Using white noise data

paulscottrobson · Aug 12, 2024 · fd3da18 · fd3da18
1 parent ea67231
commit fd3da18
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Showing 4 changed files with 6 additions and 15 deletions.
diff --git a/TODO b/TODO
@@ -1,7 +1,5 @@
 TODO List
 
-- Implement new white noise
-- Check SFX.
 - Adjust documentation
 
 

diff --git a/basic/test.bsc b/basic/test.bsc
@@ -1,4 +1,4 @@
-noise 0,100,100
+noise 0,300,100
 end
 
 proc snd(ch,fq,ms,sl,ty,v)

diff --git a/firmware/common/include/interface/whitenoise.h b/firmware/common/include/interface/whitenoise.h
@@ -16,7 +16,7 @@
 
 #define NOISE_SIZE 	(1024)
 
-static const uint8_t noisepattern[NOISE_SIZE] = {
+static const uint8_t noisePattern[NOISE_SIZE] = {
       7, 30, 30, 28, 28, 62, 60, 56,120,248,124, 30, 31,143,  7,  7,193,192,224,
     241,224,240,227,225,192,224,120,126, 60, 56,224,225,195,195,135,199,  7, 30,
      28, 31, 14, 14, 30, 14, 15, 15,195,195,241,225,227,193,227,195,195,252, 60,

diff --git a/firmware/common/sources/interface/sndcreator.cpp b/firmware/common/sources/interface/sndcreator.cpp
@@ -21,7 +21,7 @@ struct _ChannelStatus {
     int state;
     int soundType;
     int volume;
-    bool modulate;
+    int samplePos;
 } audio[CHANNEL_COUNT];
 
 // ***************************************************************************************
@@ -70,11 +70,8 @@ int16_t SNDGetNextSample(void) {
                 cs->state ^= 0xFF;
                 switch (cs->soundType) {
                     case SOUNDTYPE_NOISE:   
-                        if (cs->modulate) {
-                            level += cs->state ? rand() % cs->volume : -(rand() % cs->volume);
-                        } else {
-                            level += rand() % (cs->volume * 2) - cs->volume;
-                        }
+                        level += ((noisePattern[cs->samplePos] - 0x80) * cs->volume / 128);
+                        if (++cs->samplePos == NOISE_SIZE) cs->samplePos = 0;
                         break;
                     default:                                                        // Square wave
                         level += cs->state ? cs->volume : -cs->volume;break;
@@ -101,11 +98,7 @@ void SNDUpdateSoundChannel(uint8_t channel,SOUND_CHANNEL *c) {
         audio[channel].adder = SNDGetSampleFrequency() / c->currentFrequency / 2;
         audio[channel].soundType = c->currentType;
         audio[channel].volume = c->currentVolume;
-        audio[channel].modulate = true;
-        if (c->currentFrequency <= 100) {
-            audio[channel].modulate = false;
-            audio[channel].adder = SNDGetSampleFrequency() / 440 / 2;
-        }
+        audio[channel].samplePos = 0;
     } else {
         audio[channel].volume = 0;
     }