1 files changed, 26 insertions, 0 deletions
diff --git a/src/mbgl/renderer/property_evaluator.hpp b/src/mbgl/renderer/property_evaluator.hpp
new file mode 100644
index 0000000000..3ac0573920
--- /dev/null
+++ b/src/mbgl/renderer/property_evaluator.hpp
@@ -0,0 +1,26 @@
+#pragma once
+
+#include <mbgl/style/property_value.hpp>
+#include <mbgl/renderer/property_evaluation_parameters.hpp>
+
+namespace mbgl {
+
+template <typename T>
+class PropertyEvaluator {
+public:
+    using ResultType = T;
+
+    PropertyEvaluator(const PropertyEvaluationParameters& parameters_, T defaultValue_)
+        : parameters(parameters_),
+          defaultValue(std::move(defaultValue_)) {}
+
+    T operator()(const style::Undefined&) const { return defaultValue; }
+    T operator()(const T& constant) const { return constant; }
+    T operator()(const style::CameraFunction<T>& fn) const { return fn.evaluate(parameters.z); }
+
+private:
+    const PropertyEvaluationParameters& parameters;
+    T defaultValue;
+};
+
+} // namespace mbgl