1 files changed, 89 insertions, 0 deletions
diff --git a/platform/macos/src/MGLMapView+OpenGL.mm b/platform/macos/src/MGLMapView+OpenGL.mm
new file mode 100644
index 0000000000..f6168a4b80
--- /dev/null
+++ b/platform/macos/src/MGLMapView+OpenGL.mm
@@ -0,0 +1,89 @@
+#import "MGLMapView+OpenGL.h"
+#import "MGLOpenGLLayer.h"
+
+#include <mbgl/gl/renderable_resource.hpp>
+
+#import <OpenGL/gl.h>
+
+class MGLMapViewOpenGLRenderableResource final : public mbgl::gl::RenderableResource {
+public:
+    MGLMapViewOpenGLRenderableResource(MGLMapViewOpenGLImpl& backend_) : backend(backend_) {
+    }
+
+    void bind() override {
+        backend.restoreFramebufferBinding();
+    }
+
+private:
+    MGLMapViewOpenGLImpl& backend;
+
+public:
+    // The current framebuffer of the NSOpenGLLayer we are painting to.
+    GLint fbo = 0;
+
+    // The reference counted count of activation calls
+    NSUInteger activationCount = 0;
+};
+
+MGLMapViewOpenGLImpl::MGLMapViewOpenGLImpl(MGLMapView* nativeView_)
+    : MGLMapViewImpl(nativeView_),
+      mbgl::gl::RendererBackend(mbgl::gfx::ContextMode::Unique),
+      mbgl::gfx::Renderable(mapView.framebufferSize,
+                            std::make_unique<MGLMapViewOpenGLRenderableResource>(*this)) {
+
+    // Install the OpenGL layer. Interface Builder’s synchronous drawing means
+    // we can’t display a map, so don’t even bother to have a map layer.
+    mapView.layer =
+        mapView.isTargetingInterfaceBuilder ? [CALayer layer] : [MGLOpenGLLayer layer];
+}
+
+mbgl::gl::ProcAddress MGLMapViewOpenGLImpl::getExtensionFunctionPointer(const char* name) {
+    static CFBundleRef framework = CFBundleGetBundleWithIdentifier(CFSTR("com.apple.opengl"));
+    if (!framework) {
+        throw std::runtime_error("Failed to load OpenGL framework.");
+    }
+
+    return reinterpret_cast<mbgl::gl::ProcAddress>(CFBundleGetFunctionPointerForName(
+        framework, (__bridge CFStringRef)[NSString stringWithUTF8String:name]));
+}
+
+void MGLMapViewOpenGLImpl::activate() {
+    auto& resource = getResource<MGLMapViewOpenGLRenderableResource>();
+    if (resource.activationCount++) {
+        return;
+    }
+
+    MGLOpenGLLayer* layer = (MGLOpenGLLayer*)mapView.layer;
+    [layer.openGLContext makeCurrentContext];
+}
+
+void MGLMapViewOpenGLImpl::deactivate() {
+    auto& resource = getResource<MGLMapViewOpenGLRenderableResource>();
+    if (--resource.activationCount) {
+        return;
+    }
+
+    [NSOpenGLContext clearCurrentContext];
+}
+
+void MGLMapViewOpenGLImpl::updateAssumedState() {
+    auto& resource = getResource<MGLMapViewOpenGLRenderableResource>();
+    glGetIntegerv(GL_FRAMEBUFFER_BINDING, &resource.fbo);
+    assumeFramebufferBinding(resource.fbo);
+    assumeViewport(0, 0, mapView.framebufferSize);
+}
+
+void MGLMapViewOpenGLImpl::restoreFramebufferBinding() {
+    auto& resource = getResource<MGLMapViewOpenGLRenderableResource>();
+    setFramebufferBinding(resource.fbo);
+    setViewport(0, 0, mapView.framebufferSize);
+}
+
+mbgl::PremultipliedImage MGLMapViewOpenGLImpl::readStillImage() {
+    return readFramebuffer(mapView.framebufferSize);
+}
+
+CGLContextObj MGLMapViewOpenGLImpl::getCGLContextObj() {
+    MGLOpenGLLayer* layer = (MGLOpenGLLayer*)mapView.layer;
+    return layer.openGLContext.CGLContextObj;
+}