Funkwhale/Clementine-audio-player-Mac-Linux-Windows
1
0
Fork 0
mirror of https://github.com/clementine-player/Clementine synced 2025-01-31 11:35:24 +01:00
Code Issues Releases Wiki Activity

Precalculate the band scale constants and apply them once when adding new values, instead of every time the polyline is drawn

Browse Source
This commit is contained in:
David Sansome 2011-06-23 20:36:30 +00:00
parent aa20b6b3e2
commit decc769ebb
2 changed files with 12 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
src/analyzers/nyancatanalyzer.cpp
View File

@ -38,6 +38,10 @@ NyanCatAnalyzer::NyanCatAnalyzer(QWidget* parent)
for (int i=0 ; i<kRainbowBands ; ++i) {
colors_[i] = QPen(QColor::fromHsv(i * 255 / kRainbowBands, 255, 255), kCatHeight/kRainbowBands);
// pow constants computed so that
// | band_scale(0) | ~= .5 and | band_scale(5) | ~= 32
band_scale_[i] = -std::cos(M_PI * i / (kRainbowBands-1)) * 0.5 * std::pow(2.3, i);
}
}
@ -64,9 +68,6 @@ void NyanCatAnalyzer::analyze(QPainter& p, const Analyzer::Scope& s, bool new_fr
// Move the history of each band across by 1 frame.
memmove(band_start, band_start + 1, (kHistorySize - 1) * sizeof(float));
// And set the new frame to 0.
band_start[kHistorySize-1] = 0;
}
// Now accumulate the scope data into each band. Should maybe use a series
@ -75,10 +76,12 @@ void NyanCatAnalyzer::analyze(QPainter& p, const Analyzer::Scope& s, bool new_fr
const int samples_per_band = scope_size / kRainbowBands;
int sample = 0;
for (int band=0 ; band<kRainbowBands ; ++band) {
float* accumulator = &history_[(band+1) * kHistorySize - 1];
float accumulator = 0.0;
for (int i=0 ; i<samples_per_band ; ++i) {
*accumulator += s[sample++];
accumulator += s[sample++];
}
history_[(band+1) * kHistorySize - 1] = accumulator * band_scale_[band];
}
}
@ -92,12 +95,10 @@ void NyanCatAnalyzer::analyze(QPainter& p, const Analyzer::Scope& s, bool new_fr
for (int band=0 ; band<kRainbowBands ; ++band) {
// Calculate the Y position of this band.
const float y = float(kCatHeight) / (kRainbowBands + 1) * (band + 0.5) + top_of_cat;
// pow constants computed so that
// | band_scale(0) | ~= .5 and | band_scale(5) | ~= 32
const float band_scale = -std::cos(M_PI*band/(kRainbowBands-1))*.5*std::pow(2.3, band);
// Add each point in the line.
for (int x=0 ; x<kHistorySize; ++x) {
*dest = QPointF(px_per_frame * x, y + *source * kPixelScale * band_scale);
*dest = QPointF(px_per_frame * x, y + *source * kPixelScale);
++ dest;
++ source;
}

2
src/analyzers/nyancatanalyzer.h
View File

@ -56,6 +56,8 @@ private:
private:
QPixmap cat_;
float band_scale_[kRainbowBands];
int timer_id_;
int frame_;