class_docstr: **Bases:** :class:`GLGraphicsItem <pyqtgraph.opengl.GLGraphicsItem.GLGraphicsItem>`
  
  Displays volumetric data. 
class_docstr_tok: ["*","*","Bases",":","*","*",":","class",":","`","GLGraphicsItem","<","pyqtgraph.opengl.GLGraphicsItem.GLGraphicsItem",">","`","Displays","volumetric","data","."]
code: def drawVolume(self, ax, d):
      imax = [0, 1, 2]
      imax.remove(ax)
  
      tp = [[0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]
      vp = [[0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]
      nudge = [0.5 / x for x in self.data.shape]
      tp[0][imax[0]] = 0 + nudge[imax[0]]
      tp[0][imax[1]] = 0 + nudge[imax[1]]
      tp[1][imax[0]] = 1 - nudge[imax[0]]
      tp[1][imax[1]] = 0 + nudge[imax[1]]
      tp[2][imax[0]] = 1 - nudge[imax[0]]
      tp[2][imax[1]] = 1 - nudge[imax[1]]
      tp[3][imax[0]] = 0 + nudge[imax[0]]
      tp[3][imax[1]] = 1 - nudge[imax[1]]
  
      vp[0][imax[0]] = 0
      vp[0][imax[1]] = 0
      vp[1][imax[0]] = self.data.shape[imax[0]]
      vp[1][imax[1]] = 0
      vp[2][imax[0]] = self.data.shape[imax[0]]
      vp[2][imax[1]] = self.data.shape[imax[1]]
      vp[3][imax[0]] = 0
      vp[3][imax[1]] = self.data.shape[imax[1]]
      slices = self.data.shape[ax] * self.sliceDensity
      r = list(range(slices))
      if d == -1:
          r = r[::-1]
  
      glBegin(GL_QUADS)
      tzVals = np.linspace(nudge[ax], 1.0 - nudge[ax], slices)
      vzVals = np.linspace(0, self.data.shape[ax], slices)
      for i in r:
          z = tzVals[i]
          w = vzVals[i]
  
          tp[0][ax] = z
          tp[1][ax] = z
          tp[2][ax] = z
          tp[3][ax] = z
  
          vp[0][ax] = w
          vp[1][ax] = w
          vp[2][ax] = w
          vp[3][ax] = w
  
          glTexCoord3f(*tp[0])
          glVertex3f(*vp[0])
          glTexCoord3f(*tp[1])
          glVertex3f(*vp[1])
          glTexCoord3f(*tp[2])
          glVertex3f(*vp[2])
          glTexCoord3f(*tp[3])
          glVertex3f(*vp[3])
      glEnd()
  
file_path: pyqtgraph/pyqtgraph/opengl/items/GLVolumeItem.py
imports: from OpenGL.GL import *
  import numpy
  from ...Qt import QtGui
  from ..GLGraphicsItem import GLGraphicsItem
label_desc: Use image node_id 5 for calling the GLVolumeItem obj's underlying member method code with example usage: obj.drawVolume(ax, d) without return types