Re: [PyOpenGL-Users] recommendation for setting correctly the new direction of an object

[Roland E. <r.e...@gm...>]

Mike,

By reading the code you linked in your answer I am puzzle, and I don't 
really see how to integrate that concept into my own code without 
shamelessly copying some of your methods directly into my code and and 
adapt it :(

So, have you any book recommendation that discuss such matter for 
someone that have not played with stuff like matrices for 15 years and 
never heard of quaternions until learning OpenGL?

There is so much books on math for computer graphics, game development, 
physics, ai, ... that I don't know which one to choose.

I should have maybe precised that self.thrust and self.tick are float, 
so I don't see how that will interact with self.orientation that is a 
quaternion if I have understand correctly.


Thanks,


Roland.

Le 08/03/10 22:34, Roland Everaert a écrit :
> Thanks for the example and the explanation, I will have a look at it asap.
>
> Roland.
>
>
> Le 08/03/10 17:01, Mike C. Fletcher a écrit :
>> On 10-08-02 04:57 PM, Roland Everaert wrote:
>>> Hi,
>>>
>>> I am currently writing a third person view space shooter where the
>>> player can freely fly in the "map". I want to define an arcade flying
>>> model like in most space shooter or spaceship simulation, but I face the
>>> problem of specifying the transformation right.
>>>
>>> For the moment, my scene contains the player space ship pointing toward
>>> the negative z axis, with the camera a little bit behind it. In front of
>>> the ship there are 2 objects. When I apply some thrust to the player
>>> spaceship it goes forward, but if I turn the ship, it is not changing
>>> direction, while the ship and the camera are turning.
>>>
>>> My questions are the following:
>>>
>>> 1. Given the code below, why have I to call the method
>>> self.__chasingView() after rendering the player's ship?
>>>
>>> 2. How to change the direction of the ship? Am I missing some glRotate()
>>> functions somewhere in the code or should I change the code of method
>>> setNewPosition() in such a way that the position of the ship is computed
>>> on all 3 axis?
>>>    
>> The problem you are facing is that you want to make the motion of the 
>> ship (x,y,z) modify by currentrotation * motionvector.  You *could* 
>> do that with an ever-increasing set of glRotate/glTranslate calls 
>> (you'd need one for every change in direction), but what you really 
>> want to do is to track your position in "world" space and change that 
>> position by currentrotationmatrix * motionvector.
>>
>> I normally do that with a wrapped Quaternion class in OpenGLContext.  
>> See OpenGLContext/move/viewplatform.py for the code that wraps it 
>> (particularly the relativePosition() method, on which all of the 
>> various forward/sideways/up/down movements are built.
>>
>> http://bazaar.launchpad.net/~mcfletch/openglcontext/trunk/annotate/head:/OpenGLContext/move/viewplatform.py 
>> <http://bazaar.launchpad.net/%7Emcfletch/openglcontext/trunk/annotate/head:/OpenGLContext/move/viewplatform.py>
>>>       def setNewPosition(self):
>>>           self.addToPosition(z=-(self.thrust * self.tick))
>>>    
>> that should be something like self.addToPosition( self.thrust * 
>> self.tick * self.orientation )
>>
>> HTH,
>> Mike
>> -- 
>> ________________________________________________
>>    Mike C. Fletcher
>>    Designer, VR Plumber, Coder
>>    http://www.vrplumber.com
>>    http://blog.vrplumber.com
>>    
>>
>>
>> ------------------------------------------------------------------------------
>> The Palm PDK Hot Apps Program offers developers who use the
>> Plug-In Development Kit to bring their C/C++ apps to Palm for a share
>> of $1 Million in cash or HP Products. Visit us here for more details:
>> http://p.sf.net/sfu/dev2dev-palm
>>
>>
>> _______________________________________________
>> PyOpenGL Homepage
>> http://pyopengl.sourceforge.net
>> _______________________________________________
>> PyOpenGL-Users mailing list
>> PyO...@li...
>> https://lists.sourceforge.net/lists/listinfo/pyopengl-users
>>