fix(Terrain): fix terrain subdivision when a terrain tile only has values that should be clamped

Author: jailln

src/Parser/XbilParser.js

@@ -64,8 +64,16 @@ export function computeMinMaxElevation(texture, pitch, options) {
                 }
             }
         }
-        if (options.zmin > min) { min = options.zmin; }
-        if (options.zmax < max) { max = options.zmax; }
+        // Clamp values to zmin and zmax values configured in ElevationLayer
+        if (options.zmin != null) {
+            if (min < options.zmin) { min = options.zmin; }
+            if (max < options.zmin) { max = options.zmin; }
+        }
+
+        if (options.zmax != null) {
+            if (min > options.zmax) { min = options.zmax; }
+            if (max > options.zmax) { max = options.zmax; }
+        }
     }
 
     if (max === -Infinity || min === Infinity) {