Note: This was written in January 2011 – I just never posted it, but I’d already uploaded the video to YouTube and someone asked for the code, so here it is, in all its fixed-pipeline glory ;)
Update – September 2013: I took these camera controls and wrapped them up into a Camera class in a later post which you can find here: http://r3dux.org/2012/12/a-c-camera-class-for-simple-opengl-fps-controls/. When I did this I wasn’t used to GLM (the OpenGL Mathematics library) so I just rolled my own Vec3 class – you can happily substitute glm::vec3’s if you’d like, and in fact I’d recommend it. Cheers!
I’m working on my OpenGL skills (or lack thereof) at the moment, and wanted to implement some 3D movement controls kinda of like a FPS with clipping off, so I read some chapters of the hallowed OpenGL SuperBible and did some googling, where I came across Swiftless‘ camera tutorials (Part 1, Part 2, Part 3) which gave me a really good start (Thank you, Swiftless!) on how to manipulate the ModelView matrix so we can move around a 3D scene, only it wasn’t quite perfect…
Strange things would happen like you’d look vertically downwards (i.e. directly down the negative Y axis), then you’d push forward – and yeah, you’d move “down”, but you’d also move “forward” at the same time (oh, and I’m putting things like “down” and “forward” in quotes because these concepts are all relative to your viewing orientation – not because I’m trying to be “sarcastic” or anything =P)
Anyways, I had a play with it and sorted it out after spending some time looking at the graphs for trigonometric functions and doing a little bit of off-setting and range-limiting as required. Check it out:
It actually looks quite a lot better running live than in the video due to mis-matched frame-capture rates and the like, but you get the idea =D
Full source code is available after the jump.