在 PyQT 中将 2D 屏幕坐标转换为 3D 坐标

Question

我第一次使用 PyQT，但我无法弄清楚鼠标点击在 3D 空间中的位置。 显然，这不是一个完美的一对一映射，但假设我在QtGui上单击了一个位置（x，y，0）。 如何使用相机将鼠标单击转换为其 3D 位置？

上下文：我正在尝试让用户在 3D 中绘制样条，为此，我需要知道用户在渲染样条时单击的位置。 我正在使用PythonOCC构建一个应用程序。 我在下面附上了我的代码。

import random
import sys
import IPython
from OCC.Display.qtDisplay import qtViewer3d, get_qt_modules
from OCC.gp import gp_Pnt2d, gp_Pnt
from OCC.BRepBuilderAPI import (BRepBuilderAPI_MakeEdge,
                                BRepBuilderAPI_MakeVertex,
                                BRepBuilderAPI_MakeWire)
from OCC.BRepFill import BRepFill_Filling
from OCC.GeomAbs import GeomAbs_C0
from OCC.GeomAPI import GeomAPI_PointsToBSpline
from OCC.TColgp import TColgp_Array1OfPnt

QtCore, QtGui, QtOpenGL = get_qt_modules()
try:
    from OpenGL.GL import (glViewport, glMatrixMode, glOrtho, glLoadIdentity,
                           GL_PROJECTION, GL_MODELVIEW)
except ImportError:
    msg = "for this example, the OpenGL module is required" 
          "why not run "pip install PyOpenGL"?"
    sys.exit(status=1)

class GLWidget(qtViewer3d):
    def __init__(self, parent=None):
        super(GLWidget, self).__init__(parent)
        self._initialized = False
        midnight = QtCore.QTime(0, 0, 0)
        random.seed(midnight.secsTo(QtCore.QTime.currentTime()))
        self.object = 0
        self.xRot = 0
        self.yRot = 0
        self.zRot = 0
        self.image = QtGui.QImage()
        self.bubbles = []
        self.lastPos = QtCore.QPoint()
        self.lines = []
        self.current_point = None
        self.pts = []
        self.shiftHeld = True
        self.trolltechGreen = QtGui.QColor.fromCmykF(0.40, 0.0, 1.0, 0.0)
        self.trolltechPurple = QtGui.QColor.fromCmykF(0.39, 0.39, 0.0, 0.0)
        self.animationTimer = QtCore.QTimer()
        self.animationTimer.setSingleShot(False)
        self.animationTimer.timeout.connect(self.animate)
        self.animationTimer.start(25)
        self.setAutoFillBackground(False)
        self.setMinimumSize(200, 200)
        self.setWindowTitle("Overpainting a Scene")
        # parameters for overpainting
        self.setAttribute(QtCore.Qt.WA_NoSystemBackground, 0)
        self.setAttribute(QtCore.Qt.WA_OpaquePaintEvent)
    def setXRotation(self, angle):
        if angle != self.xRot:
            self.xRot = angle
    def setYRotation(self, angle):
        if angle != self.yRot:
            self.yRot = angle
    def setZRotation(self, angle):
        if angle != self.zRot:
            self.zRot = angle

    def mousePressEvent(self, event):
        self.lastPos = event.pos()
        super(GLWidget, self).mousePressEvent(event)
        worldCoords = super(GLWidget, self).mapToGlobal( self.lastPos )
        print self.lastPos

        if event.buttons() & QtCore.Qt.RightButton and not (event.modifiers() & QtCore.Qt.ShiftModifier):
            print 'first'
            self.pts.append(gp_Pnt(self.lastPos.x(), self.lastPos.y(), 0.0))
        elif event.buttons() & QtCore.Qt.RightButton and (event.modifiers() & QtCore.Qt.ShiftModifier):
            print 'second'
            curve = self.points_to_bspline(self.pts)
            self._display.DisplayShape(curve, update=True)
            self.pts = [] #clear it


    def mouseMoveEvent(self, event):
        dx = event.x() - self.lastPos.x()
        dy = event.y() - self.lastPos.y()
        """
        if (event.buttons() & QtCore.Qt.LeftButton):
            self.setXRotation(self.xRot + 8 * dy)
            self.setYRotation(self.yRot + 8 * dx)

        elif (event.buttons() & QtCore.Qt.RightButton):
            self.setXRotation(self.xRot + 8 * dy)
            self.setZRotation(self.zRot + 8 * dx)
        """

        self.lastPos = event.pos()
        super(GLWidget, self).mouseMoveEvent(event)
    def paintGL(self):
        if self._inited:
            self._display.Context.UpdateCurrentViewer()
    def paintEvent(self, event):
        if self._inited:
            self._display.Context.UpdateCurrentViewer()
            self.makeCurrent()
            painter = QtGui.QPainter(self)
            painter.setRenderHint(QtGui.QPainter.Antialiasing)
            if self.context().isValid():
                self.swapBuffers()
                if self._drawbox:
                    painter.setPen(QtGui.QPen(QtGui.QColor(0, 0, 0), 1))
                    rect = QtCore.QRect(*self._drawbox)
                    painter.drawRect(rect)
                """
                for bubble in self.bubbles:
                    if bubble.rect().intersects(QtCore.QRectF(event.rect())):
                        bubble.drawBubble(painter)
                """
                painter.end()
                self.doneCurrent()
            else:
                print('invalid OpenGL context: Qt cannot overpaint viewer')
    def showEvent(self, event):
        pass
        #self.createBubbles(20 - len(self.bubbles))
    def sizeHint(self):
        return QtCore.QSize(400, 400)

    def animate(self):
        pass
        """
        for bubble in self.bubbles:
            bubble.move(self.rect())
        self.update()
        """
    def setupViewport(self, width, height):
        side = min(width, height)
        glViewport((width - side) // 2, (height - side) // 2, side, side)
        glMatrixMode(GL_PROJECTION)
        glLoadIdentity()
        glOrtho(-0.5, +0.5, +0.5, -0.5, 4.0, 15.0)
        glMatrixMode(GL_MODELVIEW)
    def points_to_bspline(self, pnts):
        pts = TColgp_Array1OfPnt(0, len(pnts)-1)
        for n, i in enumerate(pnts):
            pts.SetValue(n, i)
        crv = GeomAPI_PointsToBSpline(pts)
        return crv.Curve()


if __name__ == '__main__':
    def TestOverPainting():
        class AppFrame(QtGui.QWidget):
            def __init__(self, parent=None):
                QtGui.QWidget.__init__(self, parent)
                self.setWindowTitle(self.tr("qtDisplay3d overpainting example"))
                self.resize(640, 480)
                self.canva = GLWidget(self)
                mainLayout = QtGui.QHBoxLayout()
                mainLayout.addWidget(self.canva)
                mainLayout.setContentsMargins(0, 0, 0, 0)
                self.setLayout(mainLayout)
            def runTests(self):
                self.canva._display.Test()
        app = QtGui.QApplication(sys.argv)
        frame = AppFrame()
        frame.show()
        frame.canva.InitDriver()
        frame.runTests()
        app.exec_()
    TestOverPainting()

Answer 1

回答我自己的问题：

（x， y， z， vx， vy， vz） = self._display。View.ConvertWithProj（self.lastPos.x（）， self.lastPos.y（））

给出 x 和 y

可以映射到的整条点行，其中 x、y 和 z 是一个点，vx、vy 和 vz 给出线的参数化。