OpenSubdiv/opensubdiv/far/patchMap.h

193 lines
5.8 KiB
C++

//
// Copyright 2013 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
// names, trademarks, service marks, or product names of the Licensor
// and its affiliates, except as required to comply with Section 4(c) of
// the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
#ifndef OPENSUBDIV3_FAR_PATCH_MAP_H
#define OPENSUBDIV3_FAR_PATCH_MAP_H
#include "../version.h"
#include "../far/patchTables.h"
#include <cassert>
namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {
namespace Far {
/// \brief An quadtree-based map connecting coarse faces to their sub-patches
///
/// PatchTables::PatchArrays contain lists of patches that represent the limit
/// surface of a mesh, sorted by their topological type. These arrays break the
/// connection between coarse faces and their sub-patches.
///
/// The PatchMap provides a quad-tree based lookup structure that, given a singular
/// parametric location, can efficiently return a handle to the sub-patch that
/// contains this location.
///
class PatchMap {
public:
typedef PatchTables::PatchHandle Handle;
/// \brief Constructor
///
/// @param patchTables A valid set of PatchTables
///
PatchMap( PatchTables const & patchTables );
/// \brief Returns a handle to the sub-patch of the face at the given (u,v).
/// Note : the faceid corresponds to quadrangulated face indices (ie. quads
/// count as 1 index, non-quads add as many indices as they have vertices)
///
/// @param faceid The index of the face
///
/// @param u Local u parameter
///
/// @param v Local v parameter
///
/// @return A patch handle or NULL if the face does not exist or the
/// limit surface is tagged as a hole at the given location
///
Handle const * FindPatch( int faceid, float u, float v ) const;
private:
inline void initialize( PatchTables const & patchTables );
// Quadtree node with 4 children
struct QuadNode {
struct Child {
unsigned int isSet:1, // true if the child has been set
isLeaf:1, // true if the child is a QuadNode
idx:30; // child index (either QuadNode or Handle)
};
// sets all the children to point to the patch of index patchIdx
void SetChild(int patchIdx);
// sets the child in "quadrant" to point to the node or patch of the given index
void SetChild(unsigned char quadrant, int child, bool isLeaf=true);
Child children[4];
};
typedef std::vector<QuadNode> QuadTree;
// adds a child to a parent node and pushes it back on the tree
static QuadNode * addChild( QuadTree & quadtree, QuadNode * parent, int quadrant );
// given a median, transforms the (u,v) to the quadrant they point to, and
// return the quadrant index.
//
// Quadrants indexing:
//
// (0,0) o-----o-----o
// | | |
// | 0 | 3 |
// | | |
// o-----o-----o
// | | |
// | 1 | 2 |
// | | |
// o-----o-----o (1,1)
//
template <class T> static int resolveQuadrant(T & median, T & u, T & v);
std::vector<Handle> _handles; // all the patches in the PatchTable
std::vector<QuadNode> _quadtree; // quadtree nodes
};
// given a median, transforms the (u,v) to the quadrant they point to, and
// return the quadrant index.
template <class T> int
PatchMap::resolveQuadrant(T & median, T & u, T & v) {
int quadrant = -1;
if (u<median) {
if (v<median) {
quadrant = 0;
} else {
quadrant = 1;
v-=median;
}
} else {
if (v<median) {
quadrant = 3;
} else {
quadrant = 2;
v-=median;
}
u-=median;
}
return quadrant;
}
/// Returns a handle to the sub-patch of the face at the given (u,v).
inline PatchMap::Handle const *
PatchMap::FindPatch( int faceid, float u, float v ) const {
if (faceid>=(int)_quadtree.size())
return NULL;
assert( (u>=0.0f) and (u<=1.0f) and (v>=0.0f) and (v<=1.0f) );
QuadNode const * node = &_quadtree[faceid];
float half = 0.5f;
// 0xFF : we should never have depths greater than k_InfinitelySharp
for (int depth=0; depth<0xFF; ++depth) {
float delta = half * 0.5f;
int quadrant = resolveQuadrant( half, u, v );
assert(quadrant>=0);
// is the quadrant a hole ?
if (not node->children[quadrant].isSet)
return 0;
if (node->children[quadrant].isLeaf) {
return &_handles[node->children[quadrant].idx];
} else {
node = &_quadtree[node->children[quadrant].idx];
}
half = delta;
}
assert(0);
return 0;
}
} // end namespace Far
} // end namespace OPENSUBDIV_VERSION
using namespace OPENSUBDIV_VERSION;
} // end namespace OpenSubdiv
#endif /* OPENSUBDIV3_FAR_PATCH_PARAM */