Mirrors/overte-JulianGro
3
0
Fork 0
mirror of https://github.com/JulianGro/overte.git synced 2025-04-25 16:55:07 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

Merge pull request #337 from tschw/19165

Browse source 
19165
This commit is contained in:
ZappoMan 2013-05-18 10:45:15 -07:00
commit 0ff65b44b5
2 changed files with 67 additions and 51 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

82
interface/src/Oscilloscope.cpp
View file

@ -20,13 +20,15 @@ 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;
unsigned const MAX_SAMPLES = Oscilloscope::MAX_SAMPLES_PER_CHANNEL * 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;
unsigned const MAX_COORDS_PER_CHANNEL = Oscilloscope::MAX_SAMPLES_PER_CHANNEL * 2;
// allocated once for each channel
unsigned const MAX_COORDS = MAX_COORDS_PER_CHANNEL * Oscilloscope::MAX_CHANNELS;
// total amount of memory to allocate (in 16-bit integers)
unsigned const N_INT16_TO_ALLOC = MAX_SAMPLES + MAX_COORDS;
}
@ -38,13 +40,13 @@ Oscilloscope::Oscilloscope(int w, int h, bool isEnabled) :
// 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;
_arrSamples = new short[N_INT16_TO_ALLOC];
memset(_arrSamples, 0, N_INT16_TO_ALLOC * sizeof(short));
_arrVertices = _arrSamples + MAX_SAMPLES;
// initialize write positions
// initialize write positions to start of each channel's region
for (unsigned ch = 0; ch < MAX_CHANNELS; ++ch) {
_arrWritePos[ch] = MAX_SAMPLES * ch;
_arrWritePos[ch] = MAX_SAMPLES_PER_CHANNEL * ch;
}
}
@ -58,25 +60,31 @@ 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;
// determine start/end offset of this channel's region
unsigned baseOffs = MAX_SAMPLES_PER_CHANNEL * ch;
unsigned endOffs = baseOffs + MAX_SAMPLES_PER_CHANNEL;
// fetch write position for this channel
unsigned writePos = _arrWritePos[ch];
// determine write position after adding the samples
unsigned newWritePos = writePos + n;
unsigned n2 = 0;
if (newWritePos >= endOffs) {
// passed boundary of the circular buffer? -> we need to copy two blocks
n2 = newWritePos - endOffs;
newWritePos = baseOffs + n2;
n -= n2;
}
// copy data
memcpy(_arrSamples + writePos, data, n * sizeof(short));
if (n2 > 0) {
memcpy(_arrSamples + baseOffs, data + n, n2 * sizeof(short));
}
// set new write position for this channel
_arrWritePos[ch] = newWritePos;
}
@ -85,34 +93,38 @@ void Oscilloscope::render(int x, int y) {
if (! enabled) {
return;
}
// expand data to vertex data, now
// determine lowpass / downsample factors
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 usedWidth = min(_valWidth, MAX_SAMPLES_PER_CHANNEL / (downsample * 2)) & ~1u;
unsigned usedSamples = usedWidth * downsample;
// expand samples to vertex data
for (unsigned ch = 0; ch < MAX_CHANNELS; ++ch) {
short const* basePtr = _arrSamples + MAX_SAMPLES * ch;
short const* endPtr = basePtr + MAX_SAMPLES;
// for each channel: determine memory regions
short const* basePtr = _arrSamples + MAX_SAMPLES_PER_CHANNEL * ch;
short const* endPtr = basePtr + MAX_SAMPLES_PER_CHANNEL;
short const* inPtr = _arrSamples + _arrWritePos[ch];
short* outPtr = _arrVertices + MAX_COORDS * ch;
short* outPtr = _arrVertices + MAX_COORDS_PER_CHANNEL * ch;
int sample = 0, x = usedWidth;
for (int i = int(usedSamples); --i >= 0 ;) {
if (inPtr == basePtr) {
// handle boundary, reading the circular sample buffer
inPtr = endPtr;
}
sample += ((*--inPtr - sample) * lowpass) >> 15;
// read and (eventually) filter sample
sample += ((*--inPtr - sample) * lowpass) >> 15;
// write every nth as y with a corresponding x-coordinate
if (i % downsample == 0) {
*outPtr++ = short(--x);
*outPtr++ = short(sample);
}
}
}
// set up rendering state (vertex data lives at _arrVertices)
glLineWidth(1.0);
glDisable(GL_LINE_SMOOTH);
glPushMatrix();
@ -120,12 +132,20 @@ void Oscilloscope::render(int x, int y) {
glScaled(1.0f, _valHeight / 32767.0f, 1.0f);
glVertexPointer(2, GL_SHORT, 0, _arrVertices);
glEnableClientState(GL_VERTEX_ARRAY);
// render channel 0
glColor3f(1.0f, 1.0f, 1.0f);
glDrawArrays(GL_LINE_STRIP, MAX_SAMPLES * 0, usedWidth);
glDrawArrays(GL_LINES, MAX_SAMPLES_PER_CHANNEL * 0, usedWidth);
// render channel 1
glColor3f(0.0f, 1.0f ,1.0f);
glDrawArrays(GL_LINE_STRIP, MAX_SAMPLES * 1, usedWidth);
glDrawArrays(GL_LINES, MAX_SAMPLES_PER_CHANNEL * 1, usedWidth);
// render channel 2
glColor3f(0.0f, 1.0f ,1.0f);
glDrawArrays(GL_LINE_STRIP, MAX_SAMPLES * 2, usedWidth);
glDrawArrays(GL_LINES, MAX_SAMPLES_PER_CHANNEL * 2, usedWidth);
// reset rendering state
glDisableClientState(GL_VERTEX_ARRAY);
glPopMatrix();
}

36
interface/src/Oscilloscope.h
View file

@ -13,31 +13,19 @@
class Oscilloscope {
public:
static unsigned const MAX_CHANNELS = 3;
static unsigned const MAX_SAMPLES = 4096; // per channel
private:
unsigned _valWidth;
unsigned _valHeight;
short* _arrSamples;
short* _arrVertices;
unsigned _arrWritePos[MAX_CHANNELS];
float _valLowpass;
unsigned _valDownsample;
public:
Oscilloscope(int width, int height, bool isEnabled);
~Oscilloscope();
volatile bool enabled;
volatile bool inputPaused;
void addSamples(unsigned ch, short const* data, unsigned n);
void render(int x, int y);
static unsigned const MAX_CHANNELS = 3;
static unsigned const MAX_SAMPLES_PER_CHANNEL = 4096;
volatile bool enabled;
volatile bool inputPaused;
void setLowpass(float w) { assert(w > 0.0f && w <= 1.0f); _valLowpass = w; }
void setDownsampling(unsigned f) { assert(f > 0); _valDownsample = f; }
@ -46,8 +34,16 @@ private:
Oscilloscope(Oscilloscope const&); // = delete;
Oscilloscope& operator=(Oscilloscope const&); // = delete;
// implementation
inline short* bufferBase(int i, int channel);
// state variables
unsigned _valWidth;
unsigned _valHeight;
short* _arrSamples;
short* _arrVertices;
unsigned _arrWritePos[MAX_CHANNELS];
float _valLowpass;
unsigned _valDownsample;
};
#endif /* defined(__interface__oscilloscope__) */