Merge pull request #2417 from juj/emscripten_SDL_SetEventHandler

Emscripten sdl set event handler

1 files changed, 38 insertions, 10 deletions

diff --git a/src/library_sdl.js b/src/library_sdl.js
index 7145a7ba..0cd1d27d 100644
--- a/src/library_sdl.js
+++ b/src/library_sdl.js
@@ -84,6 +84,9 @@ var LibrarySDL = {
 
     TOUCH_DEFAULT_ID: 0, // Our default deviceID for touch events (we get nothing from the browser)
     
+    eventHandler: null,
+    eventHandlerContext: null,
+    
     keyCodes: { // DOM code ==> SDL code. See https://developer.mozilla.org/en/Document_Object_Model_%28DOM%29/KeyboardEvent and SDL_keycode.h
       // For keys that don't have unicode value, we map DOM codes with the corresponding scan codes + 1024 (using "| 1 << 10")
       16: 225 | 1<<10, // shift
@@ -699,6 +702,9 @@ var LibrarySDL = {
         Module.printErr('SDL event queue full, dropping events');
         SDL.events = SDL.events.slice(0, 10000);
       }
+      // If we have a handler installed, this will push the events to the app
+      // instead of the app polling for them.
+      SDL.flushEventsToHandler();
       return;
     },
 
@@ -750,6 +756,30 @@ var LibrarySDL = {
       }
     },
 
+    flushEventsToHandler: function() {
+      if (!SDL.eventHandler) return;
+
+      // All SDLEvents take the same amount of memory
+      var sdlEventPtr = allocate({{{ C_STRUCTS.SDL_KeyboardEvent.__size__ }}}, "i8", ALLOC_STACK);
+
+      while (SDL.pollEvent(sdlEventPtr)) {
+        Runtime.dynCall('iii', SDL.eventHandler, [SDL.eventHandlerContext, sdlEventPtr]);
+      }
+    },
+
+    pollEvent: function(ptr) {
+      if (SDL.initFlags & 0x200 && SDL.joystickEventState) {
+        // If SDL_INIT_JOYSTICK was supplied AND the joystick system is configured
+        // to automatically query for events, query for joystick events.
+        SDL.queryJoysticks();
+      }
+      if (SDL.events.length === 0) return 0;
+      if (ptr) {
+        SDL.makeCEvent(SDL.events.shift(), ptr);
+      }
+      return 1;
+    },
+
     makeCEvent: function(event, ptr) {
       if (typeof event === 'number') {
         // This is a pointer to a native C event that was SDL_PushEvent'ed
@@ -1709,16 +1739,7 @@ var LibrarySDL = {
   },
 
   SDL_PollEvent: function(ptr) {
-    if (SDL.initFlags & 0x200 && SDL.joystickEventState) {
-      // If SDL_INIT_JOYSTICK was supplied AND the joystick system is configured
-      // to automatically query for events, query for joystick events.
-      SDL.queryJoysticks();
-    }
-    if (SDL.events.length === 0) return 0;
-    if (ptr) {
-      SDL.makeCEvent(SDL.events.shift(), ptr);
-    }
-    return 1;
+    return SDL.pollEvent(ptr);
   },
 
   SDL_PushEvent: function(ptr) {
@@ -1758,6 +1779,13 @@ var LibrarySDL = {
       SDL.handleEvent(event);
     });
   },
+  
+  // An Emscripten-specific extension to SDL: Some browser APIs require that they are called from within an event handler function.
+  // Allow recording a callback that will be called for each received event.
+  emscripten_SDL_SetEventHandler: function(handler, userdata) {
+    SDL.eventHandler = handler;
+    SDL.eventHandlerContext = userdata;
+  },
 
   SDL_SetColors: function(surf, colors, firstColor, nColors) {
     var surfData = SDL.surfaces[surf];