[core] RenderLayer::setRenderTiles(RenderTiles) -> prepare(LayerPrepareParameters)

RenderLayer::prepare() is responsible for the complete initialization of a render
layer, so that it can render.

src/mbgl/renderer/layers/render_symbol_layer.cpp

@@ -2,6 +2,7 @@
 #include <mbgl/renderer/buckets/symbol_bucket.hpp>
 #include <mbgl/renderer/bucket_parameters.hpp>
 #include <mbgl/renderer/property_evaluation_parameters.hpp>
+#include <mbgl/renderer/render_source.hpp>
 #include <mbgl/renderer/render_tile.hpp>
 #include <mbgl/renderer/upload_parameters.hpp>
 #include <mbgl/renderer/paint_parameters.hpp>
@@ -652,9 +653,9 @@ style::TextPaintProperties::PossiblyEvaluated RenderSymbolLayer::textPaintProper
     };
 }
 
-void RenderSymbolLayer::setRenderTiles(RenderTiles tiles, const TransformState& state) {
-    renderTiles = std::move(tiles);
-    const auto comp = [bearing = state.getBearing()](const RenderTile& a, const RenderTile& b) {
+void RenderSymbolLayer::prepare(const LayerPrepareParameters& params) {
+    renderTiles = params.source->getRenderTiles();
+    const auto comp = [bearing = params.state.getBearing()](const RenderTile& a, const RenderTile& b) {
         Point<float> pa(a.id.canonical.x, a.id.canonical.y);
         Point<float> pb(b.id.canonical.x, b.id.canonical.y);
 

src/mbgl/renderer/layers/render_symbol_layer.hpp

@@ -67,7 +67,7 @@ private:
     bool hasCrossfade() const override;
     void upload(gfx::UploadPass&, UploadParameters&) override;
     void render(PaintParameters&, RenderSource*) override;
-    void setRenderTiles(RenderTiles, const TransformState&) override;
+    void prepare(const LayerPrepareParameters&) override;
 
     // Paint properties
     style::SymbolPaintProperties::Unevaluated unevaluated;

src/mbgl/renderer/render_layer.cpp

@@ -1,5 +1,6 @@
 #include <mbgl/renderer/render_layer.hpp>
 #include <mbgl/renderer/paint_parameters.hpp>
+#include <mbgl/renderer/render_source.hpp>
 #include <mbgl/renderer/render_tile.hpp>
 #include <mbgl/style/types.hpp>
 #include <mbgl/style/layer.hpp>
@@ -44,8 +45,9 @@ bool RenderLayer::supportsZoom(float zoom) const {
     return baseImpl->minZoom <= zoom && baseImpl->maxZoom >= zoom;
 }
 
-void RenderLayer::setRenderTiles(RenderTiles tiles, const TransformState&) {
-    renderTiles = filterRenderTiles(std::move(tiles));
+void RenderLayer::prepare(const LayerPrepareParameters& params) {
+    assert(params.source);
+    renderTiles = filterRenderTiles(params.source->getRenderTiles());
 }
 
 optional<Color> RenderLayer::getSolidBackground() const {

src/mbgl/renderer/render_layer.hpp

@@ -34,6 +34,12 @@ public:
     bool rotateWithMap;
 };
 
+class LayerPrepareParameters {
+public:
+    RenderSource* source;
+    const TransformState& state;
+};
+
 class RenderLayer {
 protected:
     RenderLayer(Immutable<style::LayerProperties>);
@@ -84,8 +90,7 @@ public:
             const float,
             const mat4&) const { return false; };
 
-    using RenderTiles = std::vector<std::reference_wrapper<RenderTile>>;
-    virtual void setRenderTiles(RenderTiles, const TransformState&);
+    virtual void prepare(const LayerPrepareParameters&);
 
     const std::vector<LayerPlacementData>& getPlacementData() const { 
         return placementData; 
@@ -107,6 +112,7 @@ protected:
     void checkRenderability(const PaintParameters&, uint32_t activeBindingCount);
 
 protected:
+    using RenderTiles = std::vector<std::reference_wrapper<RenderTile>>;
     // Stores current set of tiles to be rendered for this layer.
     RenderTiles renderTiles;
 

src/mbgl/renderer/renderer_impl.cpp

@@ -300,13 +300,12 @@ void Renderer::Impl::render(const UpdateParameters& updateParameters) {
         }
     }
 
-    // Set render tiles to the render items.
     for (auto& renderItem : renderItems) {
         if (!renderItem.source) {
             continue;
         }
         RenderLayer& renderLayer = renderItem.layer;
-        renderLayer.setRenderTiles(renderItem.source->getRenderTiles(), updateParameters.transformState);
+        renderLayer.prepare({renderItem.source, updateParameters.transformState});
         if (renderLayer.needsPlacement()) {
             layersNeedPlacement.emplace_back(renderLayer);
         }