[core] Use gl::Program to resolve some rough edges in the GL binding types

* Extract `ignore` util to separate header.
* `Segment` now tracks offset and length of indices, rather than primitives. This is more natural.
* Introduce `VertexVector` and `IndexVector` types. These types carry information about the intended draw mode (`Triangles`, `LineStrip`, etc.), and ensure that elements are always appended in a group size appropriate for that draw mode, for both indexed and unindexed rendering.
* `Program`, rather than `Drawable`, is now the unifying object for draw calls. `Program` is the best place to type check the draw call, because it is typed to carry information about the intended primitive, vertex type, attributes, and uniforms.
* Use the debug shaders for debug tile rendering, like gl-js.
* Fix the draw mode for background. It was drawing triangle strips with a triangles array. Surprised this didn’t cause issues. Now it’s type checked.

42 files changed, 472 insertions, 359 deletions

diff --git a/cmake/core-files.cmake b/cmake/core-files.cmake
index 7a2ed33281..45305fdd65 100644
--- a/cmake/core-files.cmake
+++ b/cmake/core-files.cmake
@@ -65,7 +65,6 @@ set(MBGL_CORE_FILES
     src/mbgl/gl/depth_mode.cpp
     src/mbgl/gl/depth_mode.hpp
     src/mbgl/gl/draw_mode.hpp
-    src/mbgl/gl/drawable.hpp
     src/mbgl/gl/extension.cpp
     src/mbgl/gl/extension.hpp
     src/mbgl/gl/framebuffer.hpp
@@ -73,6 +72,7 @@ set(MBGL_CORE_FILES
     src/mbgl/gl/index_buffer.hpp
     src/mbgl/gl/object.cpp
     src/mbgl/gl/object.hpp
+    src/mbgl/gl/primitives.hpp
     src/mbgl/gl/program.hpp
     src/mbgl/gl/renderbuffer.hpp
     src/mbgl/gl/segment.hpp
@@ -154,6 +154,7 @@ set(MBGL_CORE_FILES
     src/mbgl/programs/circle_program.hpp
     src/mbgl/programs/collision_box_program.cpp
     src/mbgl/programs/collision_box_program.hpp
+    src/mbgl/programs/debug_program.hpp
     src/mbgl/programs/fill_program.cpp
     src/mbgl/programs/fill_program.hpp
     src/mbgl/programs/line_program.cpp
diff --git a/src/mbgl/gl/attribute.hpp b/src/mbgl/gl/attribute.hpp
index 126da38de5..a2b165fa21 100644
--- a/src/mbgl/gl/attribute.hpp
+++ b/src/mbgl/gl/attribute.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <mbgl/gl/types.hpp>
+#include <mbgl/util/ignore.hpp>
 
 #include <cstddef>
 #include <functional>
@@ -157,17 +158,14 @@ private:
     template <std::size_t... Is>
     static std::function<void (std::size_t)> binder(const State& state, std::index_sequence<Is...>) {
         return [&state] (std::size_t vertexOffset) {
-            noop((bindAttribute(std::get<Is>(state).location,
-                                std::get<Is>(state).count,
-                                std::get<Is>(state).type,
-                                sizeof(Vertex),
-                                vertexOffset,
-                                Vertex::attributeOffsets[Is]), 0)...);
+            ignore((bindAttribute(std::get<Is>(state).location,
+                                  std::get<Is>(state).count,
+                                  std::get<Is>(state).type,
+                                  sizeof(Vertex),
+                                  vertexOffset,
+                                  Vertex::attributeOffsets[Is]), 0)...);
         };
     }
-
-    // This exists only to provide a varags context for unpacking the assignments in `binder`.
-    template <int...> static void noop(int...) {}
 };
 
 } // namespace gl
diff --git a/src/mbgl/gl/context.cpp b/src/mbgl/gl/context.cpp
index b12c77c1a1..c4485ad0fd 100644
--- a/src/mbgl/gl/context.cpp
+++ b/src/mbgl/gl/context.cpp
@@ -533,9 +533,9 @@ void Context::draw(const Drawable& drawable) {
         if (drawable.indexBuffer) {
             MBGL_CHECK_ERROR(glDrawElements(
                 static_cast<GLenum>(primitiveType),
-                static_cast<GLsizei>(drawable.primitiveSize / sizeof(uint16_t) * segment.primitiveLength),
+                static_cast<GLsizei>(segment.indexLength),
                 GL_UNSIGNED_SHORT,
-                reinterpret_cast<GLvoid*>(drawable.primitiveSize * segment.primitiveOffset)));
+                reinterpret_cast<GLvoid*>(sizeof(uint16_t) * segment.indexOffset)));
         } else {
             MBGL_CHECK_ERROR(glDrawArrays(
                 static_cast<GLenum>(primitiveType),
diff --git a/src/mbgl/gl/context.hpp b/src/mbgl/gl/context.hpp
index 2a3fbea33d..154921a1b9 100644
--- a/src/mbgl/gl/context.hpp
+++ b/src/mbgl/gl/context.hpp
@@ -8,9 +8,16 @@
 #include <mbgl/gl/framebuffer.hpp>
 #include <mbgl/gl/vertex_buffer.hpp>
 #include <mbgl/gl/index_buffer.hpp>
-#include <mbgl/gl/drawable.hpp>
+#include <mbgl/gl/types.hpp>
+#include <mbgl/gl/draw_mode.hpp>
+#include <mbgl/gl/depth_mode.hpp>
+#include <mbgl/gl/stencil_mode.hpp>
+#include <mbgl/gl/color_mode.hpp>
+#include <mbgl/gl/segment.hpp>
 #include <mbgl/util/noncopyable.hpp>
 
+
+#include <functional>
 #include <memory>
 #include <vector>
 #include <array>
@@ -33,18 +40,18 @@ public:
     UniqueProgram createProgram(ShaderID vertexShader, ShaderID fragmentShader);
     UniqueTexture createTexture();
 
-    template <class V>
-    VertexBuffer<V> createVertexBuffer(std::vector<V>&& v) {
-        return VertexBuffer<V> {
-            v.size(),
-            createVertexBuffer(v.data(), v.size() * sizeof(V))
+    template <class Vertex, class DrawMode>
+    VertexBuffer<Vertex, DrawMode> createVertexBuffer(VertexVector<Vertex, DrawMode>&& v) {
+        return VertexBuffer<Vertex, DrawMode> {
+            v.vertexSize(),
+            createVertexBuffer(v.data(), v.byteSize())
         };
     }
 
-    template <class P>
-    IndexBuffer<P> createIndexBuffer(std::vector<P>&& v) {
-        return IndexBuffer<P> {
-            createIndexBuffer(v.data(), v.size() * sizeof(P))
+    template <class DrawMode>
+    IndexBuffer<DrawMode> createIndexBuffer(IndexVector<DrawMode>&& v) {
+        return IndexBuffer<DrawMode> {
+            createIndexBuffer(v.data(), v.byteSize())
         };
     }
 
@@ -111,6 +118,19 @@ public:
                optional<float> depth,
                optional<int32_t> stencil);
 
+    struct Drawable {
+        DrawMode drawMode;
+        DepthMode depthMode;
+        StencilMode stencilMode;
+        ColorMode colorMode;
+        gl::ProgramID program;
+        gl::BufferID vertexBuffer;
+        gl::BufferID indexBuffer;
+        const std::vector<Segment>& segments;
+        std::function<void ()> bindUniforms;
+        std::function<void (std::size_t)> bindAttributes;
+    };
+
     void draw(const Drawable&);
 
     void setDepthMode(const DepthMode&);
diff --git a/src/mbgl/gl/draw_mode.hpp b/src/mbgl/gl/draw_mode.hpp
index a379162210..8f7db0a3fa 100644
--- a/src/mbgl/gl/draw_mode.hpp
+++ b/src/mbgl/gl/draw_mode.hpp
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <mbgl/gl/primitives.hpp>
 #include <mbgl/util/variant.hpp>
 
 namespace mbgl {
@@ -7,21 +8,50 @@ namespace gl {
 
 class Points {
 public:
+    using Primitive = Point;
+    static constexpr std::size_t bufferGroupSize = 1;
+
     float pointSize;
 };
 
 class Lines {
 public:
+    using Primitive = Line;
+    static constexpr std::size_t bufferGroupSize = 2;
+
     float lineWidth;
 };
 
 class LineStrip {
 public:
+    // LineStrip is a form of "Line" rendering, but the element buffer
+    // cannot be grouped into logical elements beyond a single Point.
+    using Primitive = Line;
+    static constexpr std::size_t bufferGroupSize = 1;
+
     float lineWidth;
 };
 
