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Looking for a simple window renderer for Python

I'm currently looking for a simple step-by-step window renderer library for Python.
The main idea behind what I need is that I want to be able to change the input data before I call the window render function, by doing so the window would render a moving point with some additional static points. The rendered window would refresh while the program is running. For example:
# Some points
data_points_x = [2,4,6,11,22]
data_points_y = [5,-1,23,41,1]
window.add(x, y, style="point")
# Another point
important_point_x = 23
important_point_y = 13
window.add(important_point_x, important_point_y, style="star")
# Main rendering loop
while True:
# Move one point
important_point_x = important_point_x + 1
window.render()
I know matplotlib can do something similar, but I'm interested if there is any other library capable of doing more, for example, rendering text, lines and so on. Finally, pyplot does not refresh the window when calling plot.show() when the program is running.

Maya – Select objects in viewport via Python

Can anyone help me? Is it possible to make a script with Python to automatically select every object in Maya's viewport?
Is it possible?

It's very possible though you have to use Maya's api to do it. You can use OpenMayaUI.MDrawTraversal to collect all objects within a camera's frustum.
This may seem more long winded than using OpenMaya.MGlobal.selectFromScreen, but it gives you a few benefits:
You can do it on any camera, despite it not being used as an active view.
You can perform whatever you need to do all in memory without selecting and forcing a redraw.
OpenMaya.MGlobal.selectFromScreen will be interface dependent, meaning that it's not possible to execute it on Maya batch jobs. This will work on either case.
That being said, here's an example that will create a bunch of random boxes, create a camera looking at them, then select all boxes that are within the camera's view:
import random
import maya.cmds as cmds
import maya.OpenMaya as OpenMaya
import maya.OpenMayaUI as OpenMayaUI
# Create a new camera.
cam, cam_shape = cmds.camera()
cmds.move(15, 10, 15, cam)
cmds.rotate(-25, 45, 0, cam)
cmds.setAttr("{}.focalLength".format(cam), 70)
cmds.setAttr("{}.displayCameraFrustum".format(cam), True)
# Create a bunch of boxes at random positions.
val = 10
for i in range(50):
new_cube, _ = cmds.polyCube()
cmds.move(random.uniform(-val, val), random.uniform(-val, val), random.uniform(-val, val), new_cube)
# Add camera to MDagPath.
mdag_path = OpenMaya.MDagPath()
sel = OpenMaya.MSelectionList()
sel.add(cam)
sel.getDagPath(0, mdag_path)
# Create frustum object with camera.
draw_traversal = OpenMayaUI.MDrawTraversal()
draw_traversal.setFrustum(mdag_path, cmds.getAttr("defaultResolution.width"), cmds.getAttr("defaultResolution.height")) # Use render's resolution.
draw_traversal.traverse() # Traverse scene to get all objects in the camera's view.
frustum_objs = []
# Loop through objects within frustum.
for i in range(draw_traversal.numberOfItems()):
# It will return shapes at first, so we need to fetch its transform.
shape_dag_path = OpenMaya.MDagPath()
draw_traversal.itemPath(i, shape_dag_path)
transform_dag_path = OpenMaya.MDagPath()
OpenMaya.MDagPath.getAPathTo(shape_dag_path.transform(), transform_dag_path)
# Get object's long name and make sure it's a valid transform.
obj = transform_dag_path.fullPathName()
if cmds.objExists(obj):
frustum_objs.append(obj)
# At this point we have a list of objects that we can filter by type and do whatever we want.
# In this case just select them.
cmds.select(frustum_objs)
Hope that gives you a better direction.

you can try the following script
import maya.OpenMaya as om
import maya.OpenMayaUI as omUI
view = omUI.M3dView.active3dView()
om.MGlobal.selectFromScreen( 0, 0, view.portWidth(), view.portHeight(),om.MGlobal.kReplaceList)
I found this snippet on https://forums.cgsociety.org/t/list-objects-in-viewport/1463426, and it seems to do the trick. You can read through the discussion for more information

