1 files changed, 108 insertions, 0 deletions
diff --git a/src/nomute.c b/src/nomute.c
new file mode 100644
index 0000000..861062a
--- /dev/null
+++ b/src/nomute.c
@@ -0,0 +1,108 @@
+/*
+ * Copyright © 2023 Willian Henrique <wsimanbrazil@yahoo.com.br>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED “AS IS” AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+ * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+// TODO(linux): this is currently only built on Windows, but a linux
+// implementation would be also useful for some games e.g. L4D2
+
+#include "con_.h"
+#include "errmsg.h"
+#include "feature.h"
+#include "hook.h"
+#include "intdefs.h"
+#include "mem.h"
+#include "os.h"
+#include "sst.h"
+#include "x86.h"
+#include "x86util.h"
+
+// these have to come after Windows.h (via os.h) and in this order
+#include <mmeapi.h>
+#include <dsound.h>
+
+FEATURE("inactive window audio control")
+
+DEF_CVAR_UNREG(snd_mute_losefocus,
+		"Keep playing audio while tabbed out (SST reimplementation)", 1,
+		CON_ARCHIVE | CON_HIDDEN)
+
+static IDirectSoundVtbl *ds_vt = 0;
+static typeof(ds_vt->CreateSoundBuffer) orig_CreateSoundBuffer;
+static con_cmdcbv1 snd_restart_cb = 0;
+
+// early init (via VDF) happens before config is loaded, and audio is set up
+// after that, so we don't want to run snd_restart the first time the cvar is
+// set, unless we were loaded later with plugin_load, in which case audio is
+// already up and running and we'll want to restart it every time
+bool skiprestart;
+static void losefocuscb(struct con_var *v) {
+	if (!skiprestart) snd_restart_cb();
+	skiprestart = false;
+}
+
+static long __stdcall hook_CreateSoundBuffer(IDirectSound *this,
+		const DSBUFFERDESC *desc, IDirectSoundBuffer **buff, IUnknown *unk) {
+	if (!con_getvari(snd_mute_losefocus)) {
+		((DSBUFFERDESC *)desc)->dwFlags |= DSBCAPS_GLOBALFOCUS;
+	}
+	return orig_CreateSoundBuffer(this, desc, buff, unk);
+}
+
+PREINIT {
+	if (con_findvar("snd_mute_losefocus")) return false;
+	con_reg(snd_mute_losefocus);
+	return true;
+}
+
+INIT {
+	skiprestart = sst_earlyloaded; // see above
+	IDirectSound *ds_obj = 0;
+	if (DirectSoundCreate(NULL, &ds_obj, NULL) != DS_OK) {
+		errmsg_errorx("couldn't create IDirectSound instance");
+		return false;
+	}
+
+	ds_vt = ds_obj->lpVtbl;
+	if (!os_mprot(&ds_vt->CreateSoundBuffer, sizeof(void *), PAGE_READWRITE)) {
+		errmsg_errorx("couldn't make virtual table writable");
+		return false;
+	}
+
+	ds_obj->lpVtbl->Release(ds_obj);
+
+	orig_CreateSoundBuffer = ds_vt->CreateSoundBuffer;
+	ds_vt->CreateSoundBuffer = &hook_CreateSoundBuffer;
+	snd_mute_losefocus->base.flags &= ~CON_HIDDEN;
+
+	struct con_cmd *snd_restart = con_findcmd("snd_restart");
+	if (snd_restart) {
+		snd_restart_cb = con_getcmdcbv1(snd_restart);
+		snd_mute_losefocus->cb = &losefocuscb;
+	}
+	else {
+		errmsg_warnx("couldn't find snd_restart");
+		errmsg_note("changing snd_mute_losefocus will require changing other "
+				"audio settings or restarting the game with SST autoloaded in "
+				"order to have an effect");
+	}
+
+	return true;
+}
+
+END {
+	ds_vt->CreateSoundBuffer = orig_CreateSoundBuffer;
+}
+
+// vi: sw=4 ts=4 noet tw=80 cc=80