Two-dimensional graphics are uniquely positioned on the screen
by their X and Y coordinate values, with the display oriented to the screen coordinates. For three-dimensional graphics, the depth information is described by the third coordinate, the Z coordinate. The Z-size determines how deep a point is positioned in space. For example, if the Z-size of point "A" of one object is less than that of point "B" of another object, with XY coordinates of the same size, then point "A" is closer to the viewer than point "B
".Point "A", if the object is not transparent, will cover point "B" so that it is not visible. Z-buffering, an algorithm
used in 3D rendering, thereby ensures that the perspectives of the virtual 3D rendering correspond to reality. Objects that lie behind a larger object are not visible in reality and are therefore not displayed. The Zvalues are stored in the Z buffer and included in the graphics calculation
. The Z buffer is part of the working memory; the Z values stored in it correspond to the corresponding XY coordinates. For each graphic display, the Z coordinates are checked to see whether a point in the scene is in front of or behind another. The size of the Z-buffer depends on the resolution of the depth information.