Illustration 1: How does the z-buffer algorithm find out which surfaces are hidden?
Solution: Depth or Z-buffer algorithm employs a two buffer area each of two-dimensional array, one z-buffer that stores the depth value at every pixel position (x,y), the other frame- buffer that stores the intensity values of the visible surface. From setting initial values of the z-buffer to several large number that frequently the distance of back clipping plane, the matter of determining such surfaces are closer is decreased to simply comparing the present depth values saved in the z-buffer at pixel (x,y) with the newly computed depth value at pixel (x,y). If this new value is less than represent depth-buffer value, this value replaces the value saved in the z-buffer and the pixel color value is altered to the color of the new surface.