[FEAT] Audio is working

ascii.cpp

@@ -14,6 +14,9 @@ uint8_t screen_height = 30;
 uint8_t current_color = 0x1e;
 uint8_t cursor_x = 0;
 uint8_t cursor_y = 0;
+bool sounding = false;
+int audio_freq = 0;
+uint32_t audio_len = 0;
 
 #define CHRSCR(x, y) char_screen[x+y*screen_width]
 #define COLSCR(x, y) color_screen[x+y*screen_width]
@@ -21,6 +24,7 @@ uint8_t cursor_y = 0;
 SDL_Window *mini_win;
 SDL_Renderer *mini_ren;
 SDL_Texture *mini_bak;
+SDL_AudioDeviceID mini_audio_device;
 Uint32 *pixels;
 int pitch;
 
@@ -48,6 +52,19 @@ void reinit() {
     cursor_y = 0;
 }
 
+void audioCallback(void * userdata, uint8_t * stream, int len) {
+    //if (audio_len <= 0) nosound();
+    static int period=0;
+    static int v = 16;
+    SDL_memset(stream, 0, len);
+    const int flen = min(audio_len, len);
+    audio_len -= flen;
+    for (int i=0; i<flen; ++i) {
+        stream[i] = v;
+        period++; if (period>=audio_freq) {period = 0; v=-v;}
+    }
+}
+
 int main(int argc,char*argv[]) {
 
     for (int i=0; i<debug_total_size;++i) debug_text[i] = 32;
@@ -61,6 +78,10 @@ int main(int argc,char*argv[]) {
     bool exit = false;
     SDL_Event mini_eve;
 
+    SDL_AudioSpec audioSpec{44100, AUDIO_S8, 1, 0, 512, 0, 0, audioCallback, NULL};
+    mini_audio_device = SDL_OpenAudioDevice(NULL, 0, &audioSpec, NULL, 0);
+    SDL_PauseAudioDevice(mini_audio_device, 0);
+
     reinit();
     debug("ASCII SYSTEM BOOTING...");
     lua_init();
@@ -308,8 +329,13 @@ void poke(uint16_t addr, uint8_t val) {
 
 void sound(float freq, uint32_t len) {
     // [TODO]
+    audio_len = len*44.1f;
+    audio_freq = 44100.0f/freq/2.0f;
+    sounding = true;
 }
 
 void nosound() {
-    // [TODO]
+    //SDL_PauseAudioDevice(mini_audio_device, 1);
+    audio_len = 0;
+    sounding = false;
 }

game.lua

@@ -11,9 +11,11 @@ function update()
     x = x + dx
     y = y + dy
     if x == 39 or x == 0 then
+        sound(440, 50)
         dx = -dx
     end
     if y == 29 or y == 0 then
+        sound(880, 50)
         dy = -dy
     end
     locate(2, 2)