-class Triangles {};
-class TriangleStrip {};
+class Triangles {
+public:
+    using Primitive = Triangle;
+    static constexpr std::size_t bufferGroupSize = 3;
+};
+
+class TriangleStrip {
+public:
+    // TriangleStrip is a form of "Triangle" rendering, but the element buffer
+    // cannot be grouped into logical elements beyond a single Point.
+    using Primitive = Triangle;
+    static constexpr std::size_t bufferGroupSize = 1;
+};
+
+// Special draw mode for use with VertexVector<Indexed, Vertex>, in which
+// case the true draw mode is denoted by the IndexVector type.
+class Indexed {
+public:
+    static constexpr std::size_t bufferGroupSize = 1;
+};
 
 using DrawMode = variant<
     Points,
diff --git a/src/mbgl/gl/drawable.hpp b/src/mbgl/gl/drawable.hpp
deleted file mode 100644
index 747d8facf0..0000000000
--- a/src/mbgl/gl/drawable.hpp
+++ /dev/null
@@ -1,124 +0,0 @@
-#pragma once
-
-#include <mbgl/gl/types.hpp>
-#include <mbgl/gl/draw_mode.hpp>
-#include <mbgl/gl/depth_mode.hpp>
-#include <mbgl/gl/stencil_mode.hpp>
-#include <mbgl/gl/color_mode.hpp>
-#include <mbgl/gl/vertex_buffer.hpp>
-#include <mbgl/gl/index_buffer.hpp>
-#include <mbgl/gl/attribute.hpp>
-#include <mbgl/gl/uniform.hpp>
-#include <mbgl/gl/segment.hpp>
-
-#include <cstddef>
-#include <functional>
-#include <limits>
-#include <vector>
-
-namespace mbgl {
-namespace gl {
-
-template <class Vertex>
-class UnindexedVertices {
-public:
-    using VertexType = Vertex;
-
-    UnindexedVertices(DrawMode drawMode_, const VertexBuffer<Vertex>& vertexBuffer_)
-        : drawMode(std::move(drawMode_)),
-          vertexBuffer(vertexBuffer_.buffer),
-          segments({{ 0, 0, vertexBuffer_.vertexCount, 0 }}) {}
-
-    DrawMode drawMode;
-    gl::BufferID vertexBuffer;
-    static constexpr std::size_t vertexSize = sizeof(Vertex);
-    static constexpr gl::BufferID indexBuffer = 0;
-    static constexpr std::size_t primitiveSize = 0;
-    std::vector<Segment> segments;
-};
-
-template <class DrawMode, class Vertex, class...Args>
-auto Unindexed(const VertexBuffer<Vertex>& vertexBuffer,
-               Args&&... drawModeArguments) {
-    return UnindexedVertices<Vertex>(
-        DrawMode { std::forward<Args>(drawModeArguments)... },
-        vertexBuffer);
-}
-
-template <class Vertex, class Primitive>
-class SegmentedVertices {
-public:
-    using VertexType = Vertex;
-
-    SegmentedVertices(DrawMode drawMode_,
-                      const VertexBuffer<Vertex>& vertexBuffer_,
-                      const IndexBuffer<Primitive>& indexBuffer_,
-                      const std::vector<Segment>& segments_)
-        : drawMode(std::move(drawMode_)),
-          vertexBuffer(vertexBuffer_.buffer),
-          indexBuffer(indexBuffer_.buffer),
-          segments(segments_) {}
-
-    DrawMode drawMode;
-    gl::BufferID vertexBuffer;
-    static constexpr std::size_t vertexSize = sizeof(Vertex);
-    gl::BufferID indexBuffer;
-    static constexpr std::size_t primitiveSize = sizeof(Primitive);
-    const std::vector<Segment>& segments;
-};
-
-template <class DrawMode, class Vertex, class Primitive, class...Args>
-auto Segmented(const VertexBuffer<Vertex>& vertexBuffer,
-               const IndexBuffer<Primitive>& indexBuffer,
-               const std::vector<Segment>& segments,
-               Args&&... drawModeArguments) {
-    static_assert(std::is_same<typename Primitive::DrawMode, DrawMode>::value, "primitive mode mismatch");
-    return SegmentedVertices<Vertex, Primitive>(
-        DrawMode { std::forward<Args>(drawModeArguments)... },
-        vertexBuffer,
-        indexBuffer,
-        segments);
-}
-
-class Drawable {
-public:
-    template <class Program, class Subject>
-    Drawable(DepthMode depthMode_,
-             StencilMode stencilMode_,
-             ColorMode colorMode_,
-             Program& program_,
-             typename Program::UniformValues&& uniformValues,
-             const Subject& subject)
-        : drawMode(subject.drawMode),
-          depthMode(std::move(depthMode_)),
-          stencilMode(std::move(stencilMode_)),
-          colorMode(std::move(colorMode_)),
-          program(program_.program),
-          vertexBuffer(subject.vertexBuffer),
-          vertexSize(subject.vertexSize),
-          indexBuffer(subject.indexBuffer),
-          primitiveSize(subject.primitiveSize),
-          segments(subject.segments),
-          bindUniforms(Program::Uniforms::binder(program_.uniformsState, std::move(uniformValues))),
-          bindAttributes(Program::Attributes::binder(program_.attributesState))
-    {
-        static_assert(std::is_standard_layout<typename Program::Vertex>::value, "vertex type must use standard layout");
-        static_assert(std::is_same<typename Program::Vertex, typename Subject::VertexType>::value, "vertex type mismatch");
-    }
-
-    DrawMode drawMode;
-    DepthMode depthMode;
-    StencilMode stencilMode;
-    ColorMode colorMode;
-    gl::ProgramID program;
-    gl::BufferID vertexBuffer;
-    std::size_t vertexSize;
-    gl::BufferID indexBuffer;
-    std::size_t primitiveSize;
-    const std::vector<Segment>& segments;
-    std::function<void ()> bindUniforms;
-    std::function<void (std::size_t)> bindAttributes;
-};
-
-} // namespace gl
-} // namespace mbgl
diff --git a/src/mbgl/gl/index_buffer.hpp b/src/mbgl/gl/index_buffer.hpp
index 5d8630b902..8b40bf68c3 100644
--- a/src/mbgl/gl/index_buffer.hpp
+++ b/src/mbgl/gl/index_buffer.hpp
@@ -2,39 +2,37 @@
 
 #include <mbgl/gl/object.hpp>
 #include <mbgl/gl/draw_mode.hpp>
+#include <mbgl/util/ignore.hpp>
+
+#include <vector>
 
 namespace mbgl {
 namespace gl {
 
-class Line {
+template <class DrawMode>
+class IndexVector {
 public:
-    using DrawMode = Lines;
-
-    Line(uint16_t a_, uint16_t b_)
-        : a(a_), b(b_) {}
+    static constexpr std::size_t groupSize = DrawMode::bufferGroupSize;
 
-    uint16_t a;
-    uint16_t b;
-};
+    template <class... Args>
+    void emplace_back(Args&&... args) {
+        static_assert(sizeof...(args) == groupSize, "wrong buffer element count");
+        ignore({(v.emplace_back(std::forward<Args>(args)), 0)...});
+    }
 
-class Triangle {
-public:
-    using DrawMode = Triangles;
+    std::size_t indexSize() const { return v.size(); }
+    std::size_t byteSize() const { return v.size() * sizeof(uint16_t); }
 
-    Triangle(uint16_t a_, uint16_t b_, uint16_t c_)
-        : a(a_), b(b_), c(c_) {}
+    bool empty() const { return v.empty(); }
+    const uint16_t* data() const { return v.data(); }
 
-    uint16_t a;
-    uint16_t b;
-    uint16_t c;
+private:
+    std::vector<uint16_t> v;
 };
 
-template <class Primitive>
+template <class DrawMode>
 class IndexBuffer {
 public:
-    static_assert(std::is_same<Primitive, Line>::value || std::is_same<Primitive, Triangle>::value,
-                  "primitive must be Line or Triangle");
-    static constexpr std::size_t primitiveSize = sizeof(Primitive);
     UniqueBuffer buffer;
 };
 
diff --git a/src/mbgl/gl/primitives.hpp b/src/mbgl/gl/primitives.hpp
new file mode 100644
index 0000000000..fe6b1b2e5b
--- /dev/null
+++ b/src/mbgl/gl/primitives.hpp
@@ -0,0 +1,22 @@
+#pragma once
+
+namespace mbgl {
+namespace gl {
+
+class Point {
+public:
+    static constexpr std::size_t vertexCount = 1;
+};
+
+class Line {
+public:
+    static constexpr std::size_t vertexCount = 2;
+};
+
+class Triangle {
+public:
+    static constexpr std::size_t vertexCount = 3;
+};
+
+} // namespace gl
+} // namespace mbgl
diff --git a/src/mbgl/gl/program.hpp b/src/mbgl/gl/program.hpp
index ea4dbcc1df..929237037b 100644
--- a/src/mbgl/gl/program.hpp
+++ b/src/mbgl/gl/program.hpp
@@ -3,21 +3,28 @@
 #include <mbgl/gl/types.hpp>
 #include <mbgl/gl/object.hpp>
 #include <mbgl/gl/context.hpp>
+#include <mbgl/gl/vertex_buffer.hpp>
+#include <mbgl/gl/index_buffer.hpp>
+#include <mbgl/gl/attribute.hpp>
+#include <mbgl/gl/uniform.hpp>
 
 #include <string>
 
 namespace mbgl {
 namespace gl {
 
-template <class As, class Us>
+template <class P, class As, class Us>
 class Program {
 public:
+    using Primitive = P;
     using Attributes = As;
-    using Vertex = typename Attributes::Vertex;
-
     using Uniforms = Us;
+
+    using Vertex = typename Attributes::Vertex;
     using UniformValues = typename Uniforms::Values;
 
+    static_assert(std::is_standard_layout<Vertex>::value, "vertex type must use standard layout");
+
     Program(Context& context, const std::string& vertexSource, const std::string& fragmentSource)
         : vertexShader(context.createShader(ShaderType::Vertex, vertexSource)),
           fragmentShader(context.createShader(ShaderType::Fragment, fragmentSource)),
@@ -25,6 +32,57 @@ public:
           attributesState(Attributes::state(program)),
           uniformsState(Uniforms::state(program)) {}
 
