implement wheel on web

webgl/src/main.cpp

@@ -101,11 +101,19 @@ void CanvasOnPointerUp(std::string type, float x, float y, int button)
 
 void CanvasOnPointerMove(std::string type, float x, float y, float f)
 {
+    g_cursor_pos = { x, y };
     app.ui_task_async([=]{
         app.mouse_move(x, y, f, StringToType(type), false);
     });
 }
 
+void CanvasOnWheel(float y)
+{
+    app.ui_task_async([=]{
+        app.mouse_scroll(g_cursor_pos.x, g_cursor_pos.y, y);
+    });
+}
+
 void StartApp()
 {
     App::I = &app;
@@ -133,6 +141,7 @@ EMSCRIPTEN_BINDINGS(TaskCallback_bind) {
     function("CanvasOnPointerDown", &CanvasOnPointerDown);
     function("CanvasOnPointerUp", &CanvasOnPointerUp);
     function("CanvasOnPointerMove", &CanvasOnPointerMove);
+    function("CanvasOnWheel", &CanvasOnWheel);
     function("StartApp", &StartApp);
 }
 
@@ -248,13 +257,16 @@ int main()
             Module.CanvasOnPointerMove(event.pointerType, event.layerX, event.layerY, f);
         };
         Module.canvas.onpointerdown = function(event) {
-            console.log(event);
             f = event.pointerType == "pen" ? event.pressure : 1.0;
             Module.CanvasOnPointerDown(event.pointerType, event.layerX, event.layerY, f, event.button);
         };
         Module.canvas.onpointerup = function(event) {
             Module.CanvasOnPointerUp(event.pointerType, event.layerX, event.layerY, event.button);
         };
+        Module.canvas.onwheel = function(event) {
+            event.preventDefault();
+            Module.CanvasOnWheel(-event.deltaY / 100.0);
+        };
         Module.canvas.style.touchAction = 'none';
         Module.js_fs_synching = false;
         FS.mkdir('/PanoPainter');