private unsafe bool FrustumCull(ref Cluster.GpuCluster cluster, ref CBMeshBatch cbMesh)
{
Vector3 position = cluster.BoundCenter;
Vector3 extent = cluster.BoundExtent;
Vector3 minPos = position - extent;
Vector3 maxPos = position + extent;
if (cbMesh.GpuDrivenFrustumMinPoint.X > maxPos.X ||
cbMesh.GpuDrivenFrustumMinPoint.Y > maxPos.Y ||
cbMesh.GpuDrivenFrustumMinPoint.Z > maxPos.Z)
{
return(true);
}
if (cbMesh.GpuDrivenFrustumMaxPoint.X < minPos.X ||
cbMesh.GpuDrivenFrustumMaxPoint.Y < minPos.Y ||
cbMesh.GpuDrivenFrustumMaxPoint.Z < minPos.Z)
{
return(true);
}
fixed(CBMeshBatch *pCBuffer = &cbMesh)
{
Vector4 *planes = (Vector4 *)pCBuffer;
Vector3 absNormal = new Vector3();
for (uint i = 0; i < 6; ++i)
{
absNormal.X = (planes->X > 0) ? (planes->X) : (-planes->X);
absNormal.Y = (planes->Y > 0) ? (planes->Y) : (-planes->Y);
absNormal.Z = (planes->Z > 0) ? (planes->Z) : (-planes->Z);
Vector3 *planeNormal = (Vector3 *)planes;
float dist = Vector3.Dot(position, *planeNormal) + planes->W;
float df = Vector3.Dot(absNormal, extent);
if (dist - df > 0)
{
return(true);
}
planes++;
}
}
return(false);
}
private unsafe void UpdateIndexBufferCPU(CCommandList cmd, Graphics.CGfxCamera Camera)
{
if (mCpuDrawIndexBuffer == null)
{
return;
}
CBMeshBatch cbMesh = new CBMeshBatch();
{
var pPlanes = stackalloc Plane[6];
Camera.CullingFrustum.GetPlanes(pPlanes);
CBMeshBatch *pCBuffer = &cbMesh;
Plane * planesTar = (Plane *)pCBuffer;
for (uint i = 0; i < 6; i++)
{
planesTar[i] = pPlanes[i];
}
cbMesh.GpuDrivenCameraPosition = Camera.CullingFrustum.TipPos;
BoundingBox box = new BoundingBox();
Camera.CullingFrustum.GetBoundBox(ref box);
cbMesh.GpuDrivenFrustumMinPoint = box.Minimum;
cbMesh.GpuDrivenFrustumMaxPoint = box.Maximum;
cbMesh.MeshBatchVertexStride = (uint)AllVertices.Count;
cbMesh.ClusterNumber = (uint)GpuClusters.Count;
UpdateCBMeshbatch(cmd, Camera);
}
UInt32_3 tri = new UInt32_3();
mDrawIndices.Clear();
for (int i = 0; i < GpuClusters.Count; i++)
{
var cluster = GpuClusters[i];
var GpuDrivenCameraDirection = GpuClusters[i].BoundCenter - cbMesh.GpuDrivenCameraPosition;
var cameraDirInBoundSpace = Vector3.TransposeTransformNormal(GpuDrivenCameraDirection, GpuInstanceDatas[(int)cluster.InstanceId].InvMatrix);
if (FrustumCull(ref cluster, ref cbMesh) == false)
{
UInt64 visBits = 0;
if (cameraDirInBoundSpace.X >= 0)
{
visBits |= cluster.CubeFaces[(int)Cluster.GpuCluster.ECubeFace.CubeFace_NX];
}
else
{
visBits |= cluster.CubeFaces[(int)Cluster.GpuCluster.ECubeFace.CubeFace_X];
}
if (cameraDirInBoundSpace.Y >= 0)
{
visBits |= cluster.CubeFaces[(int)Cluster.GpuCluster.ECubeFace.CubeFace_NY];
}
else
{
visBits |= cluster.CubeFaces[(int)Cluster.GpuCluster.ECubeFace.CubeFace_Y];
}
if (cameraDirInBoundSpace.Z >= 0)
{
visBits |= cluster.CubeFaces[(int)Cluster.GpuCluster.ECubeFace.CubeFace_NZ];
}
else
{
visBits |= cluster.CubeFaces[(int)Cluster.GpuCluster.ECubeFace.CubeFace_Z];
}
uint InstanceStartIndex = cbMesh.MeshBatchVertexStride * cluster.InstanceId;
for (int j = 0; j < cluster.FaceCount; j++)
{
if (TestBit(visBits, j) == false)
{
continue;
}
int srcIndex = (int)(cluster.StartFaceIndex + j) * 3;
tri.x = InstanceStartIndex + AllIndices[srcIndex];
tri.y = InstanceStartIndex + AllIndices[srcIndex + 1];
tri.z = InstanceStartIndex + AllIndices[srcIndex + 2];
mDrawIndices.Add(tri);
}
}
}
mDrawArgs.InstanceCount = 1;
mDrawArgs.IndexCountPerInstance = (uint)mDrawIndices.Count * 3;
uint size = (uint)(mDrawIndices.Count * sizeof(UInt32_3));
if (mCpuDrawIndexBuffer.Desc.ByteWidth > size)
{
mCpuDrawIndexBuffer.UpdateBuffData(cmd, mDrawIndices.GetBufferPtr(), size);
}
}
