Redefined face varying "boundary interpolation" to "linear interpolation":

- redefined and documented Sdc::Options::FVarLinearInterpolation
    - included "corners only" mode not possible with Hbr
    - updated usage within Vtr::FVarLevel

opensubdiv/sdc/options.h

@@ -56,22 +56,20 @@ namespace Sdc {
 //          - "boundary interpolation" is a potential misnomer as it only affects corners
 //          - its effect is to sharpen edges/corners, but edges are always sharpened
 //          - the "None" case serves no purpose (and would be discouraged)
-//      "FVarBoundaryInterpolation" and the bool "propagate corners"
-//          - as above, both name and enumerations being reconsidered
-//          - again "boundary interpolation" a misnomer interior interpolation affected
-//          - consider "FVarInterpolation" or "FVarLinearInterpolation" which by default
-//            (0) is linear throughout and specifies where FVar interpolation is to be
-//            Linear instead of following the assigned scheme.  Since the default (0) is
-//            completely (bi)linear, each option successively removes linear features
-//            making the last fully smooth:
-//              FVAR_LINEAR_ALL,
-//              FVAR_LINEAR_EDGE_AND_CORNER,
-//              FVAR_LINEAR_CORNER,
-//              FVAR_LINEAR_CORNER_PROPAGATE (incorporates "propagate corners")
-//              FVAR_LINEAR_NONE,
-//          - the "propgate corners" option only applied to one "interpolation option"
-//            (formerly EDGE_AND_CORNER, now LINEAR_CORNER) and so has been added as a
-//            new fifth choice.
+//      "FVarLinearInterpolation":
+//          - this replaces the combination of the "face varying boundary interpolation"
+//            enum and "propagate corner" boolean
+//          - functional equivalence with previous modes is as follows:
+//              LINEAR_NONE          == "edge only" (smooth everywhere)
+//              LINEAR_CORNERS_ONLY  == (no prior equivalent)
+//              LINEAR_CORNERS_PLUS1 == "edge and corner"
+//              LINEAR_CORNERS_PLUS2 == "edge and corner" with "propagate corners"
+//              LINEAR_BOUNDARIES    == "always sharp"
+//              LINEAR_ALL           == "bilinear"
+//          - the new "corner only" mode will sharpen corners and NEVER sharpen smooth
+//            boundaries, which we believe to be expected when sharping corners -- the
+//            old "edge and corner" mode would sharpen boundaries under some situations
+//            (e.g. more than three fvar values at a vertex)
 //      "TriangleSubdivision":
 //          - hoping we can get rid of this due to lack of interest/use
 //          - specific to Catmark and only at level 0
@@ -85,12 +83,13 @@ public:
         VVAR_BOUNDARY_EDGE_ONLY,
         VVAR_BOUNDARY_EDGE_AND_CORNER
     };
-    enum FVarBoundaryInterpolation {
-        FVAR_BOUNDARY_BILINEAR = 0,
-        FVAR_BOUNDARY_EDGE_ONLY,
-        FVAR_BOUNDARY_EDGE_AND_CORNER,
-        FVAR_BOUNDARY_ALWAYS_SHARP,
-        FVAR_BOUNDARY_EDGE_AND_CORNER_PROP
+    enum FVarLinearInterpolation {
+        FVAR_LINEAR_NONE = 0,
+        FVAR_LINEAR_CORNERS_ONLY,
+        FVAR_LINEAR_CORNERS_PLUS1,
+        FVAR_LINEAR_CORNERS_PLUS2,
+        FVAR_LINEAR_BOUNDARIES,
+        FVAR_LINEAR_ALL
     };
     enum CreasingMethod {
         CREASE_UNIFORM = 0,
@@ -111,7 +110,7 @@ public:
 
     //  Trivial constructor and destructor:
     Options() : _vvarBoundInterp(VVAR_BOUNDARY_NONE),
-                _fvarBoundInterp(FVAR_BOUNDARY_BILINEAR),
+                _fvarLinInterp(FVAR_LINEAR_ALL),
                 _nonManInterp(NON_MANIFOLD_NONE),
                 _creasingMethod(CREASE_UNIFORM),
                 _triangleSub(TRI_SUB_NORMAL),
@@ -124,8 +123,8 @@ public:
     VVarBoundaryInterpolation GetVVarBoundaryInterpolation() const { return (VVarBoundaryInterpolation) _vvarBoundInterp; }
     void SetVVarBoundaryInterpolation(VVarBoundaryInterpolation b) { _vvarBoundInterp = b; }
 
