Object System

Object System. More...

Modules


Detailed Description

Object System.

Objects in HEL are movable sprites. Up to 128 objects of any size, up to 64x64 pixels, can be displayed.

Special care has been spent on performance during development. The Object-System provides functions to create, delete and manipulate objects. Object attributes as well as graphic update calls are shadowed internally to avoid screen tearing. Changes should be transmitted to hardware during vertical blank only.

Object-System Implementation details

The Object-System in HEL is implemented as a doubled linked list. Each item of the linked-list holds a handle to the previous and next item, which is basically the object. If you want to traverse the linked-list, you can do this with hel_ObjGetFirst, hel_ObjGetNext, hel_ObjGetPrev and hel_ObjGetLast. If one of these functions return HANDLE_INVALID, it indicates there is no further item. For example, if you call hel_ObjGetNext and it returns HANDLE_INVALID you just reached the end of the list. To check the result, I recommend to use the HANDLE_ISVALID macro.

Attention:
You must not mix calls to object functions from HAM and HEL. Use only one Object-System, either from HAM or HEL, otherwise the program behavior is undefined.

Generated on Fri Aug 17 12:12:38 2007 for HEL Library by  doxygen 1.5.3