+    // Indexed drawing.
+    template <class DrawMode>
+    void draw(Context& context,
+              DrawMode drawMode,
+              DepthMode depthMode,
+              StencilMode stencilMode,
+              ColorMode colorMode,
+              UniformValues&& uniformValues,
+              const VertexBuffer<Vertex>& vertexBuffer,
+              const IndexBuffer<DrawMode>& indexBuffer,
+              const std::vector<Segment>& segments) {
+        static_assert(std::is_same<Primitive, typename DrawMode::Primitive>::value, "incompatible draw mode");
+        context.draw({
+            std::move(drawMode),
+            std::move(depthMode),
+            std::move(stencilMode),
+            std::move(colorMode),
+            program,
+            vertexBuffer.buffer,
+            indexBuffer.buffer,
+            segments,
+            Uniforms::binder(uniformsState, std::move(uniformValues)),
+            Attributes::binder(attributesState)
+        });
+    }
+
+    // Unindexed drawing.
+    template <class DrawMode>
+    void draw(Context& context,
+              DrawMode drawMode,
+              DepthMode depthMode,
+              StencilMode stencilMode,
+              ColorMode colorMode,
+              UniformValues&& uniformValues,
+              const VertexBuffer<Vertex, DrawMode>& vertexBuffer) {
+        static_assert(std::is_same<Primitive, typename DrawMode::Primitive>::value, "incompatible draw mode");
+        context.draw({
+            std::move(drawMode),
+            std::move(depthMode),
+            std::move(stencilMode),
+            std::move(colorMode),
+            program,
+            vertexBuffer.buffer,
+            0,
+            {{ 0, 0, vertexBuffer.vertexCount, 0 }},
+            Uniforms::binder(uniformsState, std::move(uniformValues)),
+            Attributes::binder(attributesState)
+        });
+    }
+
+private:
     UniqueShader vertexShader;
     UniqueShader fragmentShader;
     UniqueProgram program;
diff --git a/src/mbgl/gl/segment.hpp b/src/mbgl/gl/segment.hpp
index 648d02e902..f65f2a5f7e 100644
--- a/src/mbgl/gl/segment.hpp
+++ b/src/mbgl/gl/segment.hpp
@@ -8,19 +8,19 @@ namespace gl {
 class Segment {
 public:
     Segment(std::size_t vertexOffset_,
-            std::size_t primitiveOffset_,
+            std::size_t indexOffset_,
             std::size_t vertexLength_ = 0,
-            std::size_t primitiveLength_ = 0)
+            std::size_t indexLength_ = 0)
         : vertexOffset(vertexOffset_),
-          primitiveOffset(primitiveOffset_),
+          indexOffset(indexOffset_),
           vertexLength(vertexLength_),
-          primitiveLength(primitiveLength_) {}
+          indexLength(indexLength_) {}
 
     const std::size_t vertexOffset;
-    const std::size_t primitiveOffset;
+    const std::size_t indexOffset;
 
     std::size_t vertexLength;
-    std::size_t primitiveLength;
+    std::size_t indexLength;
 };
 
 } // namespace gl
diff --git a/src/mbgl/gl/uniform.hpp b/src/mbgl/gl/uniform.hpp
index 90ca16e46f..df4de0c75a 100644
--- a/src/mbgl/gl/uniform.hpp
+++ b/src/mbgl/gl/uniform.hpp
@@ -2,6 +2,7 @@
 
 #include <mbgl/gl/types.hpp>
 #include <mbgl/util/optional.hpp>
+#include <mbgl/util/ignore.hpp>
 
 #include <array>
 #include <functional>
@@ -71,13 +72,9 @@ public:
 
     static std::function<void ()> binder(State& state, Values&& values_) {
         return [&state, values = std::move(values_)] () mutable {
-            noop((std::get<typename Us::State>(state) = std::get<typename Us::Value>(values), 0)...);
+            ignore((std::get<typename Us::State>(state) = std::get<typename Us::Value>(values), 0)...);
         };
     }
-
-private:
-    // This exists only to provide a varags context for unpacking the assignments in `binder`.
-    template <int...> static void noop(int...) {}
 };
 
 } // namespace gl
diff --git a/src/mbgl/gl/vertex_buffer.hpp b/src/mbgl/gl/vertex_buffer.hpp
index c77a9a4213..9d5532beab 100644
--- a/src/mbgl/gl/vertex_buffer.hpp
+++ b/src/mbgl/gl/vertex_buffer.hpp
@@ -1,14 +1,43 @@
 #pragma once
 
 #include <mbgl/gl/object.hpp>
+#include <mbgl/gl/primitives.hpp>
+#include <mbgl/gl/draw_mode.hpp>
+#include <mbgl/util/ignore.hpp>
+
+#include <vector>
 
 namespace mbgl {
 namespace gl {
 
-template <class Vertex>
+template <class V, class DrawMode = Indexed>
+class VertexVector {
+public:
+    using Vertex = V;
+    static constexpr std::size_t groupSize = DrawMode::bufferGroupSize;
+
+    template <class... Args>
+    void emplace_back(Args&&... args) {
+        static_assert(sizeof...(args) == groupSize, "wrong buffer element count");
+        ignore({(v.emplace_back(std::forward<Args>(args)), 0)...});
+    }
+
+    std::size_t vertexSize() const { return v.size(); }
+    std::size_t byteSize() const { return v.size() * sizeof(Vertex); }
+
+    bool empty() const { return v.empty(); }
+    const Vertex* data() const { return v.data(); }
+
+private:
+    std::vector<Vertex> v;
+};
+
+template <class V, class DrawMode = Indexed>
 class VertexBuffer {
 public:
+    using Vertex = V;
     static constexpr std::size_t vertexSize = sizeof(Vertex);
+
     std::size_t vertexCount;
     UniqueBuffer buffer;
 };
diff --git a/src/mbgl/layout/symbol_layout.cpp b/src/mbgl/layout/symbol_layout.cpp
index c2f8426785..932745aa57 100644
--- a/src/mbgl/layout/symbol_layout.cpp
+++ b/src/mbgl/layout/symbol_layout.cpp
@@ -449,7 +449,7 @@ void SymbolLayout::addSymbols(Buffer &buffer, const SymbolQuads &symbols, float
         }
 
         if (buffer.segments.empty() || buffer.segments.back().vertexLength + vertexLength > std::numeric_limits<uint16_t>::max()) {
-            buffer.segments.emplace_back(buffer.vertices.size(), buffer.triangles.size());
+            buffer.segments.emplace_back(buffer.vertices.vertexSize(), buffer.triangles.indexSize());
         }
 
         // We're generating triangle fans, so we always start with the first
@@ -476,7 +476,7 @@ void SymbolLayout::addSymbols(Buffer &buffer, const SymbolQuads &symbols, float
         buffer.triangles.emplace_back(index + 1, index + 2, index + 3);
 
         segment.vertexLength += vertexLength;
-        segment.primitiveLength += 2;
+        segment.indexLength += 6;
     }
 }
 
@@ -507,14 +507,14 @@ void SymbolLayout::addToDebugBuffers(CollisionTile& collisionTile, SymbolBucket&
                 const float maxZoom = util::clamp(zoom + util::log2(box.maxScale), util::MIN_ZOOM_F, util::MAX_ZOOM_F);
                 const float placementZoom = util::clamp(zoom + util::log2(box.placementScale), util::MIN_ZOOM_F, util::MAX_ZOOM_F);
 
-                collisionBox.vertices.emplace_back(CollisionBoxProgram::vertex(anchor, tl, maxZoom, placementZoom));
-                collisionBox.vertices.emplace_back(CollisionBoxProgram::vertex(anchor, tr, maxZoom, placementZoom));
-                collisionBox.vertices.emplace_back(CollisionBoxProgram::vertex(anchor, tr, maxZoom, placementZoom));
-                collisionBox.vertices.emplace_back(CollisionBoxProgram::vertex(anchor, br, maxZoom, placementZoom));
-                collisionBox.vertices.emplace_back(CollisionBoxProgram::vertex(anchor, br, maxZoom, placementZoom));
-                collisionBox.vertices.emplace_back(CollisionBoxProgram::vertex(anchor, bl, maxZoom, placementZoom));
-                collisionBox.vertices.emplace_back(CollisionBoxProgram::vertex(anchor, bl, maxZoom, placementZoom));
-                collisionBox.vertices.emplace_back(CollisionBoxProgram::vertex(anchor, tl, maxZoom, placementZoom));
+                collisionBox.vertices.emplace_back(CollisionBoxProgram::vertex(anchor, tl, maxZoom, placementZoom),
+                                                   CollisionBoxProgram::vertex(anchor, tr, maxZoom, placementZoom));
+                collisionBox.vertices.emplace_back(CollisionBoxProgram::vertex(anchor, tr, maxZoom, placementZoom),
+                                                   CollisionBoxProgram::vertex(anchor, br, maxZoom, placementZoom));
+                collisionBox.vertices.emplace_back(CollisionBoxProgram::vertex(anchor, br, maxZoom, placementZoom),
+                                                   CollisionBoxProgram::vertex(anchor, bl, maxZoom, placementZoom));
+                collisionBox.vertices.emplace_back(CollisionBoxProgram::vertex(anchor, bl, maxZoom, placementZoom),
+                                                   CollisionBoxProgram::vertex(anchor, tl, maxZoom, placementZoom));
             }
         };
         populateCollisionBox(symbolInstance.textCollisionFeature);
diff --git a/src/mbgl/programs/circle_program.hpp b/src/mbgl/programs/circle_program.hpp
index 690608a438..75c030b1c8 100644
--- a/src/mbgl/programs/circle_program.hpp
+++ b/src/mbgl/programs/circle_program.hpp
@@ -16,6 +16,7 @@ MBGL_DEFINE_UNIFORM_SCALAR(float, u_devicepixelratio);
 
