Creating an event at an increasing rate.

BlitzMax Forums/BlitzMax Beginners Area/Creating an event at an increasing rate.

Ryan Burnside

(Posted 2009) [#1]

I've been coding late yesterday and my mind is kind of shot. I'm working on a game at which enemies keep entering the room faster and faster. The first enemy should be created 2.75 seconds and this should get faster and faster until enemies are being created .75 seconds apart. I would like to spread this over a time period of 5 minutes so that when 5 minutes is reached enemies are spawning .75 seconds apart. This is a traditional style game where the difficulty is based on speed and number of enemies increasing...

Somehow this is really hard to figure out how to handle. I'm going to take a quick nap I think...

Czar Flavius

(Posted 2009) [#2]

Have a variable called max_time and time. Each game frame, subtract the number of milliseconds since the last game frame from time. When it reaches 0 or lower, spawn an enemy, make time equal max_time and decrease max_time by an amount. Then check that max_time is at least 0.75 seconds.

Ryan Burnside

(Posted 2009) [#3]

How do I work that subtraction so that after 5 minutes the spawn rate is at the fastest speed?

Czar Flavius

(Posted 2009) [#4]

const fastest = 750
...

'after update
if max_time < fastest then max_time = fastest

Gabriel

(Posted 2009) [#5]


Type Enemy
	
	Function Create()
		Print "Created an enemy"
	End Function
	
	Const StartRate:Float=2.75
	Const EndRate:Float=0.75
	Const LengthOfCycle:Float=300 ' KEEP EVERYTHING IN SECONDS FOR EASE OF READING
	
	Global CurrentRate:Float=StartRate
	Global MaxRateReached:Int=False
	
	Global TotalTime:Float=0.0
	Global TimeSinceLastCreated:Float=0.0
	
	Function Update(DT:Float)
		TotalTime:+DT
		TimeSinceLastCreated:+DT
		If TimeSinceLastCreated>=CurrentRate
			Create()
			TimeSinceLastCreated=0
			If MaxRateReached=False
				Local Mult:Float=TotalTime/LengthOfCycle
				If Mult>1.0
					Mult=1.0
					MaxRateReached=True
				End If
				CurrentRate=StartRate-((StartRate-EndRate)*Mult)
			End If
		End If
	End Function
	
End Type


Repeat
	Global LastTime:Int=MilliSecs()
	Global ThisTime:Int
	Delay(5)
	ThisTime=MilliSecs()
	Local DT:Float=ThisTime-LastTime
	LastTime=ThisTime
	Enemy.Update(DT*0.001)
Until KeyHit(KEY_ESCAPE)

Ryan Burnside

(Posted 2009) [#6]

Ah ok then, thanks guys! :)