diff --git a/src/components/game/Minimap.tsx b/src/components/game/Minimap.tsx
index 2ee10797..7976efa0 100644
--- a/src/components/game/Minimap.tsx
+++ b/src/components/game/Minimap.tsx
@@ -174,13 +174,13 @@ export function Minimap() {
       // Draw resources
       const resources = worldAdapter.getEntitiesWith('Transform', 'Resource');
       for (const entity of resources) {
-        const transform = entity.get('Transform') as { x: number; y: number } | undefined;
+        const transform = entity.get('Transform') as { x: number; y: number; z: number } | undefined;
         const resource = entity.get('Resource') as { resourceType: string } | undefined;
 
         if (!transform || !resource) continue;
 
         const x = transform.x * scale;
-        const y = transform.y * scale;
+        const y = transform.z * scale; // Use z (depth) for minimap Y
 
         ctx.fillStyle = resource.resourceType === 'minerals' ? '#00aaff' : '#00ff66';
         ctx.beginPath();
@@ -191,7 +191,7 @@ export function Minimap() {
       // Draw buildings
       const buildings = worldAdapter.getEntitiesWith('Transform', 'Building', 'Selectable', 'Health');
       for (const entity of buildings) {
-        const transform = entity.get('Transform') as { x: number; y: number } | undefined;
+        const transform = entity.get('Transform') as { x: number; y: number; z: number } | undefined;
         const building = entity.get('Building') as { width: number; height: number; state: string; isComplete?: () => boolean } | undefined;
         const selectable = entity.get('Selectable') as { playerId: string } | undefined;
         const health = entity.get('Health') as { current: number; max: number } | undefined;
@@ -202,13 +202,13 @@ export function Minimap() {
         // Skip enemy buildings that are not visible due to fog of war (unless spectator)
         const fogOfWarEnabled = useGameSetupStore.getState().fogOfWar;
         if (localPlayer && selectable.playerId !== localPlayer && fogOfWarEnabled && game.visionSystem && !isSpectating) {
-          if (!game.visionSystem.isVisible(localPlayer, transform.x, transform.y)) {
+          if (!game.visionSystem.isVisible(localPlayer, transform.x, transform.z)) {
             continue;
           }
         }
 
         const x = transform.x * scale;
-        const y = transform.y * scale;
+        const y = transform.z * scale; // Use z (depth) for minimap Y
         const w = Math.max(building.width * scale, 4);
         const h = Math.max(building.height * scale, 4);
 
@@ -229,7 +229,7 @@ export function Minimap() {
       // Draw units
       const units = worldAdapter.getEntitiesWith('Transform', 'Unit', 'Selectable', 'Health');
       for (const entity of units) {
-        const transform = entity.get('Transform') as { x: number; y: number } | undefined;
+        const transform = entity.get('Transform') as { x: number; y: number; z: number } | undefined;
         const selectable = entity.get('Selectable') as { playerId: string } | undefined;
         const health = entity.get('Health') as { current: number; max: number } | undefined;
 
@@ -239,13 +239,13 @@ export function Minimap() {
         // Skip enemy units that are not visible due to fog of war (unless spectator)
         const fogEnabled = useGameSetupStore.getState().fogOfWar;
         if (localPlayer && selectable.playerId !== localPlayer && fogEnabled && game.visionSystem && !isSpectating) {
-          if (!game.visionSystem.isVisible(localPlayer, transform.x, transform.y)) {
+          if (!game.visionSystem.isVisible(localPlayer, transform.x, transform.z)) {
             continue;
           }
         }
 
         const x = transform.x * scale;
-        const y = transform.y * scale;
+        const y = transform.z * scale; // Use z (depth) for minimap Y
 
         // Unit color based on player's assigned color
         const unitPlayerHex = getPlayerColor(selectable.playerId);
diff --git a/src/engine/systems/VisionSystem.ts b/src/engine/systems/VisionSystem.ts
index fd5f5772..279e742a 100644
--- a/src/engine/systems/VisionSystem.ts
+++ b/src/engine/systems/VisionSystem.ts
@@ -503,7 +503,7 @@ export class VisionSystem extends System {
 
       casters.push({
         x: transform.x,
-        y: transform.y,
+        y: transform.z, // Use Z (depth) not Y (altitude) for 2D vision grid
         sightRange: unit.sightRange,
         playerId: playerIndex,
       });
@@ -524,7 +524,7 @@ export class VisionSystem extends System {
 
