Support #include in runtime-compiled GLSL shaders #81

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2026-10-25T22:11:39-07:00

burkkyy commented

2026-10-25 22:11:39 -07:00

Problem

Shader::compile (engine/src/vulkan/shader.cpp) compiles GLSL at runtime with shaderc but never sets an includer. shaderc accepts #include syntax (GL_GOOGLE_include_directive) but has no way to resolve files, so any shader using #include "common.glsl" or #include <common.glsl> fails to compile.

This blocks sharing code (structs, buffer_reference layouts, helpers) between shaders, e.g. sandbox/shaders/common.glsl.

Proposal

Implement a shaderc::CompileOptions::IncluderInterface (FileIncluder):
- shaderc_include_type_relative ("..."): search the requesting file's directory first, then the include dirs.
- shaderc_include_type_standard (<...>): search the include dirs only.
- On failure, return an empty source_name with the error message in content (shaderc's convention).
- Own the path and content strings via user_data; free them in ReleaseInclude.
Pass it through CompileOptions::SetIncluder in Shader::compile.
Add Shader::Builder::addIncludeDir(path), and have the engine always add its own shader directory so shared engine headers are available to every app (sandbox, editor, testbed).

Notes

GLSL has no automatic include guards. Shared headers need #ifndef / #define guards.
If shader hot reload is added later, it must track include dependencies so editing a header recompiles the shaders that use it.

Acceptance criteria

#include "common.glsl" resolves relative to the including shader.
#include <x.glsl> resolves from the configured include dirs.
A missing include produces a clear compile error naming the file.

## Problem `Shader::compile` ([engine/src/vulkan/shader.cpp](engine/src/vulkan/shader.cpp)) compiles GLSL at runtime with shaderc but never sets an includer. shaderc accepts `#include` syntax (`GL_GOOGLE_include_directive`) but has no way to resolve files, so any shader using `#include "common.glsl"` or `#include <common.glsl>` fails to compile. This blocks sharing code (structs, buffer_reference layouts, helpers) between shaders, e.g. `sandbox/shaders/common.glsl`. ## Proposal 1. Implement a `shaderc::CompileOptions::IncluderInterface` (`FileIncluder`): - `shaderc_include_type_relative` (`"..."`): search the requesting file's directory first, then the include dirs. - `shaderc_include_type_standard` (`<...>`): search the include dirs only. - On failure, return an empty `source_name` with the error message in `content` (shaderc's convention). - Own the path and content strings via `user_data`; free them in `ReleaseInclude`. 2. Pass it through `CompileOptions::SetIncluder` in `Shader::compile`. 3. Add `Shader::Builder::addIncludeDir(path)`, and have the engine always add its own shader directory so shared engine headers are available to every app (sandbox, editor, testbed). ## Notes - GLSL has no automatic include guards. Shared headers need `#ifndef` / `#define` guards. - If shader hot reload is added later, it must track include dependencies so editing a header recompiles the shaders that use it. ## Acceptance criteria - `#include "common.glsl"` resolves relative to the including shader. - `#include <x.glsl>` resolves from the configured include dirs. - A missing include produces a clear compile error naming the file.

burkkyy added the enhancement label 2026-10-25 22:11:39 -07:00

burkkyy added this to the sophia project 2026-10-25 22:11:47 -07:00

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Reference: burkkyy/sophia#81