From 85a9279f2d751d0d742090c26fa4d47c281cd46b Mon Sep 17 00:00:00 2001
From: Marcin Hawryluk <70582973+mhawryluk@users.noreply.github.com>
Date: Wed, 6 Nov 2024 08:43:24 +0100
Subject: [PATCH] Remove builtins from entry function arguments in tgpu-gen
 (#532)

---
 packages/tgpu-gen/gen.mjs                 | 7 ++++++-
 packages/tgpu-gen/tests/functions.test.ts | 2 +-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/packages/tgpu-gen/gen.mjs b/packages/tgpu-gen/gen.mjs
index b7825081..def50385 100644
--- a/packages/tgpu-gen/gen.mjs
+++ b/packages/tgpu-gen/gen.mjs
@@ -472,7 +472,12 @@ function generateFunction(func, wgsl, options) {
         : 'fn';
 
   const inputs = `[${func.arguments
-    .flatMap((arg) => (arg.type ? [generateType(arg.type, options)] : []))
+    .flatMap((arg) =>
+      arg.type &&
+      arg.type.attributes?.find((attr) => attr.name === 'builtin') === undefined
+        ? [generateType(arg.type, options)]
+        : [],
+    )
     .join(', ')}]`;
 
   const output = func.returnType
diff --git a/packages/tgpu-gen/tests/functions.test.ts b/packages/tgpu-gen/tests/functions.test.ts
index 8fe7efab..b67263fb 100644
--- a/packages/tgpu-gen/tests/functions.test.ts
+++ b/packages/tgpu-gen/tests/functions.test.ts
@@ -67,7 +67,7 @@ fn mainVert(@builtin(instance_index) ii: u32, @location(0) v: vec2f) -> VertexOu
 
     expect(generate(wgsl)).toContain(`\
 export const mainVert = tgpu
-  .vertexFn([d.u32, d.location(0, d.vec2f)], VertexOutput)
+  .vertexFn([d.location(0, d.vec2f)], VertexOutput)
   .does(/* wgsl */ \`(@builtin(instance_index) ii: u32, @location(0) v: vec2f) -> VertexOutput {
     let instanceInfo = trianglePos[ii];