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GrabPixmap problem

BlitzMax Forums/BlitzMax Programming/GrabPixmap problem

Twinprogrammer(Posted 2012) [#1]
Hello,

I'm trying to use a pixmap to grabs the pixels of a certain area and draw it somewhere on the window (using DrawPixmap), but there's a problem. When I try to have the camera draw something that's off the screen(at a position of 1000, 20 when a window is 640 x 480) it doesn't draw it. I figured out that it's because the images are off screen, so it isn't drawn, is there a function to tell blitz max to draw images even if they're off screen ?

Last edited 2012


GfK(Posted 2012) [#2]
No, if you want to use grabpixmap then the parameters must be within the confines of the screen.


Twinprogrammer(Posted 2012) [#3]
Darn. Could I maybe change the viewport ?


matibee(Posted 2012) [#4]
You can change the draw origin, grab multiple images and copy them into one big pixmap. This is the [UNTESTED AND APPROXIMATE] code for grabbing 4x 640x480 pixmaps and combining them into one 1280,960 pixmap..

cls
SetOrigin 0,0
DrawScene()
pixmap0:TPixmap = GrabPixmap()
cls 
SetOrigin 640,0
DrawScene()
pixmap1:TPixmap = GrabPixmap()
cls
SetOrigin 0,480
DrawScene()
pixmap2:TPixmap = GrabPixmap()
cls
SetOrigin 640,480
DrawScene()
pixmap3:TPixmap = GrabPixmap()

bigPixmap:TPixmap = CreatePixmap( 1280, 960 )
for local x:int = 0 to 639
  for local y:Int = 0 to 479
    writepixel( bigPixmap, x, y, readpixel( pixmap0, x, y ) )
    writepixel( bigPixmap, x + 640, y, readpixel( pixmap1, x, y ) )
    writepixel( bigPixmap, x, y + 480, readpixel( pixmap2, x, y ) )
    writepixel( bigPixmap, x + 640, y + 480, readpixel( pixmap3, x, y ) )
  next 
next 
savepixmap( bigpixmap )



GfK(Posted 2012) [#5]
Any reason you wouldn't just use pixmap.paste()?


matibee(Posted 2012) [#6]
Any reason you wouldn't just use pixmap.paste()?


Yup. Sadly only API ignorance :D


Twinprogrammer(Posted 2012) [#7]
How do I use Pixmap.paste() ?
EDIT: And how would that fix my camera problem?

Last edited 2012


matibee(Posted 2012) [#8]
See what you've done Gfk :)

Pixmap.paste would only replace the for/next pixel copying loops at the end of my example code. I'm guessing there are no special optimisations in the pixmap paste routine and it's simply doing the same for/next loops internally. The rest of the code which draws the scene multiple times at different origins and stores the results, is very likely to be the solution to your "camera problem".

That is, if you really have a camera problem-- you have a great track record of asking for solutions to problems that don't exist.

Re-reading your initial post I'm guessing you want to draw some kind of windowed view into your tiled world. In which case the problem is nothing to with grabpixmap.


Twinprogrammer(Posted 2012) [#9]
Okay, thanks for the help guys !