- [NEW] audio viewer

- [FIX] Sampling rate pujat a 44100Hz, el aliasing quasi desapareix
- [NEW] Canals 2 i 3 implementats
- [FIX] El control de duració en els canals 1 i 2 era incorrecte

audio_viewer.cpp

@@ -0,0 +1,39 @@
+#include "audio_viewer.h"
+#include <SDL2/SDL.h>
+
+#define NUM_SAMPLES 256
+#define MAX_VOLUME  256
+namespace audio_viewer
+{
+    SDL_Window *win = nullptr;
+    SDL_Renderer *ren = nullptr;
+    //SDL_Texture *tex = nullptr;
+    uint8_t buffer[NUM_SAMPLES];
+    uint8_t pos = 0;
+    uint8_t screen[NUM_SAMPLES*MAX_VOLUME];
+
+    void init()
+    {
+        win = SDL_CreateWindow("Audio viewer", 1, 1, 256, 256, SDL_WINDOW_SHOWN);
+        ren = SDL_CreateRenderer(win, -1, 0);
+        //tex = SDL_CreateTexture(ren, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_STREAMING, 256, 256);
+        for (int i=0; i<NUM_SAMPLES; ++i) buffer[i] = 0;
+    }
+
+    void addsample(uint8_t sample)
+    {
+        buffer[pos] = sample;
+        pos = (pos+1)%NUM_SAMPLES;
+    }
+
+    void refresh()
+    {
+        SDL_SetRenderDrawColor(ren, 0, 0, 0, 0);
+        SDL_RenderClear(ren);
+        SDL_SetRenderDrawColor(ren, 255, 255, 255, 255);
+        for (int i=0; i<NUM_SAMPLES;++i) {
+            SDL_RenderDrawLine(ren, i, buffer[(pos+i)%NUM_SAMPLES], i+1, buffer[(pos+i+1)%NUM_SAMPLES]);
+        }
+        SDL_RenderPresent(ren);
+    }
+}