 class CircleProgram : public Program<
     shaders::circle,
+    gl::Triangle,
     gl::Attributes<
         attributes::a_pos>,
     gl::Uniforms<
diff --git a/src/mbgl/programs/collision_box_program.hpp b/src/mbgl/programs/collision_box_program.hpp
index 66b1284621..5eda3fefb0 100644
--- a/src/mbgl/programs/collision_box_program.hpp
+++ b/src/mbgl/programs/collision_box_program.hpp
@@ -17,6 +17,7 @@ MBGL_DEFINE_UNIFORM_SCALAR(float, u_maxzoom);
 
 class CollisionBoxProgram : public Program<
     shaders::collision_box,
+    gl::Line,
     gl::Attributes<
         attributes::a_pos,
         attributes::a_extrude,
diff --git a/src/mbgl/programs/debug_program.hpp b/src/mbgl/programs/debug_program.hpp
new file mode 100644
index 0000000000..3596dc1f7e
--- /dev/null
+++ b/src/mbgl/programs/debug_program.hpp
@@ -0,0 +1,23 @@
+#pragma once
+
+#include <mbgl/programs/program.hpp>
+#include <mbgl/programs/attributes.hpp>
+#include <mbgl/programs/uniforms.hpp>
+#include <mbgl/shader/debug.hpp>
+
+namespace mbgl {
+
+class DebugProgram : public Program<
+    shaders::debug,
+    gl::Line,
+    gl::Attributes<
+        attributes::a_pos>,
+    gl::Uniforms<
+        uniforms::u_matrix,
+        uniforms::u_color>>
+{
+public:
+    using Program::Program;
+};
+
+} // namespace mbgl
diff --git a/src/mbgl/programs/fill_program.hpp b/src/mbgl/programs/fill_program.hpp
index 3f738527c8..d885215c59 100644
--- a/src/mbgl/programs/fill_program.hpp
+++ b/src/mbgl/programs/fill_program.hpp
@@ -86,6 +86,7 @@ struct FillPatternUniforms : gl::Uniforms<
 
 class FillProgram : public Program<
     shaders::fill,
+    gl::Triangle,
     FillAttributes,
     FillUniforms>
 {
@@ -94,6 +95,7 @@ class FillProgram : public Program<
 
 class FillPatternProgram : public Program<
     shaders::fill_pattern,
+    gl::Triangle,
     FillAttributes,
     FillPatternUniforms>
 {
@@ -102,6 +104,7 @@ class FillPatternProgram : public Program<
 
 class FillOutlineProgram : public Program<
     shaders::fill_outline,
+    gl::Line,
     FillAttributes,
     FillUniforms>
 {
@@ -110,6 +113,7 @@ class FillOutlineProgram : public Program<
 
 class FillOutlinePatternProgram : public Program<
     shaders::fill_outline_pattern,
+    gl::Line,
     FillAttributes,
     FillPatternUniforms>
 {
diff --git a/src/mbgl/programs/line_program.hpp b/src/mbgl/programs/line_program.hpp
index 960438f4cd..07ae35b8ed 100644
--- a/src/mbgl/programs/line_program.hpp
+++ b/src/mbgl/programs/line_program.hpp
@@ -88,6 +88,7 @@ using LineVertex = LineAttributes::Vertex;
 
 class LineProgram : public Program<
     shaders::line,
+    gl::Triangle,
     LineAttributes,
     gl::Uniforms<
         uniforms::u_matrix,
@@ -113,6 +114,7 @@ public:
 
 class LinePatternProgram : public Program<
     shaders::line_pattern,
+    gl::Triangle,
     LineAttributes,
     gl::Uniforms<
         uniforms::u_matrix,
@@ -147,6 +149,7 @@ public:
 
 class LineSDFProgram : public Program<
     shaders::line_sdf,
+    gl::Triangle,
     LineAttributes,
     gl::Uniforms<
         uniforms::u_matrix,
diff --git a/src/mbgl/programs/program.hpp b/src/mbgl/programs/program.hpp
index 9f154b051a..fa41d43e5c 100644
--- a/src/mbgl/programs/program.hpp
+++ b/src/mbgl/programs/program.hpp
@@ -11,11 +11,13 @@ enum class ProgramDefines : bool {
     Overdraw = true,
 };
 
-template <class Shaders, class As, class Us>
-class Program : public gl::Program<As, Us> {
+template <class Shaders, class Primitive, class Attributes, class Uniforms>
+class Program : public gl::Program<Primitive, Attributes, Uniforms> {
 public:
+    using ParentType = gl::Program<Primitive, Attributes, Uniforms>;
+
     Program(gl::Context& context, ProgramDefines defines)
-        : gl::Program<As, Us>(context, Shaders::vertexSource, fragmentSource(defines))
+        : ParentType(context, Shaders::vertexSource, fragmentSource(defines))
         {}
 
     static std::string fragmentSource(ProgramDefines defines) {
diff --git a/src/mbgl/programs/programs.hpp b/src/mbgl/programs/programs.hpp
index aebafaec62..53ed26e969 100644
--- a/src/mbgl/programs/programs.hpp
+++ b/src/mbgl/programs/programs.hpp
@@ -5,6 +5,7 @@
 #include <mbgl/programs/line_program.hpp>
 #include <mbgl/programs/raster_program.hpp>
 #include <mbgl/programs/symbol_program.hpp>
+#include <mbgl/programs/debug_program.hpp>
 #include <mbgl/programs/collision_box_program.hpp>
 
 namespace mbgl {
@@ -24,6 +25,7 @@ public:
           symbolIcon(context, defines),
           symbolIconSDF(context, defines),
           symbolGlyph(context, defines),
+          debug(context, ProgramDefines::None),
           collisionBox(context, ProgramDefines::None) {
     }
 
@@ -40,6 +42,7 @@ public:
     SymbolSDFProgram symbolIconSDF;
     SymbolSDFProgram symbolGlyph;
 
+    DebugProgram debug;
     CollisionBoxProgram collisionBox;
 };
 
diff --git a/src/mbgl/programs/raster_program.hpp b/src/mbgl/programs/raster_program.hpp
index 1e9a0cdb6a..1bab2d5765 100644
--- a/src/mbgl/programs/raster_program.hpp
+++ b/src/mbgl/programs/raster_program.hpp
@@ -25,6 +25,7 @@ MBGL_DEFINE_UNIFORM_VECTOR(float, 2, u_tl_parent);
 
 class RasterProgram : public Program<
     shaders::raster,
+    gl::Triangle,
     gl::Attributes<
         attributes::a_pos,
         attributes::a_texture_pos>,
diff --git a/src/mbgl/programs/symbol_program.hpp b/src/mbgl/programs/symbol_program.hpp
index eb8c56b326..be987551c0 100644
--- a/src/mbgl/programs/symbol_program.hpp
+++ b/src/mbgl/programs/symbol_program.hpp
@@ -72,6 +72,7 @@ using SymbolVertex = SymbolAttributes::Vertex;
 
 class SymbolIconProgram : public Program<
     shaders::symbol_icon,
+    gl::Triangle,
     SymbolAttributes,
     gl::Uniforms<
         uniforms::u_matrix,
@@ -95,6 +96,7 @@ public:
 
 class SymbolSDFProgram : public Program<
     shaders::symbol_sdf,
+    gl::Triangle,
     SymbolAttributes,
     gl::Uniforms<
         uniforms::u_matrix,
diff --git a/src/mbgl/renderer/circle_bucket.cpp b/src/mbgl/renderer/circle_bucket.cpp
index 08f2a144a1..ba2285c4eb 100644
--- a/src/mbgl/renderer/circle_bucket.cpp
+++ b/src/mbgl/renderer/circle_bucket.cpp
@@ -46,7 +46,7 @@ void CircleBucket::addGeometry(const GeometryCollection& geometryCollection) {
 
             if (segments.empty() || segments.back().vertexLength + vertexLength > std::numeric_limits<uint16_t>::max()) {
                 // Move to a new segments because the old one can't hold the geometry.
-                segments.emplace_back(vertices.size(), triangles.size());
+                segments.emplace_back(vertices.vertexSize(), triangles.indexSize());
             }
 
             // this geometry will be of the Point type, and we'll derive
@@ -73,7 +73,7 @@ void CircleBucket::addGeometry(const GeometryCollection& geometryCollection) {
             triangles.emplace_back(index, index + 3, index + 2);
 
             segment.vertexLength += vertexLength;
-            segment.primitiveLength += 2;
+            segment.indexLength += 6;
         }
     }
 }
diff --git a/src/mbgl/renderer/circle_bucket.hpp b/src/mbgl/renderer/circle_bucket.hpp
index d5df06f110..a93b052d68 100644
--- a/src/mbgl/renderer/circle_bucket.hpp
+++ b/src/mbgl/renderer/circle_bucket.hpp
@@ -20,12 +20,12 @@ public:
     bool hasData() const override;
     void addGeometry(const GeometryCollection&);
 
