View Full Version : addition of transformation matrix

H.Stony

05-03-2005, 07:10 AM

i have a transformed modelview matrix stored in a float array. now i want to add this matrix to the current matrix (the current matrix is also in an array).

is this possible?

thanks h.stony

shinpaughp

05-03-2005, 04:58 PM

Yes though not directly - there isn't a glAddMatrix function.

pseudo code:

float mymat[16];

...

initialize mymat

...

float mat[16];

mat = glGetFloatv( GL_MODELVIEW_MATRIX );

for( i=0;i<16;i++ )

mat[i] += mymat[i];

glMatrixMode( GL_MODELVIEW );

glLoadMatrixf( mat );

But... why would you want to add a matrix to another?

Combining the effects of the matrices is a matter of multiplying matrices (use glMultMatrix).

That's how OGL handles its rotates/translates/scales.

H.Stony

05-05-2005, 01:13 AM

yes. glMultMatrix was my first idea. but the result was really strange. i know that a addition beetween the matrices is senseless. i try glMultMatrix a second time.

-pseudocode

float mymat[16];

...

initialize mymat

...

gMultMatrix(mymat);

glMatrixMode( GL_MODELVIEW ); // i am already in modelview mode. but without it doesn't work

glLoadMatrixf( mat );thanks

powerpad

05-05-2005, 04:20 AM

obtain the modelview matrix add the 2 together and load the resulting matrix

Powered by vBulletin® Version 4.2.5 Copyright © 2018 vBulletin Solutions Inc. All rights reserved.