From 83a1bd4e1d329eac66a4acbabb91f5ccd8847912 Mon Sep 17 00:00:00 2001
From: Miguel Pozo <pragma37@gmail.com>
Date: Thu, 9 Oct 2025 16:58:25 +0200
Subject: [PATCH] Fix #145750: Overlay: Attempt to index a handle range as a
 single handle

This fixes the resource indexing logic, but it looks like the flat
object outline workaround has been broken since 4.4.

Pull Request: https://projects.blender.org/blender/blender/pulls/147703
---
 .../draw/engines/overlay/overlay_outline.hh   |  4 ++--
 .../draw/engines/overlay/overlay_private.hh   | 24 ++++++++++---------
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/source/blender/draw/engines/overlay/overlay_outline.hh b/source/blender/draw/engines/overlay/overlay_outline.hh
index 54b5791e42e..f872ad1ecd1 100644
--- a/source/blender/draw/engines/overlay/overlay_outline.hh
+++ b/source/blender/draw/engines/overlay/overlay_outline.hh
@@ -210,8 +210,8 @@ class Outline : Overlay {
 
       for (FlatObjectRef flag_ob_ref : flat_objects_) {
         flag_ob_ref.if_flat_axis_orthogonal_to_view(
-            manager, view, [&](gpu::Batch *geom, ResourceHandleRange handle) {
-              pass.draw_expand(geom, GPU_PRIM_LINES, 1, 1, handle);
+            manager, view, [&](gpu::Batch *geom, ResourceIndex resource_index) {
+              pass.draw_expand(geom, GPU_PRIM_LINES, 1, 1, resource_index);
             });
       }
     }
diff --git a/source/blender/draw/engines/overlay/overlay_private.hh b/source/blender/draw/engines/overlay/overlay_private.hh
index 5380a57ad74..c433bb7e53c 100644
--- a/source/blender/draw/engines/overlay/overlay_private.hh
+++ b/source/blender/draw/engines/overlay/overlay_private.hh
@@ -1014,24 +1014,26 @@ struct FlatObjectRef {
     return -1;
   }
 
-  using Callback = FunctionRef<void(gpu::Batch *geom, ResourceHandleRange handle)>;
+  using Callback = FunctionRef<void(gpu::Batch *geom, ResourceIndex handle)>;
 
   /* Execute callback for every handles that is orthogonal to the view.
    * Note: Only works in orthogonal view. */
   void if_flat_axis_orthogonal_to_view(Manager &manager, const View &view, Callback callback) const
   {
-    const float4x4 &object_to_world =
-        manager.matrix_buf.current().get_or_resize(handle.resource_index()).model;
+    for (ResourceIndex resource_index : handle.index_range()) {
+      const float4x4 &object_to_world =
+          manager.matrix_buf.current().get_or_resize(resource_index.resource_index()).model;
 
-    float3 view_forward = view.forward();
-    float3 axis_not_flat_a = (flattened_axis_id == 0) ? object_to_world.y_axis() :
-                                                        object_to_world.x_axis();
-    float3 axis_not_flat_b = (flattened_axis_id == 1) ? object_to_world.z_axis() :
-                                                        object_to_world.y_axis();
-    float3 axis_flat = math::cross(axis_not_flat_a, axis_not_flat_b);
+      float3 view_forward = view.forward();
+      float3 axis_not_flat_a = (flattened_axis_id == 0) ? object_to_world.y_axis() :
+                                                          object_to_world.x_axis();
+      float3 axis_not_flat_b = (flattened_axis_id == 1) ? object_to_world.z_axis() :
+                                                          object_to_world.y_axis();
+      float3 axis_flat = math::cross(axis_not_flat_a, axis_not_flat_b);
 
-    if (math::abs(math::dot(view_forward, axis_flat)) < 1e-3f) {
-      callback(geom, handle);
+      if (math::abs(math::dot(view_forward, axis_flat)) < 1e-3f) {
+        callback(geom, resource_index);
+      }
     }
   }
 };