emacs-gpu
GNU Emacs with a GPU-accelerated display backend.
On macOS it renders with native Apple Metal: text goes through a GPU glyph atlas, images and inline video are textures, and the whole frame is composited by the GPU instead of CoreGraphics. The output is pixel-accurate against the stock Cocoa backend.
OpenGL support for GNU/Linux and Windows is planned but not implemented
yet. The drawing logic is already platform-neutral (src/gfxterm.c)
behind a small driver interface (src/gfxdrv.h); an OpenGL driver only
needs to implement that interface (src/glterm.c is the documented
skeleton). Contributions welcome.
Status: experimental, under active development.
Note: I am not answering issues for now. Feel free to open them as a public record (they will be read eventually), but do not expect a reply at this stage.
Building on macOS
Requires Xcode (or the Command Line Tools) and the usual Emacs build
dependencies (brew install autoconf automake gnutls texinfo pkg-config).
./autogen.sh
SDK=$(xcrun --sdk macosx --show-sdk-path)
CC="xcrun clang" OBJC="xcrun clang" \
CFLAGS="-isysroot $SDK" CPPFLAGS="-isysroot $SDK" OBJCFLAGS="-isysroot $SDK" \
./configure --with-ns --with-mtl
make -j$(sysctl -n hw.ncpu)
The binary is src/emacs (or install the app bundle from nextstep/).
Enabling the GPU backend
Emacs starts with the regular Cocoa backend; switch a frame to Metal with:
(add-to-list 'load-path "/path/to/emacs-gpu/lisp")
(require 'mtl)
(mtl-enable)
Extras once enabled:
(mtl-video-insert "video.mp4" 480 270 t) ; inline video, follows scrolling
(mtl-animations t) ; GPU cursor effects (experimental)
(mtl-draw-stats) ; renderer counters
How it works
redisplay engine (xdisp.c, untouched)
↓
src/gfxterm.c platform-neutral drawing policy
↓
src/gfxdrv.h driver interface (~25 ops)
↓
src/mtlterm.m Metal driver: glyph atlas (CoreText → R8 texture),
render cycle on a persistent texture, AVFoundation
video through CVMetalTextureCache
License
GNU General Public License v3 or later, same as GNU Emacs.