Merge branch 'blender-v4.1-release'

source/blender/draw/DRW_engine.hh

@@ -137,6 +137,11 @@ void DRW_draw_depth_object(
     Scene *scene, ARegion *region, View3D *v3d, GPUViewport *viewport, Object *object);
 void DRW_draw_select_id(Depsgraph *depsgraph, ARegion *region, View3D *v3d);
 
+/**
+ * Query that drawing is in progress (use to prevent nested draw calls).
+ */
+bool DRW_draw_in_progress();
+
 /* Grease pencil render. */
 
 /**

source/blender/draw/intern/draw_manager.h

@@ -650,6 +650,9 @@ typedef struct DRWManager {
 
   bool buffer_finish_called; /* Avoid bad usage of DRW_render_instance_buffer_finish */
 
+  /** True, when drawing is in progress, see #DRW_draw_in_progress. */
+  bool in_progress;
+
   DRWView *view_default;
   DRWView *view_active;
   DRWView *view_previous;

source/blender/draw/intern/draw_manager_c.cc

@@ -517,6 +517,8 @@ static void drw_manager_init(DRWManager *dst, GPUViewport *viewport, const int s
   RegionView3D *rv3d = dst->draw_ctx.rv3d;
   ARegion *region = dst->draw_ctx.region;
 
+  dst->in_progress = true;
+
   int view = (viewport) ? GPU_viewport_active_view_get(viewport) : 0;
 
   if (!dst->viewport && dst->vmempool) {
@@ -647,6 +649,7 @@ static void drw_manager_exit(DRWManager *dst)
   /* Avoid accidental reuse. */
   drw_state_ensure_not_reused(dst);
 #endif
+  dst->in_progress = false;
 }
 
 DefaultFramebufferList *DRW_viewport_framebuffer_list_get()
@@ -2930,6 +2933,11 @@ void DRW_draw_depth_object(
   GPU_framebuffer_free(depth_fb);
 }
 
+bool DRW_draw_in_progress()
+{
+  return DST.in_progress;
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */

source/blender/editors/include/ED_view3d_offscreen.hh

@@ -111,3 +111,10 @@ ImBuf *ED_view3d_draw_offscreen_imbuf_simple(Depsgraph *depsgraph,
                                              GPUOffScreen *ofs,
                                              GPUViewport *viewport,
                                              char err_out[256]);
+
+/**
+ * Drawing off-screen is not supported while drawing,
+ * this is a simple check to use when the code path may occur within a draw call
+ * (Python scripting for example).
+ */
+bool ED_view3d_draw_offscreen_check_nested();

source/blender/editors/space_view3d/view3d_draw.cc

@@ -2144,6 +2144,11 @@ ImBuf *ED_view3d_draw_offscreen_imbuf_simple(Depsgraph *depsgraph,
                                         err_out);
 }
 
+bool ED_view3d_draw_offscreen_check_nested()
+{
+  return DRW_draw_in_progress();
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */

source/blender/python/gpu/gpu_py_offscreen.cc

@@ -449,6 +449,13 @@ static PyObject *pygpu_offscreen_draw_view3d(BPyGPUOffScreen *self, PyObject *ar
     return nullptr;
   }
 
+  if (ED_view3d_draw_offscreen_check_nested()) {
+    /* NOTE(@ideasman42): Nested draw calls could be supported.
+     * Adding support for this looks to be possible but non-trivial. */
+    PyErr_SetString(PyExc_RuntimeError, "Nested off-screen drawing not supported");
+    return nullptr;
+  }
+
   BLI_assert(BKE_id_is_in_global_main(&scene->id));
 
   depsgraph = BKE_scene_ensure_depsgraph(G_MAIN, scene, view_layer);