Is this correct? If now can you post what would be?
this is the site I’m getting my formulas from: http://planning.cs.uiuc.edu/node103.html
float yaw = (float) -(Math.tan(m.m10/m.m00));
float pitch = (float) -(Math.tan((-m.m20)/(Math.sqrt(Math.pow(m.m21, 2) + Math.pow(m.m22, 2)))));
float roll = (float) -(Math.tan(m.m21/m.m22));
Hi
Take a look at the source for Java3D or Ardor3d, they will do the maths in there somewhere, for ardor it’s done using quaternions, which can be calculated from a matrix and then converted to euler angles.
HTH
Endolf
Euler angles: Just say no (at runtime). Seriously, they aren’t interesting unless you’re doing some specific types of integration.
Want to improved speed? If not: Do you want to improve your accuracy? If yes to at least one, then:
Math.pow(x,2) -> x*x
Math.sqrt(Math.pow(x,2)) -> Math.abs(x)
If you still decide to use Euler angles, then note that most references will be for right-handed coordinate frames (instead of OpenGL’s left-handed).
Unless you are doing simple rotations with them (land vehicles) you’re best off using quaternions.
I’m no mathematician, see here for some discussion.
Endolf
You forgot the + between the two Pow calls.
Math.sqrt(Math.pow(m.m21, 2) + Math.pow(m.m22, 2))
Also is there a way to use quaternions from a openGL call, or a matrix to move/rotate?
Alright, this is what I got so far, but my camera doesn’t seem to move at all. Even if I put lookAt on (5,50,5) it stays looking foward. This is my code so far:
import org.lwjgl.opengl.GL11;
import org.lwjgl.util.vector.Matrix3f;
import org.lwjgl.util.vector.Vector3f;
public class Camera {
//3d vector to store the camera's position in
Vector3f position = null;
Vector3f lookAt = null;
Vector3f up = null;
//the rotation around the Y axis of the camera
float yaw = 0;
//the rotation around the X axis of the camera
float pitch = 0;
//the rotation around the Z axis of the camera
float roll = 0;
public Camera(float x, float y, float z)
{
//instantiate position Vector3f to the x y z params.
position = new Vector3f(x, y, z);
lookAt = new Vector3f();
up = new Vector3f(0,1,0);
}
public void lookThrough()
{
Matrix3f m = new Matrix3f();
up = new Vector3f(0,1,0);
Vector3f out = new Vector3f();
Vector3f.sub(position, lookAt, out);
out.normalise();
Vector3f.sub(up, (Vector3f) out.scale(Vector3f.dot(out,up)), up);
Vector3f camUp = new Vector3f();
Vector3f.sub(up , (Vector3f) out.scale(Vector3f.dot(out,up)), camUp);
//set forward vector
m.m00 = 0;
m.m01 = 0;
m.m02 = 1;
//set right vector
m.m10 = 1;
m.m11 = 0;
m.m12 = 0;
//set up vector
m.m20 = camUp.x;
m.m21 = camUp.y;
m.m22 = camUp.z;
if(m.m00 != 0)
yaw = (float) Math.atan2((-m.m20),(Math.sqrt(Math.pow(m.m21, 2) + Math.pow(m.m22, 2))));
else
yaw = 0;
pitch = (float) Math.atan2(m.m21,m.m22);
if(m.m22 != 0)
roll = (float) Math.atan2(m.m10,m.m00);
else
roll = 0;
System.out.println("roll: " + roll + " pitch: " + pitch + " yaw: " + yaw);
//roatate the pitch around the X axis
GL11.glRotatef(pitch, 1.0f, 0.0f, 0.0f);
//roatate the yaw around the Y axis
GL11.glRotatef(yaw, 0.0f, 1.0f, 0.0f);
//roatate the yaw around the Y axis
GL11.glRotatef(roll, 0.0f, 0.0f, 1.0f);
//translate to the position vector's location
GL11.glTranslatef(position.x, position.y, position.z);
}
}
And this is my output:
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
roll: 1.5707964 pitch: 2.819842 yaw: 0.0
Yaw should be at something aside of 0, right?
m.m00 = 0;
if(m.m00 != 0)...;else yaw = 0;
do you see?
I’m pretty sure OpenGL is right-handed, they just do some weirdness where the camera looks down the negative z-axis.
You’re correct. It’s Direct X that uses a left handed coordinate frame…shame on me.