public static IEnumerable<CSGNode> FindChildNodes(CSGNode node)
{
yield return node;
if (node.NodeType != CSGNodeType.Brush)
{
foreach (var child in FindChildNodes(node.Left))
yield return child;
foreach (var child in FindChildNodes(node.Right))
yield return child;
}
}
public static IEnumerable<CSGNode> FindChildBrushes(CSGNode node)
{
if (node.NodeType != CSGNodeType.Brush)
{
foreach (var brush in FindChildBrushes(node.Left))
yield return brush;
foreach (var brush in FindChildBrushes(node.Right))
yield return brush;
yield break;
}
else
yield return node;
}
public static void UpdateBounds(CSGNode node)
{
if (node.NodeType != CSGNodeType.Brush)
{
var leftNode = node.Left;
var rightNode = node.Right;
UpdateBounds(leftNode);
UpdateBounds(rightNode);
node.Bounds.Clear();
node.Bounds.Add(leftNode.Bounds.Translated(Vector3.Subtract(leftNode.Translation, node.Translation)));
node.Bounds.Add(rightNode.Bounds.Translated(Vector3.Subtract(rightNode.Translation, node.Translation)));
}
}
public override CSGNode ToCSGNode(CSGNode parent, HashSet<CSGNode> animateNodes, bool ignoreAnimate)
{
var leaf = new CSGNode(this.ID, Planes);
leaf.Parent = parent;
leaf.LocalTranslation = this.Translation;
if (parent != null)
leaf.Translation = Vector3.Add(parent.Translation, leaf.LocalTranslation);
else
leaf.Translation = leaf.LocalTranslation;
if (Animate && !ignoreAnimate)
animateNodes.Add(leaf);
return leaf;
}
public override CSGNode ToCSGNode(CSGNode parent, HashSet<CSGNode> animateNodes, bool ignoreAnimate)
{
var branch = new CSGNode(this.ID, Operator);
branch.Parent = parent;
branch.LocalTranslation = this.Translation;
if (parent != null)
branch.Translation = Vector3.Add(parent.Translation, branch.LocalTranslation);
else
branch.Translation = branch.LocalTranslation;
branch.Left = Left.ToCSGNode(branch, animateNodes, Animate || ignoreAnimate);
branch.Right = Right.ToCSGNode(branch, animateNodes, Animate || ignoreAnimate);
if (Animate && !ignoreAnimate)
animateNodes.Add(branch);
return branch;
}
public static void UpdateChildTransformations(CSGNode node, Vector3 parentTranslation)
{
node.Translation = Vector3.Add(parentTranslation, node.LocalTranslation);
if (node.NodeType == CSGNodeType.Brush)
return;
UpdateChildTransformations(node.Left, node.Translation);
UpdateChildTransformations(node.Right, node.Translation);
}
public static void UpdateChildTransformations(CSGNode node)
{
if (node.NodeType == CSGNodeType.Brush)
return;
UpdateChildTransformations(node.Left, node.Translation);
UpdateChildTransformations(node.Right, node.Translation);
}
public CSGNode(string id, CSGNodeType branchOperator, CSGNode left, CSGNode right)
{
this.NodeType = branchOperator; this.Left = left; this.Right = right;
}
public abstract CSGNode ToCSGNode(CSGNode parent, HashSet<CSGNode> animateNodes, bool ignoreAnimate);
public CSGNode(string id, CSGNodeType branchOperator, CSGNode left, CSGNode right)
{
this.NodeType = branchOperator; this.Left = left; this.Right = right;
}
public CSGNode(string id, CSGNodeType branchOperator)
{
this.NodeType = branchOperator; this.Left = null; this.Right = null;
}
static void LogicalOr( CSGNode processedNode,
CSGMesh processedMesh,
CSGNode categorizationNode,
List<Polygon> inputPolygons,
List<Polygon> inside,
List<Polygon> aligned,
List<Polygon> revAligned,
List<Polygon> outside,
bool inverseLeft,
bool inverseRight)
{
var leftNode = categorizationNode.Left;
var rightNode = categorizationNode.Right;
var defaultCapacity = inputPolygons.Count / 2;
// ... Allocations are ridiculously cheap in .NET, there is a garbage collection penalty however.
// CSG can be performed without temporary buffers and recursion by using flags,
// which would increase performance and scalability (garbage collection interfers with parallelization).
