refactor(wgsl): Factorize getScreenCoord helper

Factorizes the screen coordinate calculation from scene1.wgsl into a reusable getScreenCoord function in common/shaders/math/common_utils.wgsl.

This improves code reuse and simplifies fragment shaders.

1 files changed, 10 insertions, 0 deletions

diff --git a/doc/COMPLETED.md b/doc/COMPLETED.md
index 72e389d..0dba307 100644
--- a/doc/COMPLETED.md
+++ b/doc/COMPLETED.md
@@ -29,6 +29,16 @@ Detailed historical documents have been moved to `doc/archive/` for reference:
 
 Use `read @doc/archive/FILENAME.md` to access archived documents.
 
+## Recently Completed (February 21, 2026)
+
+- [x] **WGSL Refactor: getScreenCoord Helper**
+    - **Goal**: Factorize boilerplate screen coordinate calculation into a reusable helper function.
+    - **Implementation**:
+        - Created `getScreenCoord(p, resolution)` function in `common/shaders/math/common_utils.wgsl`. It takes a fragment position and resolution, and returns aspect-corrected normalized device coordinates.
+        - Updated `workspaces/main/shaders/scene1.wgsl` to `#include "math/common_utils.wgsl"` and replaced the manual coordinate calculation with a call to the new helper.
+    - **Impact**: Reduces code duplication and simplifies fragment shaders.
+    - **Files**: `common/shaders/math/common_utils.wgsl`, `workspaces/main/shaders/scene1.wgsl`.
+
 ## Recently Completed (February 20, 2026)
 
 - [x] **Port Scene1Effect + Fix seq_compiler Timing Bug**