From 9190943bda7fde83f9cef1844798e5a1b4ec0dd1 Mon Sep 17 00:00:00 2001
From: Jim Schmitz <james.schmitz@gmail.com>
Date: Fri, 31 Jul 2026 11:16:27 -0400
Subject: [PATCH] fix #1520

---
 core/src/processing/opengl/PGraphicsOpenGL.java | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/core/src/processing/opengl/PGraphicsOpenGL.java b/core/src/processing/opengl/PGraphicsOpenGL.java
index 88164f43e1..b00fa43f92 100644
--- a/core/src/processing/opengl/PGraphicsOpenGL.java
+++ b/core/src/processing/opengl/PGraphicsOpenGL.java
@@ -5512,8 +5512,11 @@ protected void setImpl(PImage sourceImage,
                          int targetX, int targetY) {
     updatePixelSize();
 
-    // Copies the pixels
+    // make sure pixel arrays are available
     loadPixels();
+    sourceImage.loadPixels();
+
+    // Copies the pixels
     int sourceOffset = sourceY * sourceImage.pixelWidth + sourceX;
     int targetOffset = targetY * pixelWidth + targetX;
     for (int y = sourceY; y < sourceY + sourceHeight; y++) {