Assume this very basic diagram represents one of the 3d levels in a game like the original Wolfenstein from a top-down view. The x's and y's represent the walls and the numbers represent where the player is standing.

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
y                2                   x
y           x                        x
y           x                        x
y           x                        x
y    3      x                        x
y           x                        x
y           x                        x
y           x  1                     x
yyyyyyyyyyyyxxxxxxxxxxxxxxxxxxxxxxxxxx

If the player is standing at position 1, there isn't any reason to draw any of the y walls. At position 3, many of the x walls do not need to be drawn. At position 2, most of the walls would need to be drawn. Of course, it changes depending on which direction the player is facing. Using Direct3d, how do you determine which walls (or trees, objects, etc.) within a level are within the players line of sight? Would you draw all of the x's and y's and let Direct3d determine which ones are visible based on the z-buffer? Seems inefficient. [edited by - creed1 on November 11, 2003 11:52:45 AM]