void SweptAABB_BuildTriList(Vector3 start, Vector3 end, Vector3 extends, int nodeid, AABB_t AABBox, TriList_t triList)
{
// get the current node
Node_t node = m_pNodes[nodeid];
//
// fill in AABBox plane distances
//
AABBox.Dists[0] = -(node.m_BBox[0].X - ClipMap.EPSILON);
AABBox.Dists[1] = (node.m_BBox[1].X + ClipMap.EPSILON);
AABBox.Dists[2] = -(node.m_BBox[0].Y - ClipMap.EPSILON);
AABBox.Dists[3] = (node.m_BBox[1].Y + ClipMap.EPSILON);
AABBox.Dists[4] = -(node.m_BBox[0].Z - ClipMap.EPSILON);
AABBox.Dists[5] = (node.m_BBox[1].Z + ClipMap.EPSILON);
// test the swept box against the given node
if (SweptAABB_NodeTest(start, end, extends, AABBox))
{
//
// if leaf add tris to list
//
if ((node.m_fFlags & 0x01) > 0)
{
if (triList.Count < DISPCOLL_TRILIST_SIZE)
{
triList.ppTriList[triList.Count] = m_pTris[node.m_iTris[0]];
triList.ppTriList[triList.Count + 1] = m_pTris[node.m_iTris[1]];
triList.Count += 2;
}
return;
}
// continue testing with children nodes
else
{
SweptAABB_BuildTriList(start, end, extends, Nodes_GetChild(nodeid, 0), AABBox, triList);
SweptAABB_BuildTriList(start, end, extends, Nodes_GetChild(nodeid, 1), AABBox, triList);
SweptAABB_BuildTriList(start, end, extends, Nodes_GetChild(nodeid, 2), AABBox, triList);
SweptAABB_BuildTriList(start, end, extends, Nodes_GetChild(nodeid, 3), AABBox, triList);
}
}
}
bool SweptAABB_NodeTest(Vector3 start, Vector3 end, Vector3 extends, AABB_t AABBox)
{
//
// create and initialize the enter and exit fractions
//
float enterFraction = 0.0f;
float exitFraction = 1.0f;
//
// test the ray against the AABB (reduced to 1d tests)
//
float distStart, distEnd, fraction;
for (int ndxAxis = 0; ndxAxis < 3; ndxAxis++)
{
//
// test negative axial direction
//
distStart = -start[ndxAxis] - (AABBox.Dists[(ndxAxis << 1)] + extends[ndxAxis] /*+ DIST_EPSILON*/ );
distEnd = -end[ndxAxis] - (AABBox.Dists[(ndxAxis << 1)] + extends[ndxAxis] /*+ DIST_EPSILON*/ );
if ((distStart > 0.0f) && (distEnd < 0.0f))
{
fraction = (distStart - ClipMap.EPSILON) / (distStart - distEnd);
// fraction = distStart * scalar[ndxAxis];
if (fraction > enterFraction)
{
enterFraction = fraction;
}
}
else if ((distStart < 0.0f) && (distEnd > 0.0f))
{
fraction = (distStart + ClipMap.EPSILON) / (distStart - distEnd);
// fraction = distStart * scalar[ndxAxis];
if (fraction < exitFraction)
{
exitFraction = fraction;
}
}
else if ((distStart > 0.0f) && (distEnd > 0.0f))
{
return false;
}
//
// test positive axial direction
//
distStart = start[ndxAxis] - (AABBox.Dists[(ndxAxis << 1) + 1] + extends[ndxAxis] /*+ DIST_EPSILON*/ );
distEnd = end[ndxAxis] - (AABBox.Dists[(ndxAxis << 1) + 1] + extends[ndxAxis] /*+ DIST_EPSILON*/ );
if ((distStart > 0.0f) && (distEnd < 0.0f))
{
fraction = (distStart - ClipMap.EPSILON) / (distStart - distEnd);
// fraction = distStart * scalar[ndxAxis];
if (fraction > enterFraction)
{
enterFraction = fraction;
}
}
else if ((distStart < 0.0f) && (distEnd > 0.0f))
{
fraction = (distStart + ClipMap.EPSILON) / (distStart - distEnd);
// fraction = distStart * scalar[ndxAxis];
if (fraction < exitFraction)
{
exitFraction = fraction;
}
}
else if ((distStart > 0.0f) && (distEnd > 0.0f))
{
return false;
}
}
// test results
if (exitFraction < enterFraction)
return false;
return true;
}
public bool AABBSweep(Vector3 start, Vector3 end, Vector3 extends,
float startf, float endf, ref trace_t trace)
{
//
// create and initialize the triangle list
//
TriList_t trilist = new TriList_t();
//
// create and initialize the primary AABB
//
AABB_t AABBox = new AABB_t();
//
// sweep box against the axial-aligned bboxed quad-tree and generate an initial
// list of collision tris
//
SweptAABB_BuildTriList(start, end, extends, 0, AABBox, trilist);
// save the starting fraction
float preIntersectionFrac = trace.fraction;
//
// sweep axis-aligned bounding box against the triangles in the list
//
if (trilist.Count > 0)
{
SweptAABB_IntersectTriList(start, end, extends, startf, endf, ref trace, trilist);
}
// collision
if (preIntersectionFrac > trace.fraction)
return true;
// no collision
return false;
}
