1 files changed, 128 insertions, 0 deletions
diff --git a/src/mbgl/layout/pattern_layout.hpp b/src/mbgl/layout/pattern_layout.hpp
new file mode 100644
index 0000000000..9f4964ca6b
--- /dev/null
+++ b/src/mbgl/layout/pattern_layout.hpp
@@ -0,0 +1,128 @@
+#pragma once
+#include <mbgl/renderer/bucket_parameters.hpp>
+#include <mbgl/geometry/feature_index.hpp>
+#include <mbgl/renderer/render_layer.hpp>
+
+namespace mbgl {
+
+class PatternDependency {
+public:
+    std::string min;
+    std::string mid;
+    std::string max;
+};
+
+using PatternLayerMap = std::unordered_map<std::string, PatternDependency>;
+
+class PatternFeature  {
+public:
+    const uint32_t i;
+    std::unique_ptr<GeometryTileFeature> feature;
+    PatternLayerMap patterns;
+};
+
+template <class B>
+class PatternLayout {
+public:
+    PatternLayout(const BucketParameters& parameters,
+                  const std::vector<const RenderLayer*>& layers,
+                  std::unique_ptr<GeometryTileLayer> sourceLayer_,
+                  ImageDependencies& patternDependencies)
+                  : bucketLeaderID(layers.at(0)->getID()),
+                    sourceLayer(std::move(sourceLayer_)),
+                    zoom(parameters.tileID.overscaledZ),
+                    overscaling(parameters.tileID.overscaleFactor()),
+                    hasPattern(false) {
+
+        using PatternLayer = typename B::RenderLayerType;
+        const auto renderLayer = layers.at(0)->as<PatternLayer>();
+        const typename PatternLayer::StyleLayerImpl& leader = renderLayer->impl();
+        layout = leader.layout.evaluate(PropertyEvaluationParameters(zoom));
+        sourceLayerID = leader.sourceLayer;
+        groupID = renderLayer->getID();
+
+        for (const auto& layer : layers) {
+            const typename B::PossiblyEvaluatedPaintProperties evaluatedProps = layer->as<PatternLayer>()->paintProperties();
+            layerPaintProperties.emplace(layer->getID(), std::move(evaluatedProps));
+            const auto patternProperty = evaluatedProps.template get<typename PatternLayer::PatternProperty>();
+            const auto constantPattern = patternProperty.constantOr(Faded<std::basic_string<char> >{ "", ""});
+            // determine if layer group has any layers that use *-pattern property and add
+            // constant pattern dependencies.
+            if (!patternProperty.isConstant()) {
+                hasPattern = true;
+            } else if (!constantPattern.to.empty()){
+                hasPattern = true;
+                patternDependencies.emplace(constantPattern.to, ImageType::Pattern);
+                patternDependencies.emplace(constantPattern.from, ImageType::Pattern);
+            }
+        }
+
+        const size_t featureCount = sourceLayer->featureCount();
+        for (size_t i = 0; i < featureCount; ++i) {
+            auto feature = sourceLayer->getFeature(i);
+            if (!leader.filter(style::expression::EvaluationContext { this->zoom, feature.get() }))
+                continue;
+
+            std::unordered_map<std::string, PatternDependency> patternDependencyMap;
+            if (hasPattern) {
+                for (const auto& layer : layers) {
+                    const auto it = layerPaintProperties.find(layer->getID());
+                    if (it != layerPaintProperties.end()) {
+                        const auto paint = it->second;
+                        const auto patternProperty = paint.template get<typename PatternLayer::PatternProperty>();
+                        if (!patternProperty.isConstant()) {
+                            // For layers with non-data-constant pattern properties, evaluate their expression and add
+                            // the patterns to the dependency vector
+                            const auto min = patternProperty.evaluate(*feature, zoom - 1, PatternLayer::PatternProperty::defaultValue());
+                            const auto mid = patternProperty.evaluate(*feature, zoom, PatternLayer::PatternProperty::defaultValue());
+                            const auto max = patternProperty.evaluate(*feature, zoom + 1, PatternLayer::PatternProperty::defaultValue());
+
+                            patternDependencies.emplace(min.to, ImageType::Pattern);
+                            patternDependencies.emplace(mid.to, ImageType::Pattern);
+                            patternDependencies.emplace(max.to, ImageType::Pattern);
+                            patternDependencyMap.emplace(layer->getID(), PatternDependency {min.to, mid.to, max.to});
+
+                        }
+                    }
+                }
+            }
+            features.push_back({static_cast<uint32_t>(i), std::move(feature), patternDependencyMap});
+        }
+    };
+
+    bool pattern() {
+        return hasPattern;
+    }
+
+    std::unique_ptr<B> createBucket(const ImagePositions& patternPositions, std::unique_ptr<FeatureIndex>& featureIndex) {
+        auto bucket = std::make_unique<B>(layout, layerPaintProperties, zoom, overscaling);
+        for (auto & patternFeature : features) {
+            const auto i = patternFeature.i;
+            std::unique_ptr<GeometryTileFeature> feature = std::move(patternFeature.feature);
+            PatternLayerMap patterns = patternFeature.patterns;
+            GeometryCollection geometries = feature->getGeometries();
+
+            bucket->addFeature(*feature, geometries, patternPositions, patterns);
+            featureIndex->insert(geometries, i, sourceLayerID, groupID);
+        }
+        return bucket;
+    };
+
+    std::map<std::string, typename B::PossiblyEvaluatedPaintProperties> layerPaintProperties;
+    const std::string bucketLeaderID;
+
+
+private:
+    const std::unique_ptr<GeometryTileLayer> sourceLayer;
+    std::vector<PatternFeature> features;
+    typename B::PossiblyEvaluatedLayoutProperties layout;
+
+    const float zoom;
+    const uint32_t overscaling;
+    std::string sourceLayerID;
+    std::string groupID;
+    bool hasPattern;
+};
+
+} // namespace mbgl
+