From 116e409fb0f8eaf09584fc9271f6c2e8012218a0 Mon Sep 17 00:00:00 2001
From: Neil C Smith <neilcsmith.net@googlemail.com>
Date: Tue, 16 May 2023 12:26:44 +0100
Subject: [PATCH] Clean up callbacks when disposing of window.

---
 .../java/processing/lwjgl/PSurfaceLWJGL.java  | 26 ++++++++++++++-----
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/processing-lwjgl/src/main/java/processing/lwjgl/PSurfaceLWJGL.java b/processing-lwjgl/src/main/java/processing/lwjgl/PSurfaceLWJGL.java
index 2088347..c5169d2 100644
--- a/processing-lwjgl/src/main/java/processing/lwjgl/PSurfaceLWJGL.java
+++ b/processing-lwjgl/src/main/java/processing/lwjgl/PSurfaceLWJGL.java
@@ -211,6 +211,10 @@ public void initFrame(PApplet sketch) {
       
     this.sketch = sketch;
 
+    if (initCount == 0) {
+        glfwSetErrorCallback(new ErrorHandler());
+    }
+
     if (!glfwInit()) {
       PGraphics.showException("Unable to initialize GLFW");
     }
@@ -219,13 +223,6 @@ public void initFrame(PApplet sketch) {
       System.out.println("GLFW initialized: " + glfwGetVersionString());
     }
 
-    // GLFW error callback
-    addCallback(GLFW::glfwSetErrorCallback, GLFWErrorCallback
-      .create((error, description) -> {
-        String message = MemoryUtil.memUTF8(description);
-        PGraphics.showWarning("GLFW error " + error + ": " + message);
-      }));
-
     // TODO initIcons();
     initDisplay();
 
@@ -1205,11 +1202,17 @@ private void handleRun() {
         
         PApplet.mainThread().runLater(() -> {
             // Need to clean up before exiting
+            Callbacks.glfwFreeCallbacks(window);
+            callbacks.clear();
             glfwDestroyWindow(window);
             glfwPollEvents();
             initCount--;
             if (initCount <= 0) {
                 glfwTerminate();
+                GLFWErrorCallback err = glfwSetErrorCallback(null);
+                if (err != null) {
+                    err.free();
+                }
                 initCount = 0;
             }
             sketch.exitActual();
@@ -1650,4 +1653,13 @@ public void dampenForLowResTicker() {
     }
   }
 
+  private static class ErrorHandler implements GLFWErrorCallbackI {
+    @Override
+    public void invoke(int error, long description) {
+      String message = MemoryUtil.memUTF8(description);
+      PGraphics.showWarning("GLFW error " + error + ": " + message);
+    }
+
+  }
+
 }