2D Alpha with 3D Functions

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Jim Brown

Hey, thanks coffee. Did that MaskImage3D function help?

GrBrr,
If you want to try out SpriteControl for your alpha'd clouds do something like this:

; the include file
Include "Sprite Control.bb"

Const sw=640,sh=480 ; display dimensions

; set up the 3d display
Graphics3D sw,sh
SetBuffer BackBuffer()

; create a main camera
cam=CreateCamera()
CameraClsMode cam,False,True ; < do not clear color buffer

; create a sprite pivot and attach to camera
spritecam=CreateSpritePivot(cam)

; load images/sprites
bkg=LoadImage("background.jpg")
cloud=LoadImage3D("cloud.jpg")
EntityAlpha cloud,0.3 ; fade out the cloud

x#=sw*0.9 : y=sh*0.5

Repeat
	x=x-0.7
	TileBlock bkg
	DrawImage3D cloud,x,y
	RenderWorld
	Flip
Until KeyHit(1)
End

If you are using a full-screen sized image for the clouds (i.e 1024x1024) and experience slowdown (due to fillrate problems) you have a few options:

* Change the size of your clouds image to say, 512x512 and use

cloud=LoadImage3D("cloud.jpg")
ResizeImage3D cloud,1024,1024

* Cut your image up and create individual clouds. Then ..

Dim cloud(10)
For c=1 to 10
cloud(c)=LoadImage3D("cloud"+Str$(c)+".jpg")
Next

This second method at least allows you to move your clouds at different speeds.

Oh, and if you want nice and sharp clouds use ClearTextureFilters before loading the sprites.