[core] do not call glStencilFunc when we're not clipping

src/mbgl/renderer/bucket.hpp

@@ -38,6 +38,8 @@ class Bucket : private util::noncopyable {
 
     virtual bool hasData() const = 0;
 
+    virtual bool needsClipping() const = 0;
+
     inline bool needsUpload() const {
         return !uploaded;
     }

src/mbgl/renderer/circle_bucket.cpp

@@ -31,6 +31,10 @@ bool CircleBucket::hasData() const {
     return !triangleGroups_.empty();
 }
 
+bool CircleBucket::needsClipping() const {
+    return true;
+}
+
 void CircleBucket::addGeometry(const GeometryCollection& geometryCollection) {
     for (auto& circle : geometryCollection) {
         for(auto & geometry : circle) {

src/mbgl/renderer/circle_bucket.hpp

@@ -23,6 +23,7 @@ class CircleBucket : public Bucket {
     void render(Painter&, const StyleLayer&, const TileID&, const mat4&) override;
 
     bool hasData() const override;
+    bool needsClipping() const override;
     void addGeometry(const GeometryCollection&);
 
     void drawCircles(CircleShader&, gl::GLObjectStore&);

src/mbgl/renderer/fill_bucket.cpp

@@ -206,6 +206,10 @@ bool FillBucket::hasData() const {
     return !triangleGroups.empty() || !lineGroups.empty();
 }
 
+bool FillBucket::needsClipping() const {
+    return true;
+}
+
 void FillBucket::drawElements(PlainShader& shader, gl::GLObjectStore& glObjectStore) {
     GLbyte* vertex_index = BUFFER_OFFSET(0);
     GLbyte* elements_index = BUFFER_OFFSET(0);

src/mbgl/renderer/fill_bucket.hpp

@@ -35,6 +35,7 @@ class FillBucket : public Bucket {
     void upload(gl::GLObjectStore&) override;
     void render(Painter&, const StyleLayer&, const TileID&, const mat4&) override;
     bool hasData() const override;
+    bool needsClipping() const override;
 
     void addGeometry(const GeometryCollection&);
     void tessellate();

src/mbgl/renderer/line_bucket.cpp

@@ -452,6 +452,10 @@ bool LineBucket::hasData() const {
     return !triangleGroups.empty();
 }
 
+bool LineBucket::needsClipping() const {
+    return true;
+}
+
 void LineBucket::drawLines(LineShader& shader, gl::GLObjectStore& glObjectStore) {
     GLbyte* vertex_index = BUFFER_OFFSET(0);
     GLbyte* elements_index = BUFFER_OFFSET(0);

src/mbgl/renderer/line_bucket.hpp

@@ -30,6 +30,7 @@ class LineBucket : public Bucket {
     void upload(gl::GLObjectStore&) override;
     void render(Painter&, const StyleLayer&, const TileID&, const mat4&) override;
     bool hasData() const override;
+    bool needsClipping() const override;
 
     void addGeometry(const GeometryCollection&);
     void addGeometry(const GeometryCoordinates& line);

src/mbgl/renderer/painter.cpp

@@ -74,9 +74,9 @@ bool Painter::needsAnimation() const {
     return frameHistory.needsAnimation(util::DEFAULT_FADE_DURATION);
 }
 
-void Painter::prepareTile(const Tile& tile) {
-    const GLint ref = (GLint)tile.clip.reference.to_ulong();
-    const GLuint mask = (GLuint)tile.clip.mask.to_ulong();
+void Painter::setClipping(const ClipID& clip) {
+    const GLint ref = (GLint)clip.reference.to_ulong();
+    const GLuint mask = (GLuint)clip.mask.to_ulong();
     config.stencilFunc = { GL_EQUAL, ref, mask };
 }
 
@@ -249,7 +249,9 @@ void Painter::renderPass(RenderPass pass_,
             config.setDirty();
         } else {
             MBGL_DEBUG_GROUP(layer.id + " - " + std::string(item.tile->id));
-            prepareTile(*item.tile);
+            if (item.bucket->needsClipping()) {
+                setClipping(item.tile->clip);
+            }
             item.bucket->render(*this, layer, item.tile->id, item.tile->matrix);
         }
     }

src/mbgl/renderer/painter.hpp

@@ -111,7 +111,7 @@ class Painter : private util::noncopyable {
                     Iterator it, Iterator end,
                     GLsizei i, int8_t increment);
 
-    void prepareTile(const Tile& tile);
+    void setClipping(const ClipID&);
 
     template <typename BucketProperties, typename StyleProperties>
     void renderSDF(SymbolBucket &bucket,

src/mbgl/renderer/painter_debug.cpp

@@ -13,7 +13,7 @@ void Painter::renderTileDebug(const Tile& tile) {
     MBGL_DEBUG_GROUP(std::string { "debug " } + std::string(tile.id));
     assert(tile.data);
     if (data.getDebug() != MapDebugOptions::NoDebug) {
-        prepareTile(tile);
+        setClipping(tile.clip);
         if (data.getDebug() & (MapDebugOptions::Timestamps | MapDebugOptions::ParseStatus)) {
             renderDebugText(*tile.data, tile.matrix);
         }

src/mbgl/renderer/raster_bucket.cpp

@@ -37,3 +37,7 @@ void RasterBucket::drawRaster(RasterShader& shader, StaticVertexBuffer &vertices
 bool RasterBucket::hasData() const {
     return raster.isLoaded();
 }
+
+bool RasterBucket::needsClipping() const {
+    return false;
+}

src/mbgl/renderer/raster_bucket.hpp

@@ -17,6 +17,7 @@ class RasterBucket : public Bucket {
     void upload(gl::GLObjectStore&) override;
     void render(Painter&, const StyleLayer&, const TileID&, const mat4&) override;
     bool hasData() const override;
+    bool needsClipping() const override;
 
     void setImage(PremultipliedImage);
 

src/mbgl/renderer/symbol_bucket.cpp

@@ -95,6 +95,10 @@ bool SymbolBucket::hasIconData() const { return renderData && !renderData->icon.
 
 bool SymbolBucket::hasCollisionBoxData() const { return renderData && !renderData->collisionBox.groups.empty(); }
 
+bool SymbolBucket::needsClipping() const {
+    return mode == MapMode::Still;
+}
+
 void SymbolBucket::parseFeatures(const GeometryTileLayer& layer,
                                  const FilterExpression& filter) {
     const bool has_text = !layout.text.field.value.empty() && !layout.text.font.value.empty();

src/mbgl/renderer/symbol_bucket.hpp

@@ -76,6 +76,7 @@ class SymbolBucket : public Bucket {
     bool hasTextData() const;
     bool hasIconData() const;
     bool hasCollisionBoxData() const;
+    bool needsClipping() const override;
 
     void addFeatures(uintptr_t tileUID,
                      SpriteAtlas&,