I think I ran into a similar problem building the orientation state using
AxisAngles. I believe you have to first build the "default" state before
you can multiply the (yaw/pitch/roll) quaternions.
On Sun, Mar 4, 2012 at 12:31 AM, Craig Louie <craiglo...@gmail.com> wrote:
> I've tried both Joel and Tony's methods, but I'm still unsure of how I can
> escape the inherent aliasing problem of Euler Angles.
>
> With Joel's method, for instance, after I have used Slerp to get a
> rotation quaternion, I still need to convert the resulting quaternion back
> into Euler Angles (with QuaternionAngles()) because the Source engine
> ultimately needs orientation in QAngle form when I call
> engine->SetViewAngles(viewangles). Any thoughts on this?
>
> Also, I've learned more about the nature of the twisting hitch experienced
> when looking straight up/down (this was my original problem). When I turn
> off motion blur, the hitch isn't visible. My theory is that the twisting
> hitch I am seeing is a result of the player's orientation twisting at the
> instant the player looks straight up/down.
>
> Below is a part of a log showing the changes in viewangle as I pitch down
> through pitch=90 (as shown in my youtube video).
>
> 88.025864 0.000000 0.000000
> 88.136208 0.000000 0.000000
> 88.278770 0.000000 0.000000
> 88.421890 0.000000 0.000000
> 88.531670 0.000000 0.000000
> 88.683762 0.000000 0.000000
> 88.784576 0.000000 0.000000
> 88.976646 0.000000 0.000000
> 89.037476 0.000000 0.000000
> 89.261894 0.000000 0.000000
> 89.290375 0.000000 0.000000
> 89.522987 0.000000 0.000000
> 89.543274 0.000000 0.000000
> 89.787949 0.000000 0.000000
> 89.796173 0.000000 0.000000
> 89.950935 -0.000000 0.000000
> 89.989258 -0.000000 0.000000
> 89.796158 180.000000 180.000000
> 89.639793 -180.000000 -180.000000
> 89.543274 180.000000 180.000000
> 89.290382 -180.000000 -180.000000
> 89.266182 180.000000 180.000000
> 89.037491 -180.000000 -180.000000
> 88.784592 180.000000 180.000000
> 88.531693 -180.000000 -180.000000
> 88.334381 180.000000 180.000000
> 88.278809 -180.000000 -180.000000
> 88.025909 180.000000 180.000000
>
> The sudden yaw and roll change to +/-180 is probably what is causing the
> hitch. The motion blur is creating a blur effect as if the player is
> spinning for an instant. How to get around this, I am not sure.
>
>
> Here's my current code in in_joystick.cpp's JoyStickMove() function:
>
> //###############################################################################
>
> Vector vec_for, vec_rt, vec_up, vec_for_out, vec_rt_out, vec_up_out;
> Quaternion viewangles_q, turn_q, look_q, roll_q, qTemp, qDelta,
> qResult, viewangles_q_out;
>
> AngleVectors(viewangles, &vec_for, &vec_rt, &vec_up);
>
> //Converting the current viewangles to a Quaternion (viewangles_q).
> RadianEuler viewangles_euler(viewangles);
> AngleQuaternion(viewangles_euler, viewangles_q);
>
> //Build a set of quaternion transforms that rotate around
> corresponding axes in local space by corresponding angles.
> // NOTE: 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);
>
> //Combine Quaternions.
> QuaternionMult(look_q, turn_q, qTemp);
> QuaternionMult(qTemp, roll_q, qDelta);
>
> //Slerp
> QuaternionSlerp(viewangles_q, qDelta, 1.0, qResult);
>
> //Applying the Quaternion rotation.
