From 8e5214144ec4f3a4fb40b7a7e4d8f09fd10dbb78 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Konstantin=20K=C3=A4fer?= <mail@kkaefer.com>
Date: Mon, 27 Feb 2017 18:33:16 +0100
Subject: [core] Ensure that a BackendScope exists when doing GL calls

---
 include/mbgl/map/backend_scope.hpp | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

(limited to 'include/mbgl/map')

diff --git a/include/mbgl/map/backend_scope.hpp b/include/mbgl/map/backend_scope.hpp
index 5a207e6ac4..4985cd197f 100644
--- a/include/mbgl/map/backend_scope.hpp
+++ b/include/mbgl/map/backend_scope.hpp
@@ -6,13 +6,26 @@ class Backend;
 
 class BackendScope {
 public:
-    BackendScope(Backend&);
+    // There are two types of scopes: Creating an "Implicit" scope tells Mapbox GL that the
+    // supporting windowing system has already activated the GL Backend and that no further actions
+    // are required. Creating an "Explicit" scope actually enables the GL Backend, and disables it
+    // when the BackendScope is destroyed.
+    enum class ScopeType : bool {
+        Implicit,
+        Explicit,
+    };
+
+    BackendScope(Backend&, ScopeType = ScopeType::Explicit);
     ~BackendScope();
 
+    // Returns true when there is currently a BackendScope active in this thread.
+    static bool exists();
+
 private:
     BackendScope* priorScope;
     BackendScope* nextScope;
     Backend& backend;
+    const ScopeType scopeType;
 };
 
 } // namespace mbgl
-- 
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