1 files changed, 23 insertions(+), 22 deletions(-)

M src/audio.c

@@ 1,6 1,6 @@
 #define SOUND_TIMER (256.0f / 44100.0f * 1000.0f)
 #define N_CHANNELS 4
-#define ZERO_THRESHOLD 4
+#define XFADE_SAMPLES 100
 
 typedef enum EnvStage {
     ENV_ATTACK  = (1 << 0),


@@ 31,7 31,7 @@ typedef struct Sample {
 typedef struct AudioChannel {
     Sample sample;
     Sample next_sample;
-    bool wait_zero;
+    bool xfade;
     float duration;
     float vol_l;
     float vol_r;


@@ 2608,13 2608,8 @@ note_on(AudioChannel *channel, u16 duration, u8 *data, u16 len, u8 vol,
     const float *inc = &tuning[(pitch + 1) - 21][0];
     sample.inc = *(inc + FINE_TUNE);
 
-    // TODO: Check previously played sample instead of the envelope.
-    // if (channel->sample.data != NULL && channel->sample.env.vol > 0) {
-    //     channel->next_sample = sample;
-    //     channel->wait_zero = true;
-    // } else {
-        channel->sample = sample;
-    // }
+    channel->next_sample = sample;
+    channel->xfade = true;
 }
 
 void


@@ 2731,26 2726,32 @@ audio_handler(void *ctx, s16 *left, s16 *right, int len) {
         channel->duration -= SOUND_TIMER;
 
         // Process all requested samples
+        int x = 0;
+        if (channel->xfade) {
+            float delta = 1.0f / XFADE_SAMPLES;
+            for (; x < XFADE_SAMPLES; x++) {
+                float alpha = x * delta;
+                float beta = 1.0f - alpha;
+                s16 next_a = next_a = next_sample(&channel->next_sample);
+                s16 next_b = 0;
+                if (channel->sample.data != NULL) {
+                    next_b = next_sample(&channel->sample);
+                }
+                s16 next = alpha * next_a + beta * next_b;
+                left[x]  += next * channel->vol_l;
+                right[x] += next * channel->vol_r;
+            }
+            channel->sample = channel->next_sample;
+            channel->xfade = false;
+        }
         Sample *sample = &channel->sample;
-        // TODO: Don't loop everything dummy
-        sample->loop = sample->len;
-        for (int x = 0; x < len; x++) {
+        for (; x < len; x++) {
             if (sample->data == NULL) {
                 break;
             }
-
             s16 next = next_sample(sample);
-
             left[x]  += next * channel->vol_l;
             right[x] += next * channel->vol_r;
-
-            // if (channel->wait_zero) {
-            //     if (next < ZERO_THRESHOLD && next > -ZERO_THRESHOLD) {
-            //         channel->wait_zero = false;
-            //         channel->sample = channel->next_sample;
-            //         sample = &channel->sample;
-            //     }
-            // }
         }
     }
     for (int x = 0; x < len; x++) {