diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1e6f80a..60346ae 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,7 +15,7 @@ if(MSVC)
 endif()
 
 if (EMSCRIPTEN)
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g -D_DEBUG")
   set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -g -s USE_GLFW=3 --profiling -s ASSERTIONS=1 -s WASM=1 -s INITIAL_MEMORY=268435456 -s FORCE_FILESYSTEM=1 --preload-file ${CMAKE_SOURCE_DIR}/art@art/ --shell-file ${CMAKE_SOURCE_DIR}/web/eco2d.html")
   set(CMAKE_EXECUTABLE_SUFFIX ".html") # This line is used to set your executable to build with the emscripten html template so that you can directly open it.
   set(CMAKE_COMPILE_WARNING_AS_ERROR OFF)