scaling images realtime???

Blitz3D Forums/Blitz3D Beginners Area/scaling images realtime???

Nate the Great (Posted 2008) [#1]

I have seen other posts that mention that blitz3d has a way of scaling images (not using scaleimage, resizeimage, or any dlls) in real time??? Is this true? If so I have been missing out on a lot...

Ross C (Posted 2008) [#2]

There was a lib that did this, using 2d commands, but it replaced the 2d command set. The only other way is to use a 2d in 3d lib, like nSprite 2 or sprite candy.

Ross C (Posted 2008) [#3]

You could also try the fast image lib, detailed in the blitz3d user lib part of the forum.

Mortiis (Posted 2008) [#4]

You can always use sprites in 3D like sprite candy does.

Nate the Great (Posted 2008) [#5]

okay thanks for clearing that up. :)

Kryzon (Posted 2008) [#6]

Well not really in real-time, but there is always a fast scaling routine. Just that nobody would use it anymore since you can get cycle speed using the 3D Hardware.

Ross C (Posted 2008) [#7]

Sorry, i agree. I though that said rotate for some reason... Anyway, copyrect can produce a decent sclaing, and pretty fast too!

Nate the Great (Posted 2008) [#8]

how do you scale with copyrect I could never figure that out?

big10p (Posted 2008) [#9]

You can scale with copyrect? o_O

QuickSilva (Posted 2008) [#10]

I`d be interested in knowing how this is done too. Jason.

Nate the Great (Posted 2008) [#11]

okay Ross C Out with the secret! there seem to be a lot of people besides me who didn't know you could do this. :) I also couldn't find it in the code archives :(

Nate the Great (Posted 2008) [#12]

found the code for copyrect scaling ; ------------------------------------------------------------------------------------------------------------------------------------- ; This function scales an image an arbitrary amount on the X and Y axis, and returns a pointer to the new image. ; The original image is not modified. ; ; The scale can either be a relative width and height, ie, 0.5 of the width of the original image, or it can be an exact size in pixels. ; If an exact size is desired, set ExactSize to true. ; ; This function is 80x faster than the ScaleImage function that comes with Blitz! ; ------------------------------------------------------------------------------------------------------------------------------------- Function ScaleImageFast(SrcImage, ScaleX#, ScaleY#, ExactSize=False) Local SrcWidth, SrcHeight Local DestWidth, DestHeight Local ScratchImage, DestImage Local SrcBuffer, ScratchBuffer, DestBuffer Local X1, Y1, X2, Y2 ; Get the width and height of the source image. SrcWidth = ImageWidth(SrcImage) SrcHeight = ImageHeight(SrcImage) ; Calculate the width and height of the dest image, or the scale. If ExactSize = False DestWidth = Floor(SrcWidth * ScaleX#) DestHeight = Floor(SrcHeight * ScaleY#) Else DestWidth = ScaleX# DestHeight = ScaleY# ScaleX# = Float(DestWidth) / Float(SrcWidth) ScaleY# = Float(DestHeight) / Float(SrcHeight) EndIf ; If the image does not need to be scaled, just copy the image and exit the function. If (SrcWidth = DestWidth) And (SrcHeight = DestHeight) Then Return CopyImage(SrcImage) ; Create a scratch image that is as tall as the source image, and as wide as the destination image. ScratchImage = CreateImage(DestWidth, SrcHeight, 1, 1) ; Create the destination image. DestImage = CreateImage(DestWidth, DestHeight, 1, 1) ; Get pointers to the image buffers. SrcBuffer = ImageBuffer(SrcImage) ScratchBuffer = ImageBuffer(ScratchImage) DestBuffer = ImageBuffer(DestImage) ; Duplicate columns from source image to scratch image. For X2 = 0 To DestWidth-1 X1 = Floor(X2 / ScaleX#) CopyRect X1, 0, 1, SrcHeight, X2, 0, SrcBuffer, ScratchBuffer Next ; Duplicate rows from scratch image to destination image. For Y2 = 0 To DestHeight-1 Y1 = Floor(Y2 / ScaleY#) CopyRect 0, Y1, DestWidth, 1, 0, Y2, ScratchBuffer, DestBuffer Next ; Free the scratch image. FreeImage ScratchImage ; Return the new image. Return DestImage End Function :)

QuickSilva (Posted 2008) [#13]

Cool, thanks. That`s a great tip to know for the future. Jason.

Ross C (Posted 2008) [#14]

That's the one! It works by copying a line of pixels, into two lines of pixels. Then it copys in the other direction, downwards. I'm sure that's how it works :o)