public void sortByDepth(ref Matrix4 viewMatrix)
{
if (_numParticles == 0)
{
return;
}
for (int i = 0; i < _activeBlockLength; ++i)
{
if (isAlive(i))
{
// Do the transform and store z of the result
Vector3 pos = readData(_positions, i).Value;
pos = Vector3.Transform(pos, viewMatrix);
writeDataIfNeeded(ref _viewDepths, i, pos.Z);
}
else
{
// since we are doing a sort pass later, might as well make it so
// so the dead particles get pushed the back of the arrays
writeDataIfNeeded(ref _viewDepths, i, float.PositiveInfinity);
}
}
quickSort(0, _activeBlockLength - 1);
if (_numParticles < _capacity)
{
// update pointers to reflect dead particles that just got sorted to the back
_nextIdxToWrite = _numParticles - 1;
_activeBlockLength = _numParticles;
}
#if false
// set color based on the index of the particle in the arrays
SSAttributeColor[] debugColors =
{
new SSAttributeColor(OpenTKHelper.Color4toRgba(Color4.Red)),
new SSAttributeColor(OpenTKHelper.Color4toRgba(Color4.Green)),
new SSAttributeColor(OpenTKHelper.Color4toRgba(Color4.Blue)),
new SSAttributeColor(OpenTKHelper.Color4toRgba(Color4.Yellow))
};
for (int i = 0; i < m_activeBlockLength; ++i)
{
writeDataIfNeeded(ref m_colors, i, debugColors[i]);
}
#endif
}
public override void sortByDepth(ref Matrix4 viewMatrix)
{
if (_numParticles == 0)
{
return;
}
int numAlive = 0;
float prevViewDepth = float.NegativeInfinity;
bool alreadySorted = true;
for (int i = 0; i < _activeBlockLength; ++i)
{
if (isAlive(i))
{
// Do the transform and store z of the result
Vector3 pos = _readElement(_positions, i).Value;
pos = Vector3.Transform(pos, viewMatrix);
float viewDepth = pos.Z;
writeDataIfNeeded(ref _viewDepths, i, viewDepth);
++numAlive;
if (alreadySorted && pos.Z < prevViewDepth)
{
alreadySorted = false;
}
prevViewDepth = viewDepth;
}
else
{
// since we are doing a sort pass later, might as well make it so
// so the dead particles get pushed the back of the arrays
writeDataIfNeeded(ref _viewDepths, i, float.PositiveInfinity);
alreadySorted = false; //force a "sort" to puch dead particles towards the end
}
}
if (!alreadySorted)
{
quickSort(0, _activeBlockLength - 1);
// somewhat hacky workaround for zombie particles that seem to be related to sortByDepth()
_numParticles = numAlive;
_activeBlockLength = _numParticles;
if (_numParticles == 0)
{
_nextIdxToWrite = _nextIdxToOverwrite = 0;
}
else if (_numParticles < _capacity)
{
// update pointers to reflect dead particles that just got sorted to the back
_nextIdxToWrite = _numParticles - 1;
}
#if DEBUG_PARTICLE_SORTING
++debugNumSorted;
#endif
}
else
{
#if DEBUG_PARTICLE_SORTING
++debugNumSortSkipped;
#endif
}
#if DEBUG_PARTICLE_SORTING
System.Console.WriteLine(
"particle data actually sorted "
+ ((float)debugNumSorted / (float)(debugNumSorted + debugNumSortSkipped) * 100f)
+ "% of the time");
#endif
#if false
// set color based on the index of the particle in the arrays
SSAttributeColor[] debugColors =
{
new SSAttributeColor(OpenTKHelper.Color4toRgba(Color4.Red)),
new SSAttributeColor(OpenTKHelper.Color4toRgba(Color4.Green)),
new SSAttributeColor(OpenTKHelper.Color4toRgba(Color4.Blue)),
new SSAttributeColor(OpenTKHelper.Color4toRgba(Color4.Yellow))
};
for (int i = 0; i < m_activeBlockLength; ++i)
{
writeDataIfNeeded(ref m_colors, i, debugColors[i]);
}
#endif
}