# Matrice 4*4 multiplication and data information

Hi,

It is possible to know how you compute the Matrix.multiplyMM. I have been sesting the output and what i have found need explenetion.
It is not a 44 calculation it is a 33 and some mouvement in the last ligne and last colonne of the matrice.

Could you let me know how the matrice of Matrix.multiplyMM is done and the detail conc"erning the last line and last colum.

Thanks for the answer because if we do not know how the matrice are calculated we cannot and wont know anythings.

Regards.
Herve Terrolle

I found out that the output matrice far a float[16] is

0 1 2 3
4 5 6 7
8 9 10 11
12 13 14 15

may be Android implement

0 4 8 12
1 5 9 13
2 6 10 14
3 7 11 15

That is also what a need to know because in the documentation for the projection matrice for example the second solution look to be that one.

Thanks to confirm with the right implementation.

regards

Your tool for posting is not very efficient. screen to smal and no tab aniway.

That what i do not anderstand. I got a matrice organiezd like :

0 4 8 12
1 5 9 13
2 6 10 14
3 7 11 15

then i got my ViewMat

1.6666666 , 0.0, 0.0, 0.0
0.0 , 1.0, 0.0, 0.0
0.0 , 0.0, -1.020202, -2.020202
0.0 , 0.0, -1.0, 0.0

then my projection mat

-1.0, 0.0, 0.0, 0.0
0.0, 1.0, -0.0, 0.0
-0.0, -0.0, -1.0, -5.0
0.0, 0.0, 0.0, 1.0

and the result of the Matrix.multiplyMM fonction

-1.6666666, 0.0, 0.0, 0.0
0.0, 1.0, 0.0, 0.0
0.0, 0.0, 1.020202, 3.0808084
0.0, 0.0, 1.0, 5.0
I do not anderstant how we get ther red value. How are they calculated. 3.0808084 come from where and the last line ?

It look like 3*3 calculation matrice more some information which are not matrice calculation.

PS: sorry for my english.

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