Change name of 'vmap' to 'arg_vals' to fit with MeshFunc

README.md

@@ -6,18 +6,8 @@
   transformations so that I'm actually constructing things to be
   correct instead of just throwing shit at the wall.
   See my "Composing Transformations" link in log.org.
-- My "Barbs" example revealed another pesky limitation: a parent vertex
-  cannot refer to a parent vertex of the parent itself. This came up
-  because I had a rule inheriting 4 vertices (one side of a cube), and
-  creating 4 new vertices (the opposite side of a cube). I wanted its
-  child rules to be able to create faces that had 2 vertices of the
-  parent and 2 vertices that the parent inherited (basically grandparent
-  vertices) - think of one of the remaining 4 sides of the cube. I have
-  no way to do this and no easy workarounds I can see, given that the
-  rule does not have access to the exact vertex positions (so just making
-  new vertices that are 'close' and connecting them isn't an option).
 - Adaptive subdivision - which means having to generalize past some
-  `vmap` stuff.
+  `arg_vals` stuff.
 - Try some non-deterministic examples.
 - Get identical or near-identical meshes to `ramhorn_branch` from
   Python.  (Should just be a matter of tweaking parameters.)

src/examples.rs

@@ -39,7 +39,7 @@ pub fn cube_thing() -> Rule<()> {
             children: xforms.map(move |xf| Child {
                 rule: self_.clone(),
                 xf: xf,
-                vmap: vec![],
+                arg_vals: vec![],
             }).collect(),
         }
     };
@@ -85,7 +85,7 @@ pub fn barbs() -> Rule<()> {
                 Child {
                     rule: self_.clone(),
                     xf: barb_incr,
-                    vmap: (0..n).collect(),
+                    arg_vals: (0..n).collect(),
                 }
             ]
         }
@@ -128,27 +128,27 @@ pub fn barbs() -> Rule<()> {
                 Child {
                     rule: self_.clone(),
                     xf: main_incr,
-                    vmap: (0..n).collect(),
+                    arg_vals: (0..n).collect(),
                 },
                 Child {
                     rule: Rc::new(Rule { eval: barb_.clone(), ctxt: () }),
                     xf: main_barb_trans(0),
-                    vmap: vec![b0 + 0, b0 + 1, a0 + 1, a0 + 0],
+                    arg_vals: vec![b0 + 0, b0 + 1, a0 + 1, a0 + 0],
                 },
                 Child {
                     rule: Rc::new(Rule { eval: barb_.clone(), ctxt: () }),
                     xf: main_barb_trans(1),
-                    vmap: vec![b0 + 1, b0 + 2, a0 + 2, a0 + 1],
+                    arg_vals: vec![b0 + 1, b0 + 2, a0 + 2, a0 + 1],
                 },
                 Child {
                     rule: Rc::new(Rule { eval: barb_.clone(), ctxt: () }),
                     xf: main_barb_trans(2),
-                    vmap: vec![b0 + 2, b0 + 3, a0 + 3, a0 + 2],
+                    arg_vals: vec![b0 + 2, b0 + 3, a0 + 3, a0 + 2],
                 },
                 Child {
                     rule: Rc::new(Rule { eval: barb_.clone(), ctxt: () }),
                     xf: main_barb_trans(3),
-                    vmap: vec![b0 + 3, b0 + 0, a0 + 0, a0 + 3],
+                    arg_vals: vec![b0 + 3, b0 + 0, a0 + 0, a0 + 3],
                 },
                 // TODO: Factor out repetition
             ],
@@ -171,7 +171,7 @@ pub fn barbs() -> Rule<()> {
                 Child {
                     rule: Rc::new(Rule { eval: main_.clone(), ctxt: () }),
                     xf: Transform::new(),
-                    vmap: (0..n).collect(),
+                    arg_vals: (0..n).collect(),
                 },
             ],
         }
@@ -233,7 +233,7 @@ pub fn twist(f: f32, subdiv: usize) -> Rule<()> {
                     Child {
                         rule: self_.clone(),
                         xf: incr,
-                        vmap: (0..n).collect(),
+                        arg_vals: (0..n).collect(),
                     },
                 ],
             }
@@ -254,7 +254,7 @@ pub fn twist(f: f32, subdiv: usize) -> Rule<()> {
                 rule: Rc::new(Rule { eval: (recur.clone())(incr), ctxt: () }),
                 // TODO: Cleanliness fix - can macros clean up above?
                 xf: xform,
-                vmap: (0..(n+1)).collect(),
+                arg_vals: (0..(n+1)).collect(),
                 // N.B. n+1, not n. the +1 is for the centroid below.
             };
             let mut vs = xform.transform(&seed);
@@ -334,7 +334,7 @@ pub fn nest_spiral_2() -> Rule<NestSpiral2Ctxt> {
                     Child {
                         rule: Rc::new(next_rule),
                         xf: Transform::new(),
-                        vmap: (0..n2).collect(),
+                        arg_vals: (0..n2).collect(),
                     },
                 ],
             }
@@ -346,7 +346,7 @@ pub fn nest_spiral_2() -> Rule<NestSpiral2Ctxt> {
                     Child {
                         rule: Rc::new(next_rule),
                         xf: Transform::new(),
-                        vmap: (0..n).collect(),
+                        arg_vals: (0..n).collect(),
                     },
                 ],
             }
@@ -372,7 +372,7 @@ pub fn nest_spiral_2() -> Rule<NestSpiral2Ctxt> {
                     },
                 }),
                 xf: Transform::new(),
-                vmap: vec![], // no parent vertices
+                arg_vals: vec![], // no parent vertices
             }
         };
 