-    FVarBoundaryInterpolation GetFVarBoundaryInterpolation() const { return (FVarBoundaryInterpolation) _fvarBoundInterp; }
-    void SetFVarBoundaryInterpolation(FVarBoundaryInterpolation b) { _fvarBoundInterp = b; }
+    FVarLinearInterpolation GetFVarLinearInterpolation() const { return (FVarLinearInterpolation) _fvarLinInterp; }
+    void SetFVarLinearInterpolation(FVarLinearInterpolation b) { _fvarLinInterp = b; }
 
     CreasingMethod GetCreasingMethod() const { return (CreasingMethod) _creasingMethod; }
     void SetCreasingMethod(CreasingMethod c) { _creasingMethod = c; }
@@ -147,7 +146,7 @@ public:
 private:
     //  Bitfield members:
     unsigned int _vvarBoundInterp : 2;
-    unsigned int _fvarBoundInterp : 3;
+    unsigned int _fvarLinInterp   : 3;
     unsigned int _nonManInterp    : 2;
     unsigned int _creasingMethod  : 2;
     unsigned int _triangleSub     : 2;

opensubdiv/vtr/fvarLevel.cpp

@@ -112,15 +112,15 @@ FVarLevel::completeTopologyFromFaceValues() {
     using Sdc::Options;
 
     Options::VVarBoundaryInterpolation geomOptions = _options.GetVVarBoundaryInterpolation();
-    Options::FVarBoundaryInterpolation fvarOptions = _options.GetFVarBoundaryInterpolation();
+    Options::FVarLinearInterpolation   fvarOptions = _options.GetFVarLinearInterpolation();
 
-    _isLinear = (fvarOptions == Options::FVAR_BOUNDARY_BILINEAR);
+    _isLinear = (fvarOptions == Options::FVAR_LINEAR_ALL);
 
-    _hasSmoothBoundaries = (fvarOptions != Options::FVAR_BOUNDARY_BILINEAR) &&
-                           (fvarOptions != Options::FVAR_BOUNDARY_ALWAYS_SHARP);
+    _hasSmoothBoundaries = (fvarOptions != Options::FVAR_LINEAR_ALL) &&
+                           (fvarOptions != Options::FVAR_LINEAR_BOUNDARIES);
 
     bool geomCornersAreSmooth = (geomOptions != Options::VVAR_BOUNDARY_EDGE_AND_CORNER);
-    bool fvarCornersAreSharp  = (fvarOptions != Options::FVAR_BOUNDARY_EDGE_ONLY);
+    bool fvarCornersAreSharp  = (fvarOptions != Options::FVAR_LINEAR_NONE);
 
     bool makeCornersSharp = geomCornersAreSmooth && fvarCornersAreSharp;
 
@@ -140,8 +140,9 @@ FVarLevel::completeTopologyFromFaceValues() {
     //  values in cases where there are more than 2 values at a vertex, its unclear what the intent of
     //  "propagate corners" is if more than 2 are present.
     //
-    bool sharpenAllIfMoreThan2 = fvarCornersAreSharp;
-    bool sharpenAllIfAnyCorner = (fvarOptions == Options::FVAR_BOUNDARY_EDGE_AND_CORNER_PROP);
+    bool sharpenAllIfMoreThan2 = (fvarOptions == Options::FVAR_LINEAR_CORNERS_PLUS1) ||
+                                 (fvarOptions == Options::FVAR_LINEAR_CORNERS_PLUS2);
+    bool sharpenAllIfAnyCorner = (fvarOptions == Options::FVAR_LINEAR_CORNERS_PLUS2);
 
     bool sharpenDarts = sharpenAllIfAnyCorner || !_hasSmoothBoundaries;
 

opensubdiv/vtr/fvarLevel.h

@@ -78,8 +78,6 @@ namespace Vtr {
 class FVarLevel {
 
 public:
-    typedef Sdc::Options::FVarBoundaryInterpolation   BoundaryInterpolation;
-
     typedef LocalIndex      Sibling;
     typedef LocalIndexArray SiblingArray;