Quote Originally Posted by chronozphere
P.S: You are right about the fact that flipping an axis changes the rotation order. However, flipping X has some undesirable effects in this case.
Even if I use positive values on the X axis, the text is not rendered.

Hm, I've heard there's a need to map the text coordinates to the screen's coordinates before drawing in 2D mode. So it seems my current matrix calculations lead to no good, since there's a need to, I dunno how to call it, "project" the matrix onto a 2D plane? Maybe that's what should be done, what do you think?

Here's the quote:
if you were using a shader, you could just send vec2 with the screen size, then (vertex.x/(screen.x*0.5))-1 would scale the screen pixel to the correct place.. eg. (300/(600*0.5))-1 = 0 which would be the center of the screen.. in other words, you just need to send the vertex in screen coordinates and apply this scale instead of transforming it with the matrix in the shader.. it should work that way..