isFeatureStateDependent

2 files changed, 40 insertions, 0 deletions

diff --git a/src/mbgl/renderer/possibly_evaluated_property_value.hpp b/src/mbgl/renderer/possibly_evaluated_property_value.hpp
index 539df0933..b1fa0c502 100644
--- a/src/mbgl/renderer/possibly_evaluated_property_value.hpp
+++ b/src/mbgl/renderer/possibly_evaluated_property_value.hpp
@@ -26,6 +26,15 @@ public:
         return value.template is<T>();
     }
 
+    bool isFeatureStateDependent() const {
+        return this->match(
+            [&] (const T&) { return false; },
+            [&] (const style::PropertyExpression<T>& expression) {
+                return !expression.isFeatureStateConstant();
+            }
+        );
+    }
+
     optional<T> constant() const {
         return value.match(
             [&] (const T& t) { return optional<T>(t); },
@@ -83,6 +92,15 @@ public:
             [&] (const auto&) { return optional<Faded<T>>(); });
     }
 
+    bool isFeatureStateDependent() const {
+        return value.match(
+            [&] (const Faded<T>&) { return false; },
+            [&] (const style::PropertyExpression<T>& expression) {
+                return !expression.isFeatureStateConstant();
+            }
+        );
+    }
+
     Faded<T> constantOr(const Faded<T>& t) const {
         return constant().value_or(t);
     }
diff --git a/src/mbgl/style/properties.hpp b/src/mbgl/style/properties.hpp
index 1210ed914..ebc6e2ee3 100644
--- a/src/mbgl/style/properties.hpp
+++ b/src/mbgl/style/properties.hpp
@@ -169,6 +169,28 @@ public:
                 evaluate<Ps>(z, feature)...
             };
         }
+
+        template <class T>
+        static bool isFeatureStateDependent(const T&) {
+            return false;
+        }
+
+        template <class T>
+        static bool isFeatureStateDependent(const PossiblyEvaluatedPropertyValue<T>& v) {
+            return v.isFeatureStateDependent();
+        }
+
+        template <class P>
+        bool isFeatureStateDependent() const {
+            return isFeatureStateDependent(this->template get<P>());
+        }
+
+        bool isFeatureStateDependent() const {
+           bool result = false;
+            util::ignore({ result |= isFeatureStateDependent<Ps>()... });
+            return result;
+         }
+
     };
 
     class Unevaluated : public Tuple<UnevaluatedTypes> {