public MeshRay TraceRay(Vector3 start, Vector3 dir)
{
MeshRay ray = new MeshRay();
ray.distance = float.PositiveInfinity;
TraceRecursive(0, start, dir, ref ray);
ray.hit = ray.distance != float.PositiveInfinity;
return(ray);
}
public MeshRay TraceRaySlow(Vector3 start, Vector3 dir)
{
float minT, minU, minV, minW, minS;
minT = minU = minV = minW = minS = float.PositiveInfinity;
float t, u, v, w, s;
bool hit = false;
int minIndex = 0;
for (int i = 0; i < NumFaces; ++i)
{
Vector3 a = Vertices[Indices[i * 3 + 0]];
Vector3 b = Vertices[Indices[i * 3 + 1]];
Vector3 c = Vertices[Indices[i * 3 + 2]];
if (IntersectRayTriTwoSided(start, dir, a, b, c, out t, out u, out v, out w, out s))
{
if (t < minT)
{
minT = t;
minU = u;
minV = v;
minW = w;
minS = s;
minIndex = i;
hit = true;
}
}
}
MeshRay ray = new MeshRay();
ray.distance = minT;
ray.u = minU;
ray.v = minV;
ray.w = minW;
ray.faceSign = minS;
ray.faceIndex = minIndex;
ray.hit = hit;
return(ray);
}
private void TraceRecursive(int nodeIndex, Vector3 start, Vector3 dir, ref MeshRay ray)
{
AABBNode node = Nodes[nodeIndex];
if (node.Faces == null)
{
// find closest node
AABBNode leftChild = Nodes[node.Children + 0];
AABBNode rightChild = Nodes[node.Children + 1];
float[] dist = new float[] { float.PositiveInfinity, float.PositiveInfinity };
IntersectRayAABB(start, dir, leftChild.Bounds.Min, leftChild.Bounds.Max, out dist[0]);
IntersectRayAABB(start, dir, rightChild.Bounds.Min, rightChild.Bounds.Max, out dist[1]);
int closest = 0;
int furthest = 1;
if (dist[1] < dist[0])
{
closest = 1;
furthest = 0;
}
if (dist[closest] < ray.distance)
{
TraceRecursive(node.Children + closest, start, dir, ref ray);
}
if (dist[furthest] < ray.distance)
{
TraceRecursive(node.Children + furthest, start, dir, ref ray);
}
}
else
{
float t, u, v, w, s;
for (int i = 0; i < node.Faces.Length; ++i)
{
int indexStart = node.Faces[i] * 3;
Vector3 a = Vertices[Indices[indexStart + 0]];
Vector3 b = Vertices[Indices[indexStart + 1]];
Vector3 c = Vertices[Indices[indexStart + 2]];
if (IntersectRayTriTwoSided(start, dir, a, b, c, out t, out u, out v, out w, out s))
{
if (t < ray.distance)
{
ray.distance = t;
ray.u = u;
ray.v = v;
ray.w = w;
ray.faceSign = s;
ray.faceIndex = node.Faces[i];
}
}
}
}
}
public void Voxelize(IList <Vector3> vertices, IList <int> indices, Box3 bounds)
{
Array.Clear(Voxels, 0, Voxels.Length);
// build an aabb tree of the mesh
MeshRayTracer tree = new MeshRayTracer(vertices, indices);
Bounds = tree.GetBounds();
// parity count method, single pass
Vector3 extents = bounds.Size;
Vector3 delta = new Vector3(extents.x / Width, extents.y / Height, extents.z / Depth);
Vector3 offset = new Vector3(0.5f / Width, 0.5f / Height, 0.5f / Depth);
float eps = 1e-7f * extents.z;
for (int x = 0; x < Width; ++x)
{
for (int y = 0; y < Height; ++y)
{
bool inside = false;
Vector3 rayDir = new Vector3(0.0f, 0.0f, 1.0f);
// z-coord starts somewhat outside bounds
Vector3 rayStart = bounds.Min + new Vector3(x * delta.x + offset.x, y * delta.y + offset.y, -0.0f * extents.z);
while (true)
{
MeshRay ray = tree.TraceRay(rayStart, rayDir);
if (ray.hit)
{
// calculate cell in which intersection occurred
float zpos = rayStart.z + ray.distance * rayDir.z;
float zhit = (zpos - bounds.Min.z) / delta.z;
int z = (int)((rayStart.z - bounds.Min.z) / delta.z);
int zend = (int)Math.Min(zhit, Depth - 1);
if (inside)
{
for (int k = z; k <= zend; ++k)
{
Voxels[x, y, k] = 1;
Count++;
}
}
inside = !inside;
rayStart += rayDir * (ray.distance + eps);
}
else
{
break;
}
}
}
}
//end
}
