Difference between revisions of "Talk:Quaternion"

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(Answered to Strife)
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Perharps that would deserve a word of explanation here.
Perharps that would deserve a word of explanation here.


-- Catherine Pfeffer, 2007-12-08
-- [[User:Catherine Pfeffer|Catherine Pfeffer]], 2007-12-08


:It's probably an artifact of LSL having the operator operands reversed and they forgot to reverse them to not match the execution order. For that to make sence you need to know that in most systems when you do (a * b), a is put on the stack before b. In LSO, b is put on the stack before a. If a and b are functions, b is executed before a. Meaning, LSL uses right to left parsing execution. -- [[User:Strife Onizuka|Strife Onizuka]] 08:48, 8 December 2007 (PST)
:It's probably an artifact of LSL having the operator operands reversed and they forgot to reverse them to not match the execution order. For that to make sence you need to know that in most systems when you do (a * b), a is put on the stack before b. In LSO, b is put on the stack before a. If a and b are functions, b is executed before a. Meaning, LSL uses right to left parsing execution. -- [[User:Strife Onizuka|Strife Onizuka]] 08:48, 8 December 2007 (PST)


This text has two shemas at the end. If you look well at it, the 90° rotation in the first schema and
::Yes, most probably. I filed a jira issue against this. I suggest we wait for the jira issue to be processed to see if that has to be mentioned in the doc. User:Catherine Pfeffer|Catherine Pfeffer]], 2007-12-09
in the second schema are supposed to be opposite (once in z direction, the other time in -z direction)
but the pink arrow materializing the rotation is the same.


It's the first schema that is correct (LSL follows right-hand rule for direction of positive rotations)
This text has two shemas at the end. If you look well at it, the 90° rotation in the first schema and in the second schema are supposed to be opposite (once in z direction, the other time in -z direction) but the pink arrow materializing the rotation is the same.
 
It's the first schema that is correct (LSL follows right-hand rule for direction of positive rotations).


-- Catherine Pfeffer, 2007-12-07
-- Catherine Pfeffer, 2007-12-07
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:That is correct, LSL uses right-hand rule set. -- [[User:Strife Onizuka|Strife Onizuka]]
:That is correct, LSL uses right-hand rule set. -- [[User:Strife Onizuka|Strife Onizuka]]


::So what do we do to fix this page? (Cathy Pfeffer)  [PS my interpretation of z<sup>-1</sup>Qz problem was wrong, rephrased. See above]
::So what do we do to fix this page? Will you or someone else redraw the second schema, Strife? [[User:Catherine Pfeffer|Catherine Pfeffer]], 2007-12-09

Revision as of 09:54, 9 December 2007


In LSL, quaternion multiplication is written down in reverse order as in maths :

  Q2 * Q1   (LSL)

is the same as

  Q1 . Q2    (maths)

Perharps that would deserve a word of explanation here.

-- Catherine Pfeffer, 2007-12-08

It's probably an artifact of LSL having the operator operands reversed and they forgot to reverse them to not match the execution order. For that to make sence you need to know that in most systems when you do (a * b), a is put on the stack before b. In LSO, b is put on the stack before a. If a and b are functions, b is executed before a. Meaning, LSL uses right to left parsing execution. -- Strife Onizuka 08:48, 8 December 2007 (PST)
Yes, most probably. I filed a jira issue against this. I suggest we wait for the jira issue to be processed to see if that has to be mentioned in the doc. User:Catherine Pfeffer|Catherine Pfeffer]], 2007-12-09

This text has two shemas at the end. If you look well at it, the 90° rotation in the first schema and in the second schema are supposed to be opposite (once in z direction, the other time in -z direction) but the pink arrow materializing the rotation is the same.

It's the first schema that is correct (LSL follows right-hand rule for direction of positive rotations).

-- Catherine Pfeffer, 2007-12-07

That is correct, LSL uses right-hand rule set. -- Strife Onizuka
So what do we do to fix this page? Will you or someone else redraw the second schema, Strife? Catherine Pfeffer, 2007-12-09