[geometry-1] TYPO? 2.1(6) should be pre-multiply ,not post-multiply. #294

Step 6 of Section 2.1 Transforming a point with a matrix, says

Set pointVector to pointVector post-multiplied by matrix.

pointVector was defined as a column vector in the previous step. And the definition of post-multiply is:

Term A post-multiplied by term B is equal to A · B.

So that's pointVector · matrix; i.e. columnVector · matrix

That's not mathematically possible. Matrix multiplication produces a new matrix whose elements are the inner products of the left-hand matrix's rows with the right-hand's columns; so for C = A · B

A 4-element column vector multiplied by a 4x4 matrix means calculating the dot product of a 1-element row with a 4-element column. There's no way to do it.

The text should say

Set pointVector to pointVector pre-multiplied by matrix.

or

Set pointVector to matrix post-multiplied by pointVector.

or it should construct pointVector as a row vector and post-multiply by the transpose of the matrix.

I've read and re-read the spec, and I can't see I've got this wrong this time. But I've not done a PR in case my eyes have swizzled the words again.