Area and span based Z-buffer

An apparatus for generating depth information, comprising:

• a first module for representing depth information by a piecewise function;
• a second module for dividing a primitive object according to the areas defined by the piecewise function upon receiving the primitive object;
• a third module for a performing visibility test in the areas;
• and
• a fourth module for updating the piecewise function based on any results of the visibility test.

A system for performing visible surface determination on 3D images defined by a plurality of primitive objects and associated depth information, comprising:

• a processing device;
• a display device coupled to the processing device for displaying the 3D images;
• a graphics engine coupled to the processing device for performing visible surface determination;
• and
• a storage device for storing results of the visible surface determination,
• wherein regions of the primitive objects and the associated depth information are defined by analytical functions.

A computer readable medium having embodied thereon a program, the program being executable by a machine to perform method steps for performing visible surface determination, the method steps comprising:

• representing depth information of a primitive object by a piecewise function;
• upon receiving the primitive object, dividing the primitive object according to areas defined by the piecewise function;
• performing a visibility test in the areas;
• and
• updating the piecewise function based on the results of the visibility test.

A system for performing visible surface determination on 3D images defined by a plurality of primitive objects and associated depth information, comprising:

• means for representing depth information by a piecewise function;
• upon receiving a primitive object, means for dividing the primitive object according to the areas defined by the piecewise function;
• means for performing a visibility test in the areas;
• and
• means for updating the piecewise function based on the results of the visibility test.