Fixing exit crash.

src/graphics.cpp

@@ -537,12 +537,13 @@ INT WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE, _In_ PSTR, _In_
 	Clock clock;
 	double frametime = 1.0;
 	MSG msg = { 0 };
-	while(msg.message!=WM_QUIT) {
+	while(msg.message!=WM_QUIT && running) {
 		while(PeekMessage(&msg, 0, 0, 0, PM_REMOVE)) {
 			if(msg.message==WM_QUIT) break;
 			TranslateMessage(&msg);
 			DispatchMessage(&msg);
 		}
+		if(!running) break;
 		// main loop ################################################################
 		camera.rendring_frame.lock(); // block rendering for other threads until finished
 		camera.update_state(fmax(1.0/(double)camera.fps_limit, frametime));

src/graphics.hpp

@@ -109,7 +109,7 @@ class Camera {
 			case '+': input_scroll_down(); break;
 			case '-': input_scroll_up(); break;
 			case 'F': input_F(); break;
-			case 27: running=false; println(); exit(0);
+			case 27: running=false; break; // signal threads to exit cleanly (don't call exit() - causes heap corruption)
 		}
 #ifdef INTERACTIVE_GRAPHICS_ASCII
 		if(free) { // move free camera

src/main.cpp

@@ -147,7 +147,8 @@ void main_physics() {
 	info.print_logo();
 	main_setup(); // execute setup
 	running = false;
-	exit(0); // make sure that the program stops
+	// Don't call exit(0) here - let main thread join and exit cleanly
+	// exit(0) causes heap corruption due to race conditions with other threads
 }
 
 #ifndef GRAPHICS