/// <summary>
/// Uploads the given index data to the internal index buffer. If the buffer is too
/// small, a new one is created automatically.
/// </summary>
/// <param name="indexData">The IndexData instance to upload.</param>
/// <param name="bufferUsage">The expected buffer usage. Use one of the constants defined in
/// <code>BufferUsageARB</code>. Only used when the method call
/// causes the creation of a new index buffer.</param>
public void UploadIndexData(IndexData indexData, BufferUsage bufferUsage = BufferUsage.StaticDraw)
{
int numIndices = indexData.NumIndices;
bool isQuadLayout = indexData.UseQuadLayout;
bool wasQuadLayout = IndexBufferUsesQuadLayout;
if (IndexBufferName != 0)
{
if (numIndices <= IndexBufferSize)
{
if (!isQuadLayout || !wasQuadLayout)
{
indexData.UploadToIndexBuffer(IndexBufferName, bufferUsage);
IndexBufferUsesQuadLayout = isQuadLayout && numIndices == IndexBufferSize;
}
}
else
{
PurgeBuffers(false);
}
}
if (IndexBufferName == 0)
{
IndexBufferName = indexData.CreateIndexBuffer(true, bufferUsage);
IndexBufferSize = numIndices;
IndexBufferUsesQuadLayout = isQuadLayout;
}
}
/// <summary>
/// Creates a duplicate of the IndexData object.
/// </summary>
public IndexData Clone()
{
var clone = new IndexData();
clone._numIndices = _numIndices;
if (!_useQuadLayout)
{
clone.SwitchToGenericData();
Array.Copy(_rawData, clone._rawData, _rawData.Length);
}
return(clone);
}
/// <summary>
/// Copies the index data (or a range of it, defined by 'indexID' and 'numIndices')
/// of this instance to another IndexData object, starting at a certain target index.
/// If the target is not big enough, it will grow to fit all the new indices.
///
/// <p>By passing a non-zero <code>offset</code>, you can raise all copied indices
/// by that value in the target object.</p>
/// </summary>
public void CopyTo(IndexData target, int targetIndexId = 0, int offset = 0,
int indexId = 0, int numIndices = -1)
{
if (numIndices < 0 || indexId + numIndices > _numIndices)
{
numIndices = _numIndices - indexId;
}
short[] sourceData;
int newNumIndices = targetIndexId + numIndices;
if (target._numIndices < newNumIndices)
{
target._numIndices = newNumIndices;
if (_sQuadDataNumIndices < newNumIndices)
{
EnsureQuadDataCapacity(newNumIndices);
}
}
if (_useQuadLayout)
{
if (target._useQuadLayout)
{
bool keepsQuadLayout = true;
int distance = targetIndexId - indexId;
int distanceInQuads = distance / 6;
int offsetInQuads = offset / 4;
// This code is executed very often. If it turns out that both IndexData
// instances use a quad layout, we don't need to do anything here.
//
// When "distance / 6 == offset / 4 && distance % 6 == 0 && offset % 4 == 0",
// the copy operation preserves the quad layout. In that case, we can exit
// right away. The code below is a little more complex, though, to avoid the
// (surprisingly costly) mod-operations.
if (distanceInQuads == offsetInQuads && (offset & 3) == 0 &&
distanceInQuads * 6 == distance)
{
keepsQuadLayout = true;
}
else if (numIndices > 2)
{
keepsQuadLayout = false;
}
else
{
for (int i = 0; i < numIndices; ++i)
{
keepsQuadLayout = keepsQuadLayout &&
(GetBasicQuadIndexAt(indexId + i) + offset == GetBasicQuadIndexAt(targetIndexId + i));
}
}
if (keepsQuadLayout)
{
return;
}
target.SwitchToGenericData();
}
sourceData = _sQuadData;
if ((offset & 3) == 0) // => offset % 4 == 0
{
indexId += 6 * offset / 4;
offset = 0;
EnsureQuadDataCapacity(indexId + numIndices);
}
}
else
{
if (target._useQuadLayout)
{
target.SwitchToGenericData();
}
sourceData = _rawData;
}
if (target._rawData.Length < targetIndexId + numIndices)
{
Array.Resize(ref target._rawData, targetIndexId + numIndices);
}
if (offset == 0)
{
Array.Copy(sourceData, indexId, target._rawData, targetIndexId, numIndices);
}
else
{
int pos = indexId;
int targetPos = targetIndexId;
for (int i = 0; i < numIndices; i++)
{
target._rawData[targetPos] = (short)(sourceData[pos] + offset);
pos++;
targetPos++;
}
}
}