[Pkg-pascal-devel] Bug#820708: CGE and view3dscene tested with libpng 1.6

[Michalis Kamburelis]

Hi,

Quick test showed that Castle Game Engine and view3dscene work OK with
libpng 1.6. Various testing images (with colors encoded in different
ways), as well as deliberately wrong images, are handled correctly.

Tested with libpng16-16 in current Debian testing (1.6.21-2).

The necessary change in CGE is just a 2-line addition of

  if PngLibrary = nil then
    PngLibrary := TDynLib.Load('libpng16.so.16', false);

to src/images/castlepng_dynamic.inc . Nothing else is needed. I
committed this upstream (taking also the occasion to improve comments
and search order there) in
https://github.com/castle-engine/castle-engine/commit/3abd42911bd85bf3782d0fac16439d0ab301d11a
.

For testing, you can simply comment out loading other libpng versions,
to make sure that only libpng 1.6 is picked up. (In engine version
from GitHub, you would also undefine CASTLE_PNG_USING_FCL_IMAGE in
src/base/castleconf.inc, to avoid using the native Pascal version.)

Regards,
Michalis