[core] Make RendererObserver a public interface

Needed by backends implementing asyncronous rendering

1 files changed, 35 insertions, 0 deletions

diff --git a/include/mbgl/renderer/renderer_observer.hpp b/include/mbgl/renderer/renderer_observer.hpp
new file mode 100644
index 0000000000..551b5c803e
--- /dev/null
+++ b/include/mbgl/renderer/renderer_observer.hpp
@@ -0,0 +1,35 @@
+#pragma once
+
+#include <exception>
+
+namespace mbgl {
+
+class RendererObserver {
+public:
+    virtual ~RendererObserver() = default;
+
+    enum class RenderMode : uint32_t {
+        Partial,
+        Full
+    };
+
+    // Signals that a repaint is required
+    virtual void onInvalidate() {}
+
+    // Resource failed to download / parse
+    virtual void onResourceError(std::exception_ptr) {}
+
+    // First frame
+    virtual void onWillStartRenderingMap() {}
+
+    // Start of frame, initial is the first frame for this map
+    virtual void onWillStartRenderingFrame() {}
+
+    // End of frame, boolean flags that a repaint is required
+    virtual void onDidFinishRenderingFrame(RenderMode, bool) {}
+
+    // Final frame
+    virtual void onDidFinishRenderingMap() {}
+};
+
+} // namespace mbgl