ngs2: patch to a rack handle connects to its voice 0

Co-authored-by: Phr3d13 <phr3d13@gmail.com>

src/libs/ngs2.cpp

@@ -2339,6 +2339,17 @@ int KYTY_SYSV_ABI Ngs2RackGetVoiceHandle(uintptr_t rack_handle, uint32_t voice_i
 	return OK;
 }
 
+// A patch to a rack handle connects to voice #0 of that rack.
+static Ngs2VoiceInternal* Ngs2FindPatchDestination(uintptr_t handle) {
+	Common::LockGuard racks_lock(g_racks_mutex);
+	for (auto* rack = g_racks_list; rack != nullptr; rack = rack->next) {
+		if (reinterpret_cast<uintptr_t>(rack) == handle) {
+			return reinterpret_cast<Ngs2VoiceInternal*>(rack + 1);
+		}
+	}
+	return reinterpret_cast<Ngs2VoiceInternal*>(handle);
+}
+
 // NOLINTNEXTLINE(readability-function-cognitive-complexity)
 int KYTY_SYSV_ABI Ngs2VoiceControl(uintptr_t voice_handle, const Ngs2VoiceParamHeader* param_list) {
 	PRINT_NAME();
@@ -2408,7 +2419,7 @@ int KYTY_SYSV_ABI Ngs2VoiceControl(uintptr_t voice_handle, const Ngs2VoiceParamH
 						const auto* patch = reinterpret_cast<const Ngs2VoicePatchParam*>(param);
 						EXIT_NOT_IMPLEMENTED(patch->port >= voice->ports.size());
 						voice->ports[patch->port].dest =
-						    reinterpret_cast<Ngs2VoiceInternal*>(patch->dest_handle);
+						    Ngs2FindPatchDestination(patch->dest_handle);
 						voice->ports[patch->port].input = patch->dest_input_id;
 						LOGF("\t connect->port          = %u\n"
 						     "\t connect->dest_input_id = %u\n"

tests/Ngs2SamplerTests.cpp

@@ -807,6 +807,21 @@ void TestPcm16RenderOutput() {
 	      "PCM16 output retained samples from the previous render");
 }
 
+void TestPatchToRackHandle() {
+	Ngs2Internal system;
+	Ngs2RackOptionUnion sampler_option {}, mastering_option {};
+	Ngs2FillDefaultRackOption(0x1000, &sampler_option);
+	Ngs2FillDefaultRackOption(0x3000, &mastering_option);
+	sampler_option.common.max_voices = 1;
+	RenderRack sampler(system, 0x1000, sampler_option.common);
+	RenderRack master(system, 0x3000, mastering_option.common);
+	auto& source = sampler.Voice();
+	Ngs2VoicePatchParam patch {{24, 0, 5}, 0, 0, master.handle};
+	Check(Ngs2VoiceControl(reinterpret_cast<uintptr_t>(&source), &patch.header) == OK &&
+	          source.ports[0].dest == &master.Voice(),
+	      "patch to a rack handle did not connect to its voice #0");
+}
+
 void TestCustomMasteringChannelMixer() {
 	Ngs2Internal system;
 	system.option = Ngs2DefaultSystemOption();
@@ -1803,6 +1818,7 @@ int main() {
 	TestAtrac9Vibration();
 	TestAtrac9Discrete();
 	TestPcm16RenderOutput();
+	TestPatchToRackHandle();
 	TestCustomMasteringChannelMixer();
 	TestCustomVoiceStateCapacity();
 	TestSubmixerSetupAndRouting();