The following is Z-Buffering algorithm: ```csharp // zBuffer[x][y] grabs depth at that pixel foreach Object o in scene foreach Pixel p in o float depth = calculate depth at p if zBuffer[p.x][p.y] > depth draw p zBuffer[p.x][p.y] = depth end end end ```

Note that this algorithm is per-pixel based.

- a) In terms of 4 coordination systems and their transformation stages: model -> world -> camera -> projection, in which coordination system should the z-buffer algorithm be applied? Explain your answer. - b) Given a pixel p of an object o, what is your idea to calculate this pixels depth? In which coordination system and/or transformation of 2 coordination systems?