Earlier, I kept this series on hold since we wanted to have a reference userspace implementation in place.
Now, Sameer has implemented Integer scaling in Kodi Retro gaming framework which demonstrate how Integer scaling gives distinctive look to pixel art games when played on higher resolution monitors.
Kodi patches are almost reviewed and closer to merge now. Here is the userspace patch series link: https://github.com/xbmc/xbmc/pull/18194
Background on Integer scaling:
Integer scaling (IS) is a nearest-neighbor upscaling technique that simply scales up the existing pixels by an integer (i.e., whole number) multiplier. Nearest-neighbor (NN) interpolation works by filling in the missing color values in the upscaled image with that of the coordinate-mapped nearest source pixel value.
Both IS and NN preserve the clarity of the original image. In contrast, traditional upscaling algorithms, such as bilinear or bicubic interpolation, result in blurry upscaled images because they employ interpolation techniques that smooth out the transition from one pixel to another. Therefore, integer scaling is particularly useful for pixel art games that rely on sharp, blocky images to deliver their distinctive look.
Many gaming communities have been asking for integer-mode scaling support, some links and background:
https://software.intel.com/en-us/articles/integer-scaling-support-on-intel-g... http://tanalin.com/en/articles/lossless-scaling/ https://community.amd.com/thread/209107 https://www.nvidia.com/en-us/geforce/forums/game-ready-drivers/13/1002/featu...
* Changes in v5: - Rebase to latest drm-tip.
Pankaj Bharadiya (5): drm: Introduce plane and CRTC scaling filter properties drm/drm-kms.rst: Add plane and CRTC scaling filter property documentation drm/i915: Introduce scaling filter related registers and bit fields. drm/i915/display: Add Nearest-neighbor based integer scaling support drm/i915: Enable scaling filter for plane and CRTC
Documentation/gpu/drm-kms.rst | 12 ++ drivers/gpu/drm/drm_atomic_uapi.c | 8 ++ drivers/gpu/drm/drm_crtc.c | 48 +++++++ drivers/gpu/drm/drm_crtc_internal.h | 3 + drivers/gpu/drm/drm_plane.c | 90 ++++++++++++++ .../gpu/drm/i915/display/intel_atomic_plane.c | 1 + drivers/gpu/drm/i915/display/intel_display.c | 117 +++++++++++++++++- drivers/gpu/drm/i915/display/intel_display.h | 4 + .../drm/i915/display/intel_display_types.h | 2 + drivers/gpu/drm/i915/display/intel_sprite.c | 15 ++- drivers/gpu/drm/i915/i915_reg.h | 22 ++++ include/drm/drm_crtc.h | 16 +++ include/drm/drm_plane.h | 21 ++++ 13 files changed, 355 insertions(+), 4 deletions(-)