public BurstParticleCollisionConstraintsBatch(BatchData batchData) : base()
{
this.batchData = batchData;
}
public unsafe void Execute()
{
// Initialize batch data array
for (int i = 0; i < batchData.Length; ++i)
{
batchData[i] = new BatchData(i, maxBatches);
}
// temporary array containing an open work item for each batch.
WorkItem *workItems = stackalloc WorkItem[maxBatches];
for (int i = 0; i < maxBatches; i++)
{
workItems[i] = new WorkItem();
}
// find a batch for each constraint:
for (int i = 0; i < contacts.Length; ++i)
{
// OR together the batch masks of all entities involved in the constraint:
int batchMask = batchMasks[contacts[i].GetParticle(0)] | batchMasks[contacts[i].GetParticle(1)];
// look up the first free batch index for this constraint:
int batchIndex = batchIndices[i] = lut.batchIndex[batchMask];
// update the amount of constraints in the batch:
var batch = batchData[batchIndex];
batch.constraintCount++;
batchData[batchIndex] = batch;
// add the constraint to the last work item of the batch:
if (workItems[batchIndex].Add(i))
{
// if this work item does not belong to the last batch:
if (batchIndex != maxBatches - 1)
{
// tag all entities in the work item with the batch mask to close it.
// this way we know constraints referencing any of these entities can no longer be added to this batch.
for (int j = 0; j < workItems[batchIndex].constraintCount; j++)
{
K contact = contacts[workItems[batchIndex].constraints[j]];
batchMasks[contact.GetParticle(0)] |= batch.batchID;
batchMasks[contact.GetParticle(1)] |= batch.batchID;
}
}
// reuse the work item.
workItems[batchIndex].constraintCount = 0;
}
}
// fill batch data:
activeBatchCount[0] = 0;
int numConstraints = 0;
for (int i = 0; i < batchData.Length; ++i)
{
var batch = batchData[i];
// bail out when we find the first empty batch:
if (batch.constraintCount == 0)
{
break;
}
// calculate work item size, count, and index of the first constraint
batch.workItemSize = math.min(minWorkItemSize, batch.constraintCount);
batch.workItemCount = (batch.constraintCount + batch.workItemSize - 1) / batch.workItemSize;
batch.startIndex = numConstraints;
numConstraints += batch.constraintCount;
activeBatchCount[0]++;
batchData[i] = batch;
}
// write out constraints, sorted according to batches:
for (int i = 0; i < contacts.Length; ++i)
{
var batch = batchData[batchIndices[i]];
int sortedIndex = batch.startIndex + (batch.activeConstraintCount++);
sortedContacts[sortedIndex] = contacts[i];
batchData[batchIndices[i]] = batch;
}
}