Question

I am using glLookAt to control my camera view.

I use the following code to rotate around.

SPEED_TURN is a Const of 0.16 (speed we turn at)

GLfloat v[] = {[self centerAtIndex:0] - [self eyeAtIndex:0],
    [self centerAtIndex:1] - [self eyeAtIndex:1], 
[self centerAtIndex:2] - [self eyeAtIndex:2]}; 

[self setCenter:[self eyeAtIndex:0] + cos(SPEED_TURN / 2)*v[0] - sin(SPEED_TURN / 2)*v[2] atIndex:0];
[self setCenter:[self eyeAtIndex:2] + sin(SPEED_TURN / 2)*v[0] + cos(SPEED_TURN / 2)*v[2] atIndex:2]; 

My question is, how to I get the angle of the camera in degrees?

I tried this

rotAngleDegs = (cos(-SPEED_TURN)*v[0] - sin(-SPEED_TURN)*v[2]) * 180 / PI

However that give numbers from -620 to +620

Answer 1

I don’t think you are trying the right functions to give you the angle. The functions “cos()” and “sin()” both take your angle and map it to [-1,1]. If SPEED_TURN is the angle in radians, then you would just use:

float angleInDegrees = (SPEED_TURN * 180) / M_PI;