Skewing with a matrix ?

OpenGL OpenGL: Basic Coding
1

Hi,

I am a beginning opengl’r

I need to skew an object in the x.
IE the height*a factor get subtracted from the x…

How do I do this with a matrix ?

Any help greatly appreciated.

Greg.

2

well… you can’t the easiest way (I think) is to do this for each vertex’s coordinates separately. Think: You would have to do glTraslatef() for each vertex, not mentioning it’s impossible to do anything with matrix between glBegin() and glEnd()

3

It sounds like you might be able to use a shear matrix. A shear matrix that does something like you’re describing might look like this:

1 0 0 0
n 1 0 0
0 0 1 0
0 0 0 1

4

mogumbo,

Thanks, that was exactly what I needed.
Simple too.
Need to pick up a guide on matrices.

greg.