VTK update position of multiple render windows

I'm running into a bit of a problem when trying to run multiple render windows in a Python VTK application I'm writing. The application is an attempt to render a 3D model in two separate views for a stereo application (i.e. Left render and right render), but I'm having an issue with updating the cameras of each window simultaneously. I currently have two nearly identical pipelines set up, each with its own vtkCamera, vtkRenderWindow, vtkRenderer, and vtkRenderWindowInteractor, the only difference being that the right camera is positionally shifted 30 units along the X axis.
Each of the render window interactors is being updated via the vtkRenderWindowInteractor.AddObserver() method that calls a simple function to reset the cameras to their original positions and orientations. The biggest issue is that this only seems to occur on one window at a time, specifically the window in focus at the time. It's as if the interactor's timer just shuts off once the interactor loses focus. In addition, when I hold down the mouse (And thus move the camera around), the rendered image begins to 'drift', resetting to a less and less correct position even though I have hardcoded the coordinates into the function.
Obviously I'm very new to VTK, and much of what goes on is fairly confusing as so much is hidden in the backend, so it would be amazing to acquire some assistance on the matter. My code is below. Thanks guys!
from vtk import*
from parse import *
import os
import time, signal, threading
def ParseSIG(signum, stack):
print signum
return
class vtkGyroCallback():
def __init__(self):
pass
def execute(self, obj, event):
#Modified segment to accept input for leftCam position
gyro = (raw_input())
xyz = parse("{} {} {}", gyro)
#This still prints every 100ms, but camera doesn't update!
print xyz
#These arguments are updated and the call is made.
self.leftCam.SetPosition(float(xyz[0]), float(xyz[1]), float(xyz[2]))
self.leftCam.SetFocalPoint(0,0,0)
self.leftCam.SetViewUp(0,1,0)
self.leftCam.OrthogonalizeViewUp()
self.rightCam.SetPosition(10, 40, 100)
self.rightCam.SetFocalPoint(0,0,0)
self.rightCam.SetViewUp(0,1,0)
self.rightCam.OrthogonalizeViewUp()
#Just a guess
obj.Update()
return
def main():
# create two cameras
cameraR = vtkCamera()
cameraR.SetPosition(0,0,200)
cameraR.SetFocalPoint(0,0,0)
cameraL = vtkCamera()
cameraL.SetPosition(40,0,200)
cameraL.SetFocalPoint(0,0,0)
# create a rendering window and renderer
renR = vtkRenderer()
renR.SetActiveCamera(cameraR)
renL = vtkRenderer()
renL.SetActiveCamera(cameraL)
# create source
reader = vtkPolyDataReader()
path = "/home/compilezone/Documents/3DSlicer/SlicerScenes/LegoModel-6_25/Model_5_blood.vtk"
reader.SetFileName(path)
reader.Update()
# create render window
renWinR = vtkRenderWindow()
renWinR.AddRenderer(renR)
renWinR.SetWindowName("Right")
renWinL = vtkRenderWindow()
renWinL.AddRenderer(renL)
renWinL.SetWindowName("Left")
# create a render window interactor
irenR = vtkRenderWindowInteractor()
irenR.SetRenderWindow(renWinR)
irenL = vtkRenderWindowInteractor()
irenL.SetRenderWindow(renWinL)
# mapper
mapper = vtkPolyDataMapper()
mapper.SetInput(reader.GetOutput())
# actor
actor = vtkActor()
actor.SetMapper(mapper)
# assign actor to the renderer
renR.AddActor(actor)
renL.AddActor(actor)
# enable user interface interactor
renWinR.Render()
renWinL.Render()
irenR.Initialize()
irenL.Initialize()
#Create callback object for camera manipulation
cb = vtkGyroCallback()
cb.rightCam = cameraR
cb.leftCam = cameraL
renWinR.AddObserver('InteractionEvent', cb.execute)
renWinL.AddObserver('InteractionEvent', cb.execute)
irenR.AddObserver('TimerEvent', cb.execute)
irenL.AddObserver('TimerEvent', cb.execute)
timerIDR = irenR.CreateRepeatingTimer(100)
timerIDL = irenL.CreateRepeatingTimer(100)
irenR.Start()
irenL.Start()
if __name__ == '__main__':
main()
EDIT:
Upon further viewing it seems like the TimerEvents aren't firing more than once in a row after a MouseClickEvent and I have no idea why.
EDIT 2: Scratch that, they are most definitely firing as per some test outputs I embedded in the code. I modified the code to accept user input for the self.leftCam.SetPosition() call within the vtkGyroCallback.execute() method (Thus replacing the hardcoded "10, 40, 100" parameters with three input variables) then piped the output of a script that simply displayed three random values into my main program. What this should have accomplished was having a render window that would constantly change position. Instead, nothing happens until I click on the screen, at which point the expected functionality begins. The whole time, timer events are still firing and inputs are still being accepted, yet the cameras refuse to update until a mouse event occurs within the scope of their window. What is the deal?
EDIT 3: I've dug around some more and found that within the vtkObject::InvokeEvent() method that is called within every interaction event there is a focus loop that overrides all observers that do not pertain to the object in focus. I'm going to investigate if there is a way to remove focus so that it will instead bypass this focus loop and go to the unfocused loop that handles non focused objects.