-    std::vector<CircleVertex> vertices;
-    std::vector<gl::Triangle> triangles;
+    gl::VertexVector<CircleVertex> vertices;
+    gl::IndexVector<gl::Triangles> triangles;
     std::vector<gl::Segment> segments;
 
     optional<gl::VertexBuffer<CircleVertex>> vertexBuffer;
-    optional<gl::IndexBuffer<gl::Triangle>> indexBuffer;
+    optional<gl::IndexBuffer<gl::Triangles>> indexBuffer;
 
     const MapMode mode;
 };
diff --git a/src/mbgl/renderer/debug_bucket.cpp b/src/mbgl/renderer/debug_bucket.cpp
index 931d1bf30d..4beb16a996 100644
--- a/src/mbgl/renderer/debug_bucket.cpp
+++ b/src/mbgl/renderer/debug_bucket.cpp
@@ -10,13 +10,14 @@
 
 namespace mbgl {
 
-std::vector<FillVertex> buildTextVertices(const OverscaledTileID& id,
-                                                     const bool renderable,
-                                                     const bool complete,
-                                                     optional<Timestamp> modified,
-                                                     optional<Timestamp> expires,
-                                                     MapDebugOptions debugMode) {
-    std::vector<FillVertex> textPoints;
+gl::VertexVector<FillVertex, gl::Lines>
+buildTextVertices(const OverscaledTileID& id,
+                  const bool renderable,
+                  const bool complete,
+                  optional<Timestamp> modified,
+                  optional<Timestamp> expires,
+                  MapDebugOptions debugMode) {
+    gl::VertexVector<FillVertex, gl::Lines> textLines;
 
     auto addText = [&] (const std::string& text, double left, double baseline, double scale) {
         for (uint8_t c : text) {
@@ -36,8 +37,8 @@ std::vector<FillVertex> buildTextVertices(const OverscaledTileID& id,
                     };
 
                     if (prev) {
-                        textPoints.emplace_back(FillAttributes::vertex(*prev));
-                        textPoints.emplace_back(FillAttributes::vertex(p));
+                        textLines.emplace_back(FillAttributes::vertex(*prev),
+                                               FillAttributes::vertex(p));
                     }
 
                     prev = p;
@@ -64,7 +65,7 @@ std::vector<FillVertex> buildTextVertices(const OverscaledTileID& id,
         addText(expiresText, 50, baseline + 200, 5);
     }
 
-    return textPoints;
+    return textLines;
 }
 
 DebugBucket::DebugBucket(const OverscaledTileID& id,
diff --git a/src/mbgl/renderer/debug_bucket.hpp b/src/mbgl/renderer/debug_bucket.hpp
index 9b19e7f949..4c173786ae 100644
--- a/src/mbgl/renderer/debug_bucket.hpp
+++ b/src/mbgl/renderer/debug_bucket.hpp
@@ -32,7 +32,7 @@ public:
     const optional<Timestamp> expires;
     const MapDebugOptions debugMode;
 
-    gl::VertexBuffer<FillVertex> vertexBuffer;
+    gl::VertexBuffer<FillVertex, gl::Lines> vertexBuffer;
 };
 
 } // namespace mbgl
diff --git a/src/mbgl/renderer/fill_bucket.cpp b/src/mbgl/renderer/fill_bucket.cpp
index 2eee8f2d6d..96e44d6903 100644
--- a/src/mbgl/renderer/fill_bucket.cpp
+++ b/src/mbgl/renderer/fill_bucket.cpp
@@ -39,7 +39,7 @@ void FillBucket::addGeometry(const GeometryCollection& geometry) {
                 throw GeometryTooLongException();
         }
 
-        std::size_t startVertices = vertices.size();
+        std::size_t startVertices = vertices.vertexSize();
 
         for (const auto& ring : polygon) {
             std::size_t nVertices = ring.size();
@@ -48,7 +48,7 @@ void FillBucket::addGeometry(const GeometryCollection& geometry) {
                 continue;
 
             if (lineSegments.empty() || lineSegments.back().vertexLength + nVertices > std::numeric_limits<uint16_t>::max()) {
-                lineSegments.emplace_back(vertices.size(), lines.size());
+                lineSegments.emplace_back(vertices.vertexSize(), lines.indexSize());
             }
 
             auto& lineSegment = lineSegments.back();
@@ -64,7 +64,7 @@ void FillBucket::addGeometry(const GeometryCollection& geometry) {
             }
 
             lineSegment.vertexLength += nVertices;
-            lineSegment.primitiveLength += nVertices;
+            lineSegment.indexLength += nVertices * 2;
         }
 
         std::vector<uint32_t> indices = mapbox::earcut(polygon);
@@ -73,7 +73,7 @@ void FillBucket::addGeometry(const GeometryCollection& geometry) {
         assert(nIndicies % 3 == 0);
 
         if (triangleSegments.empty() || triangleSegments.back().vertexLength + totalVertices > std::numeric_limits<uint16_t>::max()) {
-            triangleSegments.emplace_back(startVertices, triangles.size());
+            triangleSegments.emplace_back(startVertices, triangles.indexSize());
         }
 
         auto& triangleSegment = triangleSegments.back();
@@ -87,7 +87,7 @@ void FillBucket::addGeometry(const GeometryCollection& geometry) {
         }
 
         triangleSegment.vertexLength += totalVertices;
-        triangleSegment.primitiveLength += nIndicies / 3;
+        triangleSegment.indexLength += nIndicies;
     }
 }
 
diff --git a/src/mbgl/renderer/fill_bucket.hpp b/src/mbgl/renderer/fill_bucket.hpp
index b2c549a758..4ea558b629 100644
--- a/src/mbgl/renderer/fill_bucket.hpp
+++ b/src/mbgl/renderer/fill_bucket.hpp
@@ -19,15 +19,15 @@ public:
 
     void addGeometry(const GeometryCollection&);
 
-    std::vector<FillVertex> vertices;
-    std::vector<gl::Line> lines;
-    std::vector<gl::Triangle> triangles;
+    gl::VertexVector<FillVertex> vertices;
+    gl::IndexVector<gl::Lines> lines;
+    gl::IndexVector<gl::Triangles> triangles;
     std::vector<gl::Segment> lineSegments;
     std::vector<gl::Segment> triangleSegments;
 
     optional<gl::VertexBuffer<FillVertex>> vertexBuffer;
-    optional<gl::IndexBuffer<gl::Line>> lineIndexBuffer;
-    optional<gl::IndexBuffer<gl::Triangle>> triangleIndexBuffer;
+    optional<gl::IndexBuffer<gl::Lines>> lineIndexBuffer;
+    optional<gl::IndexBuffer<gl::Triangles>> triangleIndexBuffer;
 };
 
 } // namespace mbgl
diff --git a/src/mbgl/renderer/line_bucket.cpp b/src/mbgl/renderer/line_bucket.cpp
index 1db075652c..554fef5ca7 100644
--- a/src/mbgl/renderer/line_bucket.cpp
+++ b/src/mbgl/renderer/line_bucket.cpp
@@ -96,7 +96,7 @@ void LineBucket::addGeometry(const GeometryCoordinates& coordinates) {
         nextNormal = util::perp(util::unit(convertPoint<double>(firstCoordinate - *currentCoordinate)));
     }
 
-    const std::size_t startVertex = vertices.size();
+    const std::size_t startVertex = vertices.vertexSize();
     std::vector<TriangleElement> triangleStore;
 
     for (std::size_t i = 0; i < len; ++i) {
@@ -345,11 +345,11 @@ void LineBucket::addGeometry(const GeometryCoordinates& coordinates) {
         startOfLine = false;
     }
 
-    const std::size_t endVertex = vertices.size();
+    const std::size_t endVertex = vertices.vertexSize();
     const std::size_t vertexCount = endVertex - startVertex;
 
     if (segments.empty() || segments.back().vertexLength + vertexCount > std::numeric_limits<uint16_t>::max()) {
-        segments.emplace_back(startVertex, triangles.size());
+        segments.emplace_back(startVertex, triangles.indexSize());
     }
 
     auto& segment = segments.back();
@@ -361,7 +361,7 @@ void LineBucket::addGeometry(const GeometryCoordinates& coordinates) {
     }
 
     segment.vertexLength += vertexCount;
-    segment.primitiveLength += triangleStore.size();
+    segment.indexLength += triangleStore.size() * 3;
 }
 
 void LineBucket::addCurrentVertex(const GeometryCoordinate& currentCoordinate,
@@ -376,7 +376,7 @@ void LineBucket::addCurrentVertex(const GeometryCoordinate& currentCoordinate,
     if (endLeft)
         extrude = extrude - (util::perp(normal) * endLeft);
     vertices.emplace_back(LineAttributes::vertex(currentCoordinate, extrude, { round, false }, endLeft, distance * LINE_DISTANCE_SCALE));
-    e3 = vertices.size() - 1 - startVertex;
+    e3 = vertices.vertexSize() - 1 - startVertex;
     if (e1 >= 0 && e2 >= 0) {
         triangleStore.emplace_back(e1, e2, e3);
     }
@@ -387,7 +387,7 @@ void LineBucket::addCurrentVertex(const GeometryCoordinate& currentCoordinate,
     if (endRight)
         extrude = extrude - (util::perp(normal) * endRight);
     vertices.emplace_back(LineAttributes::vertex(currentCoordinate, extrude, { round, true }, -endRight, distance * LINE_DISTANCE_SCALE));
-    e3 = vertices.size() - 1 - startVertex;
+    e3 = vertices.vertexSize() - 1 - startVertex;
     if (e1 >= 0 && e2 >= 0) {
         triangleStore.emplace_back(e1, e2, e3);
     }
@@ -412,7 +412,7 @@ void LineBucket::addPieSliceVertex(const GeometryCoordinate& currentVertex,
                                    std::vector<TriangleElement>& triangleStore) {
     Point<double> flippedExtrude = extrude * (lineTurnsLeft ? -1.0 : 1.0);
     vertices.emplace_back(LineAttributes::vertex(currentVertex, flippedExtrude, { false, lineTurnsLeft }, 0, distance * LINE_DISTANCE_SCALE));
-    e3 = vertices.size() - 1 - startVertex;
+    e3 = vertices.vertexSize() - 1 - startVertex;
     if (e1 >= 0 && e2 >= 0) {
         triangleStore.emplace_back(e1, e2, e3);
     }
diff --git a/src/mbgl/renderer/line_bucket.hpp b/src/mbgl/renderer/line_bucket.hpp
index 4d78a80123..9903ca1842 100644
--- a/src/mbgl/renderer/line_bucket.hpp
+++ b/src/mbgl/renderer/line_bucket.hpp
@@ -26,12 +26,12 @@ public:
 
     style::LineLayoutProperties layout;
 