@@ -463,7 +463,7 @@ pub fn twisty_torus() -> Rule<TorusCtxt> {
                     Child {
                         rule: Rc::new(next_rule),
                         xf: Transform::new(),
-                        vmap: (0..n2).collect(),
+                        arg_vals: (0..n2).collect(),
                     },
                 ],
             }
@@ -475,7 +475,7 @@ pub fn twisty_torus() -> Rule<TorusCtxt> {
                     Child {
                         rule: Rc::new(next_rule),
                         xf: Transform::new(),
-                        vmap: (0..n).collect(),
+                        arg_vals: (0..n).collect(),
                     },
                 ],
             }
@@ -538,7 +538,7 @@ pub fn twisty_torus_hardcode() -> Rule<()> {
                 Child {
                     rule: self_.clone(),
                     xf: incr,
-                    vmap: (0..n).collect(),
+                    arg_vals: (0..n).collect(),
                 },
             ],
         }
@@ -557,7 +557,7 @@ pub fn twisty_torus_hardcode() -> Rule<()> {
                 Child {
                     rule: Rc::new(Rule { eval: Rc::new(recur.clone()), ctxt: () }),
                     xf: incr,
-                    vmap: (0..n2).collect(),
+                    arg_vals: (0..n2).collect(),
                 },
             ],
         }
@@ -633,7 +633,7 @@ pub fn wind_chime_mistake_thing() -> Rule<WindChimeCtxt> {
                     Child {
                         rule: Rc::new(next_rule),
                         xf: Transform::new(),
-                        vmap: (0..n2).collect(),
+                        arg_vals: (0..n2).collect(),
                     },
                 ],
             }
@@ -645,7 +645,7 @@ pub fn wind_chime_mistake_thing() -> Rule<WindChimeCtxt> {
                     Child {
                         rule: Rc::new(next_rule),
                         xf: Transform::new(),
-                        vmap: (0..n).collect(),
+                        arg_vals: (0..n).collect(),
                     },
                 ],
             }
@@ -712,7 +712,7 @@ pub fn ramhorn() -> Rule<()> {
                 Child {
                     rule: self_.clone(),
                     xf: incr,
-                    vmap: vec![0,1,2,3],
+                    arg_vals: vec![0,1,2,3],
                 },
             ],
         }
@@ -779,22 +779,22 @@ pub fn ramhorn() -> Rule<()> {
                 Child {
                     rule: Rc::new(Rule { eval: Rc::new(recur.clone()), ctxt: () }),
                     xf: opening_xform(0.0),
-                    vmap: vec![5,2,6,8],
+                    arg_vals: vec![5,2,6,8],
                 },
                 Child {
                     rule: Rc::new(Rule { eval: Rc::new(recur.clone()), ctxt: () }),
                     xf: opening_xform(1.0),
-                    vmap: vec![4,1,5,8],
+                    arg_vals: vec![4,1,5,8],
                 },
                 Child {
                     rule: Rc::new(Rule { eval: Rc::new(recur.clone()), ctxt: () }),
                     xf: opening_xform(2.0),
-                    vmap: vec![7,0,4,8],
+                    arg_vals: vec![7,0,4,8],
                 },
                 Child {
                     rule: Rc::new(Rule { eval: Rc::new(recur.clone()), ctxt: () }),
                     xf: opening_xform(3.0),
-                    vmap: vec![6,3,7,8],
+                    arg_vals: vec![6,3,7,8],
                 },
                 // TODO: These vertex mappings appear to be right.
                 // Explain *why* they are right.
@@ -893,22 +893,22 @@ pub fn ramhorn_branch(depth: usize, f: f32) -> Rule<RamHornCtxt> {
             Child {
                 rule: Rc::new(Rule { eval: recur.clone(), ctxt }),
                 xf: opening_xform(0.0),
-                vmap: vec![5,2,6,8],
+                arg_vals: vec![5,2,6,8],
             },
             Child {
                 rule: Rc::new(Rule { eval: recur.clone(), ctxt }),
                 xf: opening_xform(1.0),
-                vmap: vec![4,1,5,8],
+                arg_vals: vec![4,1,5,8],
             },
             Child {
                 rule: Rc::new(Rule { eval: recur.clone(), ctxt }),
