fix: set water elevation during map generation to prevent depth issues

src/data/maps/core/ElevationMap.ts

@@ -105,8 +105,7 @@ export const BIOME_THEMES: Record<BiomeType, BiomeTheme> = {
 /** Standard elevation levels mapped to 0-255 range */
 export const ELEVATION = {
   VOID: 0,        // Below terrain (chasms)
-  WATER_DEEP: 10, // Deep water level (impassable)
-  WATER_SHALLOW: 30, // Shallow water level (walkable but slow)
+  WATER: 25,      // Water surface level (must be > LOW - CLIFF_THRESHOLD to avoid shoreline cliffs)
   LOW: 60,        // Ground level
   MID: 140,       // Natural expansion level
   HIGH: 220,      // Main base level

src/data/maps/core/ElevationMapGenerator.ts

@@ -198,7 +198,7 @@ function paintRamp(
 
 /**
  * Paint a feature (water, forest, etc.) on a circular area
- * Water features also set elevation to ensure proper depth rendering
+ * Water features set elevation to ELEVATION.WATER - water surface is always level
  */
 function paintFeatureCircle(
   grid: GenerationGrid,
@@ -208,9 +208,8 @@ function paintFeatureCircle(
   feature: TerrainFeature
 ): void {
   const r2 = radius * radius;
-  // Determine water elevation based on feature type
-  const waterElevation = feature === 'water_deep' ? ELEVATION.WATER_DEEP :
-    feature === 'water_shallow' ? ELEVATION.WATER_SHALLOW : null;
+  // Water surface is always at the same level (deep vs shallow is depth BELOW surface)
+  const isWater = feature === 'water_deep' || feature === 'water_shallow';
 
   for (let y = Math.floor(cy - radius); y <= Math.ceil(cy + radius); y++) {
     for (let x = Math.floor(cx - radius); x <= Math.ceil(cx + radius); x++) {
@@ -221,9 +220,9 @@ function paintFeatureCircle(
           // Don't overwrite ramps
           if (!grid.ramps[y][x]) {
             grid.features[y][x] = feature;
-            // Set water elevation to ensure water renders below terrain
-            if (waterElevation !== null) {
-              grid.elevation[y][x] = waterElevation;
+            // Set water elevation - water surface is always level
+            if (isWater) {
+              grid.elevation[y][x] = ELEVATION.WATER;
             }
           }
         }
@@ -234,7 +233,7 @@ function paintFeatureCircle(
 
 /**
  * Paint a feature on a rectangular area
- * Water features also set elevation to ensure proper depth rendering
+ * Water features set elevation to ELEVATION.WATER - water surface is always level
  */
 function paintFeatureRect(
   grid: GenerationGrid,
@@ -244,19 +243,18 @@ function paintFeatureRect(
   height: number,
   feature: TerrainFeature
 ): void {
-  // Determine water elevation based on feature type
-  const waterElevation = feature === 'water_deep' ? ELEVATION.WATER_DEEP :
-    feature === 'water_shallow' ? ELEVATION.WATER_SHALLOW : null;
+  // Water surface is always at the same level (deep vs shallow is depth BELOW surface)
+  const isWater = feature === 'water_deep' || feature === 'water_shallow';
 
   for (let py = Math.floor(y); py < Math.ceil(y + height); py++) {
     for (let px = Math.floor(x); px < Math.ceil(x + width); px++) {
       if (py >= 0 && py < grid.height && px >= 0 && px < grid.width) {
         // Don't overwrite ramps
         if (!grid.ramps[py][px]) {
           grid.features[py][px] = feature;
-          // Set water elevation to ensure water renders below terrain
-          if (waterElevation !== null) {
-            grid.elevation[py][px] = waterElevation;
+          // Set water elevation - water surface is always level
+          if (isWater) {
+            grid.elevation[py][px] = ELEVATION.WATER;
           }
         }
       }

src/editor/services/LLMMapGenerator.ts

@@ -560,9 +560,24 @@ const SYSTEM_PROMPT = `You are an expert RTS map designer creating professional
 - Place ramps FROM high ground TO low ground
 
 ### Water Features
-- shallow water: walkable at 0.6x speed, unbuildable
-- deep water: impassable (for island maps/lakes)
-- Use for naval maps, visual interest, or strategic slow zones
+Water bodies should be created with LAYERED commands for realistic appearance:
+1. First paint a LARGER shallow water area (the shoreline/edges)
+2. Then paint a SMALLER deep water area in the CENTER (this overwrites the inner shallow)
+This creates natural shores where shallow water surrounds deep water.
+
+Example lake (radius 25 at position 100,100):
+  { "cmd": "water", "x": 100, "y": 100, "radius": 25, "depth": "shallow" }  // Outer shore
+  { "cmd": "water", "x": 100, "y": 100, "radius": 18, "depth": "deep" }     // Inner deep
+
+Example river (width 20, length 80):
+  { "cmd": "water", "x": 50, "y": 60, "width": 20, "height": 80, "depth": "shallow" }  // Full width
+  { "cmd": "water", "x": 53, "y": 60, "width": 14, "height": 80, "depth": "deep" }     // Center channel
+
+Properties:
+- shallow water: walkable at 0.6x speed, unbuildable (shore/edges)
+- deep water: impassable (center of lakes, deep rivers)
+- ALWAYS create shallow water FIRST, then deep water on top for proper transitions
+- Shore width should be 5-8 cells for good visual appearance
 
 ### Strategic Features
 - Watch towers: Place at contested locations for vision control
@@ -791,14 +806,19 @@ function buildUserPrompt(settings: MapGenerationSettings, size: { width: number;
       '**Map Type**: Island/Naval map',
       '- Use deep water to separate land masses',
       '- Create island bases connected by shallow water crossings or bridges',
-      '- Consider naval gameplay with water-based choke points',
+      '- IMPORTANT: Always paint shallow water FIRST (larger), then deep water on TOP (smaller)',
+      '- This creates natural shorelines where shallow water surrounds deep water',
       ''
     );
   } else if (settings.includeWater) {
     lines.push(
-      '**Water Features**: Include water features',
-      '- Use shallow water for strategic slow zones',
-      '- Deep water for lakes or map boundaries',
+      '**Water Features**: Include lakes, rivers, or ponds',
+      '- IMPORTANT: Create water bodies in layers:',
+      '  1. Paint shallow water FIRST (larger area for shoreline)',
+      '  2. Paint deep water on TOP (smaller, in center)',
+      '- This creates natural transitions (shallow shores around deep centers)',
+      '- Shore width should be 5-8 cells',
+      '- Example lake: shallow radius 25, then deep radius 18 at same center',
       ''
     );
   }

src/rendering/water/UnifiedWaterMesh.ts

@@ -467,11 +467,8 @@ export class UnifiedWaterMesh {
 
       // Calculate world-space height
       // In Three.js: Y is up, ground plane is X-Z
-      const height = elevation * HEIGHT_SCALE + WATER_SURFACE_OFFSET;
-
-      // Shallow water renders slightly higher for visual blending
-      const heightOffset = isDeep ? 0 : 0.02;
-      const finalHeight = height + heightOffset;
+      // All water (deep and shallow) renders at the same height - water surface is always level
+      const finalHeight = elevation * HEIGHT_SCALE + WATER_SURFACE_OFFSET;
 
       // Cell size (usually 1, but may be larger if merged)
       const halfSize = size / 2;