CrankShaft

About

CrankShaft is an unofficial port of Flywheel to Minecraft 26.2, carrying forward the work of Jozufozu and the Engine-Room team as well as CrankShaft's own 1.12.2 backport. It runs on NeoForge and Fabric. Its Iris shaderpack support is an adaptation of Colorwheel: Colorwheel's shaderpack contract and wavelet OIT, rebuilt on CrankShaft's renderer. It is not affiliated with, endorsed by, or supported by Flywheel, Colorwheel, or their maintainers. Bugs in CrankShaft are CrankShaft's, not theirs — please file them here.

Shipped alongside CrankShaft is Vanillate, the 26.2 counterpart to Vanillin: instanced rendering for vanilla entities and block entities via Flywheel. It is bundled inside the CrankShaft jar and is off by default — until you opt in, it registers nothing and vanilla renders as usual. Turn it on with "enabled": true in config/vanillin.json (Fabric) or enabled = true in config/vanillin-client.toml (NeoForge). Individual entities and block entities can then be enabled or disabled per entry in the same file.

Features

• OpenGL and Vulkan. Native backends for both of Minecraft 26.2's graphics APIs, selected automatically.
• Iris shaderpacks. Instanced visuals render through the active shaderpack's own programs, including its shadow pass, instead of being switched off.
• Order-independent transparency (OIT). Overlapping translucent instances blend correctly without sorting. Five methods are available; see OIT.
• Terrain integration. Translucent chunk terrain joins the same OIT as instances by default. With Sodium, CrankShaft can also cull and draw opaque terrain on the GPU; see Terrain.

Requirements

• Minecraft 26.2 with NeoForge or Fabric (+ Fabric API), and Java 25+.
• Optional: Sodium 0.9.2 or newer, below 0.10. Needed for the opaque/full terrain modes and the mesh-shader backends.
• Optional: Iris for shaderpacks (built against 1.11.4). Requires OpenGL.

Backends

CrankShaft picks the best supported backend for your hardware. /flywheel backend shows or changes it.

Backend	API	Selected by default	Notes
flywheel:vk_indirect	Vulkan	Yes	GPU culling + indirect draws.
flywheel:vk_mesh_shader	Vulkan	No	Mesh shaders (VK_EXT_mesh_shader). Requires Sodium.
flywheel:indirect	OpenGL	Yes, except on Intel GPUs	GPU culling + indirect draws.
flywheel:gl_mesh_shader	OpenGL	No	Mesh shaders, NVIDIA only (GL_NV_mesh_shader). Requires Sodium.
flywheel:instancing	OpenGL	On Intel GPUs; fallback	Instanced draws without GPU culling.
flywheel:iris_indirect, flywheel:iris_instancing	OpenGL	While a shaderpack is active	Draw through the shaderpack's programs; see Iris.
flywheel:off	—	No	Disables CrankShaft rendering; vanilla draws everything.

If the requested backend is unsupported, CrankShaft falls back to the next one that is. While a shaderpack is active, choosing a native OpenGL backend selects its iris_ counterpart.

Vulkan

Minecraft 26.2 can render with Vulkan: Options → Video Settings → Graphics API → Vulkan, then restart the game. CrankShaft detects the Vulkan renderer and switches to its Vulkan backends; no CrankShaft setting is needed.

On NeoForge, also set earlyWindowControl = false in config/fml.toml. NeoForge's loading screen is OpenGL-only, and the game fails to start on Vulkan without this change.

Rendering features are the same on both APIs; only shaderpack support requires OpenGL.

Iris shaderpacks

With Iris and a shaderpack enabled, CrankShaft switches to its iris_ backends and renders instances through the pack's own programs, shadows included. Nothing needs configuring.

• Packs that implement Colorwheel's shaderpack contract (clrwl_ programs and colorwheel.properties) use it directly, including its OIT where the pack enables it.
• Bundled adapters fill gaps in specific packs (see below). An adapter checks the pack's actual shader sources, not its file name or version. If a pack has changed, the adapter is skipped as a whole and the pack falls back to the shared path.
• Other packs render instances through their standard programs, without OIT.
• Under a shaderpack, OIT follows the pack's own settings; /flywheel oit mode applies only to the non-Iris backends.

