quaternion":
                pos = Vector(center - self.opts['rotation'].rotatedVector(Vector(0,0,dist) ))
            else:
                # using 'euler' rotation method
                elev = radians(self.opts['elevation'])
                azim = radians(self.opts['azimuth'])
                pos = Vector(
                    center.x() + dist * cos(elev) * cos(azim),
                    center.y() + dist * cos(elev) * sin(azim),
                    center.z() + dist * sin(elev)
                )
            return pos

        def setCameraParams(self, **kwds):
            valid_keys = {'center', 'rotation', 'distance', 'fov', 'elevation', 'azimuth'}
            if not valid_keys.issuperset(kwds):
                raise ValueError(f'valid keywords are {valid_keys}')

            self.setCameraPosition(pos=kwds.get('center'), distance=kwds.get('distance'),
                                   elevation=kwds.get('elevation'), azimuth=kwds.get('azimuth'),
                                   rotation=kwds.get('rotation'))
            if 'fov' in kwds:
                self.opts['fov'] = kwds['fov']

        def cameraParams(self):
            valid_keys = {'center', 'rotation', 'distance', 'fov', 'elevation', 'azimuth'}
            return { k : self.opts[k] for k in valid_keys }

        def orbit(self, azim, elev):
            """Orbits the camera around the center position. *azim* and *elev* are given in degrees."""
            if self.opts['rotationMethod'] == 'quaternion':
                q = QtGui.QQuaternion.fromEulerAngles(
                        elev, -azim, 0
                        ) # rx-ry-rz
                q *= self.opts['rotation']
                self.opts['rotation'] = q
            else: # default euler rotation method
                self.opts['azimuth'] += azim
                self.opts['elevation'] = fn.clip_scalar(self.opts['elevation'] + elev, -90., 90.)
            self.update()

        def pan(self, dx, dy, dz, relative='global'):
            """
            Moves the center (look-at) position while holding the camera in place.

            ==============  =======================================================
            **Arguments:**
            *dx*            Distance to pan in x direction
            *dy*            Distance to pan in y direction
            *dz*            Distance to pan in z direction
            *relative*      String that determines the direction of dx,dy,dz.
                            If "global", then the global coordinate system is used.
                            If "view", then the z axis is aligned with the view
                            direction, and x and y axes are in the plane of the
                            view: +x points right, +y points up.
                            If "view-upright", then x is in the global xy plane and
                            points to the right side of the view, y is in the
                            global xy plane and orthogonal to x, and z points in
                            the global z direction.
            ==============  =======================================================

            Distances are scaled roughly such that a value of 1.0 moves
            by one pixel on screen.

            Prior to version 0.11, *relative* was expected to be either True (x-aligned) or
            False (global). These values are deprecated but still recognized.
            """
            # for backward compatibility:
            if isinstance(relative, bool):
                warnings.warn(
                    "'relative' as a boolean is deprecated, and will not be recognized in 0.13. "
                    "Acceptable values are 'global', 'view', or 'view-upright'",
                    DeprecationWarning, stacklevel=2
                )
            relative = {True: "view-upright", False: "global"}.get(relative, relative)
            if relative == 'global':
                self.opts['center'] += QtGui.QVector3D(dx, dy, dz)
            elif relative == 'view-upright':
                cPos = self.cameraPosition()
                cVec = self.opts['center'] - cPos
                dist = cVec.length()  ## distance from camera to center
                xDist = dist * 2. * tan(0.5 * radians(self.opts['fov']))  ## approx. width of view at distance of center point
                xScale = xDist / self.width()
                zVec = QtGui.QVector3D(0,0,1)
                xVec = QtGui.QVector3D.crossProduct(zVec, cVec).normalized()
                yVec = QtGui.QVector3D.crossProduct(xVec, zVec).normalized()
                self.opts['center'] = self.opts['center'] + xVec * xScale * dx + yVec * xScale * dy + zVec * xScale * dz
            elif relative == 'view':
                # pan in plane of camera

                if self.opts['rotationMethod'] == 'quaternion':
                    # obtain basis vectors
                    qc = self.opts['rotation'].conjugated()
                    xv = qc.rotatedVector( Vector(1,0,0) )
                    yv = qc.rotatedVector( Vector(0,1,0) )
                    zv = qc.rotatedVector( Vector(0,0,1) )

                    scale_factor = self.pixelSize( self.opts['center'] )

