7 files changed, 124 insertions, 9 deletions
diff --git a/src/mbgl/renderer/backend_scope.cpp b/src/mbgl/renderer/backend_scope.cpp
new file mode 100644
index 0000000000..5d57421c48
--- /dev/null
+++ b/src/mbgl/renderer/backend_scope.cpp
@@ -0,0 +1,47 @@
+#include <mbgl/renderer/backend_scope.hpp>
+#include <mbgl/renderer/renderer_backend.hpp>
+#include <mbgl/util/thread_local.hpp>
+
+#include <cassert>
+
+namespace mbgl {
+
+static util::ThreadLocal<BackendScope> currentScope;
+
+BackendScope::BackendScope(RendererBackend& backend_, ScopeType scopeType_)
+    : priorScope(currentScope.get()),
+      nextScope(nullptr),
+      backend(backend_),
+      scopeType(scopeType_) {
+    if (priorScope) {
+        assert(priorScope->nextScope == nullptr);
+        priorScope->nextScope = this;
+    }
+    if (scopeType == ScopeType::Explicit) {
+        backend.activate();
+    }
+
+    currentScope.set(this);
+}
+
+BackendScope::~BackendScope() {
+    assert(nextScope == nullptr);
+    if (priorScope) {
+        priorScope->backend.activate();
+        currentScope.set(priorScope);
+        assert(priorScope->nextScope == this);
+        priorScope->nextScope = nullptr;
+    } else {
+        if (scopeType == ScopeType::Explicit) {
+            backend.deactivate();
+        }
+
+        currentScope.set(nullptr);
+    }
+}
+
+bool BackendScope::exists() {
+    return currentScope.get();
+}
+
+} // namespace mbgl
diff --git a/src/mbgl/renderer/layers/render_custom_layer.cpp b/src/mbgl/renderer/layers/render_custom_layer.cpp
index 81b8ac301b..30649137c7 100644
--- a/src/mbgl/renderer/layers/render_custom_layer.cpp
+++ b/src/mbgl/renderer/layers/render_custom_layer.cpp
@@ -3,7 +3,7 @@
 #include <mbgl/renderer/paint_parameters.hpp>
 #include <mbgl/style/layers/custom_layer_impl.hpp>
 #include <mbgl/map/transform_state.hpp>
-#include <mbgl/map/backend_scope.hpp>
+#include <mbgl/renderer/backend_scope.hpp>
 
 namespace mbgl {
 
diff --git a/src/mbgl/renderer/render_style.cpp b/src/mbgl/renderer/render_style.cpp
index a0f1fd4049..2bf903fe5f 100644
--- a/src/mbgl/renderer/render_style.cpp
+++ b/src/mbgl/renderer/render_style.cpp
@@ -15,6 +15,7 @@
 #include <mbgl/renderer/layers/render_line_layer.hpp>
 #include <mbgl/renderer/layers/render_raster_layer.hpp>
 #include <mbgl/renderer/layers/render_symbol_layer.hpp>
+#include <mbgl/renderer/backend_scope.hpp>
 #include <mbgl/renderer/style_diff.hpp>
 #include <mbgl/renderer/image_manager.hpp>
 #include <mbgl/renderer/query.hpp>
@@ -24,7 +25,6 @@
 #include <mbgl/sprite/sprite_loader.hpp>
 #include <mbgl/text/glyph_manager.hpp>
 #include <mbgl/geometry/line_atlas.hpp>
-#include <mbgl/map/backend_scope.hpp>
 #include <mbgl/tile/tile.hpp>
 #include <mbgl/util/math.hpp>
 #include <mbgl/util/string.hpp>
diff --git a/src/mbgl/renderer/renderer.cpp b/src/mbgl/renderer/renderer.cpp
index 11d7726c79..3c9715cd50 100644
--- a/src/mbgl/renderer/renderer.cpp
+++ b/src/mbgl/renderer/renderer.cpp
@@ -5,7 +5,7 @@
 
