[core] Introduce SegmentVector

2 files changed, 17 insertions, 3 deletions

diff --git a/src/mbgl/gl/program.hpp b/src/mbgl/gl/program.hpp
index 44c16ae671..01fa51e788 100644
--- a/src/mbgl/gl/program.hpp
+++ b/src/mbgl/gl/program.hpp
@@ -42,7 +42,7 @@ public:
               UniformValues&& uniformValues,
               const VertexBuffer<Vertex>& vertexBuffer,
               const IndexBuffer<DrawMode>& indexBuffer,
-              const std::vector<Segment>& segments) {
+              const SegmentVector<Attributes>& segments) {
         static_assert(std::is_same<Primitive, typename DrawMode::Primitive>::value, "incompatible draw mode");
         context.draw({
             std::move(drawMode),
@@ -66,7 +66,8 @@ public:
               StencilMode stencilMode,
               ColorMode colorMode,
               UniformValues&& uniformValues,
-              const VertexBuffer<Vertex, DrawMode>& vertexBuffer) {
+              const VertexBuffer<Vertex, DrawMode>& vertexBuffer,
+              const SegmentVector<Attributes>& segments) {
         static_assert(std::is_same<Primitive, typename DrawMode::Primitive>::value, "incompatible draw mode");
         context.draw({
             std::move(drawMode),
@@ -76,7 +77,7 @@ public:
             program,
             vertexBuffer.buffer,
             0,
-            {{ 0, 0, vertexBuffer.vertexCount, 0 }},
+            segments,
             Uniforms::binder(uniformsState, std::move(uniformValues)),
             Attributes::binder(attributesState)
         });
diff --git a/src/mbgl/gl/segment.hpp b/src/mbgl/gl/segment.hpp
index f65f2a5f7e..283b4f572a 100644
--- a/src/mbgl/gl/segment.hpp
+++ b/src/mbgl/gl/segment.hpp
@@ -23,5 +23,18 @@ public:
     std::size_t indexLength;
 };
 
+template <class Attributes>
+class SegmentVector : public std::vector<Segment> {
+public:
+    SegmentVector() = default;
+
+    // This constructor is for unindexed rendering. It creates a SegmentVector with a
+    // single segment having 0 indexes.
+    template <class DrawMode>
+    SegmentVector(const VertexBuffer<typename Attributes::Vertex, DrawMode>& buffer) {
+        emplace_back(0, 0, buffer.vertexCount, 0);
+    }
+};
+
 } // namespace gl
 } // namespace mbgl