Implement sound

5 files changed, 92 insertions, 27 deletions

diff --git a/src/chip8.cpp b/src/chip8.cpp
index 485d061..1d46c49 100644
--- a/src/chip8.cpp
+++ b/src/chip8.cpp
@@ -1,9 +1,11 @@
 #include "chip8.hpp"
+#include "platform.hpp"
 
 #include <fstream>
 #include <iostream>
 #include <cstdint>
-#include <chrono>
+#include <thread>
+#include <mutex>
 
 const uint32_t FONTSET_START_ADDRESS = 0x050;
 const uint32_t ROM_START_ADDRESS = 0x200;
@@ -124,15 +126,24 @@ void Chip8::Cycle() {
 
   // Decode and Execute
   ((*this).*(table[(opcode & 0xF000u) >> 12u]))();
-  
-  // Decrement delay timer
-  if (delayTimer > 0) {
-    delayTimer--;
-  }
+}
 
-  if (soundTimer > 0) {
-    --soundTimer;
-  }
+void Chip8::TimerUpdateThread(Platform* platform) {
+    while (true) {
+        std::this_thread::sleep_for(std::chrono::milliseconds(16));
+
+        std::lock_guard<std::mutex> lock(timerMutex);
+        if (delayTimer > 0) {
+            delayTimer--;
+        }
+
+        if (soundTimer > 0) {
+            soundTimer--;
+            platform->StartBeep();
+        } else {
+          platform->StopBeep();
+        }
+    }
 }
 
 void Chip8::LoadROM(const char* filename) {
diff --git a/src/chip8.hpp b/src/chip8.hpp
index 5072c2e..01db296 100644
--- a/src/chip8.hpp
+++ b/src/chip8.hpp
@@ -4,6 +4,9 @@
 #include <cstdint>
 #include <random>
 #include <bitset>
+#include <mutex>
+
+#include "platform.hpp"
 
 const uint32_t VIDEO_HEIGHT = 32;
 const uint32_t VIDEO_WIDTH = 64;
@@ -33,10 +36,12 @@ class Chip8 {
   private:
     std::default_random_engine randGen;
     std::uniform_int_distribution<uint8_t> randByte;
+    std::mutex timerMutex;
 
   public:
     void LoadROM(const char* filename);
     void Cycle();
+    void TimerUpdateThread(Platform* platform);
 
   private:
     void SetupTable();
diff --git a/src/main.cpp b/src/main.cpp
index 583b4ad..7e7d90a 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,5 +1,6 @@
 #include <iostream>
 #include <unistd.h>
+#include <thread>
 
 #include "chip8.hpp"
 #include "platform.hpp"
@@ -24,7 +25,7 @@ int main(int argc, char** argv) {
   Chip8 chip8;
   chip8.LoadROM(filename);
 
-  int count = 0;
+  std::thread timerThread(&Chip8::TimerUpdateThread, &chip8, &platform);
 
   bool quit = false;
   while (!quit) {
diff --git a/src/platform.cpp b/src/platform.cpp
index 4738c66..f2d5984 100644
--- a/src/platform.cpp
+++ b/src/platform.cpp
@@ -3,38 +3,57 @@
 
 #include "platform.hpp"
 
+#define SAMPLE_RATE 44100
+#define PI 3.14159265358979323846
+#define FREQUENCY 440.0
+#define TIMEPERIOD 200
+
 Platform::Platform(const char* title, int windowWidth, int windowHeight, int textureWidth, int textureHeight) {
-  SDL_Init(SDL_INIT_VIDEO);
+  if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO) != 0) {
+      std::cerr << "SDL initialization error: " << SDL_GetError() << std::endl;
+  }
   
   window = SDL_CreateWindow(title, SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, windowWidth, windowHeight, SDL_WINDOW_SHOWN);
   renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
+
+  audioSpec.freq = SAMPLE_RATE;
+  audioSpec.format = AUDIO_S16SYS;
+  audioSpec.channels = 1;
+  audioSpec.samples = 4096;
+  audioSpec.userdata = this;
+  beepRequested = false;
+  audioSpec.callback = AudioCallback;
+
+  audioDevice = SDL_OpenAudioDevice(nullptr, 0, &audioSpec, nullptr, 0);
+  if (audioDevice == 0) {
+      std::cerr << "Audio device opening error: " << SDL_GetError() << std::endl;
+  }
+  SDL_PauseAudioDevice(audioDevice, 0);
 }
 
 Platform::~Platform() {
+  SDL_CloseAudioDevice(audioDevice);
   SDL_DestroyRenderer(renderer);
   SDL_DestroyWindow(window);
   SDL_Quit();
 }
 
 void Platform::Update(const std::bitset<2048>& bitset, int videoScale) {
-    SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
-    SDL_RenderClear(renderer);
-
-    for (int y = 0; y < 32; ++y) {
-        for (int x = 0; x < 64; ++x) {
-            SDL_Rect pixelRect = {x * videoScale, y * videoScale, videoScale, videoScale};
+  SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
+  SDL_RenderClear(renderer);
 
-            if (bitset[y * 64 + x]) {
-                SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
-            } else {
-                SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
-            }
-
-            SDL_RenderFillRect(renderer, &pixelRect);
-        }
+  for (int y = 0; y < 32; ++y) {
+    for (int x = 0; x < 64; ++x) {
+        SDL_Rect pixelRect = {x * videoScale, y * videoScale, videoScale, videoScale};
+      if (bitset[y * 64 + x]) {
+        SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
+      } else {
+        SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
+      }
+      SDL_RenderFillRect(renderer, &pixelRect);
     }
-
-    SDL_RenderPresent(renderer);
+  }
+  SDL_RenderPresent(renderer);
 }
 
 bool Platform::ProcessInput(std::bitset<16>* keys) {
@@ -93,3 +112,24 @@ bool Platform::ProcessInput(std::bitset<16>* keys) {
 
   return quit;
 }
+
+void Platform::AudioCallback(void* userdata, uint8_t* stream, int len) {
+  Platform* platform = static_cast<Platform*>(userdata);
+  if (platform->beepRequested) {
+      static double time = 0.0;
+      double freq = 440.0;
+
+      int16_t* sample = reinterpret_cast<int16_t*>(stream);
+      for (int i = 0; i < len / 2; i++) {
+          int16_t value = static_cast<int16_t>(32767.0 * sin(2.0 * PI * freq * time));
+          sample[i] = value;
+          time += 1.0 / SAMPLE_RATE;
+      }
+  } else {
+      memset(stream, 0, len);
+  }
+}
+
+void Platform::StartBeep() { beepRequested = true; }
+
+void Platform::StopBeep(){ beepRequested = false; }
diff --git a/src/platform.hpp b/src/platform.hpp
index 872f84d..a037b6e 100644
--- a/src/platform.hpp
+++ b/src/platform.hpp
@@ -16,10 +16,18 @@ class Platform {
   public:
     void Update(const std::bitset<2048>& bitset, int videoScale);
     bool ProcessInput(std::bitset<16>* keys);
+    void StartBeep();
+    void StopBeep();
+
+  private:
+    static void AudioCallback(void* userdata, uint8_t* stream, int len);
+    bool beepRequested = false;
 
   private:
     SDL_Window* window {};
     SDL_Renderer* renderer {};
+    SDL_AudioDeviceID audioDevice;
+    SDL_AudioSpec audioSpec {};
 };
 
 #endif