// It makes the code a lot harder to read however.
var leftAligned = new List<Polygon>(defaultCapacity);
var leftRevAligned = new List<Polygon>(defaultCapacity);
var leftOutside = new List<Polygon>(defaultCapacity);
//var leftInside = new List<Polygon>(defaultCapacity); // everything that's inside the left node
// is always part of the inside category
// First categorize polygons in left path ...
if (inverseLeft)
Categorize(processedNode, processedMesh, leftNode,
inputPolygons,
leftOutside, leftRevAligned, leftAligned, inside);
else
Categorize(processedNode, processedMesh, leftNode,
inputPolygons,
inside, leftAligned, leftRevAligned, leftOutside);
// ... Then categorize the polygons in the right path
// Note that no single polygon will go into more than one of the Categorize methods below
if (inverseRight)
{
if (leftAligned.Count > 0)
{
if (inside == aligned)
{
inside.AddRange(leftAligned);
} else
Categorize(processedNode, processedMesh, rightNode,
leftAligned,
aligned, inside, aligned, inside);
}
if (leftRevAligned.Count > 0)
{
if (inside == revAligned)
{
inside.AddRange(leftRevAligned);
} else
Categorize(processedNode, processedMesh, rightNode,
leftRevAligned,
revAligned, revAligned, inside, inside);
}
if (leftOutside.Count > 0)
{
Categorize(processedNode, processedMesh, rightNode,
leftOutside,
outside, revAligned, aligned, inside);
}
} else
{
if (leftAligned.Count > 0)
{
if (inside == aligned)
{
inside.AddRange(leftAligned);
} else
Categorize(processedNode, processedMesh, rightNode,
leftAligned,
inside, aligned, inside, aligned);
}
if (leftRevAligned.Count > 0)
{
if (inside == revAligned)
{
inside.AddRange(leftRevAligned);
} else
Categorize(processedNode, processedMesh, rightNode,
leftRevAligned,
inside, inside, revAligned, revAligned);
}
if (leftOutside.Count > 0)
{
Categorize(processedNode, processedMesh, rightNode,
leftOutside,
inside, aligned, revAligned, outside);
}
}
}
public static void Categorize(CSGNode processedNode,
CSGMesh processedMesh,
CSGNode categorizationNode,
List<Polygon> inputPolygons,
List<Polygon> inside,
List<Polygon> aligned,
List<Polygon> revAligned,
List<Polygon> outside)
{
// When you go deep enough in the tree it's possible that all categories point to the same
// destination. So we detect that and potentially avoid a lot of wasted work.
if (inside == revAligned &&
inside == aligned &&
inside == outside)
{
inside.AddRange(inputPolygons);
return;
}
Restart:
if (processedNode == categorizationNode)
{
// When the currently processed node is the same node as we categorize against, then
// we know that all our polygons are visible and we set their default category
// (usually aligned, unless it's an instancing node in which case it's precalculated)
foreach (var polygon in inputPolygons)
{
switch (polygon.Category)
{
case PolygonCategory.Aligned: aligned.Add(polygon); break;
case PolygonCategory.ReverseAligned: revAligned.Add(polygon); break;
case PolygonCategory.Inside: inside.Add(polygon); break;
case PolygonCategory.Outside: outside.Add(polygon); break;
}
// When brushes overlap and they share the same surface area we only want to keep
// the polygons of the last brush in the tree, and skip all others.
// At this point in the tree we know that this polygon belongs to this brush, so
// we set it to visible. If the polygon is found to share the surface area with another
// brush further on in the tree it'll be set to invisible again in mesh.Intersect.
polygon.Visible = true;
}
return;
}
var leftNode = categorizationNode.Left;
var rightNode = categorizationNode.Right;
switch (categorizationNode.NodeType)
{
case CSGNodeType.Brush:
{
processedMesh.Intersect( categorizationNode.Bounds,
categorizationNode.Planes,
categorizationNode.Translation,
processedNode.Translation,
inputPolygons,
inside, aligned, revAligned, outside);
break;
}
case CSGNodeType.Addition:
{
// ( A || B)
var relativeLeftTrans = Vector3.Subtract(processedNode.Translation, leftNode.Translation);
var relativeRightTrans = Vector3.Subtract(processedNode.Translation, rightNode.Translation);
if (AABB.IsOutside(processedNode.Bounds, relativeLeftTrans, leftNode.Bounds))
{
if (AABB.IsOutside(processedNode.Bounds, relativeRightTrans, rightNode.Bounds))
{
// When our polygons lie outside the bounds of both the left and the right node, then
// all the polygons can be categorized as being 'outside'
outside.AddRange(inputPolygons);
} else
{
//Categorize(processedNode, mesh, right,
// inputPolygons,
// inside, aligned, revAligned, outside);
categorizationNode = rightNode;
goto Restart;
}
} else
if (AABB.IsOutside(processedNode.Bounds, relativeRightTrans, rightNode.Bounds))
