dBToLinearTask.cpp

#include "SinglePingIsoSurfacesTasks.h"
#include "dBToLinearTask.h"
#include "Platform/Instrumentation.h"
 
#include "Foundation/Logging/Logger.h"
 
#include <algorithm>
 
using std::transform;
using std::exp2;
using std::min;
using std::numeric_limits;
 
using namespace Cogs::Core;
 
namespace{
  Cogs::Logging::Log logger = Cogs::Logging::getLogger("EchoLinearizeTask");
 
 
  static const float factorA = (float)(log2(10.0) / 10.0);
  static const float factorAe = (float)(log(10.0) / 10.0);
  static const float scale_dB = 100.0f; // Constant added to dB value to utilize both positive and negative exponents.
 
  inline float linearize(float v)
  {
    float w = exp2(factorA*(v + scale_dB));
    if (!isfinite(w)) {
      w = v < 0.f ? 0.f : numeric_limits<float>::max();
    }
    return w;
  };
 
 
}
 
float EchoSounder::dBToLinear(float v)
{
  return ::linearize(v);
  //float w = exp2(factorA*(v + scale_dB));
  //if (!isfinite(w)) {
  //  w = v < 0.f ? 0.f : numeric_limits<float>::max();
  //}
  //return w;
};
 
void EchoSounder::dBToLinearTask::operator()()
{
  CpuInstrumentationScope(SCOPE_ECHOSOUNDER, "Linearize");
 
  if (!std::isfinite(overflowThreshold)) overflowThreshold = std::numeric_limits<float>::max();
 
  auto end = in + N;
  while (in < end)
  {
    auto val = *in++;
 
    if (overflowThreshold < val) val = 0.f;
    else val = ::linearize(val);
 
    *out++ = val;
  }
}