From fc672bcdff57820d30826159acd5830397c79309 Mon Sep 17 00:00:00 2001
From: Duncan Tourolle <duncan@tourolle.paris>
Date: Thu, 27 Nov 2025 13:40:43 +0100
Subject: [PATCH] only make textures when GL context exists

---
 pyPhotoAlbum/models.py | 59 ++++++++++++++++++++++++++++++++++--------
 1 file changed, 48 insertions(+), 11 deletions(-)

diff --git a/pyPhotoAlbum/models.py b/pyPhotoAlbum/models.py
index 5d57491..f3b0782 100644
--- a/pyPhotoAlbum/models.py
+++ b/pyPhotoAlbum/models.py
@@ -199,6 +199,11 @@ class ImageData(BaseLayoutElement):
         # The actual image will be loaded in the background and the texture created
         # via _on_async_image_loaded() callback when ready
 
+        # Create texture from pending image if one exists (deferred from async load)
+        # This ensures texture creation happens when GL context is active
+        if hasattr(self, '_pending_pil_image') and self._pending_pil_image is not None:
+            self._create_texture_from_pending_image()
+
         # Use cached texture if available
         if hasattr(self, '_texture_id') and self._texture_id:
             texture_id = self._texture_id
@@ -337,12 +342,13 @@ class ImageData(BaseLayoutElement):
         """
         Callback when async image loading completes.
 
+        NOTE: This is called from a signal, potentially before GL context is ready.
+        We store the image and create the texture during the next render() call
+        when the GL context is guaranteed to be active.
+
         Args:
             pil_image: Loaded PIL Image (already RGBA, already resized)
         """
-        from OpenGL.GL import (glGenTextures, glBindTexture, glTexImage2D, GL_TEXTURE_2D,
-                               glTexParameteri, GL_TEXTURE_MIN_FILTER, GL_TEXTURE_MAG_FILTER,
-                               GL_LINEAR, GL_RGBA, GL_UNSIGNED_BYTE, glDeleteTextures)
         from PIL import Image
 
         try:
@@ -359,6 +365,38 @@ class ImageData(BaseLayoutElement):
                     pil_image = pil_image.transpose(Image.ROTATE_90)  # CCW 270 = rotate left
                 print(f"ImageData: Applied PIL rotation {angle}° to {self.image_path}")
 
+            # Store the image for texture creation during next render()
+            # This avoids GL context issues when callback runs on wrong thread/timing
+            self._pending_pil_image = pil_image
+            self._img_width = pil_image.width
+            self._img_height = pil_image.height
+            self._async_loading = False
+
+            # Update metadata for future renders - always update to reflect rotated dimensions
+            self.image_dimensions = (pil_image.width, pil_image.height)
+
+            # print(f"ImageData: Image ready for texture creation: {self.image_path}")
+
+        except Exception as e:
+            print(f"ImageData: Error processing async loaded image: {e}")
+            self._pending_pil_image = None
+            self._async_loading = False
+
+    def _create_texture_from_pending_image(self):
+        """
+        Create OpenGL texture from pending PIL image.
+        Called during render() when GL context is active.
+        """
+        if not hasattr(self, '_pending_pil_image') or self._pending_pil_image is None:
+            return False
+
+        from OpenGL.GL import (glGenTextures, glBindTexture, glTexImage2D, GL_TEXTURE_2D,
+                               glTexParameteri, GL_TEXTURE_MIN_FILTER, GL_TEXTURE_MAG_FILTER,
+                               GL_LINEAR, GL_RGBA, GL_UNSIGNED_BYTE, glDeleteTextures)
+
+        try:
+            pil_image = self._pending_pil_image
+
             # Delete old texture if it exists
             if hasattr(self, '_texture_id') and self._texture_id:
                 glDeleteTextures([self._texture_id])
@@ -376,19 +414,18 @@ class ImageData(BaseLayoutElement):
             # Cache texture
             self._texture_id = texture_id
             self._texture_path = self.image_path
-            self._img_width = pil_image.width
-            self._img_height = pil_image.height
-            self._async_loading = False
 
-            # Update metadata for future renders - always update to reflect rotated dimensions
-            self.image_dimensions = (pil_image.width, pil_image.height)
+            # Clear pending image to free memory
+            self._pending_pil_image = None
 
-            # print(f"ImageData: Async loaded texture for {self.image_path}")
+            # print(f"ImageData: Created texture for {self.image_path}")
+            return True
 
         except Exception as e:
-            print(f"ImageData: Error creating texture from async loaded image: {e}")
+            print(f"ImageData: Error creating texture: {e}")
             self._texture_id = None
-            self._async_loading = False
+            self._pending_pil_image = None
+            return False
 
     def _on_async_image_load_failed(self, error_msg: str):
         """