-    std::vector<LineVertex> vertices;
-    std::vector<gl::Triangle> triangles;
+    gl::VertexVector<LineVertex> vertices;
+    gl::IndexVector<gl::Triangles> triangles;
     std::vector<gl::Segment> segments;
 
     optional<gl::VertexBuffer<LineVertex>> vertexBuffer;
-    optional<gl::IndexBuffer<gl::Triangle>> indexBuffer;
+    optional<gl::IndexBuffer<gl::Triangles>> indexBuffer;
 
 private:
     struct TriangleElement {
diff --git a/src/mbgl/renderer/painter.cpp b/src/mbgl/renderer/painter.cpp
index d9e7f9fd35..a09e3b73fc 100644
--- a/src/mbgl/renderer/painter.cpp
+++ b/src/mbgl/renderer/painter.cpp
@@ -41,30 +41,44 @@ namespace mbgl {
 
 using namespace style;
 
-Painter::Painter(gl::Context& context_, const TransformState& state_)
-    : context(context_),
-      state(state_),
-      tileTriangleVertexBuffer(context.createVertexBuffer(std::vector<FillVertex> {{
+static gl::VertexVector<FillVertex, gl::Triangles> tileTriangles() {
+    gl::VertexVector<FillVertex, gl::Triangles> result;
+    result.emplace_back(
             FillAttributes::vertex({ 0,            0 }),
             FillAttributes::vertex({ util::EXTENT, 0 }),
-            FillAttributes::vertex({ 0, util::EXTENT }),
-            FillAttributes::vertex({ util::EXTENT, 0 }),
-            FillAttributes::vertex({ 0, util::EXTENT }),
-            FillAttributes::vertex({ util::EXTENT, util::EXTENT })
-      }})),
-      tileLineStripVertexBuffer(context.createVertexBuffer(std::vector<FillVertex> {{
-            FillAttributes::vertex({ 0, 0 }),
+            FillAttributes::vertex({ 0, util::EXTENT }));
+    result.emplace_back(
             FillAttributes::vertex({ util::EXTENT, 0 }),
-            FillAttributes::vertex({ util::EXTENT, util::EXTENT }),
             FillAttributes::vertex({ 0, util::EXTENT }),
-            FillAttributes::vertex({ 0, 0 })
-      }})),
-      rasterVertexBuffer(context.createVertexBuffer(std::vector<RasterVertex> {{
-            RasterProgram::vertex({ 0, 0 }, { 0, 0 }),
-            RasterProgram::vertex({ util::EXTENT, 0 }, { 32767, 0 }),
-            RasterProgram::vertex({ 0, util::EXTENT }, { 0, 32767 }),
-            RasterProgram::vertex({ util::EXTENT, util::EXTENT }, { 32767, 32767 })
-      }})) {
+            FillAttributes::vertex({ util::EXTENT, util::EXTENT }));
+    return result;
+}
+
+static gl::VertexVector<FillVertex, gl::LineStrip> tileLineStrip() {
+    gl::VertexVector<FillVertex, gl::LineStrip> result;
+    result.emplace_back(FillAttributes::vertex({ 0, 0 }));
+    result.emplace_back(FillAttributes::vertex({ util::EXTENT, 0 }));
+    result.emplace_back(FillAttributes::vertex({ util::EXTENT, util::EXTENT }));
+    result.emplace_back(FillAttributes::vertex({ 0, util::EXTENT }));
+    result.emplace_back(FillAttributes::vertex({ 0, 0 }));
+    return result;
+}
+
+static gl::VertexVector<RasterVertex, gl::TriangleStrip> rasterTriangleStrip() {
+    gl::VertexVector<RasterVertex, gl::TriangleStrip> result;
+    result.emplace_back(RasterProgram::vertex({ 0, 0 }, { 0, 0 }));
+    result.emplace_back(RasterProgram::vertex({ util::EXTENT, 0 }, { 32767, 0 }));
+    result.emplace_back(RasterProgram::vertex({ 0, util::EXTENT }, { 0, 32767 }));
+    result.emplace_back(RasterProgram::vertex({ util::EXTENT, util::EXTENT }, { 32767, 32767 }));
+    return result;
+}
+
+Painter::Painter(gl::Context& context_, const TransformState& state_)
+    : context(context_),
+      state(state_),
+      tileTriangleVertexBuffer(context.createVertexBuffer(tileTriangles())),
+      tileLineStripVertexBuffer(context.createVertexBuffer(tileLineStrip())),
+      rasterVertexBuffer(context.createVertexBuffer(rasterTriangleStrip())) {
 #ifndef NDEBUG
     gl::debugging::enable();
 #endif
diff --git a/src/mbgl/renderer/painter.hpp b/src/mbgl/renderer/painter.hpp
index 53215c5033..3f5f28dad1 100644
--- a/src/mbgl/renderer/painter.hpp
+++ b/src/mbgl/renderer/painter.hpp
@@ -156,9 +156,9 @@ private:
     std::unique_ptr<Programs> overdrawPrograms;
 #endif
 
-    gl::VertexBuffer<FillVertex> tileTriangleVertexBuffer;
-    gl::VertexBuffer<FillVertex> tileLineStripVertexBuffer;
-    gl::VertexBuffer<RasterVertex> rasterVertexBuffer;
+    gl::VertexBuffer<FillVertex, gl::Triangles> tileTriangleVertexBuffer;
+    gl::VertexBuffer<FillVertex, gl::LineStrip> tileLineStripVertexBuffer;
+    gl::VertexBuffer<RasterVertex, gl::TriangleStrip> rasterVertexBuffer;
 };
 
 } // namespace mbgl
diff --git a/src/mbgl/renderer/painter_background.cpp b/src/mbgl/renderer/painter_background.cpp
index 3e2597e47c..5e71cb7b20 100644
--- a/src/mbgl/renderer/painter_background.cpp
+++ b/src/mbgl/renderer/painter_background.cpp
@@ -28,11 +28,12 @@ void Painter::renderBackground(PaintParameters& parameters, const BackgroundLaye
         spriteAtlas->bind(true, context, 0);
 
         for (const auto& tileID : util::tileCover(state, state.getIntegerZoom())) {
-            context.draw({
+            parameters.programs.fillPattern.draw(
+                context,
+                gl::Triangles(),
                 depthModeForSublayer(0, gl::DepthMode::ReadOnly),
                 gl::StencilMode::disabled(),
                 colorModeForRenderPass(),
-                parameters.programs.fillPattern,
                 FillPatternUniforms::values(
                     matrixForTile(tileID),
                     properties.backgroundOpacity.value,
@@ -43,16 +44,17 @@ void Painter::renderBackground(PaintParameters& parameters, const BackgroundLaye
                     tileID,
                     state
                 ),
-                gl::Unindexed<gl::TriangleStrip>(tileTriangleVertexBuffer)
-            });
+                tileTriangleVertexBuffer
+            );
         }
     } else {
         for (const auto& tileID : util::tileCover(state, state.getIntegerZoom())) {
-            context.draw({
+            parameters.programs.fill.draw(
+                context,
+                gl::Triangles(),
                 depthModeForSublayer(0, gl::DepthMode::ReadOnly),
                 gl::StencilMode::disabled(),
                 colorModeForRenderPass(),
-                parameters.programs.fill,
                 FillProgram::UniformValues {
                     uniforms::u_matrix::Value{ matrixForTile(tileID) },
                     uniforms::u_opacity::Value{ properties.backgroundOpacity.value },
@@ -60,8 +62,8 @@ void Painter::renderBackground(PaintParameters& parameters, const BackgroundLaye
                     uniforms::u_outline_color::Value{ properties.backgroundColor.value },
                     uniforms::u_world::Value{ context.viewport.getCurrentValue().size },
                 },
-                gl::Unindexed<gl::TriangleStrip>(tileTriangleVertexBuffer)
-            });
+                tileTriangleVertexBuffer
+            );
         }
     }
 }
diff --git a/src/mbgl/renderer/painter_circle.cpp b/src/mbgl/renderer/painter_circle.cpp
index e4977b8abb..e9c828bcd8 100644
--- a/src/mbgl/renderer/painter_circle.cpp
+++ b/src/mbgl/renderer/painter_circle.cpp
@@ -23,13 +23,14 @@ void Painter::renderCircle(PaintParameters& parameters,
     const CirclePaintProperties& properties = layer.impl->paint;
     const bool scaleWithMap = properties.circlePitchScale.value == CirclePitchScaleType::Map;
 
