true isometric projection with opengl

Question

Hello,

I am a newbie in OpenGL programming with C++ and not very good at mathematics. Is there a simple way to have isometric projection?

I mean the true isometric projection, not the general orthogonal projection.

(Isometric projection happens only when projections of unit X, Y and Z vectors are equally long and angles between them are exactly 120 degrees.)

Code snippets are highly appreciated..

Thanks in advance..

Answer 1

Maybe I'm not quite grokking the math correctly, but couldn't you just position your camera as it explains in that Wikipedia link and use a standard orthogonal projection?

Even if it's not the same, the projection stack is entirely up to you.

glMatrixMode(GL_PROJECTION);
glLoadIdentity();
// your isometric matrix here (see math on Wikipedia)
glMatrixMode(GL_MODELVIEW);

Answer 2

An isometric projection is just a matter of using an orthographic projection with a specific rotation angle.

You should be able to choose any of the 8 potential orientations, with a orthographic projection, and get a perfect isometric view of your model. Just follow the math in your referenced Wiki article for setting up the view matrix, and do an orthographic projection for your projection matrix, and you're all set.