So the solution was surprisingly simple, but thanks to the lack of quality documentation provided by VTK, I was left to dig through the source to find it. Effectively all you have to do is pseudo-thread Render() calls from each of the interactors via whatever callback method you're using to handle your TimerEvents. I did this using ID properties added to each interactor (seen in code provided below). You can see that every time a TimerEvent is fired from the irenR interactor's internal timer (irenR handles the right eye), the irenL's Render() function is called, and vice versa.
To solve this I first realized that the standard interactor functionalities (Mouse events and the like), worked normally. So I dug around the source in vtkRenderWindowInteractor.cxx and realized that those methods were abstracted to the individual vtkInteractorStyle implementations. After rooting around in the vtkInteractorStyleTrackball.cxx source, I found that there was actually a Render() function within the vtkRenderWindowInteractor class. Go figure! The documentation sure didn't mention that!
Unfortunately, two renders at once is actually very slow. If I do this method with just one window (At which point it becomes unnecessary), it runs wonderfully. Framerate tanks with a second window though. Oh well, what can you do?
Here's my corrected code (Finally I can start working on what I was supposed to be developing):
from vtk import*
from parse import *
import os
import time, signal, threading
def ParseSIG(signum, stack):
print signum
return
class vtkGyroCallback():
def __init__(self):
pass
def execute(self, obj, event):
#Modified segment to accept input for leftCam position
gyro = (raw_input())
xyz = parse("{} {} {}", gyro)
#print xyz
# "Thread" the renders. Left is called on a right TimerEvent and right is called on a left TimerEvent.
if obj.ID == 1 and event == 'TimerEvent':
self.leftCam.SetPosition(float(xyz[0]), float(xyz[1]), float(xyz[2]))
self.irenL.Render()
#print "Left"
elif obj.ID == 2 and event == 'TimerEvent':
self.rightCam.SetPosition(float(xyz[0]), float(xyz[1]), float(xyz[2]))
self.irenR.Render()
#print "Right"
return
def main():
# create two cameras
cameraR = vtkCamera()
cameraR.SetPosition(0,0,200)
cameraR.SetFocalPoint(0,0,0)
cameraL = vtkCamera()
cameraL.SetPosition(40,0,200)
cameraL.SetFocalPoint(0,0,0)
# create a rendering window and renderer
renR = vtkRenderer()
renR.SetActiveCamera(cameraR)
renL = vtkRenderer()
renL.SetActiveCamera(cameraL)
# create source
reader = vtkPolyDataReader()
path = "/home/compilezone/Documents/3DSlicer/SlicerScenes/LegoModel-6_25/Model_5_blood.vtk"
reader.SetFileName(path)
reader.Update()
# create render window
renWinR = vtkRenderWindow()
renWinR.AddRenderer(renR)
renWinR.SetWindowName("Right")
renWinL = vtkRenderWindow()
renWinL.AddRenderer(renL)
renWinL.SetWindowName("Left")
# create a render window interactor
irenR = vtkRenderWindowInteractor()
irenR.SetRenderWindow(renWinR)
irenL = vtkRenderWindowInteractor()
irenL.SetRenderWindow(renWinL)
# mapper
mapper = vtkPolyDataMapper()
mapper.SetInput(reader.GetOutput())
# actor
actor = vtkActor()
actor.SetMapper(mapper)
# assign actor to the renderer
renR.AddActor(actor)
renL.AddActor(actor)
# enable user interface interactor
renWinR.Render()
renWinL.Render()
irenR.Initialize()
irenL.Initialize()
#Create callback object for camera manipulation
cb = vtkGyroCallback()
cb.rightCam = renR.GetActiveCamera()#cameraR
cb.leftCam = renL.GetActiveCamera()#cameraL
cb.irenR = irenR
cb.irenL = irenL
irenR.ID = 1
irenL.ID = 2
irenR.AddObserver('TimerEvent', cb.execute)
irenL.AddObserver('TimerEvent', cb.execute)
timerIDR = irenR.CreateRepeatingTimer(100)
timerIDL = irenL.CreateRepeatingTimer(100)
irenL.Start()
irenR.Start()
if __name__ == '__main__':
main()

Is it possible to parent to only one or two axes in Blender?

