[CSM] sound_play & sound_stop support + client_lua_api doc (#5096)

* squashed: CSM: Implement register_globalstep
  * Re-use fatal error mechanism from server to disconnect client on CSM error
  * Little client functions cleanups

* squashed: CSM: add core.after function
  * core.after is shared code between client & server
  * ModApiUtil get_us_time feature enabled for client

2 files changed, 20 insertions, 0 deletions

diff --git a/src/script/cpp_api/s_client.cpp b/src/script/cpp_api/s_client.cpp
index f0676f4c2..ce88d67e3 100644
--- a/src/script/cpp_api/s_client.cpp
+++ b/src/script/cpp_api/s_client.cpp
@@ -20,6 +20,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "s_client.h"
 #include "s_internal.h"
+#include "client.h"
 
 void ScriptApiClient::on_shutdown()
 {
@@ -94,3 +95,20 @@ void ScriptApiClient::on_death()
 	// Call callbacks
 	runCallbacks(0, RUN_CALLBACKS_MODE_FIRST);
 }
+
+void ScriptApiClient::environment_step(float dtime)
+{
+	SCRIPTAPI_PRECHECKHEADER
+
+	// Get core.registered_globalsteps
+	lua_getglobal(L, "core");
+	lua_getfield(L, -1, "registered_globalsteps");
+	// Call callbacks
+	lua_pushnumber(L, dtime);
+	try {
+		runCallbacks(1, RUN_CALLBACKS_MODE_FIRST);
+	} catch (LuaError &e) {
+		getClient()->setFatalError(std::string("Client environment_step: ") + e.what() + "\n"
+				+ script_get_backtrace(L));
+	}
+}
diff --git a/src/script/cpp_api/s_client.h b/src/script/cpp_api/s_client.h
index 3155c7e67..3d373f97c 100644
--- a/src/script/cpp_api/s_client.h
+++ b/src/script/cpp_api/s_client.h
@@ -36,5 +36,7 @@ public:
 	void on_damage_taken(int32_t damage_amount);
 	void on_hp_modification(int32_t newhp);
 	void on_death();
+
+	void environment_step(float dtime);
 };
 #endif