The quaternion calculations you're doing are similar to just manipulating the Euler Angles, which cause Gimbal Lock.
The way I did it in my flight simulation is to create a Current Quaternion (from the starting Matrix Transformation when user spawns) and Target Quaternion (where they want to rotate to). I also used some formulas to rotate the quaternion in the individual yaw/pitch/roll orientations, I recommend googling for these formulas. I then used the Slerp formula to animate from the Current quaternion to the Target quaternion. Slerp will avoid Gimbal-Lock entirely, which is very neat. After you do those calculations, just convert the new Current Quaternion into a Matrix Transformation and set the Entity to take that transform. I've used this to control the entity rotation as well as the camera, it allows you to do some pretty nifty tricks. I'll look for the code, if I still have it, and I'll post it here for you. Or if you figure out, please post a video =D Regards, Joel On Thu, Mar 1, 2012 at 11:55 AM, Minh <minh...@telus.net> wrote: > You can try spitting out the results to a file so you can observe the > hitch more closely. > Look for a function called COM_Log > > COM_Log ( "viewangle_hitch.txt", "%.2f %.2f %.2f \n", viewangles.x, > viewangles.y, viewangles.z ); > > On 3/1/2012 3:55 AM, Craig Louie wrote: > > Thanks for the reply Saul. I hadn't thought of disabling prediction. I > just gave it a shot. I changed to "engine->ClientCmd( "cl_predict 0" );" in > cdll_client_int.cpp. With another test, the unsmooth rotation when looking > straight up/down still occurs. > > My main theories at this point: > 1) Something is occurring in VectorAngles(vec_for_out, vec_up_out, > viewangles) to cause this. VectorAngles() might not produce straight > up/down Euler angles properly - choking because of aliasing perhaps? This > is a big guess because I don't know the inner workings of VectorAngles(). > 2) There is some code somewhere else that is conflicting with the full, > unclamped rotation I've implemented. I've tried to remove all instances of > pitch clamping, for example. But I may have missed something. Also, it's > possible mouse rotation is somehow conflicting with my changes to joystick > rotation. > > Here's a video of the issue I'm seeing. It happens a few times in the > video. You'll see it happen the first time at about 11 seconds in when the > text on the floor twists/shakes. > http://www.youtube.com/watch?v=PLN641Qsn08 > > Thanks! > > > > On Wed, Feb 29, 2012 at 11:34 PM, Saul Rennison > <saul.renni...@gmail.com>wrote: > >> The hitching is most likely something trying to revert your angle changes >> (I.e. in prediction). Have you tried disabling prediction? >> >> >> On Thursday, March 1, 2012, Craig Louie wrote: >> >>> Hello Coders, >>> >>> I'm trying to create a space flight combat game with the Source SDK. >>> Currently, I am trying to achieve rotation around the player's local axes >>> for airplane-like pitch, yaw and roll. Below is the code I'm using to try >>> to implement full 3D rotation. I'm running into a problem where the >>> player's view twists and hitches unsmoothly when the player looks straight >>> up or straight down. I think this may be because of the inherent problem of >>> aliasing/Gimbal-lock when using Euler angles. Any advise? >>> >>> //######################################### >>> //Take the Euler angles for the player's orientation (viewangles) and >>> convert them to vectors. >>> Vector vec_for, vec_rt, vec_up, vec_for_out, vec_rt_out, vec_up_out; >>> AngleVectors(viewangles, &vec_for, &vec_rt, &vec_up); >>> >>> //Take the resulting vectors and the desired rotation amounts and >>> convert them to Quaternions. >>> Quaternion turn_q, look_q, roll_q; >>> // NOTE: Assumes axis is a unit vector, non-unit vectors will bias the >>> resulting rotation angle (but not the axis) >>> VectorNormalize(vec_up); >>> AxisAngleQuaternion(vec_up, turn_angle, turn_q); >>> >>> VectorNormalize(vec_rt); >>> AxisAngleQuaternion(vec_rt, look_angle, look_q); >>> >>> VectorNormalize(vec_for); >>> AxisAngleQuaternion(vec_for, roll_angle, roll_q); >>> >>> //Convert the quaternions to matrices. >>> matrix3x4_t xform0, xform1, xform2; >>> QuaternionMatrix(turn_q, xform0); >>> QuaternionMatrix(look_q, xform1); >>> QuaternionMatrix(roll_q, xform2); >>> >>> //Combine matrices. >>> matrix3x4_t xformA, xformB; >>> MatrixMultiply(xform0, xform1, xformA); >>> MatrixMultiply(xformA, xform2, xformB); >>> >>> //Rotate the vectors with our combined rotation matrix. >>> VectorRotate(vec_for, xformB, vec_for_out); >>> VectorRotate(vec_rt, xformB, vec_rt_out); >>> VectorRotate(vec_up, xformB, vec_up_out); >>> >>> //Determine the new viewangles based on our rotated vectors. >>> VectorAngles(vec_for_out, vec_up_out, viewangles); >>> //######################################### >>> >>> I put this code into in_joystick.cpp in the JoyStickMove( float >>> frametime, CUserCmd *cmd ) function. >>> >>> >>> Thanks! >>> >>> >>> >> >> -- >> >> >> Kind regards, >> *Saul Rennison* >> >> _______________________________________________ >> To unsubscribe, edit your list preferences, or view the list archives, >> please visit: >> https://list.valvesoftware.com/cgi-bin/mailman/listinfo/hlcoders >> >> >> > > > _______________________________________________ > To unsubscribe, edit your list preferences, or view the list archives, please > visit:https://list.valvesoftware.com/cgi-bin/mailman/listinfo/hlcoders > > > > _______________________________________________ > To unsubscribe, edit your list preferences, or view the list archives, > please visit: > https://list.valvesoftware.com/cgi-bin/mailman/listinfo/hlcoders > > >
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