wavetable loading checkpoint

.gitignore

@@ -1,2 +1,3 @@
 build/*
 .vscode/*
+scripts/_pycache_/*

README.md

@@ -21,7 +21,7 @@ This synthesizer isn't very good, but it's neat :3
       oscillators increase the sound complexity considerably
 - [x] Create a UI scope to visualize the synthesized composite waveform
 - [x] Create wavetables for more complex tone generation. Needs to be selectable from ui
-- [ ] Wavetable file loading
+- [x] Wavetable file loading
 - [x] Create digital filters, prob biquad. Controllable from ui obv (cutoff + resonance)
 - [x] Add polyphony somewhere. Probably involves a voice class. If processing power
       allows it, tie a voice to each midi note

scripts/example_wavetable.py

@@ -1,3 +1,5 @@
 
+import math
+
 def process(phase):
-    print("im from process")
+    return math.sin(phase)

scripts/generate_wavetable.py

@@ -3,30 +3,60 @@
 # a wavetable file consists of a one-dimensional array of samples representing one period of a waveform
 # metadata includes: 
 #    - file version (for program compatibility)
-#    - binary format (float, double, int32, etc.)
+#    - binary format (float, double, int32, etc.) (RIGHT NOW I ONLY USE FLOAT)
 #    - domain (normal is a phase from x=0 to x=2pi)
 #    - range (depending on datatypes, e.g. float=[-1,1], int32=[-2^15, 2^15-1])
 #    - waveform RMS (for loudness normalization)
+#    - sample count 
 # the synth program uses the filename, not any metadata
 
 # this script uses the function defined in example_wavetable.py to calculate samples
 # if you want a custom wavetable, copy/edit/modify the example function (desmos is great for brainstorming)
 
+from array import array
+import math
+
 import example_wavetable
 
+wavetableLength = 2048
+
 def createFile():
     print("creating file")
-    return 1
+    file = open("sine.wt", "wb")
+    return file
 
 def writeMetadata(file):
-    print("im writing metadata")
+    print(">> im writing metadata")
 
 def generateWavetable(file):
-    print("im generating the wavetable")
-    example_wavetable.process()
+    print(">> im generating the wavetable")
+
+    # init variables
+    data_list = [None] * wavetableLength
+    phaseInc = 2*math.pi / wavetableLength
+    x = 0
+    accumulator = 0
+
+    # generate each discrete sample
+    for i in range(wavetableLength): 
+        sample = example_wavetable.process(x)
+        accumulator += sample * sample
+        x += phaseInc
+        data_list[i] = sample
+
+    # normalize by rms
+    rms = math.sqrt(accumulator/wavetableLength)
+    print(">> wavetable RMS: ", rms)
+    for i in range(wavetableLength): 
+        data_list[i] /= rms
+
+    # write to file
+    binary_data = array("f", data_list)
+    file.write(binary_data)
 
 def closeFile(file): 
-    print("finishing up")
+    print(">> finishing up")
+    file.close()
 
 def main():
     print("Hello main")

src/synth/WavetableController.cpp

@@ -3,6 +3,7 @@
 
 #include <cmath>
 #include <iostream>
+#include <fstream>
 
 WavetableController::WavetableController() {
     // load from files
@@ -17,17 +18,19 @@ void WavetableController::init() {
 
     wavetables_.resize(4); // resize for however many files we find
 
-    // don't really know how the files are gonna work
-    // but I'd like two files- a yaml that contains metadata like name, length, range, datatype, etc.
-    // and the main data be just a big array of that data type in a binary file
-    // although having it all in a single bin makes the most sense with the metadata being in the header
+    // wavetable file structure is best explained in scripts/generate_wavetable.py
+
+    // read the wavetable file
+    std::ifstream inputFile("config/wavetables/sine.wt", std::ios::in | std::ios::binary);
+    if(!inputFile) std::cout << "error opening file" << std::endl;
+    inputFile.read(reinterpret_cast<char*>(wavetables_[0].data()), SYNTH_WAVETABLE_SIZE * sizeof(float));
 
     float phase = 0.0f;
     float phaseInc = 2.0f * M_PI / static_cast<float>(SYNTH_WAVETABLE_SIZE);
 
     for(int i = 0; i < SYNTH_WAVETABLE_SIZE; i++) {
 
-        wavetables_[0][i] = std::sin(phase) / 0.707f; // sine
+        //wavetables_[0][i] = std::sin(phase) / 0.707f; // sine
         wavetables_[1][i] = (phase >= M_PI) ? 1.0f : -1.0f; // square
         wavetables_[2][i] = ((phase / M_PI) - 1.0f) / 0.577f; // saw