SoundData:setSample

src/api/l_data_soundData.c

@@ -24,8 +24,17 @@ static int l_lovrSoundDataAppend(lua_State* L) {
   return 1;
 }
 
+static int l_lovrSoundDataSetSample(lua_State* L) {
+  SoundData* soundData = luax_checktype(L, 1, SoundData);
+  int index = luaL_checkinteger(L, 2);
+  float value = luax_checkfloat(L, 3);
+  lovrSoundDataSetSample(soundData, index, value);
+  return 0;
+}
+
 const luaL_Reg lovrSoundData[] = {
   { "getBlob", l_lovrSoundDataGetBlob },
   { "append", l_lovrSoundDataAppend },
+  { "setSample", l_lovrSoundDataSetSample },
   { NULL, NULL }
 };

src/modules/data/soundData.c

@@ -7,6 +7,7 @@
 #include "audio/audio_internal.h"
 #include <stdlib.h>
 #include <string.h>
+#include <limits.h>
 
 static uint32_t lovrSoundDataReadRaw(SoundData* soundData, uint32_t offset, uint32_t count, void* data) {
   uint8_t* p = soundData->blob->data;
@@ -175,6 +176,16 @@ size_t lovrSoundDataStreamAppendSound(SoundData *dest, SoundData *src) {
   return lovrSoundDataStreamAppendBlob(dest, src->blob);
 }
 
+void lovrSoundDataSetSample(SoundData* soundData, size_t index, float value) {
+  size_t byteIndex = index * bytesPerAudioFrame(soundData->channels, soundData->format);
+  lovrAssert(byteIndex < soundData->blob->size, "Sample index out of range");
+  switch (soundData->format) {
+    case SAMPLE_I16: ((int16_t*) soundData->blob->data)[index] = value * SHRT_MAX; break;
+    case SAMPLE_F32: ((float*) soundData->blob->data)[index] = value; break;
+    default: lovrThrow("Unsupported SoundData format %d\n", soundData->format); break;
+  }
+}
+
 bool lovrSoundDataIsStream(SoundData *soundData) {
   return soundData->read == lovrSoundDataReadRing;
 }

src/modules/data/soundData.h

@@ -34,6 +34,7 @@ SoundData* lovrSoundDataCreateFromFile(struct Blob* blob, bool decode);
 // returns the number of frames successfully appended (if it's less than the size of blob, the internal ring buffer is full)
 size_t lovrSoundDataStreamAppendBlob(SoundData *dest, struct Blob* blob);
 size_t lovrSoundDataStreamAppendSound(SoundData *dest, SoundData *src);
+void lovrSoundDataSetSample(SoundData* soundData, size_t index, float value);
 
 uint32_t lovrSoundDataGetDuration(SoundData *soundData);