Tested shaderpacks:

Shaderpack	Version	Colorwheel contract	Bundled adapter	OIT
Complementary Reimagined	r5.9.3	Yes	Yes	Yes
Complementary Unbound	r5.9.3	Yes	Yes	Yes
Solas	V3.7b	Yes	Yes	Yes
BSL	v10.1.5	No	Yes	Yes
MakeUp UltraFast	9.5e	No	Yes	Yes
Sundial	Alpha Build 2026-08-28	Yes	Yes	Opt-in, -Dcrankshaft.iris.oit.deferred=true below
IterationRP	Alpha 0.8.28	Yes	Yes	No (the pack disables it)
Bliss	v2.1.2 (Chocapic13 edit)	No	No	No
Sildur's Vibrant Shaders	v2.01 Extreme	No	No	No
Photon	v1.3b	No	No	No

Instances drawn through a pack can differ slightly from what the pack's own renderer would produce.

Experimental options, off by default, are enabled with Java arguments in your launcher:

Argument	Effect
-Dcrankshaft.iris.terrain=true	Draw chunk terrain through the pack's terrain programs with GPU culling. Use with /flywheel terrain full (or opaque) and Sodium.
-Dcrankshaft.iris.mesh=true	With the argument above: mesh-shader terrain. flywheel:iris_mesh_shader is then selected on supported NVIDIA GPUs.
-Dcrankshaft.iris.mesh.direct=true	With both arguments above: opaque terrain skips task-shader culling, lowering its overhead.
-Dcrankshaft.iris.oit.deferred=true	Multi-layer OIT for Sundial's deferred translucents. Costs significant GPU time and memory.

Commands

Commands are client-side; settings they change are saved to the config file. Tab completion lists every option.

Command	Effect
/flywheel backend	Show the active backend.
/flywheel backend <id> / /flywheel backend DEFAULT	Use a specific backend / let CrankShaft choose. Reloads renderers.
/flywheel terrain off|translucent|opaque|full	Terrain integration mode; see below.
/flywheel oit	Show the OIT method, layer budgets and weather mode.
/flywheel oit mode auto|wavelet|kbuffer|mlab|abuffer	Choose the OIT method; see below.
/flywheel oit layers <0-32>	Layer budget of the active insert method (0 = its preset).
/flywheel oit reset	Restore all layer budgets to their presets.
/flywheel oit exactweather true|false	true: rain and snow sort per fragment against other translucents. false (default): weather is blended as one layer, which is much cheaper in rain.
/flywheel lightSmoothness <mode>	flat, tri_linear, smooth (default) or smooth_inner_face_corrected.
/flywheel limitUpdates on|off	Update distant instances less often (default on).
/flywheel debug info	Version, backend, settings and visual/instance counts; useful for bug reports.
/flywheel debug gpuTimer on|off|once|summary	Per-pass GPU timings.

Order-independent transparency

Mode	Method
auto (default)	mlab where the GPU supports fragment-shader interlock, otherwise wavelet.
wavelet	Flywheel's multi-pass wavelet transmittance. Works everywhere.
kbuffer	Stores the first K fragments to reach each pixel (preset 4), then sorts them.
mlab	Multi-layer alpha blending: K sorted layers (preset 8). Needs fragment-shader interlock.
abuffer	Per-pixel fragment lists, resolving the nearest N (preset 16). Highest memory use.

wavelet is always an approximation. kbuffer, mlab and abuffer are single-pass insert methods and are exact while no pixel has more translucent fragments than the layer budget (K, or N for abuffer). Past the budget, kbuffer drops the extra fragments regardless of depth, mlab merges its farthest layers and abuffer drops the farthest. abuffer is also only exact while its fragment pool, 8 per screen pixel across the whole frame, doesn't run out. More layers keep deeper stacks of stained-glass exact at a higher GPU cost.

On OpenGL the insert methods run on the GPU-driven backends (indirect, gl_mesh_shader); instancing always uses wavelet. Without fragment-shader interlock, mlab falls back to wavelet.

Terrain modes

Mode	Opaque terrain	Translucent terrain (water, glass, ice)	Requires
off	Vanilla / Sodium	Vanilla / Sodium	—
translucent (default)	Vanilla / Sodium	CrankShaft OIT, blended with instances	Any backend, Sodium optional
opaque	CrankShaft, GPU-culled	Sodium	Sodium, GPU-driven backend
full	CrankShaft, GPU-culled	CrankShaft OIT, blended with instances	Sodium, GPU-driven backend

GPU-driven backends are indirect, gl_mesh_shader, vk_indirect and vk_mesh_shader. On other backends or without Sodium, opaque behaves like off and full like translucent.

Configuration

Commands write the same files you can edit by hand: config/crankshaft.json on Fabric, config/flywheel-client.toml on NeoForge. Settings: backend, limitUpdates, workerThreads, useCommonPool, and under flw_backends: lightSmoothness, terrain and the OIT settings.