1 files changed, 88 insertions, 0 deletions
diff --git a/src/mbgl/layer/layer_impl.hpp b/src/mbgl/layer/layer_impl.hpp
new file mode 100644
index 0000000000..3d6b5cccfd
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+++ b/src/mbgl/layer/layer_impl.hpp
@@ -0,0 +1,88 @@
+#pragma once
+
+#include <mbgl/style/layer.hpp>
+#include <mbgl/style/types.hpp>
+#include <mbgl/style/filter.hpp>
+#include <mbgl/renderer/render_pass.hpp>
+#include <mbgl/util/noncopyable.hpp>
+#include <mbgl/util/rapidjson.hpp>
+#include <mbgl/tile/geometry_tile.hpp>
+
+#include <memory>
+#include <string>
+#include <limits>
+
+namespace mbgl {
+
+class StyleCascadeParameters;
+class StyleCalculationParameters;
+class StyleBucketParameters;
+class Bucket;
+
+/**
+ * `Layer::Impl` contains the internal implementation of `Layer`: the details that need to be accessible to other parts
+ * of the code, but hidden from the public API. Like `Layer`, it is an abstract base class, with derived classes for
+ * each layer type.
+ *
+ * Members that are public in `Layer` are part of the public API for all layers.
+ * Members that are public in `FooLayer` are part of the public API for "foo" layers.
+ * Members that are public in `Layer::Impl` are part of the internal API for all layers.
+ * Members that are public in `FooLayer::Impl` are part of the internal API for "foo" layers.
+ * Members that are private in `FooLayer::Impl` are internal to "foo" layers.
+ */
+class Layer::Impl {
+public:
+    virtual ~Impl() = default;
+
+    // Create an identical copy of this layer.
+    virtual std::unique_ptr<Layer> clone() const = 0;
+
+    virtual void parseLayout(const JSValue& value) = 0;
+    virtual void parsePaints(const JSValue& value) = 0;
+
+    // If the layer has a ref, the ref. Otherwise, the id.
+    const std::string& bucketName() const;
+
+    // Partially evaluate paint properties based on a set of classes.
+    virtual void cascade(const StyleCascadeParameters&) = 0;
+
+    // Fully evaluate cascaded paint properties based on a zoom level.
+    // Returns true if any paint properties have active transitions.
+    virtual bool recalculate(const StyleCalculationParameters&) = 0;
+
+    virtual std::unique_ptr<Bucket> createBucket(StyleBucketParameters&) const = 0;
+
+    // Checks whether this layer needs to be rendered in the given render pass.
+    bool hasRenderPass(RenderPass) const;
+
+    // Checks whether this layer can be rendered.
+    bool needsRendering() const;
+
+    virtual float getQueryRadius() const { return 0; }
+    virtual bool queryIntersectsGeometry(
+            const GeometryCollection&,
+            const GeometryCollection&,
+            const float,
+            const float) const { return false; };
+
+public:
+    std::string id;
+    std::string ref;
+    std::string source;
+    std::string sourceLayer;
+    Filter filter;
+    float minZoom = -std::numeric_limits<float>::infinity();
+    float maxZoom = std::numeric_limits<float>::infinity();
+    VisibilityType visibility = VisibilityType::Visible;
+
+protected:
+    Impl() = default;
+    Impl(const Impl&) = default;
+    Impl& operator=(const Impl&) = delete;
+
+    // Stores what render passes this layer is currently enabled for. This depends on the
+    // evaluated StyleProperties object and is updated accordingly.
+    RenderPass passes = RenderPass::None;
+};
+
+} // namespace mbgl