From Retrosoftware

Revision as of 12:57, 5 November 2009

Sparse Invaders Main.txt

This is the main entry point for Invaders. At the top of this file, please note the .merge

commands to load in the other source. Please refer to SWIFT help, however this is a very good

feature, allowing moduled code development and when calling functions you will note the

prefix (file name) before the function name. Allow flexable function names and is more

readable.

   ;-------------------------------------------------------------------------------
   ;  Main  - Invaders ...
   ;  Written by Neil Beresford.
   ;
   ;
   ;  Copyright 2008,2009 Neil Beresford
   ;
   ;    This file is part of Sparse Invaders.
   ;    Sparse Invaders is free software: you can redistribute it and/or modify
   ;    it under the terms of the GNU General Public License as published by
   ;    the Free Software Foundation, either version 3 of the License, or
   ;    (at your option) any later version.
   ;
   ;    Sparse Invaders is distributed in the hope that it will be useful,
   ;    but WITHOUT ANY WARRANTY; without even the implied warranty of
   ;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   ;    GNU General Public License for more details.
   ;
   ;    You should have received a copy of the GNU General Public License
   ;    along with Sparse Invaders.  If not, see <http://www.gnu.org/licenses/>.
   ;
   ;
   ;
   ;-------------------------------------------------------------------------------
   
   .ORG $0900                         ; Good place to start, so it fits ...
   ;.ORG $0900
   
   .require "Constands"               ; BBC and general constants
   .require "Macros"                  ; general macros
   
   .merge   "ScreenFunctionality"     ; screen functionality
   .merge   "SpriteController"        ; Sprite controller and drawer
   ;.merge   "FileLoad"                ; File System loading 
   ;.merge   "Debug"                   ; debug functionality
   .merge   "Timer"                   ; VSync timer
   .merge   "Keyboard"                ; Keyboard handling
   .merge   "Invader_Player"          ; Invader code - player setup
   .merge   "BlockDrawer"             ; Block Drawer ...
   .merge   "Invader_Baddies"         ; Baddies for the invader game
   .merge   "Invader_Bullets"         ; Baddie bullets
   .merge   "Invader_Bases"           ; Bases, logic and drawing...
   .merge   "Invader_Hiscore"         ; Hiscore display...
   .merge   "Sound"                   ; Hiscore display...

Main is the starting point (0x900), this initializes the sound, video, keyboard and timer

etc.

   ;-------------------------------------------------------------------------------
   ;  Main - 
   ;     Main Entry Point
   ;-------------------------------------------------------------------------------
   
   Main:
  
      ; initialization of the system...
      jsr  Sound._INITSOUND
      `MODE 2
      `CURSOROFF
   
   
      jsr  ScreenFunctionality.Screen_Clear   ; clear the screen...
   
   
      jsr  SpriteController.SpriteInit          ; init the sprite system
   
      jsr  BlockDrawer.BlockInit                ; init the block system
      jsr  Keyboard.Keyboard_Init               ; setup the keyboard handling
   
   
      jsr  Timer.Timer_Init                     ; set the user timer off to handle VBlanks our own way...
      jsr  Invader_Hiscore.Invader_Hiscore_Init ; init the hiscore, only done here to allow the score to be kept between games
   
      LDA  #0
      STA  FIREBUTTON_DELAY

main_restart main drops through into 'main_restart'. At this point the game is setup, so

this is a good point to jump to upon game over.

Intro screen is displayed, followed by start level screen - then clears and draws the score,

life, invaders and bases.

   main_restart:
   
      LDA #0   	;fire bullet
      JSR Sound._MAKE_SOUND
     
      jsr  ScreenFunctionality.Screen_Clear  ; Display main message...
      jsr  Invader_Player.Player_GameMessage
      jsr  ScreenFunctionality.Screen_Clear  ; clear the screen...
   
      LDA #0   	;fire bullet
      JSR Sound._MAKE_SOUND
   
      ; main game initialization
      jsr  Invader_Baddies.BaddiesNewGame     ; initializes a new game
      jsr  Invader_Bases.Init
   
      jsr  Invader_Player.PlayerInit          ; initialize the player, 
      jsr  Invader_Baddies.BaddiesInit
          
      jsr  Invader_Player.Player_StartLevel
      jsr  ScreenFunctionality.Screen_Clear   ; clear the screen...
      LDA   #100
      STA   FIREBUTTON_DELAY
   
      ; pre-draw the screen ...
      jsr  ScreenFunctionality.DrawScore      ; draw score and lifes
      jsr  Invader_Baddies.BaddiesDraw        ; draw the invaders
      jsr  Invader_Bases.DrawBases            ; draw the bottom bases
   
      LDA #0   	;fire bullet
      JSR Sound._MAKE_SOUND
      
 

main_loop

   main_loop: 
   
      ;
      ;  Please note the importance of the spritewipe being just
      ;  before the spritedraw and where the vsync timer flag is 
      ;  placed...
      ;
   
   ;;   `BORDERCOLOUR 2
   
      jsr  SpriteController.SpritesDrawActive 
   
   ;;   `BORDERCOLOUR 3
   
      jsr  keyboard.Keyboard_checkkeys
      jsr  keyboard.Keyboard_MovePlayer
      jsr  Invader_Baddies.BaddiesUpdate
      jsr  Invader_Baddies.BaddiesUpdateMother
      jsr  Invader_Player.Player_BulletMove
      jsr  ScreenFunctionality.UpdateScreen
   
      jsr  Invader_Baddies.BaddiesGeneralUpdate
   
   ;;   `BORDERCOLOUR 0
   
      LDA  #0
      STA  TIMER_FLAG
   VB:
      LDA  TIMER_FLAG
      BEQ  VB
      LDA  #0
      STA  TIMER_FLAG
   
   ;;   `BORDERCOLOUR 1
    
      jsr  SpriteController.SpritesWipeActive 
      jsr  Invader_Bullets.Control
   
      jmp  main_loop
      
   end:   
      rts
      
   
   
   ;-------------------------------------------------------------------------------
   ;-------------------------------------------------------------------------------
   ; End of Main
   ;-------------------------------------------------------------------------------