EvanPMeth
30-07-2008 04:24:50
Alright, im still very new to ogre. My question is: I have a node that is facing one direction and i want it to face a point specified by the user. How would i get the amount it has to rotate to face that direction. I only want to rotate about the y-axis(yaw), i dont want to change the pitch and roll. I want the amount of rotation, so that i can slowly rotate the node to face the direction i need it to.
I found this from inter tut 1:
src = self.node.getOrientation() * ogre.Vector3.UNIT_X
if 1.0 + src.dotProduct(self.direction) < 0.0001:
self.node.yaw(ogre.Degree(180))
else:
quat = src.getRotationTo(self.direction)
self.node.rotate(quat)
the problem with this is it rotates it on all axis
chpod
30-07-2008 10:35:23
How do you compute the direction?
Myself I use:
direction = nodeToRotate.getPosition() - nodeToLookAt.getPosition()
I made one demo Demo_WX_direction.py that shows how to use it. Here it is:
import sys
sys.path.insert(0,'..')
import PythonOgreConfig
if __name__=="__main__":
from OgreWindowWx import *
import wx.py as py #This modules gives access to the pyCrust interpreter widget
class DemoOgreWindow(OgreWindow):
"""This is a demo of how to subclass OgreWindow.
Many parts of the code are directely inspired from the beginner to
advance tutorials"""
fishIsSwiming=False #A variable to keep track whether the fish is swiming or not
def _PopulateScene(self):
"Creation of scene objects"
# create scene
sceneManager=self.sceneManager
sceneManager.AmbientLight = ogre.ColourValue(0.7, 0.7, 0.7 )
sceneManager.setSkyDome(True, 'Examples/CloudySky', 4.0, 8.0)
light = sceneManager.createLight('MainLight')
light.setPosition ( ogre.Vector3(20, 80, 130) )
self.sceneEntities.MainLight = light
# add some fog
sceneManager.setFog(ogre.FOG_EXP, ogre.ColourValue.White, 0.0002)
plane = ogre.Plane()
plane.normal = ogre.Vector3(0, 1, 0)
plane.d = 200
ogre.MeshManager.getSingleton().createPlane('FloorPlane', "General",plane, 200000.0, 200000.0,
20, 20, True, 1, 50.0, 50.0,ogre.Vector3(0, 0, 1),
ogre.HardwareBuffer.HBU_STATIC_WRITE_ONLY,
ogre.HardwareBuffer.HBU_STATIC_WRITE_ONLY,
True,True )
# create floor entity
entity = sceneManager.createEntity('floor', 'FloorPlane')
entity.setMaterialName('Examples/RustySteel')
sceneManager.getRootSceneNode().createChildSceneNode().attachObject(entity)
self.sceneEntities.floor = entity
# create fish entity
fishNode = sceneManager.getRootSceneNode().createChildSceneNode("fishNode")
entity = sceneManager.createEntity('Wanda', 'fish.mesh')
fishNode.attachObject(entity)
fishNode.setScale(10.0,10.0,10.0)
# create fish entity
fishNode2 = sceneManager.getRootSceneNode().createChildSceneNode("fishNode2")
entity2 = sceneManager.createEntity('Wanda2', 'fish.mesh')
entity2.setMaterialName("Examples/RustySteel")
fishNode2.attachObject(entity2)
fishNode2.setScale(20.0,20.0,20.0)
fishNode2.setPosition(100.0,0.0,0.0)
self.sceneEntities.fishNode2 = fishNode2
self.sceneEntities.fishNode = fishNode
self.sceneEntities.fish = entity
self.swimAnimationState = entity.getAnimationState('swim')
self.swimAnimationState.Enabled = True
#create fish swiming path