I'm in the process of creating a 2d platformer using the Blender Game Engine. I'm having trouble getting the camera to follow my character and keep him in the center of the screen. Initially, I tried simply parenting the camera to my character, but whenever my character turns (rotates around the Z-axis 180 degrees), so does my camera, making it face the back of the level. So, I was wondering if there was a way to "parent" only one or two axes of an object to another, or restrain an axes from moving even if it is parented. This way I could keep the camera from rotating, but still have it follow on the Y and Z axes.
One thing I looked into was using Python code. I came up with...
import bpy
char = bpy.data.objects['HitBox']
obj = bpy.data.objects['Camera']
obj.location.x = 69.38762 # this is the set distance from the character to camera
obj.location.y = char.location.y
obj.location.z = char.location.z
bpy.data.scenes[0].update()
I realize I need a loop for this after assigning the 'char' variable, but I can't get any Python loops working that would run through the entire game, as 'while' loops crash the BGE. If you could help with either the parenting issue, or the Python code, I'd really appreciate it.

you just need to use the bge module, because it is for the game engine. So your problem is: you used blender python, but not bge python. Try to reach the camera with cam = bge.logic.getCurrentScene().active_camera. ... so this should work:
import bge
def main():
cam = bge.logic.getCurrentScene().active_camera
obj = bge.logic.getCurrentController().owner
obj.worldPosition.y = cam.worldPosition.y
obj.worldPosition.z = cam.worldPosition.z
main()
(Attach this script to your 'HitBox' with a true triggered always sensor so it can cycle forever.)
Other solution:
You can try to make vertex parent to your player.

Blender's internal data won't update after an scale operation

I have the following script:
import bpy
import os
print("Starter")
selection = bpy.context.selected_objects
for obj in selection:
print("Obj selected")
me = obj.data
for edge in me.edges:
vert1 = me.vertices[edge.vertices[0]]
vert2 = me.vertices[edge.vertices[1]]
print("<boundingLine p1=\"{0}f,0.0f,{1}f,1.0f\" p2=\"{2}f,0.0f,{3}f,1.0f\" />".format(vert1.co.x, vert1.co.y, vert2.co.x, vert2.co.y))
Pretty basic, right? It just prints out all the edges into the console, for me to copy paste into an xml document.
When I scale an object, and perform this script on the object, I get the OLD, unscaled values for the object outputed to the console, before it was scaled. I have tried moving every vertice in the object in all axises, which results in the values outputed being those outscaled and then transformed according to my movement.
If i press n to check the vertices global values, they are properly scaled.
Why am I not getting the correct values?!?
This script was supposed to save time, but getting anything to work in blender is a CHORE! It does not help that they has just updated their api, so all example code out there is outdated!

Allright, this is the deal: when you scale, translate or rotate an object in Blender, or otherwise perform an transformation, that transformation is "stored" somehow. What you need to do I choose the object of which you applied the transformation, and use the short cut CTRL + A, and then apply your transformation.
...
So there was no lack of contingency (am I using this word right? Checked out it's definition and it seems right) between the internal data accessible through the blender api, and the values actually displayed.
I am sure this design makes sense, but right now I want to punch the guy that came up with it, in the throat. If I scale something, I intend the thing that got scaled to be scaled!
But anyways, the reason I got weird values was because the scaling was not applied, which you do with CTRL + A, once you in object mode have selected the object that you scaled.

I`m not really a Blender user(but a Maya one), I think you could try something different(I woulds say slower too...), just iterate over the selected vertices, creating a locator or a null object and constraining it to the vertex position and getting it's x,y,z coordinates. I've done it in maya and works.
Lets say something like this:
data_list = []
selection = #selection code here#
for v in selection:
loc = locator()
pointconstraint(v, loc)
data_list.append(loc.translation_attributes)

Mesh objects have an internal coordinate system for their vertices, as well as global translation, scaling, and rotation transforms that apply to the entire object. You can apply the global scaling matrix to the mesh data, and convert the vertex coordinates to the global coordinate system as follows:
bpy.ops.object.select_all(action='SELECT')
bpy.ops.object.transform_apply(scale=True)
bpy.ops.object.select_all(action='DESELECT')
Other options to transform_apply() allow rotation and translation matrices to be applied as well.