[apriltag] Cache layout loaded from AprilTagFields resource json (wpi…

…libsuite#6385)
chauser · May 30, 2024 · 2eadedb · 2eadedb
1 parent 0038caf
commit 2eadedb
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Showing 2 changed files with 14 additions and 5 deletions.
diff --git a/apriltag/src/main/java/edu/wpi/first/apriltag/AprilTagFieldLayout.java b/apriltag/src/main/java/edu/wpi/first/apriltag/AprilTagFieldLayout.java
@@ -230,12 +230,19 @@ public void serialize(Path path) throws IOException {
    * @throws UncheckedIOException If the layout does not exist.
    */
   public static AprilTagFieldLayout loadField(AprilTagFields field) {
-    try {
-      return loadFromResource(field.m_resourceFile);
-    } catch (IOException e) {
-      throw new UncheckedIOException(
-          "Could not load AprilTagFieldLayout from " + field.m_resourceFile, e);
+    if (field.m_fieldLayout == null) {
+      try {
+        field.m_fieldLayout = loadFromResource(field.m_resourceFile);
+      } catch (IOException e) {
+        throw new UncheckedIOException(
+            "Could not load AprilTagFieldLayout from " + field.m_resourceFile, e);
+      }
     }
+    // Copy layout because the layout's origin is mutable
+    return new AprilTagFieldLayout(
+        field.m_fieldLayout.getTags(),
+        field.m_fieldLayout.getFieldLength(),
+        field.m_fieldLayout.getFieldWidth());
   }
 
   /**

diff --git a/apriltag/src/main/java/edu/wpi/first/apriltag/AprilTagFields.java b/apriltag/src/main/java/edu/wpi/first/apriltag/AprilTagFields.java
@@ -24,6 +24,8 @@ public enum AprilTagFields {
   /** Resource filename. */
   public final String m_resourceFile;
 
+  AprilTagFieldLayout m_fieldLayout;
+
   AprilTagFields(String resourceFile) {
     m_resourceFile = kBaseResourceDir + resourceFile;
   }