Best method to work with pixels
BlitzMax Forums/BlitzMax Programming/Best method to work with pixels
| ||
| Hi, I want to move my Blitz+ code over to BMax, most of it works on images at pixel level, reading, altering and writing pixels. What is the best method in Max, I see there is DX and OpenGL Max2D also pixmaps seem to be the way. Any help would be great just started play with Max and still quite lost. |
| ||
| You have to use TPixmap (if you didn't know that already). I used to do lots of pixel level but found I didn't need to hardly at all with Bmax as I just started using setscale, setcolour, setblend, setrotation etc instead. |
| ||
| For pixel level access use... loadimage lockimage readpixel/writepixel Unlockimage (not needed but in case it does something in the future). drawimage |
| ||
I found that the quickest way to work with pixels is to use PixmapPixelPtr and set the pixmap format to one that is easy to work with. this will give you the memory location of a pixel. so thatpixmap:tpixmap = createpixmap(100,100,PF_BGRA8888) p:byte ptr = pixmappixelptr(pixmap,0,0) ' get RGB b:int = p[0] g:int = p[1] r:int = p[2] ' set to orange p[0] = 0 p[1] = 128 p[2] = 255 edit - got RGB the right way round now |
| ||
| Thanks, thats a great start. |
| ||
| Hi, I have been playing with pixmappixelptr and it is fast but when getting the pixmap from loading different types of images the pixel format changes depending on the image file, making the RGB colors change, I have tried to use ConvertPixmap(pixmap,PF_BGRA8888) but it seems to make no difference? any clues? Thanks. |
| ||
| are you shure you are using convertpixmap correctly? the correct way is: newpixmap:tpixmap = convertpixmap(pixmap,PF_BGRA8888) the new image is stored in newpixmap, pixmap will still have the original loaded image/pixmap. |
| ||
| Thanks, I was not doing that. I`ll give it a try. |
   |