fishAnimationNode = sceneManager.getRootSceneNode().createChildSceneNode("fishAnimationNode")
self.sceneEntities.fishAnimationNode = fishAnimationNode
animation = sceneManager.createAnimation('fishTrack', 10)
animation.interpolationMode = ogre.Animation.IM_SPLINE
animationTrack = animation.createNodeTrack(0, fishAnimationNode)
key = animationTrack.createNodeKeyFrame(0.0)
key = animationTrack.createNodeKeyFrame(1.0)
key.setTranslate (ogre.Vector3(80.0, 0.0, -40.0) )
key = animationTrack.createNodeKeyFrame(2.0)
key.setTranslate ( ogre.Vector3(120.0, 0.0, 0.0))
key = animationTrack.createNodeKeyFrame(3.0)
key.setTranslate(ogre.Vector3(80.0, 0.0, 80.0) )
key = animationTrack.createNodeKeyFrame(5.0)
key.setTranslate ( ogre.Vector3(-80.0, 0.0, -40.0) )
key = animationTrack.createNodeKeyFrame(6.0)
key.setTranslate ( ogre.Vector3(-120.0, 0.0, 0.0) )
key = animationTrack.createNodeKeyFrame(7.0)
key.setTranslate ( ogre.Vector3(-80.0, 0.0, 100.0))
key = animationTrack.createNodeKeyFrame(8.0)
key.setTranslate ( ogre.Vector3(30.0, 0.0, 90.0) )
key = animationTrack.createNodeKeyFrame(9.0)
key.setTranslate( ogre.Vector3(-20.0, 0.0, 40.0) )
key = animationTrack.createNodeKeyFrame(10.0)
key.setTranslate ( ogre.Vector3(0.0, 0.0, 0.0) )
self.fishAnimationState = sceneManager.createAnimationState('fishTrack')
self.fishAnimationState.Enabled = True
#create a duplicate fish swiming path for determining where the fish has to look to
self.sceneEntities.fishLookAtNode = fishLookAtNode = sceneManager.getRootSceneNode().createChildSceneNode("fishLookAtNode")
animation = sceneManager.createAnimation('fishLookAtTrack', 10)
animation.interpolationMode = ogre.Animation.IM_SPLINE
animationTrack = animation.createNodeTrack(0, fishLookAtNode)
key = animationTrack.createNodeKeyFrame(0.0)
key = animationTrack.createNodeKeyFrame(1.0)
key.Translate = ogre.Vector3(80.0, 0.0, -40.0)
key = animationTrack.createNodeKeyFrame(2.0)
key.Translate = ogre.Vector3(120.0, 0.0, 0.0)
key = animationTrack.createNodeKeyFrame(3.0)
key.Translate = ogre.Vector3(80.0, 0.0, 80.0)
key = animationTrack.createNodeKeyFrame(5.0)
key.Translate = ogre.Vector3(-80.0, 0.0, -40.0)
key = animationTrack.createNodeKeyFrame(6.0)
key.Translate = ogre.Vector3(-120.0, 0.0, 0.0)
key = animationTrack.createNodeKeyFrame(7.0)
key.Translate = ogre.Vector3(-80.0, 0.0, 100.0)
key = animationTrack.createNodeKeyFrame(8.0)
key.Translate = ogre.Vector3(30.0, 0.0, 90.0)
key = animationTrack.createNodeKeyFrame(9.0)
key.Translate = ogre.Vector3(-20.0, 0.0, 40.0)
key = animationTrack.createNodeKeyFrame(10.0)
key.Translate = ogre.Vector3(0.0, 0.0, 0.0)
self.fishLookAtAnimationState = sceneManager.createAnimationState('fishLookAtTrack')
self.fishLookAtAnimationState.Enabled = True
self.fishLookAtAnimationState.addTime(0.033) #Gives a 33ms headstart to the lookat node
def OnFrameStarted(self,event):
"In this example, we will make the fish swim along a path"
if self.fishIsSwiming :
#First : updates the position of the fish to the position of the moving node on the animation path
#The reason that we did not create an animationTrack for fishNode is that we are interested in
#keyframing only the node position, not the scale, orientation etc...