       casters.push({
         x: transform.x,
-        y: transform.y,
+        y: transform.z, // Use Z (depth) not Y (altitude) for 2D vision grid
         sightRange: building.sightRange,
         playerId: playerIndex,
       });
@@ -569,8 +569,8 @@ export class VisionSystem extends System {
         if (!transform || !selectable) continue;
 
         const dx = transform.x - tower.x;
-        const dy = transform.y - tower.y;
-        const distSq = dx * dx + dy * dy;
+        const dz = transform.z - tower.y; // tower.y is stored depth, compare with transform.z
+        const distSq = dx * dx + dz * dz;
 
         if (distSq <= captureRadiusSq) {
           tower.controllingPlayers.add(selectable.playerId);
@@ -699,7 +699,7 @@ export class VisionSystem extends System {
       units.push({
         id: entity.id,
         x: transform.x,
-        y: transform.y,
+        y: transform.z, // Use Z (depth) for 2D vision grid
         sightRange: unit.sightRange,
         playerId: selectable.playerId,
       });
@@ -729,7 +729,7 @@ export class VisionSystem extends System {
       buildings.push({
         id: entity.id,
         x: transform.x,
-        y: transform.y,
+        y: transform.z, // Use Z (depth) for 2D vision grid
         sightRange: building.sightRange,
         playerId: selectable.playerId,
         isOperational: building.isOperational(),
@@ -869,8 +869,8 @@ export class VisionSystem extends System {
         if (!transform || !selectable) continue;
 
         const dx = transform.x - tower.x;
-        const dy = transform.y - tower.y;
-        const distSq = dx * dx + dy * dy;
+        const dz = transform.z - tower.y; // tower.y is stored depth, compare with transform.z
+        const distSq = dx * dx + dz * dz;
 
         if (distSq <= captureRadiusSq) {
           tower.controllingPlayers.add(selectable.playerId);
@@ -883,7 +883,7 @@ export class VisionSystem extends System {
     for (const tower of this.watchTowers) {
       if (tower.isActive) {
         for (const playerId of tower.controllingPlayers) {
-          this.revealArea(playerId, tower.x, tower.y, tower.radius);
+          this.revealArea(playerId, tower.x, tower.y, tower.radius); // tower.y is depth (Z)
         }
       }
     }
@@ -896,7 +896,7 @@ export class VisionSystem extends System {
 
     if (!transform || !unit || !selectable) return;
 
-    this.revealArea(selectable.playerId, transform.x, transform.y, unit.sightRange);
+    this.revealArea(selectable.playerId, transform.x, transform.z, unit.sightRange);
   }
 
   private updateBuildingVision(entity: Entity): void {
@@ -909,10 +909,10 @@ export class VisionSystem extends System {
     // Only provide vision if building is operational
     if (!building.isOperational()) return;
 
-    this.revealArea(selectable.playerId, transform.x, transform.y, building.sightRange);
+    this.revealArea(selectable.playerId, transform.x, transform.z, building.sightRange);
   }
 
-  private revealArea(playerId: string, worldX: number, worldY: number, range: number): void {
+  private revealArea(playerId: string, worldX: number, worldZ: number, range: number): void {
     this.ensurePlayerRegistered(playerId);
 
     const visionGrid = this.visionMap.playerVision.get(playerId)!;
@@ -921,7 +921,7 @@ export class VisionSystem extends System {
     const gridHeight = this.visionMap.height;
 
     const cellX = Math.floor(worldX / this.cellSize);
-    const cellY = Math.floor(worldY / this.cellSize);
+    const cellY = Math.floor(worldZ / this.cellSize); // cellY maps to worldZ (depth)
     const cellRange = Math.ceil(range / this.cellSize);
 
     const cellRangeSq = cellRange * cellRange;
@@ -948,7 +948,7 @@ export class VisionSystem extends System {
    */
   private detectCloakedUnitsInArea(
     playerId: string,
-    position: { x: number; y: number },
+    position: { x: number; y: number }, // y here is actually Z (depth) in world space
     radius: number
   ): void {
     const units = this.world.getEntitiesWith('Unit', 'Transform', 'Selectable');
@@ -963,21 +963,21 @@ export class VisionSystem extends System {
       if (selectable.playerId === playerId) continue;
       if (!unit.isCloaked) continue;
 
