I am building a visualizer for some data and want to use 3D spheres plotted in pyqtgraphs 3D OpenGL components to represent targets identified within the data provided.
I am able to generate the spheres and move them using GLMeshItem.translate() commands, however I am not able to find a convenient way of setting coordinates of the sphere without first getting the current position of said spheres through a call to .transform() and then generating a translate command from it's current position to the new absolute coordinates I would like it to be moved to. It may be that that is the only way to accomplish this, I just suspect there is a more direct set the mesh items absolute coordinates that I just can't seem to identify.
The following code shows a basic framework for what I am doing, and also the current method I am using to move the sphere.
from pyqtgraph.Qt import QtCore, QtGui
import pyqtgraph as pg
import pyqtgraph.opengl as gl
import numpy as np
app = QtGui.QApplication([])
w = gl.GLViewWidget()
w.showMaximized()
w.setWindowTitle('pyqtgraph example: GLMeshItem')
w.setCameraPosition(distance=40)
g = gl.GLGridItem()
g.scale(2,2,1)
w.addItem(g)
verts = np.array([
[0, 0, 0],
[2, 0, 0],
[1, 2, 0],
[1, 1, 1],
])
faces = np.array([
[0, 1, 2],
[0, 1, 3],
[0, 2, 3],
[1, 2, 3]
])
colors = np.array([
[1, 0, 0, 0.3],
[0, 1, 0, 0.3],
[0, 0, 1, 0.3],
[1, 1, 0, 0.3]
])
md = gl.MeshData.sphere(rows=4, cols=4)
colors = np.ones((md.faceCount(), 4), dtype=float)
colors[::2,0] = 0
colors[:,1] = np.linspace(0, 1, colors.shape[0])
md.setFaceColors(colors)
m3 = gl.GLMeshItem(meshdata=md, smooth=False)#, shader='balloon')
w.addItem(m3)
target = gl.MeshData.sphere(4,4,10)
targetMI = gl.GLMeshItem(meshdata = target, drawFaces = True,smooth = False)
w.addItem(targetMI)
while(1):
targetMI.translate(0.1,0,0)
app.processEvents()
## Start Qt event loop unless running in interactive mode.
if __name__ == '__main__':
import sys
if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
QtGui.QApplication.instance().exec_()
As can be seen in this example. translate works fine for moving relative to the current position. I am just curious as to whether there is a method for doing an absolute position move on the GLMeshItem (in this case targetMI) such that I could make it move to a coordinate without having to first get the transform and then calculating the translate required to move to the desired coordinates.
An option is to reset the item’s transform to an identity transformation by resetTransform(), before you set the absolute position by translate(). e.g:
targetMI.resetTransform()
targetMI.translate(10, 0, 0)