1 files changed, 85 insertions, 0 deletions
diff --git a/platform/default/src/mbgl/gl/headless_backend.cpp b/platform/default/src/mbgl/gl/headless_backend.cpp
new file mode 100644
index 0000000000..ba08aecab7
--- /dev/null
+++ b/platform/default/src/mbgl/gl/headless_backend.cpp
@@ -0,0 +1,85 @@
+#include <mbgl/gl/headless_backend.hpp>
+#include <mbgl/gl/context.hpp>
+#include <mbgl/renderer/backend_scope.hpp>
+
+#include <cassert>
+#include <stdexcept>
+#include <type_traits>
+
+namespace mbgl {
+
+class HeadlessBackend::View {
+public:
+    View(gl::Context& context, Size size_)
+        : color(context.createRenderbuffer<gl::RenderbufferType::RGBA>(size_)),
+          depthStencil(context.createRenderbuffer<gl::RenderbufferType::DepthStencil>(size_)),
+          framebuffer(context.createFramebuffer(color, depthStencil)) {
+    }
+
+    gl::Renderbuffer<gl::RenderbufferType::RGBA> color;
+    gl::Renderbuffer<gl::RenderbufferType::DepthStencil> depthStencil;
+    gl::Framebuffer framebuffer;
+};
+
+HeadlessBackend::HeadlessBackend(Size size_)
+    : size(size_) {
+}
+
+HeadlessBackend::~HeadlessBackend() {
+    BackendScope guard { *this };
+    view.reset();
+    context.reset();
+}
+
+gl::ProcAddress HeadlessBackend::getExtensionFunctionPointer(const char* name) {
+    assert(impl);
+    return impl->getExtensionFunctionPointer(name);
+}
+
+void HeadlessBackend::activate() {
+    active = true;
+
+    if (!impl) {
+        createImpl();
+    }
+
+    assert(impl);
+    impl->activateContext();
+}
+
+void HeadlessBackend::deactivate() {
+    assert(impl);
+    impl->deactivateContext();
+    active = false;
+}
+
+void HeadlessBackend::bind() {
+    gl::Context& context_ = getContext();
+
+    if (!view) {
+        view = std::make_unique<View>(context_, size);
+    }
+
+    context_.bindFramebuffer = view->framebuffer.framebuffer;
+    context_.scissorTest = false;
+    context_.viewport = { 0, 0, size };
+}
+
+Size HeadlessBackend::getFramebufferSize() const {
+    return size;
+}
+
+void HeadlessBackend::updateAssumedState() {
+    // no-op
+}
+
+void HeadlessBackend::setSize(Size size_) {
+    size = size_;
+    view.reset();
+}
+
+PremultipliedImage HeadlessBackend::readStillImage() {
+    return getContext().readFramebuffer<PremultipliedImage>(size);
+}
+
+} // namespace mbgl