-      // Check if within detection radius
+      // Check if within detection radius (position.y is depth/Z coordinate)
       const dx = transform.x - position.x;
-      const dy = transform.y - position.y;
-      const distSq = dx * dx + dy * dy;
+      const dz = transform.z - position.y; // position.y is Z in 2D map space
+      const distSq = dx * dx + dz * dz;
 
       if (distSq <= radiusSq) {
         // Emit detection event
         this.game.eventBus.emit('unit:detected', {
           entityId: entity.id,
           detectedBy: playerId,
-          position: { x: transform.x, y: transform.y },
+          position: { x: transform.x, y: transform.z }, // Report 2D map position
         });
 
         debugPathfinding.log(
-          `[VisionSystem] Detected cloaked unit ${entity.id} at (${transform.x.toFixed(1)}, ${transform.y.toFixed(1)})`
+          `[VisionSystem] Detected cloaked unit ${entity.id} at (${transform.x.toFixed(1)}, ${transform.z.toFixed(1)})`
         );
       }
     }
@@ -985,12 +985,12 @@ export class VisionSystem extends System {
 
   // Public API for checking visibility
 
-  public getVisionState(playerId: string, worldX: number, worldY: number): VisionState {
+  public getVisionState(playerId: string, worldX: number, worldZ: number): VisionState {
     const visionGrid = this.visionMap.playerVision.get(playerId);
     if (!visionGrid) return 'unexplored';
 
     const cellX = Math.floor(worldX / this.cellSize);
-    const cellY = Math.floor(worldY / this.cellSize);
+    const cellY = Math.floor(worldZ / this.cellSize); // cellY maps to worldZ (depth)
 
     if (cellX < 0 || cellX >= this.visionMap.width || cellY < 0 || cellY >= this.visionMap.height) {
       return 'unexplored';
@@ -999,12 +999,12 @@ export class VisionSystem extends System {
     return visionGrid[cellY][cellX];
   }
 
-  public isVisible(playerId: string, worldX: number, worldY: number): boolean {
-    return this.getVisionState(playerId, worldX, worldY) === 'visible';
+  public isVisible(playerId: string, worldX: number, worldZ: number): boolean {
+    return this.getVisionState(playerId, worldX, worldZ) === 'visible';
   }
 
-  public isExplored(playerId: string, worldX: number, worldY: number): boolean {
-    const state = this.getVisionState(playerId, worldX, worldY);
+  public isExplored(playerId: string, worldX: number, worldZ: number): boolean {
+    const state = this.getVisionState(playerId, worldX, worldZ);
     return state === 'visible' || state === 'explored';
   }
 
diff --git a/src/rendering/BuildingRenderer.ts b/src/rendering/BuildingRenderer.ts
index 62a3251c..15757ca7 100644
--- a/src/rendering/BuildingRenderer.ts
+++ b/src/rendering/BuildingRenderer.ts
@@ -647,7 +647,7 @@ export class BuildingRenderer {
       // Check visibility for enemy buildings (skip in spectator mode - show all)
       let shouldShow = true;
       if (isEnemy && this.visionSystem && this.playerId) {
-        shouldShow = this.visionSystem.isExplored(this.playerId, transform.x, transform.y);
+        shouldShow = this.visionSystem.isExplored(this.playerId, transform.x, transform.z);
       }
 
       // PERF: Get cached terrain height (buildings rarely move)
diff --git a/src/rendering/UnitRenderer.ts b/src/rendering/UnitRenderer.ts
index 805f9ddd..63693afb 100644
--- a/src/rendering/UnitRenderer.ts
+++ b/src/rendering/UnitRenderer.ts
@@ -1005,7 +1005,7 @@ export class UnitRenderer {
       // Check visibility for enemy units (skip in spectator mode - show all)
       let shouldShow = true;
       if (isEnemy && this.visionSystem && this.playerId) {
-        shouldShow = this.visionSystem.isVisible(this.playerId, transform.x, transform.y);
+        shouldShow = this.visionSystem.isVisible(this.playerId, transform.x, transform.z);
       }
 
       // Skip dead units
diff --git a/src/rendering/compute/VisionCompute.ts b/src/rendering/compute/VisionCompute.ts
index becf166d..5e3046fb 100644
--- a/src/rendering/compute/VisionCompute.ts
+++ b/src/rendering/compute/VisionCompute.ts
@@ -197,9 +197,10 @@ export class VisionCompute {
         return;
       });
 
