From 67b6f8da24198ccccc5ab0856aa5528b78d8a051 Mon Sep 17 00:00:00 2001
From: Martin Valigursky <mvaligursky@snapchat.com>
Date: Wed, 27 May 2026 09:55:11 +0100
Subject: [PATCH] feat(graphics): expose WGSL pointer_composite_access as a
 device cap
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Adds detection and automatic wiring for the WGSL `pointer_composite_access`
language feature, which provides syntactic sugar for dereferencing pointers
to composite types — `p.field` and `p[i]` instead of `(*p).field` and
`(*p)[i]`. Follows the same pattern as `unrestricted_pointer_parameters`
and `linear_indexing`:

- `supportsPointerCompositeAccess` device flag, probed from
  navigator.gpu.wgslLanguageFeatures.
- `CAPS_POINTER_COMPOSITE_ACCESS` shader define for conditional compilation.
- `requires pointer_composite_access;` directive automatically injected into
  WGSL shaders on supporting devices.

See https://developer.chrome.com/blog/new-in-webgpu-123#syntax_sugar_for_dereferencing_composites_in_wgsl
---
 src/platform/graphics/graphics-device.js           | 14 ++++++++++++++
 src/platform/graphics/shader-definition-utils.js   |  3 +++
 .../graphics/webgpu/webgpu-graphics-device.js      |  1 +
 3 files changed, 18 insertions(+)

diff --git a/src/platform/graphics/graphics-device.js b/src/platform/graphics/graphics-device.js
index 066a119938b..554fea11727 100644
--- a/src/platform/graphics/graphics-device.js
+++ b/src/platform/graphics/graphics-device.js
@@ -295,6 +295,19 @@ class GraphicsDevice extends EventHandler {
      */
     supportsLinearIndexing = false;
 
+    /**
+     * True if the device supports the WGSL `pointer_composite_access` language feature, which
+     * provides syntactic sugar for dereferencing pointers to composite types: `p.field` and
+     * `p[i]` may be written instead of `(*p).field` and `(*p)[i]`. The
+     * `requires pointer_composite_access;` directive is automatically injected into WGSL
+     * shaders when this feature is available, and the shader define
+     * `CAPS_POINTER_COMPOSITE_ACCESS` is set for conditional compilation.
+     *
+     * @type {boolean}
+     * @readonly
+     */
+    supportsPointerCompositeAccess = false;
+
     /**
      * True if the device supports the WGSL `unrestricted_pointer_parameters` language feature,
      * which allows passing pointers in the `storage`, `uniform`, and `workgroup` address spaces
@@ -697,6 +710,7 @@ class GraphicsDevice extends EventHandler {
         if (this.supportsSubgroupId) capsDefines.set('CAPS_SUBGROUP_ID', '');
         if (this.supportsLinearIndexing) capsDefines.set('CAPS_LINEAR_INDEXING', '');
         if (this.supportsUnrestrictedPointerParameters) capsDefines.set('CAPS_UNRESTRICTED_POINTER_PARAMETERS', '');
+        if (this.supportsPointerCompositeAccess) capsDefines.set('CAPS_POINTER_COMPOSITE_ACCESS', '');
         if (this.supportsStorageTextureRead) capsDefines.set('CAPS_STORAGE_TEXTURE_READ', '');
 
         // Platform defines
diff --git a/src/platform/graphics/shader-definition-utils.js b/src/platform/graphics/shader-definition-utils.js
index 9eabe9ad422..06b923bc5d4 100644
--- a/src/platform/graphics/shader-definition-utils.js
+++ b/src/platform/graphics/shader-definition-utils.js
@@ -233,6 +233,9 @@ class ShaderDefinitionUtils {
         if (device.supportsUnrestrictedPointerParameters) {
             code += 'requires unrestricted_pointer_parameters;\n';
         }
+        if (device.supportsPointerCompositeAccess) {
+            code += 'requires pointer_composite_access;\n';
+        }
         return code;
     }
 
diff --git a/src/platform/graphics/webgpu/webgpu-graphics-device.js b/src/platform/graphics/webgpu/webgpu-graphics-device.js
index 43cd9389cd8..6cf67156387 100644
--- a/src/platform/graphics/webgpu/webgpu-graphics-device.js
+++ b/src/platform/graphics/webgpu/webgpu-graphics-device.js
@@ -325,6 +325,7 @@ class WebgpuGraphicsDevice extends GraphicsDevice {
         this.supportsSubgroupId = wgslFeatures?.has('subgroup_id');
         this.supportsLinearIndexing = wgslFeatures?.has('linear_indexing');
         this.supportsUnrestrictedPointerParameters = wgslFeatures?.has('unrestricted_pointer_parameters');
+        this.supportsPointerCompositeAccess = wgslFeatures?.has('pointer_composite_access');
 
         this.initCapsDefines();
     }