self.sceneEntities.fishNode.setPosition( self.sceneEntities.fishAnimationNode.Position )
#Then, takes care of the direction that the fish has to face to
directionToGo = self.sceneEntities.fishLookAtNode.Position - self.sceneEntities.fishAnimationNode.Position
src = self.sceneEntities.fishNode.Orientation * (-ogre.Vector3.UNIT_X) #the fish is originally
#facing the negative X direction
quat = src.getRotationTo(directionToGo) #Calculates the quaternion of the appropriate rotation
self.sceneEntities.fishNode.rotate(quat)#Rotates, the fish. Here, we know that no rotation of 180
#degrees will occur so we do not have to care about it
print "POS2",self.sceneEntities.fishNode2.getPosition()
direction = self.sceneEntities.fishNode2.getPosition() - self.sceneEntities.fishNode.getPosition()
src = self.sceneEntities.fishNode2.getOrientation() * ogre.Vector3.UNIT_X
if 1.0 + src.dotProduct(direction) < 0.0001:
self.node.yaw(ogre.Degree(180))
else:
quat = src.getRotationTo(direction)
self.sceneEntities.fishNode2.rotate(quat)
def ToggleSwimAnimation(self):
"Toggles on and off the animation"
self.fishIsSwiming = not self.fishIsSwiming
if self.fishIsSwiming : #Adds the animation states for use
self.animStates["fishAnimation"] = (self.fishAnimationState, 1.0)
self.animStates["fishLookAtAnimation"] = (self.fishLookAtAnimationState, 1.0)
self.animStates["swimAnimation"] = (self.swimAnimationState, 4)
else : #Removes animation states
self.animStates.pop("fishAnimation")
self.animStates.pop("fishLookAtAnimation")
self.animStates.pop("swimAnimation")
class DemoFrame(wx.Frame):
"""Creates a frame with an Ogre window and a pyCrust window
pyCrust is always nice to have around for study/debug purposes"""
def __init__(self, *args, **kwds):
kwds["style"] = wx.DEFAULT_FRAME_STYLE
wx.Frame.__init__(self, *args, **kwds)
self.pyCrust = wx.py.crust.Crust(self, -1)
self.ogreWin = DemoOgreWindow(self, -1)
self.swimButton = wx.Button(self, -1, "Start/Stop Swiming")
self.trackButton = wx.ToggleButton(self, -1, "Camera Auto Tracking")
self.__set_properties()
self.__do_layout()
self.Bind(wx.EVT_BUTTON, self.swimButtonCallback, self.swimButton)
self.Bind(wx.EVT_TOGGLEBUTTON, self.ToggleAutoTracking, self.trackButton)
def __set_properties(self):
self.SetTitle("wxPyOgre Demo")
self.ogreWin.SetMinSize((640,480))
self.trackButton.SetValue(False)
def __do_layout(self):
sizer_1 = wx.BoxSizer(wx.VERTICAL)
sizer_1.Add(self.ogreWin, 2, wx.EXPAND, 0)
sizer_1.Add(self.swimButton,0, wx.ALIGN_CENTER, 0)
sizer_1.Add(self.trackButton,0, wx.ALIGN_CENTER, 0)
sizer_1.Add(self.pyCrust, 1, wx.EXPAND, 0)
self.SetAutoLayout(True)
self.SetSizer(sizer_1)
sizer_1.Fit(self)
sizer_1.SetSizeHints(self)
self.Layout()
def swimButtonCallback(self,event):
self.ogreWin.ToggleSwimAnimation()
def ToggleAutoTracking(self,event):
"Toggles on and off the automatic tracking of the fish by the camera"
self.ogreWin.sceneEntities.Camera.setAutoTracking(event.Checked(), self.ogreWin.sceneEntities.fishNode)
DemoApp = wx.PySimpleApp(0)
wx.InitAllImageHandlers() #you may or may not need this
MainFrame = DemoFrame(None, -1, "")
#put all the entities in self.ogreWin.sceneEntities in the local variables so that
#introspection with pyCrust is more user friendly
localVariableDic=locals()
localVariableDic.update(MainFrame.ogreWin.sceneEntities.__dict__)
DemoApp.SetTopWindow(MainFrame)
MainFrame.ogreWin.StartRendering()
MainFrame.Show()
DemoApp.MainLoop()
Hope this helps,
chpod
EvanPMeth
30-07-2008 16:59:02
Thanks for the help chpod, i think i was just too tired yesterday to think clearly. What you gave me help me look at it differently so i just went through the api and figured it out here is my solution:
self.direction = self.destination - self.mainNode.getPosition()
src = self.mainNode.Orientation * (-ogre.Vector3.UNIT_X)
quat = src.getRotationTo(self.direction)
self.mainNode.yaw(quat.getYaw(True) + ogre.Radian(-1.5708))
the ogre.Radian(-1.5708)) is 90 degrees to adjust for proper orientation