-      // Cell center in world coordinates
+      // Cell center in world coordinates (X horizontal, Z depth)
+      // Note: cellY maps to worldZ (depth), not worldY (altitude)
       const worldX = cellX.toFloat().mul(cellSize).add(cellSize.mul(0.5));
-      const worldY = cellY.toFloat().mul(cellSize).add(cellSize.mul(0.5));
+      const worldZ = cellY.toFloat().mul(cellSize).add(cellSize.mul(0.5));
 
       // Read previous frame's data for temporal accumulation
       const prevUV = vec2(
@@ -218,13 +219,13 @@ export class VisionCompute {
       Loop(casterCount, () => {
         const caster = casterBuffer.element(i);
         const casterX = caster.x;
-        const casterY = caster.y;
+        const casterZ = caster.y; // caster.y stores Z (depth) coordinate
         const sightRange = caster.z;
         const casterPlayer = caster.w.toInt();
 
         const dx = worldX.sub(casterX);
-        const dy = worldY.sub(casterY);
-        const distSq = dx.mul(dx).add(dy.mul(dy));
+        const dz = worldZ.sub(casterZ);
+        const distSq = dx.mul(dx).add(dz.mul(dz));
         const rangeSq = sightRange.mul(sightRange);
 
         If(distSq.lessThanEqual(rangeSq).and(casterPlayer.equal(targetPlayerId)), () => {
diff --git a/src/rendering/tsl/FogOfWar.ts b/src/rendering/tsl/FogOfWar.ts
index 6904c53e..b1703a10 100644
--- a/src/rendering/tsl/FogOfWar.ts
+++ b/src/rendering/tsl/FogOfWar.ts
@@ -201,9 +201,9 @@ 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 needed - grid y maps directly to texture row
+        // Grid y=0 (worldZ~0) → texture row 0 (UV v~0)
+        const i = y * this.gridWidth + x;
         const state = visionGrid[y]?.[x] ?? 'unexplored';
 
         // Current visibility (target)
@@ -281,9 +281,9 @@ 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 needed - grid y maps directly to texture row
+        // Grid y=0 (worldZ~0) → texture row 0 (UV v~0)
+        const textureIndex = y * this.gridWidth + x;
         const dataIndex = y * this.gridWidth + x;
         const state = serializedData[dataIndex];
 
diff --git a/src/rendering/tsl/PostProcessing.ts b/src/rendering/tsl/PostProcessing.ts
index 6277829e..eb218efa 100644
--- a/src/rendering/tsl/PostProcessing.ts
+++ b/src/rendering/tsl/PostProcessing.ts
@@ -857,10 +857,13 @@ export class RenderPipeline {
 
   /**
    * Set fog of war map dimensions for proper world-space calculations
+   * @param width Map width in world units
+   * @param height Map height in world units
+   * @param cellSize Optional cell size for vision grid (default: 2)
    */
-  setFogOfWarMapDimensions(width: number, height: number): void {
+  setFogOfWarMapDimensions(width: number, height: number, cellSize: number = 2): void {
     if (this.fogOfWarPass) {
-      this.fogOfWarPass.uniforms.mapDimensions.value.set(width, height);
+      this.fogOfWarPass.setMapDimensions(width, height, cellSize);
     }
   }
 
diff --git a/src/rendering/tsl/effects/EffectPasses.ts b/src/rendering/tsl/effects/EffectPasses.ts
index 52cd3859..c0f65566 100644
--- a/src/rendering/tsl/effects/EffectPasses.ts
+++ b/src/rendering/tsl/effects/EffectPasses.ts
@@ -659,6 +659,7 @@ export interface FogOfWarPassResult {
   updateTime: (t: number) => void;
   updateCamera: (cam: THREE.PerspectiveCamera) => void;
   applyConfig: (config: Partial<FogOfWarConfig>) => void;
+  setMapDimensions: (width: number, height: number, cellSize?: number) => void;
 }
 
 /**
@@ -1011,6 +1012,18 @@ export function createFogOfWarPass(
     }
   };
 
+  const setMapDimensions = (width: number, height: number, cellSize?: number) => {
+    uMapDimensions.value.set(width, height);
+    if (cellSize !== undefined) {
+      uCellSize.value = cellSize;
+      // Update grid dimensions based on map dimensions and cell size
+      uGridDimensions.value.set(
+        Math.ceil(width / cellSize),
+        Math.ceil(height / cellSize)
+      );
+    }
+  };
+
   return {
     node: fogOfWarNode(),
     uniforms,
@@ -1019,6 +1032,7 @@ export function createFogOfWarPass(
     updateTime,
     updateCamera,
     applyConfig,
+    setMapDimensions,
   };
 }