OpenSubdiv/opensubdiv/far/patchParam.h
barry f6172f9608 Minor public extensions to support multi-precision evaluation of patches:
- templated PatchParam normalization methods for multiple precision
    - instantiated double precision basis evaluation templates
    - converted PatchTable::EvaluateBasis...() methods to templates
        - added overloaded versions to assist template parameter resolution
    - extended PatchMap::FindPatch() to double precision
2018-07-28 14:43:32 -07:00

290 lines
11 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_PARAM_H
#define OPENSUBDIV3_FAR_PATCH_PARAM_H
#include "../version.h"
#include "../far/types.h"
namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {
namespace Far {
/// \brief Patch parameterization
///
/// Topological refinement splits coarse mesh faces into refined faces.
///
/// This patch parameterzation describes the relationship between one
/// of these refined faces and its corresponding coarse face. It is used
/// both for refined faces that are represented as full limit surface
/// parametric patches as well as for refined faces represented as simple
/// triangles or quads. This parameterization is needed to interpolate
/// primvar data across a refined face.
///
/// The U,V and refinement level parameters describe the scale and offset
/// needed to map a location on the patch between levels of refinement.
/// The encoding of these values exploits the quad-tree organization of
/// the faces produced by subdivision. We encode the U,V origin of the
/// patch using two 10-bit integer values and the refinement level as
/// a 4-bit integer. This is sufficient to represent up through 10 levels
/// of refinement.
///
/// Special consideration must be given to the refined faces resulting from
/// irregular coarse faces. We adopt a convention similar to Ptex texture
/// mapping and define the parameterization for these faces in terms of the
/// regular faces resulting from the first topological splitting of the
/// irregular coarse face.
///
/// When computing the basis functions needed to evaluate the limit surface
/// parametric patch representing a refined face, we also need to know which
/// edges of the patch are interpolated boundaries. These edges are encoded
/// as a boundary bitmask identifying the boundary edges of the patch in
/// sequential order starting from the first vertex of the refined face.
///
/// A sparse topological refinement (like feature adaptive refinement) can
/// produce refined faces that are adjacent to faces at the next level of
/// subdivision. We identify these transitional edges with a transition
/// bitmask using the same encoding as the boundary bitmask.
///
/// For triangular subdivision schemes we specify the parameterization using
/// a similar method. Alternate triangles at a given level of refinement
/// are parameterized from their opposite corners and encoded as occupying
/// the opposite diagonal of the quad-tree hierarchy. The third barycentric
/// coordinate is dependent on and can be derived from the other two
/// coordinates. This encoding also takes inspiration from the Ptex
/// texture mapping specification.
///
/// Bitfield layout :
///
/// Field0 | Bits | Content
/// -----------|:----:|------------------------------------------------------
/// faceId | 28 | the faceId of the patch
/// transition | 4 | transition edge mask encoding
///
/// Field1 | Bits | Content
/// -----------|:----:|------------------------------------------------------
/// level | 4 | the subdivision level of the patch
/// nonquad | 1 | whether patch is refined from a non-quad face
/// regular | 1 | whether patch is regular
/// unused | 2 | unused
/// boundary | 4 | boundary edge mask encoding
/// v | 10 | log2 value of u parameter at first patch corner
/// u | 10 | log2 value of v parameter at first patch corner
///
/// Note : the bitfield is not expanded in the struct due to differences in how
/// GPU & CPU compilers pack bit-fields and endian-ness.
///
/*!
\verbatim
Quad Patch Parameterization
(0,1) (1,1)
+-------+-------+---------------+
| | | |
| L2 | L2 | |
|0,3 |1,3 | |
+-------+-------+ L1 |
| | | |
| L2 | L2 | |
|0,2 |1,2 |1,1 |
+-------+-------+---------------+
| | |
| | |
| | |
| L1 | L1 |
| | |
| | |
|0,0 |1,0 |
+---------------+---------------+
(0,0) (1,0)
\endverbatim
*/
/*!
