This is a version of 3D Tetris written in C++ and OpenGL that I wrote for my computer graphics class in college in 2008.
I took an introduction to computer graphics class in the Fall of 2008. In this class, everyone had to make a final project to show off to the class. I chose to make a 3D version of my favorite puzzle game: Tetris!
Choose one block of your tetris piece to be the center of the piece.
Create a temporary tetris piece that moves the center piece to the origin of the plane you are rotating on. For example, if you are rotating on the Z axis then you will want the center to be at 0,0 on the x-y plane.
Rotate the piece along the plane. So in the case of the x-y plane, then each blocks (x,y) becomes (y,-x) if rotating CW or (-y,x) if rotating CCW.
Now translate each block back from the origin to where it was before (i.e. if your center was originally at (0,2,19) then you originally translated each block -2 on the y axis to the origin (0,0,19). Now translate each piece back 2 on the y axis such that the center is again at (0,2,19)).
Your rotation is done! Repeat the process for each axis that you need to rotate along.
