From 49ce2573e08a6194f7d5f59d1e285db3ba21d678 Mon Sep 17 00:00:00 2001
From: Marko Tintor <marko@tintor.net>
Date: Fri, 20 Dec 2024 19:28:27 -0800
Subject: [PATCH] Add new 'opts' attribute to shader_binary() rule AND allow .h
 files in 'srcs' attribute to be #include-d

Enables sharing of code and definitions between shaders and C/C++ code.
Enables setting optimization level (-O) and setting defines (-D) from bazel.
---
 defs.bzl | 37 ++++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)

diff --git a/defs.bzl b/defs.bzl
index 9fcbd39..3a82a81 100644
--- a/defs.bzl
+++ b/defs.bzl
@@ -7,6 +7,7 @@ _shader_file_extensions = [
     '.comp',
     '.glsl',
     '.spvasm',
+    '.h',
 ]
 
 _shader_stages = [
@@ -18,29 +19,46 @@ _shader_stages = [
     'compute',
 ]
 
-def _SpvOutput(srcs):
-    return [src.basename + '.spv' for src in srcs]
-
-def _SpvasmOutput(srcs):
-    return [src.basename + '.spvasm' for src in srcs]
+def _gather_incdirs(files):
+    # Use a dict to avoid duplicates (sets are not allowed in Starlark)
+    incdirs_dict = {}
+    for f in files:
+        path = f.path
+        if "/" in path:
+            parent_dir = path.rsplit("/", 1)[0]
+            incdirs_dict[parent_dir] = True
+    incdirs_list = []
+    for d in sorted(incdirs_dict.keys()):
+        incdirs_list.append("-I" + d)
+    return incdirs_list
 
 def _shader_binary(ctx):
     spvOut = ctx.actions.declare_file(ctx.attr.name + ".spv")
-    shaderStage = ''
+
+    all_inputs = list(ctx.files.srcs)
+    incArgs = _gather_incdirs(all_inputs)
 
     glslcArgs = []
 
     if ctx.attr.stage:
         glslcArgs.append("-shader-stage=" + ctx.attr.stage)
 
-    for src in ctx.files.srcs:
-        glslcArgs.append(src.path)
+    # Add include paths and user options
+    glslcArgs += incArgs
+    glslcArgs += ctx.attr.opts
+
+    # Add sources (excluding headers)
+    compile_inputs = []
+    for f in all_inputs:
+        if not f.path.endswith(".h"):
+            glslcArgs.append(f.path)
+            compile_inputs.append(f)
 
     glslcArgs.append('-o')
     glslcArgs.append(spvOut.path)
 
     ctx.actions.run(
-        inputs = ctx.files.srcs,
+        inputs = all_inputs,
         outputs = [spvOut],
         executable = ctx.executable.glslc,
         arguments = glslcArgs,
@@ -62,6 +80,7 @@ shader_binary = rule(
             default = '',
             values = [''] + _shader_stages,
         ),
+        "opts": attr.string_list(default = []),
         "glslc": attr.label(
             default = Label("@vulkan_sdk//:glslc"),
             allow_single_file = True,