\verbatim
Triangle Patch Parameterization
(0,1) (1,1) (0,1,0)
+-------+-------+---------------+ +
| \ | \ | \ | | \
|L2 \ |L2 \ | \ | | \
|0,3 \ |1,3 \ | \ | | L2 \
+-------+-------+ \ | +-------+
| \ | \ | L1 \ | | \ L2 | \
|L2 \ |L2 \ | \ | | \ | \
|0,2 \ |1,2 \ |1,1 \ | | L2 \ | L2 \
+-------+-------+---------------+ +-------+-------+
| \ | \ | | \ | \
| \ | \ | | \ | \
| \ | \ | | \ L1 | \
| \ | \ | | \ | \
| L1 \ | L1 \ | | L1 \ | L1 \
| \ | \ | | \ | \
|0,0 \ |1,0 \ | | \ | \
+---------------+---------------+ +---------------+---------------+
(0,0) (1,0) (0,0,1) (1,0,0)
\endverbatim
*/
struct PatchParam {
/// \brief Sets the values of the bit fields
///
/// @param faceid face index
///
/// @param u value of the u parameter for the first corner of the face
/// @param v value of the v parameter for the first corner of the face
///
/// @param depth subdivision level of the patch
/// @param nonquad true if the root face is not a quad
///
/// @param boundary 4-bits identifying boundary edges
/// @param transition 4-bits identifying transition edges
///
/// @param regular whether the patch is regular
///
void Set(Index faceid, short u, short v,
unsigned short depth, bool nonquad,
unsigned short boundary, unsigned short transition,
bool regular = false);
/// \brief Resets everything to 0
void Clear() { field0 = field1 = 0; }
/// \brief Returns the faceid
Index GetFaceId() const { return Index(unpack(field0,28,0)); }
/// \brief Returns the log2 value of the u parameter at
/// the first corner of the patch
unsigned short GetU() const { return (unsigned short)unpack(field1,10,22); }
/// \brief Returns the log2 value of the v parameter at
/// the first corner of the patch
unsigned short GetV() const { return (unsigned short)unpack(field1,10,12); }
/// \brief Returns the transition edge encoding for the patch.
unsigned short GetTransition() const { return (unsigned short)unpack(field0,4,28); }
/// \brief Returns the boundary edge encoding for the patch.
unsigned short GetBoundary() const { return (unsigned short)unpack(field1,4,8); }
/// \brief True if the parent base face is a non-quad
bool NonQuadRoot() const { return (unpack(field1,1,4) != 0); }
/// \brief Returns the level of subdivision of the patch
unsigned short GetDepth() const { return (unsigned short)unpack(field1,4,0); }
/// \brief Returns the fraction of unit parametric space covered by this face.
float GetParamFraction() const;
/// \brief A (u,v) pair in the fraction of parametric space covered by this
/// face is mapped into a normalized parametric space.
///
/// @param u u parameter
/// @param v v parameter
///
template <typename REAL>
void Normalize( REAL & u, REAL & v ) const;
/// \brief A (u,v) pair in a normalized parametric space is mapped back into the
/// fraction of parametric space covered by this face.
///
/// @param u u parameter
/// @param v v parameter
///
template <typename REAL>
void Unnormalize( REAL & u, REAL & v ) const;
/// \brief Returns whether the patch is regular
bool IsRegular() const { return (unpack(field1,1,5) != 0); }
unsigned int field0:32;
unsigned int field1:32;
private:
unsigned int pack(unsigned int value, int width, int offset) const {
return (unsigned int)((value & ((1<<width)-1)) << offset);
}
unsigned int unpack(unsigned int value, int width, int offset) const {
return (unsigned int)((value >> offset) & ((1<<width)-1));
}
};
typedef std::vector<PatchParam> PatchParamTable;
typedef Vtr::Array<PatchParam> PatchParamArray;
typedef Vtr::ConstArray<PatchParam> ConstPatchParamArray;
inline void
PatchParam::Set(Index faceid, short u, short v,
unsigned short depth, bool nonquad,
unsigned short boundary, unsigned short transition,
bool regular) {
field0 = pack(faceid, 28, 0) |
pack(transition, 4, 28);
field1 = pack(u, 10, 22) |
pack(v, 10, 12) |
pack(boundary, 4, 8) |
pack(regular, 1, 5) |
pack(nonquad, 1, 4) |
pack(depth, 4, 0);
}
inline float
PatchParam::GetParamFraction( ) const {
return 1.0f / (float)(1 << (GetDepth() - NonQuadRoot()));
}
template <typename REAL>
inline void
PatchParam::Normalize( REAL & u, REAL & v ) const {
REAL fracInv = (REAL)(1.0f / GetParamFraction());
u = u * fracInv - (REAL)GetU();
v = v * fracInv - (REAL)GetV();
}
template <typename REAL>
inline void
PatchParam::Unnormalize( REAL & u, REAL & v ) const {
REAL frac = (REAL)GetParamFraction();
u = (u + (REAL)GetU()) * frac;
v = (v + (REAL)GetV()) * frac;
}
} // end namespace Far
} // end namespace OPENSUBDIV_VERSION
using namespace OPENSUBDIV_VERSION;
} // end namespace OpenSubdiv
#endif /* OPENSUBDIV3_FAR_PATCH_PARAM */