docs: Mark SDF Macros attack plan as completed in TODO.md

1 files changed, 1 insertions, 1 deletions

diff --git a/TODO.md b/TODO.md
index f0c16ae..47eb77b 100644
--- a/TODO.md
+++ b/TODO.md
@@ -18,7 +18,7 @@ This file tracks prioritized tasks with detailed attack plans.
 
 ## Priority 3: Shader Optimization (Task #21)
 **Goal:** Improve GPU performance and reduce shader source bloat.
-- [ ] **Attack Plan - SDF Macros:** Use `#define` macros in WGSL to simplify sampling and bump mapping logic.
+- [x] **Attack Plan - SDF Macros:** Use `#define` macros in WGSL to simplify sampling and bump mapping logic.
 
 ## Future Goals
 - [ ] **Task #5: Spectrogram Editor**: Web-based visual tool for extreme audio compression.