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Shader Preprocessing

Shaders/GlavaPreprocessor.cs

GLava's own preprocessor is a full custom language extension: it handles #request (configuring the host and defining values shaders read back), #include (with @ = module-relative and : = shader-root-relative paths), #expand, hex-color literals, and a @fg:/@bg: foreground/background compositing model with a dedicated blending pass.

GlavaPreprocessor implements a deliberately small subset — enough to load real, unmodified GLava module files as plain GLSL:

  • #include "@x" / #include ":x" — resolved and inlined recursively, deduplicated per top-level Process() call (so re-including the same file, which GLava's own shaders do routinely, e.g. bars.glsl via both @ and : paths in bars/1.frag, doesn't redefine macros), capped at depth 32 as a sanity backstop against genuine include cycles.
  • #request setsmoothfactor <n> / #request setsmoothpass <bool> — turned into #defines, because util/smooth.glsl reads them back as plain GLSL identifiers (_SMOOTH_FACTOR, _PRE_SMOOTHED_AUDIO).
  • #request uniform "<role>" <name> — GLava lets a pass declare its own GLSL identifier for a semantic role (screen, audio_sz, audio_l, audio_r, prev, history [GlavaSharp-original, see GlavaSharp-Original Modules], ...) instead of GlavaSharp assuming a fixed name. Process() returns these role → name bindings alongside the source (not just stripping the line like everything else here) so ShaderModule can bind each pass's previous-output sampler by whatever name the shader actually used, instead of guessing. This matters in practice: the bundled tree always names it tex, and ShaderModule used to hardcode "tex0" — see Status & Roadmap for the bug that caused. Every other #request line is stripped as a no-op.
  • #expand NAME COUNT → NAME(0) NAME(1) ... NAME(COUNT-1), one call per line, when COUNT is already a literal integer.
  • #RRGGBB[AA] hex-color literals → vec4(...).
  • The @fg:/@bg: tags are stripped rather than driving a real compositing pass — GlavaSharp just draws the resulting color with normal alpha blending.
  • A redundant in vec4 gl_FragCoord; redeclaration (legacy GLSL-version compat in GLava's own shaders) is stripped, since core-profile GLSL already declares it implicitly and strict drivers reject the redeclaration.

What's explicitly not implemented: GLava's #request transform ... pipeline and the full compositing model behind @fg:/@bg: — see Status & Roadmap.