Drop-in mgfxc Replacement

ShadowDusk's CLI tool is a transparent substitute for MonoGame's mgfxc: same positional arguments, the same .mgfx output format, the same exit codes, and MGCB-parseable error messages on stderr. Games using the MonoGame Content Pipeline require zero code changes to switch.

Install

dotnet tool install --global ShadowDusk.Cli

This registers a ShadowDuskCLI command.

Usage

ShadowDuskCLI <SourceFile> <OutputFile> [options]

Output is positional — <SourceFile> then <OutputFile>. There is no /Output: flag. See the full CLI Reference for every flag.

# Compile for OpenGL
ShadowDuskCLI MyShader.fx MyShader.mgfx /Profile:OpenGL

# Compile for DirectX 11 (the CLI default profile)
ShadowDuskCLI MyShader.fx MyShader.mgfx /Profile:DirectX_11

Default profile: with no /Profile, the CLI defaults to DirectX_11 (matching mgfxc). Note this differs from the library default (CompilerOptions.Target = OpenGL). See Parameters & Caveats.

Replacing mgfxc in a build

Two common patterns:

  1. PATH override (Tier-1). Expose ShadowDusk's CLI under the name mgfxc (a renamed copy/symlink of a published build, or a wrapper script named mgfxc that forwards to ShadowDuskCLI) ahead of MonoGame's mgfxc on PATH — MGCB and mgfxc-shelling scripts look for the name mgfxc, not ShadowDuskCLI, so the tool command alone is not picked up. This is the shipping MGCB integration path — see MGCB Content Pipeline for the exact steps.
  2. Explicit invocation. Call ShadowDuskCLI directly from your build script / Makefile / CI step.

Because the flags, output, and exit codes match, nothing downstream needs to know it swapped tools.

Why it works where mgfxc can't

mgfxc depends on fxc.exe from the DirectX SDK and only runs on Windows. ShadowDusk runs the faithful pipeline — DXC → SPIR-V → SPIRV-Cross → GLSL for OpenGL, and vkd3d-shader → DXBC for DirectX — on Linux, macOS, and Windows. The DirectX path uses vkd3d-shader (cross-platform) rather than DXC, because DXC only emits SM6 DXIL while MonoGame's DX11 runtime loads DXBC (SM ≤ 5); see DirectX DXBC (vkd3d) Path.

Output equivalence. ShadowDusk's .mgfx is behaviorally equivalent to mgfxc's — it loads in the same Effect and renders the same pixels — not byte-for-byte equal. Determinism is ShadowDusk's own (same version + source + target → same bytes).

Edit this page