So, to find out an angle from the camera, going through the mouse position, I would be able to use this. For example, if the mouse was at the center of the screen, the projected angle would be the same as the camera angle, but if the mouse was at the top of the screen, the projected angle would be slightly steeper than the camera angle.
To find the projected angle (vertically), I think I would do the following:
angle=(70/screen height())*mousey()
70 is the camera fov (69.9621 is about 70). This would need some extra adjustment using the actual camera angle, but I think this is about right.
The only problem was, I tried this, and all it gave was 0. I am pretty sure I am right, or I could be being very stupid, so can someone please check this?
Thanks, David
Spec - Abit NF7-S nForce 2, AMD Athlon 2100+, 256Mb PC2700, ATI Radeon 9000Pro, 20Gb Seagate U6, DVD-ROM, Zip 100, 15" TFT monitor