refactor mouse wheel handling code to be shared across SDL, glfw, glut

4 files changed, 7 insertions, 9 deletions

diff --git a/src/library_browser.js b/src/library_browser.js
index d6526d9c..50a8fc6f 100644
--- a/src/library_browser.js
+++ b/src/library_browser.js
@@ -446,6 +446,10 @@ mergeInto(LibraryManager.library, {
              0;
     },
 
+    getMouseWheelDelta: function(event) {
+      return Math.max(-1, Math.min(1, event.type === 'DOMMouseScroll' ? event.detail : -event.wheelDelta));
+    },
+
     mouseX: 0,
     mouseY: 0,
     mouseMovementX: 0,
diff --git a/src/library_glfw.js b/src/library_glfw.js
index 17e8956a..b54205ad 100644
--- a/src/library_glfw.js
+++ b/src/library_glfw.js
@@ -197,13 +197,7 @@ var LibraryGLFW = {
     },
 
     onMouseWheel: function(event) {
-      if (event.detail > 0) {
-        GLFW.wheelPos++;
-      }
-
-      if (event.detail < 0) {
-        GLFW.wheelPos--;
-      }
+      GLFW.wheelPos += Browser.getMouseWheelDelta(event);
 
       if (GLFW.mouseWheelFunc && event.target == Module["canvas"]) {
         Runtime.dynCall('vi', GLFW.mouseWheelFunc, [GLFW.wheelPos]);
diff --git a/src/library_glut.js b/src/library_glut.js
index 65ac10c4..167e5272 100644
--- a/src/library_glut.js
+++ b/src/library_glut.js
@@ -229,7 +229,7 @@ var LibraryGLUT = {
 
       // cross-browser wheel delta
       var e = window.event || event; // old IE support
-      var delta = Math.max(-1, Math.min(1, (e.wheelDelta || -e.detail)));
+      var delta = -Browser.getMouseWheelDelta(event);
 
       var button = 3; // wheel up
       if (delta < 0) {
diff --git a/src/library_sdl.js b/src/library_sdl.js
index 8c70ceee..0e82203c 100644
--- a/src/library_sdl.js
+++ b/src/library_sdl.js
@@ -411,7 +411,7 @@ var LibrarySDL = {
           }
 
           if (event.type == 'DOMMouseScroll' || event.type == 'mousewheel') {
-            var button = (event.type == 'DOMMouseScroll' ? event.detail : -event.wheelDelta) > 0 ? 4 : 3;
+            var button = Browser.getMouseWheelDelta(event) > 0 ? 4 : 3;
             var event2 = {
               type: 'mousedown',
               button: button,