Allow changing the color serialization format to hex.

chunky/src/java/se/llbit/util/JsonUtil.java

@@ -17,10 +17,7 @@
  */
 package se.llbit.util;
 
-import se.llbit.json.Json;
-import se.llbit.json.JsonArray;
-import se.llbit.json.JsonObject;
-import se.llbit.json.JsonValue;
+import se.llbit.json.*;
 import se.llbit.math.ColorUtil;
 import se.llbit.math.QuickMath;
 import se.llbit.math.Vector3;
@@ -74,7 +71,8 @@ public static Vector3 rgbFromJson(JsonValue json) {
 
   /**
    * Parse RGB color from JSON.
-   * @param json Either an object with red, green and blue keys (0…1), an array with 1…3 values (r,g,b) in range 0…1, or six digit hex color.
+   *
+   * @param json  Either an object with red, green and blue keys (0…1), an array with 1…3 values (r,g,b) in range 0…1, or six digit hex color.
    * @param color Target color vector (r,g,b from 0…1)
    */
   public static void rgbFromJson(JsonValue json, Vector3 color) {
@@ -93,15 +91,26 @@ public static void rgbFromJson(JsonValue json, Vector3 color) {
   }
 
   /**
-   * Parse RGB color from JSON.
-   * @param json Either an object with red, green and blue keys (0…1), an array with 1…3 values (r,g,b) in range 0…1, or six digit hex color.
-   * @param color Target color vector (r,g,b from 0…1)
+   * Serialize an RGB color to JSON in a way that can be parsed by {@link #rgbFromJson(JsonValue)}.
+   * <p/>
+   * Depending on the <code>chunky.colorSerializationFormat</code> system property, this returns either an object with red, green and blue keys, or a hex string.
+   *
+   * @param color Color vector (r,g,b from 0…1)
+   * @return Serialized color
    */
   public static JsonValue rgbToJson(Vector3 color) {
-    JsonObject colorObj = new JsonObject();
-    colorObj.add("red", color.x);
-    colorObj.add("green", color.y);
-    colorObj.add("blue", color.z);
-    return colorObj;
+    switch (System.getProperty("chunky.colorSerializationFormat", "hex")) {
+      case "hex": {
+        return new JsonString(String.format("#%02x%02x%02x", (int) (color.x * 255), (int) (color.y * 255), (int) (color.z * 255)));
+      }
+      case "object":
+      default: {
+        JsonObject colorObj = new JsonObject();
+        colorObj.add("red", color.x);
+        colorObj.add("green", color.y);
+        colorObj.add("blue", color.z);
+        return colorObj;
+      }
+    }
   }
 }