/// <inheritdoc />
public override unsafe void BuildUVCoordinates(ref ParticleBufferState bufferState, ref ParticleList sorter, AttributeDescription texCoordsDescription)
{
var lifeField = sorter.GetField(ParticleFields.RemainingLife);
if (!lifeField.IsValid())
{
return;
}
var texAttribute = bufferState.GetAccessor(texCoordsDescription);
if (texAttribute.Size == 0 && texAttribute.Offset == 0)
{
return;
}
var texDefault = bufferState.GetAccessor(bufferState.DefaultTexCoords);
if (texDefault.Size == 0 && texDefault.Offset == 0)
{
return;
}
foreach (var particle in sorter)
{
var normalizedTimeline = 1f - *(float *)(particle[lifeField]);
var spriteId = startingFrame + (int)(normalizedTimeline * animationSpeedOverLife);
Vector4 uvTransform = new Vector4((spriteId % xDivisions) * xStep, (spriteId / xDivisions) * yStep, xStep, yStep);
bufferState.TransformAttributePerParticle(texDefault, texAttribute, this, ref uvTransform);
bufferState.NextParticle();
}
bufferState.StartOver();
}
