public void DrawBatch(SpriteSortMode sortMode)
{
// nothing to do
if (_batchItemList.Count == 0)
{
return;
}
// sort the batch items
switch (sortMode)
{
case SpriteSortMode.Texture:
_batchItemList.Sort(CompareTexture);
break;
case SpriteSortMode.FrontToBack:
_batchItemList.Sort(CompareDepth);
break;
case SpriteSortMode.BackToFront:
_batchItemList.Sort(CompareReverseDepth);
break;
}
// setup the vertexArray array
int startIndex = 0;
int index = 0;
Texture2D tex = null;
// make sure the vertexArray has enough space
if (_batchItemList.Count * 4 > _vertexArray.Length)
{
ExpandVertexArray(_batchItemList.Count);
}
//Populate the vertexArray
for (int i = 0; i < _batchItemList.Count; i++)
{
var item = _batchItemList[i];
// store the SpriteBatchItem data in our vertexArray
_vertexArray[index++] = item.vertexTL;
_vertexArray[index++] = item.vertexTR;
_vertexArray[index++] = item.vertexBL;
_vertexArray[index++] = item.vertexBR;
_freeBatchItemQueue.Enqueue(item);
}
//Get and fill the PssVertexBuffer
var vertexBuffer = _device.GetVertexBuffer(_vertexFormat, 4 * InitialVertexArraySize, 6 * InitialVertexArraySize);
vertexBuffer.SetIndices(_index, 0, 0, 6 * InitialVertexArraySize);
_device._graphics.SetVertexBuffer(0, vertexBuffer);
vertexBuffer.SetVertices(_vertexArray, 0, 0, index);
startIndex = index = 0;
//Draw each batch in the sprite batch (based on texture changes)
for (int i = 0; i < _batchItemList.Count; i++)
{
var item = _batchItemList[i];
// if the texture changed, we need to draw and bind the new texture
bool shouldFlush = item.Texture != tex;
if (shouldFlush)
{
DrawVertexArray(startIndex, index);
startIndex = index;
tex = item.Texture;
_device._graphics.SetTexture(0, tex._texture2D);
}
index += 4;
}
// flush the remaining vertexArray data
DrawVertexArray(startIndex, index);
_batchItemList.Clear();
}