Files
MapLibreParticleLab/src/renderer/frame_history.cpp
2014-07-01 05:20:03 -07:00

48 lines
1.4 KiB
C++

#include <llmr/renderer/frame_history.hpp>
using namespace llmr;
// Record frame history that will be used to calculate fading params
void FrameHistory::record(timestamp now, float zoom) {
// first frame ever
if (!history.size()) {
history.emplace_back(FrameSnapshot{0, zoom});
history.emplace_back(FrameSnapshot{0, zoom});
}
if (history.size() > 0 || history.back().z != zoom) {
history.emplace_back(FrameSnapshot{now, zoom});
}
}
bool FrameHistory::needsAnimation(const timestamp duration) const {
if (!history.size()) {
return false;
}
// If we have a value that is older than duration and whose z value is the
// same as the most current z value, and if all values inbetween have the
// same z value, we don't need animation, otherwise we probably do.
const FrameSnapshot &pivot = history.back();
int i = -1;
while ((int)history.size() > i + 1 && history[i + 1].t + duration < pivot.t) {
i++;
}
if (i < 0) {
// There is no frame that is older than the duration time, so we need to
// check all frames.
i = 0;
}
// Make sure that all subsequent snapshots have the same zoom as the last
// pivot element.
for (; (int)history.size() > i; i++) {
if (history[i].z != pivot.z) {
return true;
}
}
return false;
}