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.