 namespace mbgl {
 
-Renderer::Renderer(Backend& backend,
+Renderer::Renderer(RendererBackend& backend,
                    float pixelRatio_,
                    FileSource& fileSource_,
                    Scheduler& scheduler_,
diff --git a/src/mbgl/renderer/renderer_backend.cpp b/src/mbgl/renderer/renderer_backend.cpp
new file mode 100644
index 0000000000..159ef432b3
--- /dev/null
+++ b/src/mbgl/renderer/renderer_backend.cpp
@@ -0,0 +1,69 @@
+#include <mbgl/renderer/renderer_backend.hpp>
+#include <mbgl/renderer/backend_scope.hpp>
+#include <mbgl/gl/context.hpp>
+#include <mbgl/gl/extension.hpp>
+#include <mbgl/gl/debugging.hpp>
+
+#include <cassert>
+
+namespace mbgl {
+
+RendererBackend::RendererBackend() = default;
+
+gl::Context& RendererBackend::getContext() {
+    assert(BackendScope::exists());
+    std::call_once(initialized, [this] {
+        context = std::make_unique<gl::Context>();
+        context->enableDebugging();
+        context->initializeExtensions(
+            std::bind(&RendererBackend::initializeExtension, this, std::placeholders::_1));
+    });
+    return *context;
+}
+
+PremultipliedImage RendererBackend::readFramebuffer(const Size& size) const {
+    assert(context);
+    return context->readFramebuffer<PremultipliedImage>(size);
+}
+
+void RendererBackend::assumeFramebufferBinding(const gl::FramebufferID fbo) {
+    getContext().bindFramebuffer.setCurrentValue(fbo);
+    if (fbo != ImplicitFramebufferBinding) {
+        assert(gl::value::BindFramebuffer::Get() == getContext().bindFramebuffer.getCurrentValue());
+    }
+}
+
+void RendererBackend::assumeViewport(int32_t x, int32_t y, const Size& size) {
+    getContext().viewport.setCurrentValue({ x, y, size });
+    assert(gl::value::Viewport::Get() == getContext().viewport.getCurrentValue());
+}
+
+void RendererBackend::assumeScissorTest(bool enabled) {
+    getContext().scissorTest.setCurrentValue(enabled);
+    assert(gl::value::ScissorTest::Get() == getContext().scissorTest.getCurrentValue());
+}
+
+bool RendererBackend::implicitFramebufferBound() {
+    return getContext().bindFramebuffer.getCurrentValue() == ImplicitFramebufferBinding;
+}
+
+void RendererBackend::setFramebufferBinding(const gl::FramebufferID fbo) {
+    getContext().bindFramebuffer = fbo;
+    if (fbo != ImplicitFramebufferBinding) {
+        assert(gl::value::BindFramebuffer::Get() == getContext().bindFramebuffer.getCurrentValue());
+    }
+}
+
+void RendererBackend::setViewport(int32_t x, int32_t y, const Size& size) {
+    getContext().viewport = { x, y, size };
+    assert(gl::value::Viewport::Get() == getContext().viewport.getCurrentValue());
+}
+
+void RendererBackend::setScissorTest(bool enabled) {
+    getContext().scissorTest = enabled;
+    assert(gl::value::ScissorTest::Get() == getContext().scissorTest.getCurrentValue());
+}
+
+RendererBackend::~RendererBackend() = default;
+
+} // namespace mbgl
diff --git a/src/mbgl/renderer/renderer_impl.cpp b/src/mbgl/renderer/renderer_impl.cpp
index accdbc1332..38aaf95671 100644
--- a/src/mbgl/renderer/renderer_impl.cpp
+++ b/src/mbgl/renderer/renderer_impl.cpp
@@ -5,7 +5,7 @@
 #include <mbgl/renderer/painter.hpp>
 #include <mbgl/renderer/update_parameters.hpp>
 #include <mbgl/map/transform_state.hpp>
-#include <mbgl/map/backend_scope.hpp>
+#include <mbgl/renderer/backend_scope.hpp>
 
 namespace mbgl {
 
@@ -14,7 +14,7 @@ static RendererObserver& nullObserver() {
     return observer;
 }
 
-Renderer::Impl::Impl(Backend& backend_,
+Renderer::Impl::Impl(RendererBackend& backend_,
                      float pixelRatio_,
                      FileSource& fileSource_,
                      Scheduler& scheduler_,
diff --git a/src/mbgl/renderer/renderer_impl.hpp b/src/mbgl/renderer/renderer_impl.hpp
index 645b33b354..2294dde91e 100644
--- a/src/mbgl/renderer/renderer_impl.hpp
+++ b/src/mbgl/renderer/renderer_impl.hpp
@@ -1,11 +1,10 @@
 #pragma once
 #include <mbgl/renderer/renderer.hpp>
+#include <mbgl/renderer/renderer_backend.hpp>
 #include <mbgl/renderer/renderer_observer.hpp>
 #include <mbgl/renderer/render_style_observer.hpp>
 #include <mbgl/style/style.hpp>
 
-#include <mbgl/map/backend.hpp>
-
 #include <memory>
 #include <string>
 
@@ -25,7 +24,7 @@ class View;
 
 class Renderer::Impl : public RenderStyleObserver {
 public:
-    Impl(Backend&, float pixelRatio_, FileSource&, Scheduler&, GLContextMode,
+    Impl(RendererBackend&, float pixelRatio_, FileSource&, Scheduler&, GLContextMode,
          const optional<std::string> programCacheDir);
     ~Impl() final;
 
@@ -47,7 +46,7 @@ public:
 private:
     friend class Renderer;
 
-    Backend& backend;
+    RendererBackend& backend;
 
     RendererObserver* observer;