Converting a colour to do a WritePixelFast

How do you convert a colour, say 255,0,255 to an
integer to use with WritePixelFast ?

okee

RGB = ( RED SHL 16 ) + ( GREEN SHL 8 ) + BLUE, so in your example it would be: RGB = ( 255 shl 16 ) + ( 0 shl 8) + 255

Thanks a lot zawran

No problem. :)

However, if you say make white (using 255,255,255) like this and compare it to a ReadPixelFast call that has read a white pixel, readpixelfast returns -1 which is not the same! But if you subtract -16777216 (the ARGB value for black) they will match. Note that write pixel fast doesn't mind either type of value but Readpixelfast seems to be limited. Anyone want to explain why?

you can or instead of + for a "speed boost" if you are crazy like me :)

; A 32-bit pixel-making function
Function MakePixel(opaque, r%, g%, b%)
	If opaque Then
		Return (255 Shl 24) Or (r Shl 16) Or (g Shl 8) Or b
	Else
		Return (r Shl 16) Or (g Shl 8) Or b
	EndIf
End Function

OR sounds good to me

When using ReadPixelFast() it's best to read it as:

RGB=ReadPixelFast(x,y) And $FFFFFF

Since the alpha channel is not used.

thanks snarty