Add redraw handler setter

include/scratchcpp/iengine.h

@@ -5,6 +5,7 @@
 #include <memory>
 #include <vector>
 #include <unordered_map>
+#include <functional>
 
 #include "global.h"
 
@@ -90,6 +91,9 @@ class LIBSCRATCHCPP_EXPORT IEngine
          */
         virtual void runEventLoop() = 0;
 
+        /*! Sets the function which is called on every frame. */
+        virtual void setRedrawHandler(const std::function<void()> &handler) = 0;
+
         /*! Returns true if the project is currently running. */
         virtual bool isRunning() const = 0;
 

src/engine/internal/engine.cpp

@@ -322,6 +322,11 @@ void Engine::runEventLoop()
     eventLoop();
 }
 
+void Engine::setRedrawHandler(const std::function<void()> &handler)
+{
+    m_redrawHandler = handler;
+}
+
 void Engine::eventLoop(bool untilProjectStops)
 {
     updateFrameDuration();
@@ -374,7 +379,8 @@ void Engine::eventLoop(bool untilProjectStops)
             break;
 
         // Redraw
-        // TODO: Redraw here
+        if (m_redrawHandler)
+            m_redrawHandler();
 
         // If the timeout hasn't been reached yet (redraw was requested), sleep
         if (!timeout)

src/engine/internal/engine.h

@@ -40,6 +40,8 @@ class Engine : public IEngine
         void run() override;
         void runEventLoop() override;
 
+        void setRedrawHandler(const std::function<void()> &handler) override;
+
         bool isRunning() const override;
 
         double fps() const override;
@@ -180,6 +182,7 @@ class Engine : public IEngine
 
         bool m_running = false;
         bool m_redrawRequested = false;
+        std::function<void()> m_redrawHandler = nullptr;
 };
 
 } // namespace libscratchcpp

test/engine/engine_test.cpp

@@ -19,6 +19,12 @@ using ::testing::Return;
 
 // NOTE: resolveIds() and compile() are tested in load_project_test
 
+class RedrawMock
+{
+    public:
+        MOCK_METHOD(void, redraw, ());
+};
+
 TEST(EngineTest, Clock)
 {
     Engine engine;
@@ -98,6 +104,9 @@ TEST(EngineTest, FpsProject)
     p.run();
 
     engine->setFps(10);
+    RedrawMock redrawMock;
+    auto handler = std::bind(&RedrawMock::redraw, &redrawMock);
+    engine->setRedrawHandler(std::function<void()>(handler));
     std::chrono::steady_clock::time_point time5(std::chrono::milliseconds(100));
     std::chrono::steady_clock::time_point time6(std::chrono::milliseconds(115));
     std::chrono::steady_clock::time_point time7(std::chrono::milliseconds(200));
@@ -113,6 +122,7 @@ TEST(EngineTest, FpsProject)
         .WillOnce(Return(time8));
     EXPECT_CALL(clock, sleep(std::chrono::milliseconds(100)));
     EXPECT_CALL(clock, sleep(std::chrono::milliseconds(15)));
+    EXPECT_CALL(redrawMock, redraw()).Times(4);
     p.run();
 
     engine->setTurboModeEnabled(true);

test/mocks/enginemock.h

@@ -26,6 +26,8 @@ class EngineMock : public IEngine
         MOCK_METHOD(void, run, (), (override));
         MOCK_METHOD(void, runEventLoop, (), (override));
 
+        MOCK_METHOD(void, setRedrawHandler, (const std::function<void()> &), (override));
+
         MOCK_METHOD(bool, isRunning, (), (const, override));
 
         MOCK_METHOD(double, fps, (), (const, override));