                    # apply translation
                    self.opts['center'] += scale_factor * (xv*-dx + yv*dy + zv*dz)
                else: # use default euler rotation method
                    elev = radians(self.opts['elevation'])
                    azim = radians(self.opts['azimuth'])
                    fov = radians(self.opts['fov'])
                    dist = (self.opts['center'] - self.cameraPosition()).length()
                    fov_factor = tan(fov / 2) * 2
                    scale_factor = dist * fov_factor / self.width()
                    z = scale_factor * cos(elev) * dy
                    x = scale_factor * (sin(azim) * dx - sin(elev) * cos(azim) * dy)
                    y = scale_factor * (cos(azim) * dx + sin(elev) * sin(azim) * dy)
                    self.opts['center'] += QtGui.QVector3D(x, -y, z)
            else:
                raise ValueError("relative argument must be global, view, or view-upright")

            self.update()

        def pixelSize(self, pos):
            """
            Return the approximate size of a screen pixel at the location pos
            Pos may be a Vector or an (N,3) array of locations
            """
            cam = self.cameraPosition()
            if isinstance(pos, np.ndarray):
                cam = np.array(cam).reshape((1,)*(pos.ndim-1)+(3,))
                dist = ((pos-cam)**2).sum(axis=-1)**0.5
            else:
                dist = (pos-cam).length()
            xDist = dist * 2. * tan(0.5 * radians(self.opts['fov']))
            return xDist / self.width()

        def mousePressEvent(self, ev):
            lpos = ev.position() if hasattr(ev, 'position') else ev.localPos()
            self.mousePos = lpos

        def mouseMoveEvent(self, ev):
            lpos = ev.position() if hasattr(ev, 'position') else ev.localPos()
            diff = lpos - self.mousePos
            self.mousePos = lpos

            if ev.buttons() == QtCore.Qt.MouseButton.LeftButton:
                if (ev.modifiers() & QtCore.Qt.KeyboardModifier.ControlModifier):
                    self.pan(diff.x(), diff.y(), 0, relative='view')
                else:
                    self.orbit(-diff.x(), diff.y())
            elif ev.buttons() == QtCore.Qt.MouseButton.MiddleButton:
                if (ev.modifiers() & QtCore.Qt.KeyboardModifier.ControlModifier):
                    self.pan(diff.x(), 0, diff.y(), relative='view-upright')
                else:
                    self.pan(diff.x(), diff.y(), 0, relative='view-upright')

        def mouseReleaseEvent(self, ev):
            pass
            # Example item selection code:
            #region = (ev.pos().x()-5, ev.pos().y()-5, 10, 10)
            #print(self.itemsAt(region))

            ## debugging code: draw the picking region
            #glViewport(*self.getViewport())
            #glClear( GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT )
            #region = (region[0], self.height()-(region[1]+region[3]), region[2], region[3])
            #self.paintGL(region=region)
            #self.swapBuffers()

        def wheelEvent(self, ev):
            delta = ev.angleDelta().x()
            if delta == 0:
                delta = ev.angleDelta().y()
            if (ev.modifiers() & QtCore.Qt.KeyboardModifier.ControlModifier):
                self.opts['fov'] *= 0.999**delta
            else:
                self.opts['distance'] *= 0.999**delta
            self.update()

        def keyPressEvent(self, ev):
            if ev.key() in self.noRepeatKeys:
                ev.accept()
                if ev.isAutoRepeat():
                    return
                self.keysPressed[ev.key()] = 1
                self.evalKeyState()

        def keyReleaseEvent(self, ev):
            if ev.key() in self.noRepeatKeys:
                ev.accept()
                if ev.isAutoRepeat():
                    return
                try:
                    del self.keysPressed[ev.key()]
                except KeyError:
                    self.keysPressed = {}
                self.evalKeyState()

