[glfw] Main loop integration

This new code can be used for rendering on the Main thread
while it will also work for rendering on the Map thread
before we make the switch. Needed by #2909.

3 files changed, 19 insertions, 3 deletions

diff --git a/include/mbgl/platform/default/glfw_view.hpp b/include/mbgl/platform/default/glfw_view.hpp
index ae5bf340d5..802f61b0c0 100644
--- a/include/mbgl/platform/default/glfw_view.hpp
+++ b/include/mbgl/platform/default/glfw_view.hpp
@@ -2,6 +2,8 @@
 #define MBGL_COMMON_GLFW_VIEW
 
 #include <mbgl/mbgl.hpp>
+#include <mbgl/util/run_loop.hpp>
+#include <mbgl/util/timer.hpp>
 
 #ifdef MBGL_USE_GLES2
 #define GLFW_INCLUDE_ES2
@@ -92,6 +94,9 @@ private:
 
     std::function<void()> changeStyleCallback;
 
+    mbgl::util::RunLoop runLoop;
+    mbgl::util::Timer frameTick;
+
     GLFWwindow *window = nullptr;
     std::atomic_flag clean = ATOMIC_FLAG_INIT;
 };
diff --git a/src/mbgl/util/timer.hpp b/include/mbgl/util/timer.hpp
index 783241847d..783241847d 100644
--- a/src/mbgl/util/timer.hpp
+++ b/include/mbgl/util/timer.hpp
diff --git a/platform/default/glfw_view.cpp b/platform/default/glfw_view.cpp
index 6a7e798625..e65693c4c0 100644
--- a/platform/default/glfw_view.cpp
+++ b/platform/default/glfw_view.cpp
@@ -419,8 +419,16 @@ void GLFWView::onMouseMove(GLFWwindow *window, double x, double y) {
 }
 
 void GLFWView::run() {
-    while (!glfwWindowShouldClose(window)) {
-        glfwWaitEvents();
+    auto callback = [&] {
+        if (glfwWindowShouldClose(window)) {
+            frameTick.stop();
+            runLoop.stop();
+
+            return;
+        }
+
+        glfwPollEvents();
+
         const bool dirty = !clean.test_and_set();
         if (dirty) {
             const double started = glfwGetTime();
@@ -430,7 +438,10 @@ void GLFWView::run() {
                 map->update(mbgl::Update::Repaint);
             }
         }
-    }
+    };
+
+    frameTick.start(mbgl::Duration::zero(), mbgl::Milliseconds(1000 / 60), callback);
+    runLoop.run();
 }
 
 float GLFWView::getPixelRatio() const {