I’ve acquired a hard and fast projection perspective digicam with a vertical FOV of 70 deg and rotated 45deg on Y axis.

Player motion is alongside Camera’s X axis (proper/left), Z axis (entrance/again), Y axis is about to 0.

What I’d like to realize is for the participant to maneuver instantly in the direction of the display screen high/backside when urgent ahead/again keys as an alternative of shifting alongside digicam’s Z axis which causes and phantasm of touring at an angle the farther from the middle of the display screen you might be (which is sensible however shouldn’t be desired on this case).

The screenshot beneath depicts:

• Green: Direction to digicam
• Blue: Camera’s Z axis (participant motion
  ahead/again)
• Red: Desired ahead/again motion vector

I used to be capable of brute-force some values like if digicam’s Z axis are at 45deg to the player-camera course then the specified rotation could be half of that (22.5deg) however I can not seem to discover a resolution for the remainder of the world positions on account of my lack of Math data.