/// <summary>
/// Converts a single piece of input geometry into our instanced format.
/// </summary>
void ProcessGeometry(GeometryContent geometry)
{
int indexCount = geometry.Indices.Count;
int vertexCount = geometry.Vertices.VertexCount;
// Validate that the number of vertices is suitable for instancing.
if (vertexCount > ushort.MaxValue)
{
throw new InvalidContentException(
string.Format("Geometry contains {0} vertices: " +
"this is too many to be instanced.", vertexCount));
}
if (vertexCount > ushort.MaxValue / 8)
{
context.Logger.LogWarning(null, rootNode.Identity,
"Geometry contains {0} vertices: " +
"this will only allow it to be instanced " +
"{1} times per batch. A model with fewer " +
"vertices would be more efficient.",
vertexCount, ushort.MaxValue / vertexCount);
}
// Validate that the vertex channels we are going to use to pass
// through our instancing data aren't already in use.
VertexChannelCollection vertexChannels = geometry.Vertices.Channels;
for (int i = 1; i <= 4; i++)
{
if (vertexChannels.Contains(VertexChannelNames.TextureCoordinate(i)))
{
throw new InvalidContentException(
string.Format("Model already contains data for texture " +
"coordinate channel {0}, but instancing " +
"requires this channel for its own use.", i));
}
}
// Flatten the flexible input vertex channel data into
// a simple GPU style vertex buffer byte array.
VertexBufferContent vertexBufferContent;
VertexElement[] vertexElements;
geometry.Vertices.CreateVertexBuffer(out vertexBufferContent,
out vertexElements,
context.TargetPlatform);
int vertexStride = VertexDeclaration.GetVertexStrideSize(vertexElements, 0);
// Convert the input material.
MaterialContent material = ProcessMaterial(geometry.Material);
// Add the new piece of geometry to our output model.
outputModel.AddModelPart(indexCount, vertexCount, vertexStride,
vertexElements, vertexBufferContent,
geometry.Indices, material);
}
} // Process
#endregion
#region Process Vertex Channel
/// <summary>
/// Processes geometry content vertex channels at the specified index.
/// </summary>
protected override void ProcessVertexChannel(GeometryContent geometry, int vertexChannelIndex, ContentProcessorContext context)
{
VertexChannelCollection channels = geometry.Vertices.Channels;
// If the model has only position and normals a UV channel is added.
// http://xnafinalengine.codeplex.com/wikipage?title=Compressed%20Vertex%20Data
if (channels.Count == 1 && channels.Contains(VertexChannelNames.Normal()))
{
channels.Add<Vector2>(VertexChannelNames.TextureCoordinate(0), null);
}
// If the model has position, normal and UV then the data is packed on 32 bytes aliagned vertex data.
if (channels.Count == 2 && channels.Contains(VertexChannelNames.Normal()) && channels.Contains(VertexChannelNames.TextureCoordinate(0)))
{
// No compressed Vertex Data
base.ProcessVertexChannel(geometry, vertexChannelIndex, context);
}
else // If not then the data is compressed.
{
string name = channels[vertexChannelIndex].Name;
if (name == VertexChannelNames.Normal())
{
channels.ConvertChannelContent<NormalizedShort4>(vertexChannelIndex);
}
else if (name == VertexChannelNames.TextureCoordinate(0))
{
// Clamp values.
/*for (int i = 0; i < channels[vertexChannelIndex].Count; i++)
{
Vector2 uv = (Vector2)channels[vertexChannelIndex][i];
if (uv.X < 0)
uv.X *= -1;
if (uv.Y < 0)
uv.Y *= -1;
Vector2 uvCampled = new Vector2(uv.X - (float)Math.Truncate(uv.X), uv.Y - (float)Math.Truncate(uv.Y));
channels[vertexChannelIndex][i] = uvCampled;
}
// If the resource has texture coordinates outside the range [-1, 1] the values will be clamped.
channels.ConvertChannelContent<NormalizedShort2>(vertexChannelIndex);*/
// Sometimes you can't just clamp values, because the distance between vertices surpass 1 uv unit.
// And given that I am not removing the binormals I won't normalize the UVs.
channels.ConvertChannelContent<HalfVector2>(vertexChannelIndex);
}
else if (name == VertexChannelNames.TextureCoordinate(1))
channels.Remove(VertexChannelNames.TextureCoordinate(1));
else if (name == VertexChannelNames.TextureCoordinate(2))
channels.Remove(VertexChannelNames.TextureCoordinate(2));
else if (name == VertexChannelNames.TextureCoordinate(3))
channels.Remove(VertexChannelNames.TextureCoordinate(3));
else if (name == VertexChannelNames.TextureCoordinate(4))
channels.Remove(VertexChannelNames.TextureCoordinate(4));
else if (name == VertexChannelNames.TextureCoordinate(5))
channels.Remove(VertexChannelNames.TextureCoordinate(5));
else if (name == VertexChannelNames.TextureCoordinate(6))
channels.Remove(VertexChannelNames.TextureCoordinate(6));
else if (name == VertexChannelNames.TextureCoordinate(7))
channels.Remove(VertexChannelNames.TextureCoordinate(7));
else if (name == VertexChannelNames.Color(0))
channels.Remove(VertexChannelNames.Color(0));
else if (name == VertexChannelNames.Tangent(0))
{
channels.ConvertChannelContent<NormalizedShort4>(vertexChannelIndex);
}
else if (name == VertexChannelNames.Binormal(0))
{
channels.ConvertChannelContent<NormalizedShort4>(vertexChannelIndex);
// If the binormal is removed then the position, the normal,
// the tangent and one texture coordinate can be fetched in one single block of 32 bytes.
// Still, it is more fast to just pass the value. At least on the test I made.
//channels.Remove(VertexChannelNames.Binormal(0));
}
else
{
base.ProcessVertexChannel(geometry, vertexChannelIndex, context);
}
}
} // ProcessVertexChannel
