[Commits] [wesnoth/wesnoth] 31b068: disable "alpha thresholding" in our bilinear inter...

[GitHub]

  Branch: refs/heads/1.12
  Home:   https://github.com/wesnoth/wesnoth
  Commit: 31b068ba3f43973e23a004af07bd7b64e5ed3108
      https://github.com/wesnoth/wesnoth/commit/31b068ba3f43973e23a004af07bd7b64e5ed3108
  Author: Chris Beck <render787 at gmail.com>
  Date:   2014-09-17 (Wed, 17 Sep 2014)

  Changed paths:
    M src/sdl_utils.cpp

  Log Message:
  -----------
  disable "alpha thresholding" in our bilinear interpolation algo

In this commit from late 2005, boucman added a bilinear interpolation
routine for scaling images which we use everywhere.

https://github.com/wesnoth/wesnoth/commit/2df60619

It is a modified bilinear interpolation -- one of the tweaks is that
at the very end an "alpha thresholding" step occurs. If the alpha
of a pixel is less than half of the average alpha of its neighbors,
it is discarded and set to fully transparent. Boucman writes that
this was done to combat a gametime artifact that would occur when
moving the hexagonal selector around with the mouse -- however, it
creates a small loss in image quality. Boucman writes that skeleton
archer bowstrings don't look as good -- I notice also that the edges
of the wings of drakes seem a bit sharper / more pixelated somehow.

In this commit I tried disabling the alpha thresholding, since the
way that the hex selector works has been changed since 2005, so this
might no longer be an issue. Sure enough the "hexagonal haloes" are
gone now, so it seems that we can safely get rid of the alpha
thresholding.


  Commit: a5824c210138d9ca40d356a8c76fed6d614e7d70
      https://github.com/wesnoth/wesnoth/commit/a5824c210138d9ca40d356a8c76fed6d614e7d70
  Author: Chris Beck <beck.ct at gmail.com>
  Date:   2014-10-10 (Fri, 10 Oct 2014)

  Changed paths:
    M src/sdl_utils.cpp

  Log Message:
  -----------
  Merge pull request #285 from cbeck88/disable_alpha_thresholding

disable "alpha thresholding" in our bilinear interpolation algo


Compare: https://github.com/wesnoth/wesnoth/compare/6e38c0d008fe...a5824c210138