[core] split off render layers

1 files changed, 87 insertions, 0 deletions

diff --git a/src/mbgl/renderer/render_layer.hpp b/src/mbgl/renderer/render_layer.hpp
new file mode 100644
index 0000000000..af5345d5e3
--- /dev/null
+++ b/src/mbgl/renderer/render_layer.hpp
@@ -0,0 +1,87 @@
+#pragma once
+
+#include <mbgl/renderer/render_pass.hpp>
+#include <mbgl/style/layer_impl.hpp>
+#include <mbgl/style/layer_type.hpp>
+#include <mbgl/tile/geometry_tile_data.hpp>
+
+#include <memory>
+#include <string>
+
+namespace mbgl {
+
+class Bucket;
+class BucketParameters;
+
+namespace style {
+class CascadeParameters;
+class PropertyEvaluationParameters;
+} // namespace style
+
+class RenderLayer {
+
+protected:
+    RenderLayer(style::LayerType, const style::Layer::Impl&);
+
+    const style::LayerType type;
+
+public:
+
+    virtual ~RenderLayer() = default;
+
+    // Create an identical copy of this layer.
+    virtual std::unique_ptr<RenderLayer> clone() const = 0;
+
+    // Partially evaluate paint properties based on a set of classes.
+    virtual void cascade(const style::CascadeParameters&) = 0;
+
+    // Fully evaluate cascaded paint properties based on a zoom level.
+    // Returns true if any paint properties have active transitions.
+    virtual bool evaluate(const style::PropertyEvaluationParameters&) = 0;
+
+    // Check whether this layer is of the given subtype.
+    template <class T>
+    bool is() const;
+
+    // Dynamically cast this layer to the given subtype.
+    template <class T>
+    T* as() {
+        return is<T>() ? reinterpret_cast<T*>(this) : nullptr;
+    }
+
+    template <class T>
+    const T* as() const {
+        return is<T>() ? reinterpret_cast<const T*>(this) : nullptr;
+    }
+
+    const std::string& getID() const;
+
+    // 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(float zoom) const;
+
+    // Check wether the given geometry intersects
+    // with the feature
+    virtual bool queryIntersectsFeature(
+            const GeometryCoordinates&,
+            const GeometryTileFeature&,
+            const float,
+            const float,
+            const float) const { return false; };
+
+    virtual std::unique_ptr<Bucket> createBucket(const BucketParameters&, const std::vector<const RenderLayer*>&) const = 0;
+
+    // Private implementation
+    const style::Layer::Impl& baseImpl;
+
+    friend std::string layoutKey(const RenderLayer&);
+protected:
+
+    // 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