overte-HifiExperiments/interface/src/Oscilloscope.cpp

130 lines
3.8 KiB
C++

//
// Oscilloscope.cpp
// interface
//
// Created by Philip on 1/28/13.
// Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
//
#include "Oscilloscope.h"
#include "InterfaceConfig.h"
#include <limits>
#include <cstring>
#include <algorithm>
// Reimplemented 4/26/13 (tosh) - don't blame Philip for bugs
using namespace std;
namespace { // everything in here only exists while compiling this .cpp file
// one sample buffer per channel
unsigned const N_SAMPLES_ALLOC = Oscilloscope::MAX_SAMPLES * Oscilloscope::MAX_CHANNELS;
// adding an x-coordinate yields twice the amount of vertices
unsigned const MAX_COORDS = Oscilloscope::MAX_SAMPLES * 2;
unsigned const N_COORDS_ALLOC = MAX_COORDS * Oscilloscope::MAX_CHANNELS;
unsigned const N_ALLOC_TOTAL = N_SAMPLES_ALLOC + N_COORDS_ALLOC;
}
Oscilloscope::Oscilloscope(int w, int h, bool isEnabled) :
_valWidth(w), _valHeight(h),
_arrSamples(0l), _arrVertices(0l),
_valLowpass(0.4f), _valDownsample(3),
enabled(isEnabled), inputPaused(false) {
// allocate enough space for the sample data and to turn it into
// vertices and since they're all 'short', do so in one shot
_arrSamples = new short[N_ALLOC_TOTAL];
memset(_arrSamples, 0, N_ALLOC_TOTAL * sizeof(short));
_arrVertices = _arrSamples + N_SAMPLES_ALLOC;
// initialize write positions
for (unsigned ch = 0; ch < MAX_CHANNELS; ++ch) {
_arrWritePos[ch] = MAX_SAMPLES * ch;
}
}
Oscilloscope::~Oscilloscope() {
delete[] _arrSamples;
}
void Oscilloscope::addSamples(unsigned ch, short const* data, unsigned n) {
if (! enabled || inputPaused) {
return;
}
unsigned baseOffs = MAX_SAMPLES * ch;
unsigned endOffs = baseOffs + MAX_SAMPLES;
unsigned writePos = _arrWritePos[ch];
unsigned newWritePos = writePos + n;
unsigned n2 = 0;
if (newWritePos >= endOffs) {
n2 = newWritePos - endOffs;
newWritePos = baseOffs + n2;
n -= n2;
}
memcpy(_arrSamples + writePos, data, n * sizeof(short));
if (n2 > 0) {
memcpy(_arrSamples + baseOffs, data + n, n2 * sizeof(short));
}
_arrWritePos[ch] = newWritePos;
}
void Oscilloscope::render() {
if (! enabled) {
return;
}
// expand data to vertex data, now
int lowpass = -int(std::numeric_limits<short>::min()) * _valLowpass;
unsigned downsample = _valDownsample;
// keep half of the buffer for writing and ensure an even vertex count
unsigned usedWidth = min(_valWidth, MAX_SAMPLES / (downsample * 2)) & ~1u;
unsigned usedSamples = usedWidth * downsample;
for (unsigned ch = 0; ch < MAX_CHANNELS; ++ch) {
short const* basePtr = _arrSamples + MAX_SAMPLES * ch;
short const* endPtr = basePtr + MAX_SAMPLES;
short const* inPtr = _arrSamples + _arrWritePos[ch];
short* outPtr = _arrVertices + MAX_COORDS * ch;
int sample = 0, x = usedWidth;
for (int i = int(usedSamples); --i >= 0 ;) {
if (inPtr == basePtr) {
inPtr = endPtr;
}
sample += ((*--inPtr - sample) * lowpass) >> 15;
if (i % downsample == 0) {
*outPtr++ = short(--x);
*outPtr++ = short(sample);
}
}
}
glPushMatrix();
glTranslatef(0.0f, _valHeight / 2.0f, 0.0f);
glScaled(1.0f, _valHeight / 32767.0f, 1.0f);
glVertexPointer(2, GL_SHORT, 0, _arrVertices);
glEnableClientState(GL_VERTEX_ARRAY);
glColor3f(1.0f, 1.0f, 1.0f);
glDrawArrays(GL_LINES, MAX_SAMPLES * 0, usedWidth);
glColor3f(0.0f, 1.0f ,1.0f);
glDrawArrays(GL_LINES, MAX_SAMPLES * 1, usedWidth);
glColor3f(1.0f, 1.0f ,0.0f);
glDrawArrays(GL_LINES, MAX_SAMPLES * 2, usedWidth);
glDisableClientState(GL_VERTEX_ARRAY);
glPopMatrix();
}