Le 2 févr. 2017 à 21:31, Bert Freudenberg bert@freudenbergs.de a écrit :
I was thinking about if it's safe to ignore endianness in this VM primitive. And I think it's safe in 32 bpp, but not in lower bit depths.
#(1 -1 16 -16 32 -32) collect: [:d | ((Form extent: 1@1 depth: d) colorAt: 0@0 put: Color red; bits) first hex]
==> #('16r80000000' '16r1' '16r7C000000' '16r7C00' '16rFFFF0000' '16rFFFF0000’)
#('16r80000000' '16r1' '16r7C000000' '16r7C00' '16rFFFF0000' '16rFFFF0000’)
same result in Pharo
So from the image's perspective, there is no difference for little endian / big endian forms in the raw bitmap values in 32 bpp.
And to the VM it looks the same. It just needs to know that on a little endian architecture it's BGRA while on big endian it's ARGB. Neither helps SqueakJS, because Javascript's Canvas.putImageData() uses RGBA. May be I should add a WebGL rendering path ... the swizzling would be easy in a fragment shader.
- Bert -