-    context.draw({
+    parameters.programs.circle.draw(
+        context,
+        gl::Triangles(),
         depthModeForSublayer(0, gl::DepthMode::ReadOnly),
         frame.mapMode == MapMode::Still
             ? stencilModeForClipping(tile.clip)
             : gl::StencilMode::disabled(),
         colorModeForRenderPass(),
-        parameters.programs.circle,
         CircleProgram::UniformValues {
             uniforms::u_matrix::Value{ tile.translatedMatrix(properties.circleTranslate.value,
                                        properties.circleTranslateAnchor.value,
@@ -47,12 +48,10 @@ void Painter::renderCircle(PaintParameters& parameters,
                 : pixelsToGLUnits },
             uniforms::u_devicepixelratio::Value{ frame.pixelRatio },
         },
-        gl::Segmented<gl::Triangles>(
-            *bucket.vertexBuffer,
-            *bucket.indexBuffer,
-            bucket.segments
-        )
-    });
+        *bucket.vertexBuffer,
+        *bucket.indexBuffer,
+        bucket.segments
+    );
 }
 
 } // namespace mbgl
diff --git a/src/mbgl/renderer/painter_clipping.cpp b/src/mbgl/renderer/painter_clipping.cpp
index b64c5d5efc..2054424475 100644
--- a/src/mbgl/renderer/painter_clipping.cpp
+++ b/src/mbgl/renderer/painter_clipping.cpp
@@ -6,7 +6,9 @@
 namespace mbgl {
 
 void Painter::renderClippingMask(const UnwrappedTileID& tileID, const ClipID& clip) {
-    context.draw({
+    programs->fill.draw(
+        context,
+        gl::Triangles(),
         gl::DepthMode::disabled(),
         gl::StencilMode {
             gl::StencilMode::Always(),
@@ -17,7 +19,6 @@ void Painter::renderClippingMask(const UnwrappedTileID& tileID, const ClipID& cl
             gl::StencilMode::Replace
         },
         gl::ColorMode::disabled(),
-        programs->fill,
         FillProgram::UniformValues {
             uniforms::u_matrix::Value{ matrixForTile(tileID) },
             uniforms::u_opacity::Value{ 0.0f },
@@ -25,8 +26,8 @@ void Painter::renderClippingMask(const UnwrappedTileID& tileID, const ClipID& cl
             uniforms::u_outline_color::Value{ Color {} },
             uniforms::u_world::Value{ context.viewport.getCurrentValue().size },
         },
-        gl::Unindexed<gl::Triangles>(tileTriangleVertexBuffer)
-    });
+        tileTriangleVertexBuffer
+    );
 }
 
 } // namespace mbgl
diff --git a/src/mbgl/renderer/painter_debug.cpp b/src/mbgl/renderer/painter_debug.cpp
index a0fc98b8c1..8969354d23 100644
--- a/src/mbgl/renderer/painter_debug.cpp
+++ b/src/mbgl/renderer/painter_debug.cpp
@@ -18,21 +18,19 @@ void Painter::renderTileDebug(const RenderTile& renderTile) {
 
     MBGL_DEBUG_GROUP(std::string { "debug " } + util::toString(renderTile.id));
 
-    auto draw = [&] (Color color, auto subject) {
-        context.draw({
+    auto draw = [&] (Color color, const auto& vertexBuffer, auto drawMode) {
+        programs->debug.draw(
+            context,
+            drawMode,
             gl::DepthMode::disabled(),
             stencilModeForClipping(renderTile.clip),
             gl::ColorMode::unblended(),
-            programs->fill,
-            FillProgram::UniformValues {
+            DebugProgram::UniformValues {
                 uniforms::u_matrix::Value{ renderTile.matrix },
-                uniforms::u_opacity::Value{ 1.0f },
-                uniforms::u_color::Value{ color },
-                uniforms::u_outline_color::Value{ color },
-                uniforms::u_world::Value{ context.viewport.getCurrentValue().size },
+                uniforms::u_color::Value{ color }
             },
-            subject
-        });
+            vertexBuffer
+        );
     };
 
     if (frame.debugOptions & (MapDebugOptions::Timestamps | MapDebugOptions::ParseStatus)) {
@@ -47,15 +45,12 @@ void Painter::renderTileDebug(const RenderTile& renderTile) {
                 tile.expires, frame.debugOptions, context);
         }
 
-        const auto& vertexBuffer = tile.debugBucket->vertexBuffer;
-
-        draw(Color::white(), gl::Unindexed<gl::Lines>(vertexBuffer, 4.0f * frame.pixelRatio));
-        draw(Color::black(), gl::Unindexed<gl::Points>(vertexBuffer, 2.0f));
-        draw(Color::black(), gl::Unindexed<gl::Lines>(vertexBuffer, 2.0f * frame.pixelRatio));
+        draw(Color::white(), tile.debugBucket->vertexBuffer, gl::Lines { 4.0f * frame.pixelRatio });
+        draw(Color::black(), tile.debugBucket->vertexBuffer, gl::Lines { 2.0f * frame.pixelRatio });
     }
 
     if (frame.debugOptions & MapDebugOptions::TileBorders) {
-        draw(Color::red(), gl::Unindexed<gl::LineStrip>(tileLineStripVertexBuffer, 4.0f * frame.pixelRatio));
+        draw(Color::red(), tileLineStripVertexBuffer, gl::LineStrip { 4.0f * frame.pixelRatio });
     }
 }
 
diff --git a/src/mbgl/renderer/painter_fill.cpp b/src/mbgl/renderer/painter_fill.cpp
index cdce181e1c..e5a536fde3 100644
--- a/src/mbgl/renderer/painter_fill.cpp
+++ b/src/mbgl/renderer/painter_fill.cpp
@@ -35,12 +35,18 @@ void Painter::renderFill(PaintParameters& parameters,
 
         spriteAtlas->bind(true, context, 0);
 
-        auto draw = [&] (uint8_t sublayer, auto& program, const auto& subject) {
-            context.draw({
+        auto draw = [&] (uint8_t sublayer,
+                         auto& program,
+                         const auto& drawMode,
+                         const auto& vertexBuffer,
+                         const auto& indexBuffer,
+                         const auto& segments) {
+            program.draw(
+                context,
+                drawMode,
                 depthModeForSublayer(sublayer, gl::DepthMode::ReadWrite),
                 stencilModeForClipping(tile.clip),
                 colorModeForRenderPass(),
-                program,
                 FillPatternUniforms::values(
                     tile.translatedMatrix(properties.fillTranslate.value,
                                           properties.fillTranslateAnchor.value,
@@ -53,16 +59,18 @@ void Painter::renderFill(PaintParameters& parameters,
                     tile.id,
                     state
                 ),
-                subject
-            });
+                vertexBuffer,
+                indexBuffer,
+                segments
+            );
         };
 
         draw(0,
              parameters.programs.fillPattern,
-             gl::Segmented<gl::Triangles>(
-                 *bucket.vertexBuffer,
-                 *bucket.triangleIndexBuffer,
-                 bucket.triangleSegments));
+             gl::Triangles(),
+             *bucket.vertexBuffer,
+             *bucket.triangleIndexBuffer,
+             bucket.triangleSegments);
 
         if (!properties.fillAntialias.value || !properties.fillOutlineColor.isUndefined()) {
             return;
@@ -70,18 +78,24 @@ void Painter::renderFill(PaintParameters& parameters,
 
         draw(2,
              parameters.programs.fillOutlinePattern,
-             gl::Segmented<gl::Lines>(
-                 *bucket.vertexBuffer,
-                 *bucket.lineIndexBuffer,
-                 bucket.lineSegments,
-                 2.0f));
+             gl::Lines { 2.0f },
+             *bucket.vertexBuffer,
+             *bucket.lineIndexBuffer,
+             bucket.lineSegments);
     } else {
-        auto draw = [&] (uint8_t sublayer, auto& program, Color outlineColor, const auto& subject) {
-            context.draw({
+        auto draw = [&] (uint8_t sublayer,
+                         auto& program,
+                         Color outlineColor,
+                         const auto& drawMode,
+                         const auto& vertexBuffer,
+                         const auto& indexBuffer,
+                         const auto& segments) {
+            program.draw(
+                context,
+                drawMode,
                 depthModeForSublayer(sublayer, gl::DepthMode::ReadWrite),
                 stencilModeForClipping(tile.clip),
                 colorModeForRenderPass(),
-                program,
                 FillProgram::UniformValues {
                     uniforms::u_matrix::Value{ tile.translatedMatrix(properties.fillTranslate.value,
                                                properties.fillTranslateAnchor.value,
@@ -91,19 +105,20 @@ void Painter::renderFill(PaintParameters& parameters,
                     uniforms::u_outline_color::Value{ outlineColor },
                     uniforms::u_world::Value{ context.viewport.getCurrentValue().size },
                 },
-                subject
-            });
+                vertexBuffer,
+                indexBuffer,
+                segments
+            );
         };
 
         if (properties.fillAntialias.value && !properties.fillOutlineColor.isUndefined() && pass == RenderPass::Translucent) {
             draw(2,
                  parameters.programs.fillOutline,
                  properties.fillOutlineColor.value,
-                 gl::Segmented<gl::Lines>(
-                     *bucket.vertexBuffer,
-                     *bucket.lineIndexBuffer,
-                     bucket.lineSegments,
-                     2.0f));
+                 gl::Lines { 2.0f },
+                 *bucket.vertexBuffer,
+                 *bucket.lineIndexBuffer,
+                 bucket.lineSegments);
         }
 