                 xf: opening_xform(2.0),
-                vmap: vec![7,0,4,8],
+                arg_vals: vec![7,0,4,8],
             },
             Child {
                 rule: Rc::new(Rule { eval: recur.clone(), ctxt }),
                 xf: opening_xform(3.0),
-                vmap: vec![6,3,7,8],
+                arg_vals: vec![6,3,7,8],
             },
             // TODO: These vertex mappings appear to be right.
             // Explain *why* they are right.
@@ -940,7 +940,7 @@ pub fn ramhorn_branch(depth: usize, f: f32) -> Rule<RamHornCtxt> {
                     Child {
                         rule: Rc::new(next_rule),
                         xf: incr,
-                        vmap: vec![0,1,2,3],
+                        arg_vals: vec![0,1,2,3],
                     },
                 ],
             }
@@ -970,7 +970,7 @@ pub fn ramhorn_branch(depth: usize, f: f32) -> Rule<RamHornCtxt> {
                 Child {
                     rule: Rc::new(Rule { eval: Rc::new(trans.clone()), ctxt: self_.ctxt }),
                     xf: Transform::new(),
-                    vmap: vec![0,1,2,3],
+                    arg_vals: vec![0,1,2,3],
                 },
             ],
         }
@@ -1066,22 +1066,22 @@ pub fn ramhorn_branch_random(depth: usize, f: f32) -> Rule<RamHornCtxt2> {
             Child {
                 rule: Rc::new(Rule { eval: recur.clone(), ctxt }),
                 xf: opening_xform(0.0),
-                vmap: vec![5,2,6,8],
+                arg_vals: vec![5,2,6,8],
             },
             Child {
                 rule: Rc::new(Rule { eval: recur.clone(), ctxt }),
                 xf: opening_xform(1.0),
-                vmap: vec![4,1,5,8],
+                arg_vals: vec![4,1,5,8],
             },
             Child {
                 rule: Rc::new(Rule { eval: recur.clone(), ctxt }),
                 xf: opening_xform(2.0),
-                vmap: vec![7,0,4,8],
+                arg_vals: vec![7,0,4,8],
             },
             Child {
                 rule: Rc::new(Rule { eval: recur.clone(), ctxt }),
                 xf: opening_xform(3.0),
-                vmap: vec![6,3,7,8],
+                arg_vals: vec![6,3,7,8],
             },
             // TODO: These vertex mappings appear to be right.
             // Explain *why* they are right.
@@ -1114,7 +1114,7 @@ pub fn ramhorn_branch_random(depth: usize, f: f32) -> Rule<RamHornCtxt2> {
                     Child {
                         rule: Rc::new(next_rule),
                         xf: incr,
-                        vmap: vec![0,1,2,3],
+                        arg_vals: vec![0,1,2,3],
                     },
                 ],
             }
@@ -1144,7 +1144,7 @@ pub fn ramhorn_branch_random(depth: usize, f: f32) -> Rule<RamHornCtxt2> {
                 Child {
                     rule: Rc::new(Rule { eval: Rc::new(trans.clone()), ctxt: self_.ctxt }),
                     xf: Transform::new(),
-                    vmap: vec![0,1,2,3],
+                    arg_vals: vec![0,1,2,3],
                 },
             ],
         }
@@ -1178,7 +1178,7 @@ impl CurveHorn {
                 Child {
                     rule: Rule { eval: Rc::new(move || self.do_nothing()) },
                     xf: self.id_xform,
-                    vmap: vec![0,1,2,3],
+                    arg_vals: vec![0,1,2,3],
                 },
             ],
         }
@@ -1215,12 +1215,12 @@ impl CurveHorn {
                 Child {
                     rule: Rule { eval: Rc::new(move || self.recur()) },
                     xf: self.id_xform,
-                    vmap: vec![0,1,2,3],
+                    arg_vals: vec![0,1,2,3],
                 },
                 Child {
                     rule: Rule { eval: Rc::new(move || self.recur()) },
                     xf: self.flip180,
-                    vmap: vec![3,2,1,0],
+                    arg_vals: vec![3,2,1,0],
                 },
             ],
         }
@@ -1266,7 +1266,7 @@ impl CurveHorn {
                 Child {
                     rule: Rule { eval: Rc::new(move || self.recur()) },
                     xf: self.incr,
-                    vmap: vec![0,1,2,3],
+                    arg_vals: vec![0,1,2,3],
                 },
             ],
         }

