[core] add getResource template to gfx::*Resource classes

1 files changed, 11 insertions, 0 deletions

diff --git a/src/mbgl/gfx/draw_scope.hpp b/src/mbgl/gfx/draw_scope.hpp
index 60aae7a44c..5cdb588317 100644
--- a/src/mbgl/gfx/draw_scope.hpp
+++ b/src/mbgl/gfx/draw_scope.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <memory>
+#include <cassert>
 
 namespace mbgl {
 namespace gfx {
@@ -14,6 +15,16 @@ public:
 
 class DrawScope {
 public:
+    explicit DrawScope(std::unique_ptr<DrawScopeResource> resource_) : resource(std::move(resource_)) {
+    }
+
+    template <typename T = DrawScopeResource>
+    T& getResource() const {
+        assert(resource);
+        return static_cast<T&>(*resource);
+    }
+
+protected:
     std::unique_ptr<DrawScopeResource> resource;
 };