        def evalKeyState(self):
            speed = 2.0
            if len(self.keysPressed) > 0:
                for key in self.keysPressed:
                    if key == QtCore.Qt.Key.Key_Right:
                        self.orbit(azim=-speed, elev=0)
                    elif key == QtCore.Qt.Key.Key_Left:
                        self.orbit(azim=speed, elev=0)
                    elif key == QtCore.Qt.Key.Key_Up:
                        self.orbit(azim=0, elev=-speed)
                    elif key == QtCore.Qt.Key.Key_Down:
                        self.orbit(azim=0, elev=speed)
                    elif key == QtCore.Qt.Key.Key_PageUp:
                        pass
                    elif key == QtCore.Qt.Key.Key_PageDown:
                        pass
                    self.keyTimer.start(16)
            else:
                self.keyTimer.stop()

        def readQImage(self):
            """
            Read the current buffer pixels out as a QImage.
            """
            return self.grabFramebuffer()

        def renderToArray(self, size, format=GL_BGRA, type=GL_UNSIGNED_BYTE, textureSize=1024, padding=256):
            w,h = map(int, size)

            self.makeCurrent()
            tex = None
            fb = None
            depth_buf = None
            try:
                output = np.empty((h, w, 4), dtype=np.ubyte)
                fb = glfbo.glGenFramebuffers(1)
                glfbo.glBindFramebuffer(glfbo.GL_FRAMEBUFFER, fb )

                glEnable(GL_TEXTURE_2D)
                tex = glGenTextures(1)
                glBindTexture(GL_TEXTURE_2D, tex)
                texwidth = textureSize
                data = np.zeros((texwidth,texwidth,4), dtype=np.ubyte)

                ## Test texture dimensions first
                glTexImage2D(GL_PROXY_TEXTURE_2D, 0, GL_RGBA, texwidth, texwidth, 0, GL_RGBA, GL_UNSIGNED_BYTE, None)
                if glGetTexLevelParameteriv(GL_PROXY_TEXTURE_2D, 0, GL_TEXTURE_WIDTH) == 0:
                    raise RuntimeError("OpenGL failed to create 2D texture (%dx%d); too large for this hardware." % data.shape[:2])
                ## create texture
                glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texwidth, texwidth, 0, GL_RGBA, GL_UNSIGNED_BYTE, data)

                # Create depth buffer
                depth_buf = glGenRenderbuffers(1)
                glBindRenderbuffer(GL_RENDERBUFFER, depth_buf)
                glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, texwidth, texwidth)
                glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depth_buf)

                self.opts['viewport'] = (0, 0, w, h)  # viewport is the complete image; this ensures that paintGL(region=...)
                                                      # is interpreted correctly.
                p2 = 2 * padding
                for x in range(-padding, w-padding, texwidth-p2):
                    for y in range(-padding, h-padding, texwidth-p2):
                        x2 = min(x+texwidth, w+padding)
                        y2 = min(y+texwidth, h+padding)
                        w2 = x2-x
                        h2 = y2-y

                        ## render to texture
                        glfbo.glFramebufferTexture2D(glfbo.GL_FRAMEBUFFER, glfbo.GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex, 0)

                        self.paintGL(region=(x, h-y-h2, w2, h2), viewport=(0, 0, w2, h2))  # only render sub-region
                        glBindTexture(GL_TEXTURE_2D, tex) # fixes issue #366

                        ## read texture back to array
                        data = glGetTexImage(GL_TEXTURE_2D, 0, format, type)
                        data = np.frombuffer(data, dtype=np.ubyte).reshape(texwidth,texwidth,4)[::-1, ...]
                        output[y+padding:y2-padding, x+padding:x2-padding] = data[-(h2-padding):-padding, padding:w2-padding]

            finally:
                self.opts['viewport'] = None
                glfbo.glBindFramebuffer(glfbo.GL_FRAMEBUFFER, 0)
                glBindTexture(GL_TEXTURE_2D, 0)
                if tex is not None:
                    glDeleteTextures([tex])
                if fb is not None:
                    glfbo.glDeleteFramebuffers([fb])
                if depth_buf is not None:
                    glDeleteRenderbuffers(1, [depth_buf])

            return output