src/mesh.rs

@@ -74,8 +74,11 @@ impl Mesh {
 pub enum VertexUnion {
     /// A concrete vertex.
     Vertex(Vertex),
-    /// An 'unbound' vertex - something like an argument to a function with
+    /// A vertex argument - something like an argument to a function with
     /// the given positional index.
+    ///
+    /// The job of `MeshFunc.connect` is to bind these arguments to concrete
+    /// vertices.
     Arg(usize),
 }
 
@@ -155,13 +158,15 @@ impl MeshFunc {
 
     /// Treat this mesh as a 'parent' mesh to connect with any number
     /// of 'child' meshes, all of them paired with their respective
-    /// parent vertex mappings.  This returns a tuple of (new mesh,
+    /// vertex argument values (i.e. `arg_vals` from `Child`).
-    /// offsets), where 'offsets' gives the offset of where child
+    /// This returns a tuple of (new mesh, offsets), where 'offsets'
-    /// meshes were shifted in the new mesh.
+    /// gives the offset of where child meshes were shifted in the new
+    /// mesh.
     ///
     /// That is, the vertices of 'children[i]' begin at vertex
-    /// 'offset[i]' of the new mesh. This is needed in some cases for
+    /// 'offset[i]' of the new mesh. This is needed in order to adjust
-    /// adjusting a parent vertex mapping, like 'vmap' of Rule::Child.
+    /// references to vertices of a mesh in 'children' - such as
+    /// 'arg_vals' of `rule::Child`.
     pub fn connect<T, U>(&self, children: T) -> (MeshFunc, Vec<usize>)
     where U: Borrow<MeshFunc>,
           T: IntoIterator<Item = (U, Vec<usize>)>

src/rule.rs

@@ -46,6 +46,8 @@ pub struct RuleEval<S> {
     ///
     /// Parent vertex references will be resolved directly to `geom`
     /// with no mapping.
+    /// (TODO: Does this make sense? Nowhere else do I treat Arg(n) as
+    /// an index - it's always a positional argument.)
     pub final_geom: Rc<MeshFunc>,
 
     /// The child invocations (used if recursion continues).  The
@@ -67,12 +69,15 @@ pub struct Child<S> {
     /// as all sub-geometry produced recursively).
     pub xf: Transform,
 
-    /// The parent vertex mapping: a mapping to apply to turn a
+    /// The 'argument values' to apply to vertex arguments of a `MeshFunc`
-    /// Tag::Parent vertex reference into a vertex index of the parent
+    /// from `geom` and `final_geom` that `rule` produces when evaluated.
-    /// mesh.  That is, if `rule` produces a `MeshFunc` with a face
+    /// The values of this are treated as indices into the parent
-    /// of `Tag::Parent(n)`, this will correspond to index `vmap[n]`
+    /// `RuleEval` that produced this `Child`.
-    /// in the parent mesh.
+    ///
-    pub vmap: Vec<usize>,
+    /// In specific: if `arg_vals[i] = j` and `rule` produces some `geom` or
+    /// `final_geom`, then any vertex of `VertexUnion::Arg(i)` will be mapped
+    /// to `geom.verts[j]` in the *parent* geometry.
+    pub arg_vals: Vec<usize>,
 }
 
 impl<S> Rule<S> {
@@ -88,7 +93,7 @@ impl<S> Rule<S> {
         if iters_left <= 0 {
             return ((*rs.final_geom).clone(), 1);
             // TODO: This is probably wrong because of the way that
-            // sub.vmap is used below.  final_geom is not supposed to
+            // sub.arg_vals is used below.  final_geom is not supposed to
             // have any vertex mapping applied.
         }
 
