[core] Render fill-extrusion layers (#8431)

1 files changed, 74 insertions, 0 deletions

diff --git a/src/mbgl/style/light_impl.hpp b/src/mbgl/style/light_impl.hpp
new file mode 100644
index 0000000000..d1825090fc
--- /dev/null
+++ b/src/mbgl/style/light_impl.hpp
@@ -0,0 +1,74 @@
+#pragma once
+
+#include <mbgl/style/light.hpp>
+#include <mbgl/style/transitioning_property.hpp>
+#include <mbgl/style/cascade_parameters.hpp>
+#include <mbgl/style/property_evaluator.hpp>
+#include <mbgl/style/property_evaluation_parameters.hpp>
+#include <mbgl/util/ignore.hpp>
+
+namespace mbgl {
+namespace style {
+
+template <class TypeList>
+class Transitioning;
+
+template <class... Ps>
+class Transitioning<TypeList<Ps...>> : public IndexedTuple<
+    TypeList<Ps...>,
+    TypeList<TransitioningProperty<typename Ps::ValueType>...>>
+{
+private:
+    using Properties = TypeList<Ps...>;
+    using Raw = IndexedTuple<Properties, Properties>;
+    using Super = IndexedTuple<
+        TypeList<Ps...>,
+        TypeList<TransitioningProperty<typename Ps::ValueType>...>>;
+
+public:
+    Transitioning() = default;
+    Transitioning(const Raw& raw, Transitioning&& prior, const CascadeParameters& params)
+        : Super {
+            TransitioningProperty<typename Ps::ValueType>(
+                raw.template get<Ps>().value,
+                std::move(prior.template get<Ps>()),
+                raw.template get<Ps>().transition.reverseMerge(params.transition),
+                params.now)...
+        } {}
+
+    bool hasTransition() const {
+        bool result = false;
+        util::ignore({ result |= this->template get<Ps>().hasTransition()... });
+        return result;
+    }
+};
+
+template <class TypeList>
+class Evaluated;
+
+template <class... Ps>
+class Evaluated<TypeList<Ps...>> : public IndexedTuple<
+    TypeList<Ps...>,
+    TypeList<typename Ps::Type...>>
+{
+private:
+    using Properties = TypeList<Ps...>;
+    using TransitioningPs = Transitioning<Properties>;
+    using Super = IndexedTuple<
+        TypeList<Ps...>,
+        TypeList<typename Ps::Type...>>;
+
+public:
+    Evaluated() = default;
+    Evaluated(TransitioningPs& transitioning, const PropertyEvaluationParameters& params)
+        : Super {
+            transitioning.template get<Ps>()
+                .evaluate(PropertyEvaluator<typename Ps::Type>(params, Ps::defaultValue()), params.now)...
+        } {}
+};
+
+using TransitioningLight = Transitioning<LightProperties>;
+using EvaluatedLight     = Evaluated<LightProperties>;
+
+} // namespace style
+} // namespace mbgl