Integrate Perfetto with Godot-CPP

This change adds an example on how to integrate Perfetto
with Godot-CPP projects.

SConstruct

@@ -179,6 +179,7 @@ opts.Add(
 )
 
 opts.Add(BoolVariable("build_library", "Build the godot-cpp library.", True))
+opts.Add(PathVariable("perfetto", "Path to the perfetto include directory in the Godot Engine source", None, PathVariable.PathIsDir))
 
 opts.Update(env)
 Help(opts.GenerateHelpText(env))

test/SConstruct

@@ -6,6 +6,10 @@ env = SConscript("../SConstruct")
 env.Append(CPPPATH=['src/'])
 sources = Glob('src/*.cpp')
 
+if env["perfetto"]:
+    env.Append(CPPDEFINES=["ENABLE_PERFETTO"])
+    env.Append(CPPPATH=[env["perfetto"]])
+
 library = env.SharedLibrary(
     "bin/libgdexample.{}.{}.{}{}".format(
         env["platform"], env["target"], env["arch_suffix"], env["SHLIBSUFFIX"]

test/src/init.cpp

@@ -31,6 +31,8 @@
 #include <Godot.hpp>
 #include <Reference.hpp>
 
+#include "godot_profiler.h"
+
 using namespace godot;
 
 class SimpleClass : public Reference {
@@ -41,15 +43,18 @@ public:
 
 	/** `_init` must exist as it is called by Godot. */
 	void _init() {
+		TRACE_EVENT("app_main", "SimpleClass::_init");
 		_name = String("SimpleClass");
 		_value = 0;
 	}
 
 	void test_void_method() {
+		TRACE_EVENT("app_main", "SimpleClass::test_void_method");
 		Godot::print("This is test");
 	}
 
 	Variant method(Variant arg) {
+		TRACE_EVENT("app_main", "SimpleClass::method");
 		Variant ret;
 		ret = arg;
 
@@ -57,6 +62,7 @@ public:
 	}
 
 	static void _register_methods() {
+		TRACE_EVENT("app_main", "_register_methods");
 		register_method("method", &SimpleClass::method);
 
 		/**