@@ -103,7 +108,7 @@ impl<S> Rule<S> {
             
             let m2 = submesh.transform(&sub.xf);
             
-            (m2, sub.vmap.clone())
+            (m2, sub.arg_vals.clone())
                 // TODO: Fix clone?
         }).collect();
         
@@ -181,8 +186,8 @@ impl<S> Rule<S> {
                 // geometry properly:
                 let final_geom = eval.final_geom.transform(&xf);
                 // TODO: Fix the awful hack below.  I do this only to
-                // generate an identity mapping for vmap when I don't
+                // generate an identity mapping for arg_vals when I don't
-                // actually need vmap.
+                // actually need arg_vals.
                 let m = {
                     let mut m_ = 0;
                     for v in &final_geom.verts {
@@ -197,10 +202,10 @@ impl<S> Rule<S> {
                     }
                     m_ + 1
                 };
-                let vmap: Vec<usize> = (0..m).collect();
+                let arg_vals: Vec<usize> = (0..m).collect();
-                let (geom2, _) = new_geom.connect(vec![(final_geom, vmap)]);
+                let (geom2, _) = new_geom.connect(vec![(final_geom, arg_vals)]);
                 
-                geom = geom.connect(vec![(geom2, child.vmap.clone())]).0;
+                geom = geom.connect(vec![(geom2, child.arg_vals.clone())]).0;
                 // TODO: Fix clone?
 
                 // If we end recursion on one child, we must end it
@@ -216,23 +221,19 @@ impl<S> Rule<S> {
                 continue;
             }
 
-            let (g, offsets) = geom.connect(vec![(new_geom, child.vmap.clone())]);
+            let (g, offsets) = geom.connect(vec![(new_geom, child.arg_vals.clone())]);
             geom = g;
 
-            // 'new_geom' may itself be parent geometry for
+            // 'eval.children' may contain (via 'arg_vals') references to
-            // 'eval.children' (via Tag::Parent), and vmap is there to
+            // indices of 'new_geom'. However, we don't connect() to
-            // resolve Tag::Parent references to the right vertices in
+            // 'new_geom', but to the global geometry we just merged it
-            // 'new_geom'.
+            // into.  To account for this, we must shift 'arg_vals' by
-            //
+            // the offset that 'geom.connect' gave us.
-            // However, we connect() on the global geometry which we
-            // merged 'new_geom' into, not 'new_geom' directly.  To
-            // account for this, we must shift vmap by the offset that
-            // 'geom.connect' gave us:
             let off = offsets[0];
             // (We pass a one-element vector to geom.connect() above
             // so offsets always has just one element.)
             for child in eval.children.iter_mut() {
-                child.vmap = child.vmap.iter().map(|n| n + off).collect();
+                child.arg_vals = child.arg_vals.iter().map(|n| n + off).collect();
             }
 
             // We're done evaluating this rule, so increment 'next'.
@@ -263,7 +264,7 @@ impl<S> Rule<S> {
 
 impl<S> RuleEval<S> {
     /// Turn an iterator of (MeshFunc, Child) into a single RuleEval.
-    /// All meshes are merged, and the `vmap` in each child has the
+    /// All meshes are merged, and the `arg_vals` in each child has the
     /// correct offsets applied to account for this merge.
     ///
     /// (`final_geom` is passed through to the RuleEval unmodified.)
@@ -274,13 +275,13 @@ impl<S> RuleEval<S> {
         let (meshes, children): (Vec<_>, Vec<_>) = m.into_iter().unzip();
         let (mesh, offsets) = MeshFunc::append(meshes);
 
-        // Patch up vmap in each child, and copy everything else:
+        // Patch up arg_vals in each child, and copy everything else:
         let children2: Vec<Child<S>> = children.iter().zip(offsets.iter()).map(|(c,off)| {
             Child {
                 rule: c.rule.clone(),
                 xf: c.xf.clone(),
                 // simply add offset:
-                vmap: c.vmap.iter().map(|i| i + off).collect(),
+                arg_vals: c.arg_vals.iter().map(|i| i + off).collect(),
             }
         }).collect();