Hi, im pretty new to openGL. Ive just started on a little project on the Nintendo DS, and right now im just trying to create a program that will navigate a 3D environment. I am following the methods of navigation found in Tutorial 10 on the NeHe site. I have no Trouble Strafing the 'camera' forwards and backwards, or rotating it left and right, the problems arise when i try to strafe left and right, it seems to move diagonally, ive tried editing the code for hours, and searched the internet but i cant find whats wrong. Here is my (pseudo)code: //Rotate Left if L is pressed then { y_rotate += 1; } //Rotate Right if R is pressed then { y_rotate += 1; } //Move/Strafe forwards if UP is pressed then { xposition += SIN[y_rotate && LUT_MASK] >> 4; zposition -= COS[y_rotate && LUT_MASK] >> 4; } //Move/Strafe Backwards if DOWN is pressed then { xposition -= SIN[y_rotate && LUT_MASK] >> 4; zposition += COS[y_rotate && LUT_MASK] >> 4; } //Move/Strafe Right if RIGHT is pressed then { xposition -= SIN[(y_rotate-90) && LUT_MASK] >> 4; zposition += COS[(y_rotate-90) && LUT_MASK] >> 4; } //Move/Strafe Right if LEFT is pressed then { xposition -= SIN[(y_rotate+90) && LUT_MASK] >> 4; zposition += COS[(y_rotate+90) && LUT_MASK] >> 4; } //Then in my DrawGLScene glRotatef32i((int)(LUT_SIZE - y_rotate),0,(1<<12),0); glTranslate3f32( (int32)(-xposition/), 0.5f, (int32)(-zposition) ); I use this method as opposed to the method in the NeHe example (multiplying by piOver180) as i keep getting error messages when compiling.

By "this method" do you mean all the shifts you're doing?

I haven't looked into what NeHe suggests but I did the following to get a FPS style camera

Vectors: position, left, forward.
Flots: pitch, yaw.

The camera is created by specifying position, pitch, and yaw. An UpdateVectors function computes the correct left and forward vectors (assuming a right-handed system (which OpenGL is)). With UpdateVectors, you only need to use cos & sin when you change pitch and yaw. UpdateVectors calculates the left and forward vectors like this



Then when it comes time to position the camera you rotate pitch degrees around the x direction, then yaw degrees around the y direction, then you translate to the camera position. Hoepfully this helps. My source for those vector calculations was Wolfram's Mathworld: Spherical Coordinates

Thanks alot for your help, i have figured it out now,

i was adding/subtracting 90 to the rotation value to change the rotation by 90 degrees. I actually needed to add/subtract 128 to rotate by 90 degrees, because my LUT_MASK was 0x1FF.