From 6cbc04425131120096ce06081a2b17f871c7ac2b Mon Sep 17 00:00:00 2001
From: Stephen Seo <seo.disparate@gmail.com>
Date: Thu, 31 Aug 2023 22:11:04 +0900
Subject: [PATCH] Add test fn to clear screens from js

---
 src/game.cc                  |  2 ++
 src/game.h                   |  2 ++
 src/main.cc                  | 14 ++++++++++++++
 wasm_build/custom_shell.html |  3 +++
 4 files changed, 21 insertions(+)

diff --git a/src/game.cc b/src/game.cc
index 72359dc..6522250 100644
--- a/src/game.cc
+++ b/src/game.cc
@@ -21,3 +21,5 @@ void Game::update() {
 }
 
 void Game::draw() { screen_stack->draw(); }
+
+void Game::clear_screens() { screen_stack->clear_screens(); }
diff --git a/src/game.h b/src/game.h
index b3fd492..1d6c764 100644
--- a/src/game.h
+++ b/src/game.h
@@ -22,6 +22,8 @@ class Game {
   void update();
   void draw();
 
+  void clear_screens();
+
  private:
   ScreenStack::Ptr screen_stack;
   std::chrono::steady_clock::time_point prev_time;
diff --git a/src/main.cc b/src/main.cc
index 85a52fc..a0287e2 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -15,6 +15,9 @@
 #include "game.h"
 
 #ifdef __EMSCRIPTEN__
+
+extern Game *global_game_ptr = nullptr;
+
 extern "C" {
 
 EM_BOOL resize_event_callback(int event_type, const EmscriptenUiEvent *event,
@@ -25,6 +28,15 @@ EM_BOOL resize_event_callback(int event_type, const EmscriptenUiEvent *event,
   }
   return false;
 }  // resize_event_callback(...)
+
+int EMSCRIPTEN_KEEPALIVE clear_all_screens() {
+  if (global_game_ptr) {
+    global_game_ptr->clear_screens();
+    return 0;
+  }
+  return 1;
+}
+
 }  // extern "C"
 #endif
 
@@ -46,6 +58,8 @@ int main() {
 #ifdef __EMSCRIPTEN__
   Game game{};
 
+  global_game_ptr = &game;
+
   SetWindowSize(call_js_get_canvas_width(), call_js_get_canvas_height());
 
   emscripten_set_resize_callback(EMSCRIPTEN_EVENT_TARGET_WINDOW, &game, false,
diff --git a/wasm_build/custom_shell.html b/wasm_build/custom_shell.html
index b295623..2bf70b1 100644
--- a/wasm_build/custom_shell.html
+++ b/wasm_build/custom_shell.html
@@ -59,6 +59,9 @@
       window.onerror = function() {
         console.log("onerror: " + event);
       };
+      function demo0_clear_all_screens() {
+        Module.ccall('clear_all_screens', 'number', [], []);
+      };
     </script>
     {{{ SCRIPT }}}
   </body>