1 files changed, 69 insertions, 0 deletions
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