{
//Categorize(processedNode, left, mesh,
// inputPolygons,
// inside, aligned, revAligned, outside);
categorizationNode = leftNode;
goto Restart;
} else
{
LogicalOr(processedNode, processedMesh, categorizationNode,
inputPolygons,
inside, aligned, revAligned, outside,
false, false);
}
break;
}
case CSGNodeType.Common:
{
// !(!A || !B)
var relativeLeftTrans = Vector3.Subtract(processedNode.Translation, leftNode.Translation);
var relativeRightTrans = Vector3.Subtract(processedNode.Translation, rightNode.Translation);
if (AABB.IsOutside(processedNode.Bounds, relativeLeftTrans, leftNode.Bounds) ||
AABB.IsOutside(processedNode.Bounds, relativeRightTrans, rightNode.Bounds))
{
// When our polygons lie outside the bounds of both the left and the right node, then
// all the polygons can be categorized as being 'outside'
outside.AddRange(inputPolygons);
} else
{
LogicalOr(processedNode, processedMesh, categorizationNode,
inputPolygons,
outside, revAligned, aligned, inside,
true, true);
}
break;
}
case CSGNodeType.Subtraction:
{
// !(!A || B)
var relativeLeftTrans = Vector3.Subtract(processedNode.Translation, leftNode.Translation);
var relativeRightTrans = Vector3.Subtract(processedNode.Translation, rightNode.Translation);
if (AABB.IsOutside(processedNode.Bounds, relativeLeftTrans, leftNode.Bounds))
{
// When our polygons lie outside the bounds of both the left node, then
// all the polygons can be categorized as being 'outside'
outside.AddRange(inputPolygons);
} else
if (AABB.IsOutside(processedNode.Bounds, relativeRightTrans, rightNode.Bounds))
{
categorizationNode = leftNode;
goto Restart;
} else
{
LogicalOr(processedNode, processedMesh, categorizationNode,
inputPolygons,
outside, revAligned, aligned, inside,
true, false);
}
break;
}
}
}
public static ConcurrentDictionary<CSGNode, CSGMesh> ProcessCSGNodes(CSGNode root, IEnumerable<CSGNode> nodes)
{
var meshes = new ConcurrentDictionary<CSGNode, CSGMesh>();
var buildMesh =
(Action<CSGNode>)
delegate(CSGNode node)
{
CSGMesh mesh;
if (!cachedBaseMeshes.TryGetValue(node, out mesh))
{
// If the node we're performing csg on is a brush, we simply create the geometry from the planes
// If the node is a more complicated node, we perform csg on it's child nodes and combine the
// meshes that are created.
// Note that right now we cache brushes per node, but we can improve on this by caching on
// node type instead. Since lots of nodes will have the same geometry in real life and only
// need to be created once. It won't help much in runtime performance considering they're
// cached anyway, but it'll save on memory usage.
if (node.NodeType != CSGNodeType.Brush)
{
var childNodes = CSGUtility.FindChildBrushes(node);
var brushMeshes = ProcessCSGNodes(node, childNodes);
mesh = CSGMesh.Combine(node.Translation, brushMeshes);
} else
mesh = CSGMesh.CreateFromPlanes(node.Planes);
// Cache the mesh
cachedBaseMeshes[node] = mesh;
}
// Clone the cached mesh so we can perform CSG on it.
var clonedMesh = mesh.Clone();
node.Bounds.Set(clonedMesh.Bounds);
meshes[node] = clonedMesh;
};
var updateDelegate =
(Action<KeyValuePair<CSGNode, CSGMesh>>)
delegate(KeyValuePair<CSGNode, CSGMesh> item)
{
var processedNode = item.Key;
var processedMesh = item.Value;
var inputPolygons = processedMesh.Polygons;
var insidePolygons = new List<Polygon>(inputPolygons.Count);
var outsidePolygons = new List<Polygon>(inputPolygons.Count);
var alignedPolygons = new List<Polygon>(inputPolygons.Count);
var reversedPolygons = new List<Polygon>(inputPolygons.Count);
CSGCategorization.Categorize(processedNode,
processedMesh,
root,
inputPolygons, // these are the polygons that are categorized
insidePolygons,
alignedPolygons,
reversedPolygons,
outsidePolygons
);
// Flag all non aligned polygons as being invisible, and store their categorizations
// so we can use it if we instance this mesh.
foreach (var polygon in insidePolygons)
{
polygon.Category = PolygonCategory.Inside;
polygon.Visible = false;
}
foreach (var polygon in outsidePolygons)
{
polygon.Category = PolygonCategory.Outside;
polygon.Visible = false;
}
foreach (var polygon in alignedPolygons)
polygon.Category = PolygonCategory.Aligned;
foreach (var polygon in reversedPolygons)
polygon.Category = PolygonCategory.ReverseAligned;
};
//
// Here we run build the meshes and perform csg on them either in serial or parallel
//
/*
foreach (var node in nodes)
buildMesh(node);
CSGUtility.UpdateBounds(root);
foreach (var item in meshes)
updateDelegate(item);
/*/
Parallel.ForEach(nodes, buildMesh);
CSGUtility.UpdateBounds(root);
Parallel.ForEach(meshes, updateDelegate);
//*/
return meshes;
}
