hi dudes,

i am fairly new to OpenGL, so this might seem as a stupid question to you.

In one class i am supposed to explain the principals of matrix stacks and matrix post multiplication.

1.) Principals of Matrix stacks.

Well, i know about the glPushMatrix() and glPopMatrix(). These are used to store the transformation matrices, object positions and viewing transformations etc.

all good - i understand this part as how the code works. Unfortunately i dont understand why does OpenGL need these? To save and throw away transformations? or these stacks? Whats the deal? Also, are these stacks saved in the RAM, or the CPU/GPU?

2.) I have to explain Matrix post-multiplication. I've tried googling this, but i got more confused. Pre- and post-matrix multiplication just means multiplying a matrix on one side or the other of another vector or matrix - but how is this done in the code? I am a bit confused here.

Help is greatly appreciated!