8 replies to this topic

[rogerdv]

I want to move the camera following a circle around a point. Im using gluLookAt, so I know that I only have to change the first vector (the position of the camera) and leave the target unmodified. Can somebody suggest me an idea?

[davepermen]

using sine and cosine (wich take radians.. not degrees :D) to calculate your position..


and yes, leave your target unchanged, of course.. :D

[rogerdv]

But how do I convert that to opengl coordinates (x,y,z)? Sorry, Im bad with maths.

[davepermen]

hm..

xdistfrommidpoint = radius * sinf(rotation);
ydistfrommidpoint = 0;
zdistfrommidpoint = radius * cosf(rotation);

cameraxpos = xdistfrommidpoint + midpointx;
cameraypos = ydistfrommidpoint + midpointy;
camerazpos = zdistfrommidpoint + midpointz;

and voilà, you have your camerapos, and your target (midpoint)..

hope that inspires you..

oh, and math is the most important thing in graphics, quick! catch up! vector math all the way! its not much actually..

[rogerdv]

Thanks a lot! Ill try that tomorrow. Maybe some kicks in the head in the training session now clear my mind.

[Jesse M]

Our graphic-programmer forebears would laugh. The advent of the device-independant graphics API has stolen away our knowledge of simple 3D math. :lol:

I remember the day I was squeezing every processor tick out of my 3D routines. All for not I guess...

[davepermen]

jesse, i like your sign


and yeah.. todays apis allow you to "forget about 3d".. but just to render some cubes or so.. at the first point after THAT, you'll learn that you need to understand math anyways..

and once you do, the world is so much simpler...

[anubis]

luckily programable gpus reintroduce math to 3d programming...

[davepermen]

partially, yes:D