diff --git a/assets/index.html b/assets/index.html
index 53246dd..13fad04 100644
--- a/assets/index.html
+++ b/assets/index.html
@@ -170,6 +170,11 @@
 
             var water = isWater(h);
 
+            var sunX = wx + TILE;
+            var sunY = wy - TILE;
+            var sunH = heightMap[sunX + ',' + sunY] || 0;
+            var isInShadow = (sunH >= h);
+
             for (var level = 1; level <= h; level++) {
                 var hRight;
                 if (level > (heightMap[(wx + TILE) + ',' + wy] || 0)) {
@@ -187,26 +192,20 @@
                 drawTile(wx, wy, level, true, hRight, hBack, false);
             }
 
-            for (var level = 1; level <= h; level++) {
-                var sunX = wx + TILE;
-                var sunY = wy - TILE;
-                var sunH = heightMap[sunX + ',' + sunY] || 0;
+            if (isInShadow && h > 0) {
+                var top1 = project(wx + GAP/2, wy + TILE - GAP/2, h * HEIGHT_UNIT);
+                var top2 = project(wx + TILE - GAP/2, wy + TILE - GAP/2, h * HEIGHT_UNIT);
+                var top3 = project(wx + TILE - GAP/2, wy + GAP/2, h * HEIGHT_UNIT);
+                var top4 = project(wx + GAP/2, wy + GAP/2, h * HEIGHT_UNIT);
 
-                if (sunH > level) {
-                    var top1 = project(wx + GAP/2, wy + TILE - GAP/2, level * HEIGHT_UNIT);
-                    var top2 = project(wx + TILE - GAP/2, wy + TILE - GAP/2, level * HEIGHT_UNIT);
-                    var top3 = project(wx + TILE - GAP/2, wy + GAP/2, level * HEIGHT_UNIT);
-                    var top4 = project(wx + GAP/2, wy + GAP/2, level * HEIGHT_UNIT);
-
-                    ctx.fillStyle = 'rgba(0, 0, 0, 0.4)';
-                    ctx.beginPath();
-                    ctx.moveTo(top1[0], top1[1]);
-                    ctx.lineTo(top2[0], top2[1]);
-                    ctx.lineTo(top3[0], top3[1]);
-                    ctx.lineTo(top4[0], top4[1]);
-                    ctx.closePath();
-                    ctx.fill();
-                }
+                ctx.fillStyle = 'rgba(0, 0, 0, 0.35)';
+                ctx.beginPath();
+                ctx.moveTo(top1[0], top1[1]);
+                ctx.lineTo(top2[0], top2[1]);
+                ctx.lineTo(top3[0], top3[1]);
+                ctx.lineTo(top4[0], top4[1]);
+                ctx.closePath();
+                ctx.fill();
             }
         }
     }