warn when rendering without setAnimationFrame

1 files changed, 10 insertions, 2 deletions

diff --git a/src/library_browser.js b/src/library_browser.js
index 458a8dd2..5d53b867 100644
--- a/src/library_browser.js
+++ b/src/library_browser.js
@@ -13,6 +13,7 @@ mergeInto(LibraryManager.library, {
   $Browser: {
     mainLoop: {
       scheduler: null,
+      method: '',
       shouldPause: false,
       paused: false,
       queue: [],
@@ -784,6 +785,11 @@ mergeInto(LibraryManager.library, {
       GL.newRenderingFrameStarted();
 #endif
 
+      if (Browser.mainLoop.method === 'timeout' && Module.ctx) {
+        Module.printErr('Looks like you are rendering without using requestAnimationFrame for the main loop. You should use 0 for the frame rate in emscripten_set_main_loop in order to use requestAnimationFrame, as that can greatly improve your frame rates!');
+        Browser.mainLoop.method = ''; // just warn once per call to set main loop
+      }
+
       if (Module['preMainLoop']) {
         Module['preMainLoop']();
       }
@@ -814,11 +820,13 @@ mergeInto(LibraryManager.library, {
     if (fps && fps > 0) {
       Browser.mainLoop.scheduler = function Browser_mainLoop_scheduler() {
         setTimeout(Browser.mainLoop.runner, 1000/fps); // doing this each time means that on exception, we stop
-      }
+      };
+      Browser.mainLoop.method = 'timeout';
     } else {
       Browser.mainLoop.scheduler = function Browser_mainLoop_scheduler() {
         Browser.requestAnimationFrame(Browser.mainLoop.runner);
-      }
+      };
+      Browser.mainLoop.method = 'rAF';
     }
     Browser.mainLoop.scheduler();