How To create a Timage in realtime

BlitzMax Forums/BlitzMax Beginners Area/How To create a Timage in realtime

christian223

(Posted 2008) [#1]

I mean, i dont want to load a pitmap and then make it a timage from it, i want to create an white oval for example, and make a timage from that oval so i can manipulate it in many ways.

What is faster? to drawoval each frame or to make a timage from the oval drawn?.

Thanks.

Sledge

(Posted 2008) [#2]

Look at the CreateImage() and GrabImage() commands. I'd expect blitting an image to be faster than drawing a geometric shape but there's only one way to find out for sure ;)

christian223

(Posted 2008) [#3]

Let me see if i get it right:

Createimage makes an empty timage with its width and height.

Grabimage copyies a piece of the backbuffer using a timage width and height at a certain x and y coords and pastes it into a timage. Something like a cookie cutter?.

So, if i want a white masked circle i would need to draw it before any image is drawn on the backbuffer, and use the cls color matching the mask color, right?.

Thanks again.

InvisibleKid

(Posted 2008) [#4]

is this something like what your after?

Strict
 Graphics 800, 600
 
 Global tempPic:TImage
 
 Global background:TImage = LoadImage("bg.png") 
 Global forground:TImage = LoadImage("fg.png") 
 Global mask:TImage = LoadImage("mask.png") 
  
 GetImage() 
 
 Repeat
 	Cls
	TileImage background, 0, 0
	DrawImage tempPic, MouseX(), MouseY() 
	Flip
 Until KeyDown(KEY_ESCAPE) 
 
 
 
 Function GetImage() 
 	SetMaskColor 255, 255, 255
 	Cls
	DrawImage forground, 0, 0
	DrawImage mask, 0, 0
	tempPic = CreateImage(256, 256) 
	GrabImage tempPic, 0, 0
 End Function

images used:

bg.png
http://www.mediafire.com/?jvdy4gwjdtm

fg.png
http://www.mediafire.com/?fjrlvjjrwcb

mask.png
http://www.mediafire.com/?mmzylhxkdb1

EDIT:
after rereading the thread instead of just skimming over it, it doesn't look like this is exactly what you need. but i hope still helps somewhat.

Sledge

(Posted 2008) [#5]

That's pretty much it, except the mask defaults to black so, using MASKBLEND to draw the image, you'll get a masked oval regardless of the background colour.

OOP-fied example:

SuperStrict
SeedRnd(MilliSecs())

Const GWIDTH:Int = 800
Const GHEIGHT:Int = 600
Const OVAL_SIZE:Int = 32
Const NUMBER_OF_PARALLAX_FIELDS:Byte = 4

Graphics GWIDTH,GHEIGHT
OvalField.Init(NUMBER_OF_PARALLAX_FIELDS)
SetClsColor 100,200,200

While Not KeyHit(KEY_ESCAPE)
	Cls
	OvalField.Update()
	Flip True
Wend

Type OvalField
	Global OvalPic:TImage = CreateImage(OVAL_SIZE,OVAL_SIZE)
	Global OvalList:TList = CreateList()

	Function Init(Fields_arg:Byte)
		SetBlend SOLIDBLEND
		Cls
		DrawOval 0,0,OVAL_SIZE,OVAL_SIZE
		GrabImage OvalPic,0,0
		
		For Local Scanline:Int = 0 To (GHEIGHT - 1)
			Local NewOval:Oval = New Oval
			NewOval.YPos = Scanline
			NewOval.XPos = Rand(0,GWIDTH-1)
			NewOval.Speed = Rand(1,Fields_arg)
			NewOval.Shade = ( (200/Fields_arg)*NewOval.Speed ) + 55
			NewOval.Scale = (1.0 / 255)*NewOval.Shade
			ListAddLast OvalList,NewOval
		Next
		SortList(OvalList, True, CompareSpeed)		
	End Function
	
	Function Update()
		SetBlend MASKBLEND
		For Local CurrentOval:Oval = EachIn OvalList
			CurrentOval.XPos = CurrentOval.XPos - CurrentOval.Speed
			If CurrentOval.XPos < -OVAL_SIZE Then CurrentOval.XPos:+GWIDTH+OVAL_SIZE	
			CurrentOval.Draw()
		Next
	End Function

	Function CompareSpeed:Int(ObjectA_arg:Object, ObjectB_arg:Object)
		If Oval(ObjectA_arg).Speed > Oval(ObjectB_arg).Speed
			Return True
		Else
			Return False
		EndIf		
	End Function
End Type

Type Oval
	Field XPos:Int
	Field YPos:Int
	Field Shade:Byte
	Field Speed:Byte
	Field Scale:Float
	
	Method Draw()
		SetColor Self.Shade,Self.Shade,Self.Shade
		SetScale Self.Scale,Self.Scale
		DrawImage OvalField.OvalPic, Self.XPos, Self.YPos 
	End Method
End Type

christian223

(Posted 2008) [#6]

Thanks both, very usefull code, now i get it, thanks again.