// box intersect face and return intersection distance, point and normal
public override bool BoxIntersect(CollisionBox ray_box, Vector3 ray_origin, Vector3 ray_direction, Vector3[] vert_pos,
out float intersect_distance, out Vector3 intersect_position, out Vector3 intersect_normal)
{
intersect_distance = float.MaxValue;
intersect_position = ray_origin;
intersect_normal = Vector3.Zero;
bool intersected = false;
Vector3 p1, p2, p3, p4;
uint i, j;
CollisionBox world_box = new CollisionBox(ray_box.min + ray_origin, ray_box.max + ray_origin);
Vector3[] box_verts = world_box.GetVertices();
Vector3[] box_edges = world_box.GetEdges();
// intersect box edges to face edges
for (i = 0; i < 12; i++)
{
// cull edges with normal more than 135 degree from moving direction
if (Vector3.Dot(CollisionBox.edge_normals[i], ray_direction) < -0.70710678)
continue;
p1 = box_edges[i * 2];
p2 = box_edges[i * 2 + 1];
p4 = vert_pos[vertices[0]];
for (j = 0; j < vertices.Length; j++)
{
p3 = p4;
p4 = vert_pos[vertices[(j + 1) % vertices.Length]];
float distance;
Vector3 position;
if (CollisionFace.EdgeIntersect(p1, p2, ray_direction, p3, p4, out distance, out position))
{
if (distance < intersect_distance)
{
intersect_distance = distance;
intersect_position = position;
intersect_normal = Vector3.Normalize(Vector3.Cross(p2-p1,p3-p4));
if (Vector3.Dot(ray_direction, intersect_normal) > 0)
intersect_normal = Vector3.Negate(intersect_normal);
intersected = true;
}
}
}
}
// intersect from face vertices to box
for (i = 0; i < 3; i++)
{
float tnear, tfar;
p1 = vert_pos[vertices[i]];
int box_face_id = world_box.RayIntersect(p1, -ray_direction, out tnear, out tfar);
if (box_face_id > -1)
{
if (tnear < intersect_distance)
{
intersect_distance = tnear;
intersect_position = p1;
intersect_normal = -CollisionBox.face_normals[box_face_id];
intersected = true;
}
}
}
// intersect from box vertices to face polygon
Vector3 v1 = vert_pos[vertices[0]];
Vector3 v2 = vert_pos[vertices[1]];
Vector3 v3 = vert_pos[vertices[2]];
for (i = 0; i < 8; i++)
{
// cull vertices with normal more than 135 degree from moving direction
if (Vector3.Dot(CollisionBox.vertex_normals[i], ray_direction) < -0.70710678)
continue;
Vector3 uvt;
if (CollisionFace.RayTriangleIntersect(box_verts[i], ray_direction, v1, v2, v3, out uvt.Z, out uvt.X, out uvt.Y))
{
if (uvt.Z < intersect_distance)
{
intersect_distance = uvt.Z;
intersect_position = (1.0f - uvt.X - uvt.Y) * v1 + uvt.X * v2 + uvt.Y * v3;
intersect_normal = Vector3.Normalize(Vector3.Cross(v3 - v1, v2 - v1));
intersected = true;
}
}
}
return intersected;
}
// box intersect face and return intersection distance, point and normal
public override bool BoxIntersect(
CollisionBox rayBox,
Vector3 rayOrigin,
Vector3 rayDirection,
Vector3[] vertices,
out float intersectDistance,
out Vector3 intersectPosition,
out Vector3 intersectNormal)
{
intersectDistance = float.MaxValue;
intersectPosition = rayOrigin;
intersectNormal = Vector3.Zero;
bool intersected = false;
Vector3 p1, p2, p3, p4;
uint i, j;
CollisionBox worldBox = new CollisionBox(rayBox.min + rayOrigin,
rayBox.max + rayOrigin);
Vector3[] boxVerts = worldBox.GetVertices();
Vector3[] boxEdges = worldBox.GetEdges();
float distance;
Vector3 position;
// intersect box edges to face edges
for (i = 0; i < 12; i++)
{
// cull edges with normal more than 135 degree from moving direction
float dot = Vector3.Dot(CollisionBox.edgeNormals[i], rayDirection);
if (dot < -0.70710678)
{
continue;
}
p1 = boxEdges[i * 2];
p2 = boxEdges[i * 2 + 1];
p4 = vertices[indices[0]];
for (j = 0; j < indices.Length; j++)
{
p3 = p4;
p4 = vertices[indices[(j + 1) % indices.Length]];
if (CollisionFace.EdgeIntersect(p1, p2, rayDirection,
p3, p4, out distance, out position))
{
if (distance < intersectDistance)
{
intersectDistance = distance;
intersectPosition = position;
intersectNormal = Vector3.Cross(p2 - p1, p3 - p4);
intersectNormal = Vector3.Normalize(intersectNormal);
if (Vector3.Dot(rayDirection, intersectNormal) > 0)
{
intersectNormal = Vector3.Negate(intersectNormal);
}
intersected = true;
}
}
}
}
// intersect from face vertices to box
for (i = 0; i < 3; i++)
{
float tnear, tfar;
p1 = vertices[indices[i]];
int box_face_id = worldBox.RayIntersect(p1, -rayDirection,
out tnear, out tfar);
if (box_face_id > -1)
{
if (tnear < intersectDistance)
{
intersectDistance = tnear;
intersectPosition = p1;
intersectNormal = -CollisionBox.faceNormals[box_face_id];
intersected = true;
}
}
}
// intersect from box vertices to face polygon
Vector3 v1 = vertices[indices[0]];
Vector3 v2 = vertices[indices[1]];
Vector3 v3 = vertices[indices[2]];
Vector3 uvt;
for (i = 0; i < 8; i++)
{
// cull vertices with normal more than 135 degree from moving direction
float dot = Vector3.Dot(CollisionBox.vertexNormals[i], rayDirection);
if (dot < -0.70710678)
{
continue;
}
if (CollisionFace.RayTriangleIntersect(boxVerts[i], rayDirection,
v1, v2, v3, out uvt.Z, out uvt.X, out uvt.Y))
{
if (uvt.Z < intersectDistance)
{
intersectDistance = uvt.Z;
intersectPosition = (1.0f - uvt.X - uvt.Y) *
v1 + uvt.X * v2 + uvt.Y * v3;
intersectNormal = Vector3.Cross(v3 - v1, v2 - v1);
intersectNormal = Vector3.Normalize(intersectNormal);
intersected = true;
}
}
}
return(intersected);
}
