public override int OneProcess(ProcessTimer <CommandTimerType, int> target, CommandTimerType msg, int total, int current)
{
DebugUtils.Info("AutoCountTimer", "AutoCountTimer OneProcess");
return(0);
}
/// <summary>
/// 绘制一个物体到缓冲区
/// </summary>
/// <param name="obj">待绘制物体</param>
private void DrawOccluder(OOModel obj)
{
// 获取物体的模型
OOMesh mdl = obj.Model;
// 计算 ModelView 矩阵.注意：这里需要相机的变换矩阵的逆矩阵
// 另一问题：左手系和右手系问题。
Matrix4x4 modelViewMatrix = mView * obj.ModelWorldMatrix;
// 变换mesh的顶点到 相机空间 和 裁剪空间
for (int i = 0; i < mdl.NumVert; i++)
{
// Vector3 p = obj.ModelWorldMatrix.MultiplyPoint3x4(mdl.Vertices[i]);
Vector4 tmp = modelViewMatrix.MultiplyPoint3x4(mdl.Vertices[i]);
mdl.CameraSpaceVertices[i] = tmp;
tmp.w = 1;
mdl.ClipSpaceVertices[i] = mProject * tmp;
}
int xmin = 100000;
int xmax = 0;
int ymin = 100000;
int ymax = 0;
// 遍历所有面
for (int i = 0; i < mdl.NumFace; i++)
{
// 面索引
int p1 = mdl.Faces[i][0];
int p2 = mdl.Faces[i][1];
int p3 = mdl.Faces[i][2];
// 计算法向量。此处可以优化成：初始化时计算，而后变换一下法向量即可。
// 构建右手坐标系 逆时针为正方向
Vector3 a = mdl.CameraSpaceVertices[p2] - mdl.CameraSpaceVertices[p1];
Vector3 b = mdl.CameraSpaceVertices[p3] - mdl.CameraSpaceVertices[p1];
Vector3 n = Vector3.Cross(a, b);
// 背面剔除。可计算相机的朝向，然后与三角面的法线计算即可。
// 此处实际上计算 Camera 空间 原点到平面的距离是否小于0
if (Vector3.Dot(n, mdl.CameraSpaceVertices[p1]) < 0)
{
mClip.mClipSpaceVertices[0] = mdl.ClipSpaceVertices[p1];
mClip.mClipSpaceVertices[1] = mdl.ClipSpaceVertices[p2];
mClip.mClipSpaceVertices[2] = mdl.ClipSpaceVertices[p3];
// 裁剪计算
int nv = mClip.ClipAndProject(3);
#if TEST_DRAW_ONE
DebugUtils.Info("ClipAndProject", string.Format("world1({0}, {1})", mClip.mScreenSpaceVertices[0][0], mClip.mScreenSpaceVertices[0][1]));
DebugUtils.Info("ClipAndProject", string.Format("world2({0}, {1})", mClip.mScreenSpaceVertices[1][0], mClip.mScreenSpaceVertices[1][1]));
DebugUtils.Info("ClipAndProject", string.Format("world3({0}, {1})", mClip.mScreenSpaceVertices[2][0], mClip.mScreenSpaceVertices[2][1]));
#endif
// 裁剪判断
if (nv > 2)
{
// 裁剪后，计算屏幕区域的AABB
for (int j = 0; j < nv; j++)
{
if (mClip.mScreenSpaceVertices[j][0] < xmin)
{
xmin = mClip.mScreenSpaceVertices[j][0];
}
else
{
if (mClip.mScreenSpaceVertices[j][0] > xmax)
{
xmax = mClip.mScreenSpaceVertices[j][0];
}
}
if (mClip.mScreenSpaceVertices[j][1] < ymin)
{
ymin = mClip.mScreenSpaceVertices[j][1];
}
else if (mClip.mScreenSpaceVertices[j][1] > ymax)
{
ymax = mClip.mScreenSpaceVertices[j][1];
}
}
// 绘制多边形到缓冲
Map.DrawPolygon(mClip.mScreenSpaceVertices, nv);
}
}
}
// 设置该区域内有被覆盖
Map.SetDirtyRectangle(xmin, ymin, xmax, ymax);
}
public override void StartByDerive()
{
DebugUtils.Info("EffectBehaviour", "StartByDerive");
}
/// <summary>
/// 遮挡剔除 算法入口
/// </summary>
private void OcclusionCull()
{
Stat[0] = Stat[1] = 0;
Map.Clear();
mMinQueue.Clear();
mMaxQueue.Clear();
PushBox2(Tree.Root, ref Tree.Root.Box);
// 按 负无穷范数(最小值) 作为优先权中 遍历
while (mMinQueue.Size > 0)
{
OONode nd = (OONode)mMinQueue.Dequeue();
nd.Distribute(mMaxLevel, mMaxItems);
MinMax(ref nd.Box, ref nd.Box.Zmin, ref nd.Box.Zmax);
if (nd.SplitAxis != OONode.LEAF) // 非叶节点
{
// 该节点存在两个子节点
// 如果 该节点 Visible 为可见 ,则不需要进一步计算
// 如果 该结点 Visible 为不可见,则进一步计算判断可见性
// KDTree的Node不是每次重新分配，带有一定的缓存功能。所以， Visible 可以加速计算
// 存在一个问题：如果所有的物体都分到了一个Node中，可能会不停的划分到最大深度。后期需要优化
if ((nd.Visible != 0) || IsVisible(1, ref nd.Box, nd.Box.Zmin) != 0)
{
// 标记为可见
nd.Visible = 1;
// 父节点可见,接下来判断左右孩子结点的可见性
PushBox2(nd.Left, ref nd.Left.Box);
PushBox2(nd.Right, ref nd.Right.Box);
}
else
{
// 标记为不可见
nd.Visible = 0;
if (nd.Parent != null)
{
nd.Parent.Visible = 0;
}
}
}
else // 叶节点
{
// 叶节点的Box测试
if (IsVisible(1, ref nd.Box, nd.Box.Zmin) != 0)
{
OOItem itm = nd.Head.Next;
// 保存需要绘制的物体，以 Zmax 为优先级排序
while (itm != nd.Tail)
{
if (itm.Obj.TouchId != Tree.TouchCounter)
{
itm.Obj.TouchId = Tree.TouchCounter;
OOModel obj = itm.Obj;
MinMax(ref obj.Box, ref obj.Box.Zmin, ref obj.Box.Zmax);
// 查询物体的Box是否可见
if (IsVisible(0, ref obj.Box, 0) != 0)
{
// 如果一个物体的Box可见，则为待绘制的物体
mMaxQueue.Enqueue(obj.Box.Zmax, obj, obj.Box.Zmax);
obj.Next = null;
if (mVisible == null)
{
mVisible = mTail = obj;
}
else
{
mTail.Next = obj;
mTail = obj;
}
}
}
itm = itm.Next;
}
}
if (nd.Parent != null)
{
nd.Parent.Visible = 0;
}
}
}
#if TEST_DRAW
VisualKDTree(Tree.Root);
if (mMaxQueue.Size > 0)
{
DebugUtils.Info("OcclusionCull", "Before Max Left: ", mMaxQueue.Size);
FlushOccluders(float.MaxValue);
DebugUtils.Info("OcclusionCull", "After Max Left: ", mMaxQueue.Size);
}
Map.DrawScreenShot();
#endif
}
protected override void InterruptWhenUsing()
{
DebugUtils.Info("EffectBehaviour", "InterruptWhenUsing");
}