More progress on audio and rendering

util/audio.h

@@ -9,9 +9,18 @@
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include "../tiles/tile.h"
 
 #define SAMPLE_RATE 44100
 #define NUM_SYNTH_VOICES 256
+#define SMOOTHING_FACTOR 0.001f
+
+typedef struct {
+    float timeSec;     // When to trigger this event
+    uint8_t type;      // 0 = Note On, 1 = Note Off
+    uint8_t note;
+    uint8_t velocity;
+} MidiEvent;
 
 typedef enum Waveform {
     WAVE_SINE,
@@ -23,16 +32,18 @@ typedef enum Waveform {
 
 typedef struct SynthVoice {
     Waveform waveform;
-    uint8_t phase;
+    double phase;
     uint16_t frequency;
     uint8_t volume;
-    SDL_Rect sourceRect;
+    MiniRect sourceRect;
+    float smoothedAmp; // a float that holds the exponentially smoothed amplitude
 } SynthVoice;
 
 typedef struct AudioData {
     SynthVoice synthVoices[NUM_SYNTH_VOICES];
     SDL_Rect *playerRect;
     float maxPanDistance;
+    uint64_t totalSamples;
 } AudioData;
 
 extern AudioData audioData;
@@ -41,4 +52,6 @@ void audio_callback(void *userdata, Uint8 *stream, int len);
 
 uint16_t getAvailableChannel();
 
+void load_midi_file(const char *path);
+
 #endif //RISCB_AUDIO_H