## [Mesa3d-users] Compound rotations

 [Mesa3d-users] Compound rotations From: Adam Majer - 2001-09-06 03:21:30 ```Hi all, I would like to perform compound rotations using three angles - Xi, Theta and Mu. Xi - initial rotation in x-y plane Theta - angle b/w the z axis and the x-y plane Mu - and of rotation (ccw) around the "new" z axis - ie. the resulting normal to the screen after performing the above two rotations... Now this is all nice and easy... But now I need to perform the same rotations in the already rotated frame of reference... And I also need to keep track of Xi Theta and Mu - the angles that will allow me to get to the "second" and "third" etc... from Identity matrix... Does anyone know of an easy way of doing this? Or at least the steps of doing this? I have tried to calculate the rotations but it becomes very messy after about 3pp of scrap... This becomes quite complicated analyticly when you take into account the Mu angle... But there must be a fast solution as even Wing Commander has it. Thanks in advance, Adam PS. I figured out the glFrustum function :) Thanks for your help. I only had to read the specification more carefully... ```

 [Mesa3d-users] Compound rotations From: Adam Majer - 2001-09-06 03:21:30 ```Hi all, I would like to perform compound rotations using three angles - Xi, Theta and Mu. Xi - initial rotation in x-y plane Theta - angle b/w the z axis and the x-y plane Mu - and of rotation (ccw) around the "new" z axis - ie. the resulting normal to the screen after performing the above two rotations... Now this is all nice and easy... But now I need to perform the same rotations in the already rotated frame of reference... And I also need to keep track of Xi Theta and Mu - the angles that will allow me to get to the "second" and "third" etc... from Identity matrix... Does anyone know of an easy way of doing this? Or at least the steps of doing this? I have tried to calculate the rotations but it becomes very messy after about 3pp of scrap... This becomes quite complicated analyticly when you take into account the Mu angle... But there must be a fast solution as even Wing Commander has it. Thanks in advance, Adam PS. I figured out the glFrustum function :) Thanks for your help. I only had to read the specification more carefully... ```