Pixmap to Image?

BlitzMax Forums/BlitzMax Beginners Area/Pixmap to Image?

Shagwana

(Posted 2004) [#1]

Whats the best way to copy a pixmap to an image including the alpha channel?.

Shagwana

(Posted 2004) [#2]

Well well, wiebo the wit on irc just says the magic words

"Look at LoadAnimImage, it can load from a pixmap", lo and behold, hes correct!. Looks like the same for just plain old LoadImage too!

Talk about RTFM! (read the f**king manual)

ImaginaryHuman

(Posted 2004) [#3]

I did something like this:

img:TPixmap=LoadPixmap("incbin::ball.png") 'load the pixmap from the inbin'd image file
wid=img.width 'get width of pixmap
hig=img.height 'get height of pixmap
If img.format<>PF_RGBA8888 Then img=ConvertPixmap( img,PF_RGBA8888 ) 'Make sure image format is in the format needed for OpenGL to render it properly
Local psource:Byte Ptr 'define pointer for source pixmap data location
psource=PixmapPixelPtr(img,0,0) 'get source pixmap data location
Global psize:Int=wid*hig*4 '4 bytes per pixel assuming RGBA8888 format pixmap
txtri:TImage=CreateImage(wid,hig,1,iflags|DYNAMICIMAGE) 'create dummy image in case we want to do realtime conversion between pixmaps and images/textures
txtrp:TPixmap=LockImage(txtri,0,False,True) 'Lock our dummy image so we can draw to it
pdest=PixmapPixelPtr(txtrp,0,0) 'Set our destination pointer to the image's pixmap
MemCopy(pdest,psource,psize) 'Copy the pixels from the pixmap in memory to the image/texture's pixmap
UnlockImage(txtri) 'Let the image be rendered now

DrawImage txtri,objpos[o,0],objpos[o,1] 'Render the image/texture

ImaginaryHuman

(Posted 2004) [#4]

There are also some OpenGL functions that you can use to write pixels, read pixels, convert pixel formats, and create textures (images) out of pixmaps. These are what BlitzMax's higher-level commands are based on. But then you would need to know how to set up the rest of the OpenGL environment, draw vertices and bind textures etc.