Lexicon


  • Boot Loader - A series of machine language instructions which enables an Apple II computer to boot and run a program without first loading DOS. Typically this involves customizing boot 1.

  • Boot 0 -machine language instructions stored in the ROM of Apple II computers. When the power is turned on to the computer, the computer automatically executes the instructions in boot 0. The boot 0 instructions load the contents of track 0, sector 1 from the 5.25" floppy disk in the drive.
     
  • Boot 1 -machine language instructions stored on track 0, sector 0 of a 5.25" floppy disk. The boot 1 instructions normally initiate loading DOS into memory from the floppy disk. 


  • Map Object-A moveable tile graphic which is stacked on top of terrain tiles. Map objects typically represent things which logically have the ability to move or be moved, such as furniture and people. However, movement of specific map objects can be restricted.

  • Mob - An enemy in the game represented by a tile on the view screen, which tends to move toward and attack the player. 


  • NPC - Non-player character. For example, merchants, guards, townsfolk. 


  • Player Icon Buffer - Usually graphics system loads graphics data based on a tile ID. For example, if a tile in a given location on the screen has a tile ID of $34 then grass is drawn in that tile. The player icon also has a tile ID associated with it. However, the player icon's tile ID is used to load the graphics data into the player icon buffer. The graphics system uses the graphics data in the player icon buffer to draw the player icon on the view screen. Having this buffer in between the Tile ID and the actual draw to the screen is used to create special effects which temporarily alter the player icon.  

  • RWTS -This acronym stands for Read-Write-Track-Sector. It is the name of a low-level subroutine in DOS 3.3. which is used to read and write tracks and sectors from/to floppy disk. Higher level DOS 3.3 subroutines like File Manager make calls to RWTS to perform their functions. Assembly language programs can call RWTS directly for increased speed, flexibility and efficiency.     

  • Screen Scrolling A graphics engine process to facilitate movement on the game map which involves copying the values in the memory addresses that control which monitor pixels are turned on. This process is much faster than drawing each tile graphic from scratch, as is done to generate the first graphics screen the player sees after game launch.  

  • Sentient Entity (S_ENTITY)-A map object which represents something that is alive or otherwise sentient. For example, MOBs and Non-Player Characters.

  • Surf- The water tiles typically adjacent to land, containing small white lines symbolizing cresting waves. 


  • Tile - A unique graphics shape displayed on the view screen, which is 14 pixels wide x 16 pixels deep. In assembly terms: 2 screen bytes wide x 16 lines deep. 



  • Tile ID - All tile graphics shapes (i.e. water, grass, mountains, etc). have a unique ID number. For example, grass tiles are currently assigned the hexadecimal number $34. Mountains are assigned $00. Tile IDs are used to tell the graphics engine which shapes to drawn on the view screen.








No comments:

Post a Comment