bionic-fg

Standalone Android/Bionic Vulkan frame generation layer.

What is here

• libbionic_fg.so: native framegen runtime and Vulkan implicit layer
• VK_LAYER_BIONIC_framegen: intercepts swapchain presentation and injects generated frames
• Android Hardware Buffer sharing between the producer Vulkan device and the framegen device
• Embedded SPIR-V shader bundle with model 0 and model 1 selection
• Optional JNI bootstrap API under io.github.bionicfg.BionicFGNative

Runtime configuration

The Vulkan layer is enabled with BIONIC_FG_ENABLE=1 and reads a TOML config file. The config path defaults to $HOME/.config/bionic-fg/conf.toml and can be overridden with BIONIC_FG_CONFIG.

BIONIC_FG_ENABLE=1
BIONIC_FG_CONFIG=/path/to/conf.toml # optional
VK_LAYER_PATH=/path/to/implicit_layer.d

version = 1

[global]
enabled = true
multiplier = 2   # 0=off, or 2..4
flow_scale = 0.8 # 0.2..1.0
model = 0        # 0 or 1

For backwards compatibility, BIONIC_FG_MULTIPLIER, BIONIC_FG_FLOW_SCALE, and BIONIC_FG_MODEL are still accepted when the TOML file is missing. If the TOML file exists, it wins.

The layer polls the config file timestamp during presentation.

• flow_scale hot-reloads in place.
• multiplier and model hot-reload by rebuilding the internal framegen context against the already-provisioned AHB outputs and swapchain image pool. Setting multiplier = 0 turns frame generation off without recreating the app swapchain.
• enabled still returns VK_ERROR_OUT_OF_DATE_KHR once so the application can recreate its swapchain with or without the layer active.

Install layout expected by the manifest:

.local/lib/libbionic_fg.so
.local/share/vulkan/implicit_layer.d/VkLayer_BIONIC_framegen.json

The manifest uses ../../../lib/libbionic_fg.so relative to implicit_layer.d.

Build

cmake -S . -B build/android-arm64 \
  -DANDROID_ABI=arm64-v8a \
  -DANDROID_PLATFORM=android-26 \
  -DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK_HOME/build/cmake/android.toolchain.cmake
cmake --build build/android-arm64 -j