Fix #187

CHANGELOG.md

@@ -16,6 +16,9 @@ a design goal is to avoid a 2.x release for as long as possible.
 - Fixed encrypted NDS ROMs failing to load without any feedback;
   loading one without using the native BIOS will now display an error message.
   [#228](https://github.com/JesseTG/melonds-ds/issues/228)
+- Fixed Blow mode for emulated microphone input not being implemented
+  despite being available in the core options.
+  [#187](https://github.com/JesseTG/melonds-ds/issues/187)
 
 ## [1.1.7] - 2024-08-20
 

src/libretro/config/parse.hpp

@@ -160,6 +160,7 @@ namespace MelonDsDs {
     constexpr std::optional<MicInputMode> ParseMicInputMode(std::string_view value) noexcept {
         if (value == config::values::MICROPHONE) return MicInputMode::HostMic;
         if (value == config::values::NOISE) return MicInputMode::WhiteNoise;
+        if (value == config::values::BLOW) return MicInputMode::Blow;
         if (value == config::values::SILENCE) return MicInputMode::None;
 
         return std::nullopt;

src/libretro/config/types.hpp

@@ -54,6 +54,7 @@ namespace MelonDsDs {
 
     enum class MicInputMode {
         None,
+        Blow,
         HostMic,
         WhiteNoise,
     };

src/libretro/microphone.cpp

@@ -19,6 +19,7 @@
 #include <optional>
 
 #include <libretro.h>
+#include <frontend/mic_blow.h>
 
 #include "config/config.hpp"
 #include "environment.hpp"
@@ -126,6 +127,18 @@ void MelonDsDs::MicrophoneState::Read(std::span<int16_t> buffer) noexcept {
 
             break;
         }
+        case MicInputMode::Blow: {
+            constexpr size_t MIC_BLOW_LENGTH = sizeof(mic_blow) / sizeof(mic_blow[0]);
+
+            // builtin sample is 16-bit signed PCM
+            // sample rate is 44.1KHz
+            for (int i = 0; i < buffer.size(); ++i) {
+                buffer[i] = static_cast<int16_t>(mic_blow[_blowSampleOffset] ^ 0x8000);
+                _blowSampleOffset = (_blowSampleOffset + 1) % MIC_BLOW_LENGTH;
+            }
+
+            break;
+        }
         case MicInputMode::HostMic: {
             if (_microphone && _microphone->IsActive() && _microphone->Read(buffer)) {
                 // If the microphone is open and turned on, and we read from it successfully...

src/libretro/microphone.hpp

@@ -53,6 +53,7 @@ namespace MelonDsDs {
         std::optional<retro::Microphone> _microphone {};
         MicInputMode _micInputMode = MicInputMode::None;
         MicButtonMode _micButtonMode = MicButtonMode::Hold;
+        size_t _blowSampleOffset = 0;
         std::default_random_engine _randomEngine;
         std::uniform_int_distribution<int16_t> _random {std::numeric_limits<int16_t>::min(), std::numeric_limits<int16_t>::max()};
         bool _micButtonDown = false;

test/cmake/Basics.cmake

@@ -324,6 +324,14 @@ add_python_test(
     CORE_OPTION melonds_boot_mode=direct
 )
 
+add_python_test(
+    NAME "Core accepts microphone input with Blow mode"
+    TEST_MODULE basics.core_accepts_microphone_input
+    CONTENT "${MICRECORD_NDS}"
+    CORE_OPTION melonds_boot_mode=direct
+    CORE_OPTION melonds_mic_input=blow
+)
+
 add_python_test(
     NAME "Core queries device power state"
     TEST_MODULE basics.core_gets_power_state