         // Only draw the fill when it's opaque and we're drawing opaque fragments,
@@ -112,21 +127,20 @@ void Painter::renderFill(PaintParameters& parameters,
             draw(1,
                  parameters.programs.fill,
                  properties.fillOutlineColor.value,
-                 gl::Segmented<gl::Triangles>(
-                     *bucket.vertexBuffer,
-                     *bucket.triangleIndexBuffer,
-                     bucket.triangleSegments));
+                 gl::Triangles(),
+                 *bucket.vertexBuffer,
+                 *bucket.triangleIndexBuffer,
+                 bucket.triangleSegments);
         }
 
         if (properties.fillAntialias.value && properties.fillOutlineColor.isUndefined() && pass == RenderPass::Translucent) {
             draw(2,
                  parameters.programs.fillOutline,
                  properties.fillColor.value,
-                 gl::Segmented<gl::Lines>(
-                     *bucket.vertexBuffer,
-                     *bucket.lineIndexBuffer,
-                     bucket.lineSegments,
-                     2.0f));
+                 gl::Lines { 2.0f },
+                 *bucket.vertexBuffer,
+                 *bucket.lineIndexBuffer,
+                 bucket.lineSegments);
         }
     }
 }
diff --git a/src/mbgl/renderer/painter_line.cpp b/src/mbgl/renderer/painter_line.cpp
index 7f9556fd3f..a495edc428 100644
--- a/src/mbgl/renderer/painter_line.cpp
+++ b/src/mbgl/renderer/painter_line.cpp
@@ -24,18 +24,17 @@ void Painter::renderLine(PaintParameters& parameters,
     const auto& properties = layer.impl->paint;
 
     auto draw = [&] (auto& program, auto&& uniformValues) {
-        context.draw({
+        program.draw(
+            context,
+            gl::Triangles(),
             depthModeForSublayer(0, gl::DepthMode::ReadOnly),
             stencilModeForClipping(tile.clip),
             colorModeForRenderPass(),
-            program,
             std::move(uniformValues),
-            gl::Segmented<gl::Triangles>(
-                *bucket.vertexBuffer,
-                *bucket.indexBuffer,
-                bucket.segments
-            )
-        });
+            *bucket.vertexBuffer,
+            *bucket.indexBuffer,
+            bucket.segments
+        );
     };
 
     if (!properties.lineDasharray.value.from.empty()) {
diff --git a/src/mbgl/renderer/painter_raster.cpp b/src/mbgl/renderer/painter_raster.cpp
index c619cad2aa..e19cde289a 100644
--- a/src/mbgl/renderer/painter_raster.cpp
+++ b/src/mbgl/renderer/painter_raster.cpp
@@ -54,11 +54,12 @@ void Painter::renderRaster(PaintParameters& parameters,
     context.bindTexture(*bucket.texture, 0, gl::TextureFilter::Linear);
     context.bindTexture(*bucket.texture, 1, gl::TextureFilter::Linear);
 
-    context.draw({
+    parameters.programs.raster.draw(
+        context,
+        gl::TriangleStrip(),
         depthModeForSublayer(0, gl::DepthMode::ReadOnly),
         gl::StencilMode::disabled(),
         colorModeForRenderPass(),
-        parameters.programs.raster,
         RasterProgram::UniformValues {
             uniforms::u_matrix::Value{ tile.matrix },
             uniforms::u_image0::Value{ 0 },
@@ -74,8 +75,8 @@ void Painter::renderRaster(PaintParameters& parameters,
             uniforms::u_scale_parent::Value{ 1.0f },
             uniforms::u_tl_parent::Value{ std::array<float, 2> {{ 0.0f, 0.0f }} },
         },
-        gl::Unindexed<gl::TriangleStrip>(rasterVertexBuffer)
-    });
+        rasterVertexBuffer
+    );
 }
 
 } // namespace mbgl
diff --git a/src/mbgl/renderer/painter_symbol.cpp b/src/mbgl/renderer/painter_symbol.cpp
index 2f94544486..d2dee5d99d 100644
--- a/src/mbgl/renderer/painter_symbol.cpp
+++ b/src/mbgl/renderer/painter_symbol.cpp
@@ -46,7 +46,9 @@ void Painter::renderSymbol(PaintParameters& parameters,
         const bool drawAcrossEdges = (frame.mapMode == MapMode::Continuous) && (true || !(layout.textAllowOverlap || layout.iconAllowOverlap ||
               layout.textIgnorePlacement || layout.iconIgnorePlacement));
 
-        context.draw({
+        program.draw(
+            context,
+            gl::Triangles(),
             values_.pitchAlignment == AlignmentType::Map
                 ? depthModeForSublayer(0, gl::DepthMode::ReadOnly)
                 : gl::DepthMode::disabled(),
@@ -54,14 +56,11 @@ void Painter::renderSymbol(PaintParameters& parameters,
                 ? gl::StencilMode::disabled()
                 : stencilModeForClipping(tile.clip),
             colorModeForRenderPass(),
-            program,
             std::move(uniformValues),
-            gl::Segmented<gl::Triangles>(
-                *buffers.vertexBuffer,
-                *buffers.indexBuffer,
-                buffers.segments
-            )
-        });
+            *buffers.vertexBuffer,
+            *buffers.indexBuffer,
+            buffers.segments
+        );
     };
 
     if (bucket.hasIconData()) {
@@ -119,22 +118,20 @@ void Painter::renderSymbol(PaintParameters& parameters,
     }
 
     if (bucket.hasCollisionBoxData()) {
-        context.draw({
+        programs->collisionBox.draw(
+            context,
+            gl::Lines { 1.0f },
             gl::DepthMode::disabled(),
             gl::StencilMode::disabled(),
             colorModeForRenderPass(),
-            programs->collisionBox,
             CollisionBoxProgram::UniformValues {
                 uniforms::u_matrix::Value{ tile.matrix },
                 uniforms::u_scale::Value{ std::pow(2.0f, float(state.getZoom() - tile.tile.id.overscaledZ)) },
                 uniforms::u_zoom::Value{ float(state.getZoom() * 10) },
                 uniforms::u_maxzoom::Value{ float((tile.id.canonical.z + 1) * 10) },
             },
-            gl::Unindexed<gl::Lines>(
-                *bucket.collisionBox.vertexBuffer,
-                1.0f
-            )
-        });
+            *bucket.collisionBox.vertexBuffer
+        );
     }
 }
 
diff --git a/src/mbgl/renderer/symbol_bucket.hpp b/src/mbgl/renderer/symbol_bucket.hpp
index d33341008e..f1fc3d324e 100644
--- a/src/mbgl/renderer/symbol_bucket.hpp
+++ b/src/mbgl/renderer/symbol_bucket.hpp
@@ -34,26 +34,26 @@ public:
     const bool iconsNeedLinear;
 
     struct TextBuffer {
-        std::vector<SymbolVertex> vertices;
-        std::vector<gl::Triangle> triangles;
+        gl::VertexVector<SymbolVertex> vertices;
+        gl::IndexVector<gl::Triangles> triangles;
         std::vector<gl::Segment> segments;
 
         optional<gl::VertexBuffer<SymbolVertex>> vertexBuffer;
-        optional<gl::IndexBuffer<gl::Triangle>> indexBuffer;
+        optional<gl::IndexBuffer<gl::Triangles>> indexBuffer;
     } text;
 
     struct IconBuffer {
-        std::vector<SymbolVertex> vertices;
-        std::vector<gl::Triangle> triangles;
+        gl::VertexVector<SymbolVertex> vertices;
+        gl::IndexVector<gl::Triangles> triangles;
         std::vector<gl::Segment> segments;
 
         optional<gl::VertexBuffer<SymbolVertex>> vertexBuffer;
-        optional<gl::IndexBuffer<gl::Triangle>> indexBuffer;
+        optional<gl::IndexBuffer<gl::Triangles>> indexBuffer;
     } icon;
 
     struct CollisionBoxBuffer {
-        std::vector<CollisionBoxVertex> vertices;
-        optional<gl::VertexBuffer<CollisionBoxVertex>> vertexBuffer;
+        gl::VertexVector<CollisionBoxVertex, gl::Lines> vertices;
+        optional<gl::VertexBuffer<CollisionBoxVertex, gl::Lines>> vertexBuffer;
     } collisionBox;
 };
 
diff --git a/src/mbgl/util/ignore.hpp b/src/mbgl/util/ignore.hpp
new file mode 100644
index 0000000000..31cd092c0e
--- /dev/null
+++ b/src/mbgl/util/ignore.hpp
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <initializer_list>
+
+namespace mbgl {
+
+// Accept any number of parameters of any types, and do nothing with them.
+// Useful for providing a context for parameter pack expansion where a legal
+// expansion context is not otherwise available.
+//
+// See https://github.com/mapbox/cpp/blob/master/C%2B%2B%20Structural%20Metaprogramming.md
+// for more details.
+//
+template <class... Ts> void ignore(Ts&&...) {}
+
+// std::initializer_list overload, for situations where you need sequenced
+// modifications.
+//
+template <class T> void ignore(const std::initializer_list<T>&) {}
+
+} // namespace mbgl