diff --git a/src/rendering/tsl/FogOfWar.ts b/src/rendering/tsl/FogOfWar.ts
index 6904c53e..af1b9f6c 100644
--- a/src/rendering/tsl/FogOfWar.ts
+++ b/src/rendering/tsl/FogOfWar.ts
@@ -201,9 +201,8 @@ export class TSLFogOfWar {
     // Update CPU texture from vision grid with temporal smoothing
     for (let y = 0; y < this.gridHeight; y++) {
       for (let x = 0; x < this.gridWidth; x++) {
-        // Flip Y for texture coordinates
-        const textureY = this.gridHeight - 1 - y;
-        const i = textureY * this.gridWidth + x;
+        // No Y-flip - matches GPU path (VisionCompute) which writes directly to (cellX, cellY)
+        const i = y * this.gridWidth + x;
         const state = visionGrid[y]?.[x] ?? 'unexplored';
 
         // Current visibility (target)
@@ -281,9 +280,8 @@ export class TSLFogOfWar {
     // Update CPU texture from serialized data with temporal smoothing
     for (let y = 0; y < this.gridHeight; y++) {
       for (let x = 0; x < this.gridWidth; x++) {
-        // Flip Y for texture coordinates
-        const textureY = this.gridHeight - 1 - y;
-        const textureIndex = textureY * this.gridWidth + x;
+        // No Y-flip - matches GPU path (VisionCompute)
+        const textureIndex = y * this.gridWidth + x;
         const dataIndex = y * this.gridWidth + x;
         const state = serializedData[dataIndex];
 
diff --git a/src/rendering/tsl/effects/EffectPasses.ts b/src/rendering/tsl/effects/EffectPasses.ts
index c0f65566..e1bbd5c8 100644
--- a/src/rendering/tsl/effects/EffectPasses.ts
+++ b/src/rendering/tsl/effects/EffectPasses.ts
@@ -770,8 +770,9 @@ export function createFogOfWarPass(
     const worldZ = worldPos4.z;
 
     // Convert world position to vision grid UV
+    // Note: This codebase uses Y as depth (north-south), not Z
     const visionU = worldX.div(uMapDimensions.x);
-    const visionV = worldZ.div(uMapDimensions.y);
+    const visionV = worldY.div(uMapDimensions.y);
     const visionUV = vec2(visionU, visionV).toVar();
 
     // Clamp to valid range