Project PLASMA FPS 2004: Thread 4

I really felt a detailed explanation of my Database methodology was in order. I have used the concept of Primary ID Keys to devise a flexible Resource Management System that may be useful in other projects.

My Resource Management System relies on Array of Types, ID field in the Blitz Custom type, and a dedicated FILO Stack. Each type stores a unique index number in the ID field. A single element array of types stores a reference to the game object matching the id%. A FILO stack is used to track the ids in use. All types can be linked to another by id%. Thus, if you need to know "What invader shot that defender and witch vampire bit some ghostships? And why is everything moving in slow motion? Oops; where did those 10.000 guided missiles come from?" you can store a id reference to it.

;Example of missile object

Const MISSILE_MAX%=100 ;<-- Predefined maximum number of missiles
Global missileIndex.stack=stackIndexCreate(MISSILE_MAX%) ;<-- Dedicated FILO Stack

Type missile ;<-- missile Game Object Custom Type
	Field id%<-- Primary Key
	Field typeid% <-- Composite Key
	Field shipid%<-- Foreign Key
	Field entityid%
	Field targetid%	
	Field state%
	Field life%
	Field damage%
End Type

Dim missileID.missile(MISSILE_MAX%) ;<-- Array of Types (Reference)

Function missileNew.missile() ;<-- initiallizes a new instance of object aka constructor
	this.missile=New missile
	this\id%=0 ;<-- Default values (optional)
	this\typeid%=0
	this\shipid%=0
	this\entityid%=0
	this\targetid%=0
	this\state%=0
	this\life%=0
	this\damage%=0
	this\id%=StackPop(missileIndex.stack) ;<-- Pops available ID off FILO Stack
	missileId(this\id%)=this ;<-- assign Primary Key to object matching array index/object id
	Return this
End Function

Function missileDelete(this.missile)
	missileId(this\id%)=Null
	StackPush(missileIndex.stack,this\id%)
	Delete this
End Function 

Function missileCreate.missile(typeid%,shipid%,targetid%,state%,life%,damage%)
	this.missile=missileNew()
	this\typeid%=typeid%
	this\shipid%=shipid%
	this\entityid%=stackPop(missileEntity.stack[this\typeid])
	this\targetid%=targetid%
	this\state%=state%
	this\life%=life%
	this\damage%=damage%	
End Function

Function missileDestroy(this.missile)
	stackPush(missileEntity.stack[this\typeid],this\entityid%)
	missileDelete(this)
End Function

Function missileUpdate() ;<-- update function included in primary game loop
	For this.missile = Each missile
		Select this\state%
			Case 1 ;flight movement and collsion
				Select this\typeid% ;<-- 
					Case 1 ;guided 
						missileGuide(this)
					Case 2 ;heatseeker
						missileHeatSeek(this)
					Case 3 ;rocket
						missileMove(this)
				End Select
			Case 2 ;impact
				missileDamage(this)
			Case 3 ;detonated
				missileDestroy(this)
		End Select
	Next
End Function

I've developed the TypeWriter][ Code Wizard for Project PLASMA FPS 2004 to generate common initialization, deletion, update, open, and save functions from a Custom Type based on my object-based programming methodology. The code produced takes into count the Resource Management System, types within types, and type arrays. Ultimately its all about the design of your game objects.