Add basic docs

Copyright.txt

@@ -1,3 +1,3 @@
-Copyright © 2022 Robert Marskars
+Copyright © 2022 Robert Marskar
 
 See LICENSE for redistribution rights. 

Examples/Sphere/example.cpp

@@ -19,7 +19,6 @@ int main() {
   // Aliases for cutting down on typing.
   using BV        = BoundingVolumes::AABBT<precision>;  
   using Vec3      = Vec3T<precision>;  
-  using Mesh      = MeshT<precision>;
   using Face      = FaceT<precision>;
   using slowSDF   = SignedDistanceDcel<precision>;
   using fastSDF   = SignedDistanceBVH<precision, BV, K>;    

README.md

@@ -1,7 +1,37 @@
 EBGeometry
 ----------
 
-Support for signed-distance functions of tesselated surfaces. Used with embedded-boundary (EB) codes. 
+Support for signed-distance functions of tesselated surfaces. Used with embedded-boundary (EB) codes.
+
+EBGeometry is a compact code for creating signed distance functions from watertight 3D surface tesselations.
+The surface mesh is stored in a doubly-connected edge list (DCEL), i.e. a half-edge data structure.
+Since the distance to any feature (facet, edge, vertex) in a surface mesh is well defined, the distance to the mesh can be computed from any point in space.
+Naively, this can be done by computing the shortest distance to every facet/edge/vertex in the surface mesh. 
+For computing the signed distance one needs to define a suitable normal vector for edges and vertices.
+
+EBGeometry provides bounding volume hierarchies (BVHs) for bounding geometric primitives in space.
+The BVHs are tree structures which permit accelerated closest-point searches.
+We point out that the BVHs in EBGeometry are shallow implementations without deep performance optimizations. 
+In the DCEL context the BVHs are used for bounding the facets on the surface mesh, but there are no fundamental limitations on which objects that can be bounded. 
+Querying the distance to the mesh through the BVH is much faster than directly computing the distance.
+On average, if the mesh consists of N facets then a BVH has O(log(N)) complexity while a direct search has O(N) complexity. 
+
+Requirements
+------------
+
+C++14
+
+Usage
+-----
+
+The library is header-only, simple make EBGeometry.hpp visible to your code and include it.
+Examples are given in Examples.
+
+Caveats
+-------
+
+EBGeometry takes, as input, a watertight and orientable surface.
+Although EBGeometry will process grids that contain self-intersections, it does not warn about these, and the signed distance functions is not well-defined either.
 
 License
 -------

Source/EBGeometry_DcelFaceImplem.hpp

@@ -99,7 +99,7 @@ namespace Dcel {
     // This computes the area of any N-side polygon. 
     const auto vertices = this->gatherVertices();
 
-    for (int i = 0; i < vertices.size() - 1; i++){
+    for (unsigned int i = 0; i < vertices.size() - 1; i++){
       const auto& v1 = vertices[i]  ->getPosition();
       const auto& v2 = vertices[i+1]->getPosition();
       m_area += m_normal.dot(v2.cross(v1));

Source/EBGeometry_DcelParserImplem.hpp

@@ -192,7 +192,7 @@ namespace Dcel {
 
       // Associate next/previous for the half edges inside the current face. Wish we had a circular iterator
       // but this will have to do. 
-      for (int i = 0; i < halfEdges.size(); i++){
+      for (unsigned int i = 0; i < halfEdges.size(); i++){
 	auto& curEdge  = halfEdges[i];
 	auto& nextEdge = halfEdges[(i+1)%halfEdges.size()];