pseudo-isometric projection matrix

My maths is awful.
I last did matrices when I was 15 at secondary school.
I didn’t even pay very much attention.
I now regret this.

Who might be able to give me a ready made projection matrix which will give me that pseudo-isometric view we all know and love from the days of the Spectrum?

The matrix should work given a particular width and height of screen.

Origin at 0,0 should be in the middle of the screen. X coordinate goes right and down half as much; Y coordinate goes right, and up half as much. Z coordinate is simply added to Y coordinate.

If I could just remember how to multiply matrices I might be able to figure this out for myself…



well, you could just try using an orthogonal projection matrix and an appropriate modelview transform to rotate the scene at 45 degrees around the y axis and some degrees around the z axis. That’d work, I reckon