> QuaternionMult(qResult, viewangles_q, viewangles_q_out);
>
> //Converting Quaternion into a QAngle for
> engine->SetViewAngles(viewangles_out)
> QAngle viewangles_out;
> QuaternionAngles(viewangles_q_out, viewangles_out);
>
> COM_Log("viewangle_hitch.txt", "%2f %2f %2f \n", viewangles_out.x,
> viewangles_out.y, viewangles_out.z);
>
> if (viewangles_out[PITCH] > 180)
> {
> viewangles_out[PITCH] -= 360;
> }
> else if (viewangles_out[PITCH] < -180)
> {
> viewangles_out[PITCH] += 360;
> }
>
> if (viewangles_out[YAW] > 180)
> {
> viewangles_out[YAW] -= 360;
> }
> else if (viewangles_out[YAW] < -180)
> {
> viewangles_out[YAW] += 360;
> }
>
> if (viewangles_out[ROLL] > 180)
> {
> viewangles_out[ROLL] -= 360;
> }
> else if (viewangles_out[ROLL] < -180)
> {
> viewangles_out[ROLL] += 360;
> }
>
> //###############################################################################
>
>
> Thanks!
>
>
>
> On Fri, Mar 2, 2012 at 12:40 AM, Craig Louie <craiglo...@gmail.com> wrote:
>
>> Thanks Tony and Joel for more awesome help. I didn't get as much time as
>> I would have liked to work on it tonight. I will have to continue tomorrow
>> night (and probably into the weekend). I'll keep the thread posted. Thanks!
>>
>> P.S. cool flight sim vid, Joel. Are you a fellow X-Wing/Tie Fighter fan?
>> Freespace perhaps?
>>
>>
>>
>> On Thu, Mar 1, 2012 at 10:29 PM, Joel R. <joelru...@gmail.com> wrote:
>>
>>> http://www.youtube.com/watch?v=5y6a_oFtNiI
>>>
>>>
>>> On Thu, Mar 1, 2012 at 10:35 PM, Tony "omega" Sergi <omegal...@gmail.com
>>> > wrote:
>>>
>>>> This actually will work in Source, as the input/view stuff is basically
>>>> identical:
>>>> http://articles.thewavelength.net/269/
>>>> -Tony
>>>>
>>>>
>>>>
>>>> On Fri, Mar 2, 2012 at 5:09 AM, Craig Louie <craiglo...@gmail.com>wrote:
>>>>
>>>>> Thanks Joel! I'll also try out your method when I get home. I'll keep
>>>>> everyone posted on my results.
>>>>>
>>>>> Thanks!
>>>>>
>>>>>
>>>>>
>>>>> On Thu, Mar 1, 2012 at 11:12 AM, Joel R. <joelru...@gmail.com> wrote:
>>>>>
>>>>>> Quaternion.h
>>>>>> http://pastebin.com/hxTBab3T
>>>>>>
>>>>>> Quaternion.cpp
>>>>>> http://pastebin.com/2WizAewD
>>>>>>
>>>>>> Quaternion Rotation Formulas (Yaw/Pitch/Roll)
>>>>>> http://pastebin.com/BHRvcbCG
>>>>>>
>>>>>> I got most of the quaternion stuff from Ogre engine and converted to
>>>>>> work on Source Engine. The functions you will be interested in using are
>>>>>> FromRotationMatrix, ToRotationMatrix, AxisAngle, ToAxisAngle,
>>>>>> GetRotationTo, ToAxes, Slerp, GetAngles, GetMatrix
>>>>>>
>>>>>> So basically you'll do what's below: (this is psuedocode, function
>>>>>> names are not exact!)
>>>>>>
>>>>>>
>>>>>> Quat current, target;
>>>>>> current.FromRotationMatrix( ent->EntityWorldTransform() );
>>>>>>
>>>>>> target = current;
>>>>>> target = yaw( target, 10 ); //10 degrees to the right, this function
>>>>>> is not part of Quat class for some reason
>>>>>>
>>>>>> current = Slerp( current, target, 0.2 ); //This is only 20%, you'll
>>>>>> need to calculate the angle difference between current/target, and then
>>>>>> move based on your angles per second speed.
>>>>>>
>>>>>> matrix3x4_t newRot;
>>>>>> current.ToRotationMatrix( newRot );
>>>>>> ent->SetWorldTransform( newRot );
>>>>>>
>>>>>>
>>>>>>
>>>>>> Enjoy!
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Thu, Mar 1, 2012 at 12:46 PM, Joel R. <joelru...@gmail.com> wrote:
>>>>>>
>>>>>>> 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
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> 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
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> -Tony
>>>>
>>>>
>>>> _______________________________________________
>>>> 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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> please visit:
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