feat: support Viewpoints, translating PerspectiveCamera (#21)

Reviewed-on: #21
Co-authored-by: Glen Whitney <glen@studioinfinity.org>
Co-committed-by: Glen Whitney <glen@studioinfinity.org>

README.md

@@ -1,13 +1,28 @@
 # vrml1to97
 
-JavaScript converter from VRML 1.0 to VRML97 file format, based on Wings 3D
-conversion logic.
+JavaScript converter from VRML 1.0 to VRML97 file format.
 
-Essentially, this is a JavaScript reimplementation of the algorithm of the
-"token rearranger" found in the
+This converter was originally a JavaScript reimplementation of the algorithm
+of the "token rearranger" found in the
 [Wings 3D x3d importer](https://github.com/dgud/wings/blob/master/plugins_src/import_export/x3d_import.erl)
 (which was written in Erlang).
 
+However, from version 0.3, it adds support for a significantly larger subset of
+VRML 1.0. Overall, it recognizes and converts
+
+  * Title, SceneInfo, BackgroundColor, and View "Info" nodes [this node type
+    was removed in VRML97].
+  * All Light nodes
+  * PerspectiveCamera nodes (converted into Viewpoint nodes)
+  * Grouping nodes including Separator, Group, Switch, and WWWAnchor
+  * Interprets a Switch named "Cameras" (by a DEF) as a list of Viewpoints
+  * ShapeHints
+  * Transformation nodes including Translation, Rotation, Scale, and Transform
+  * All shape nodes including Cube, Cone, Cylinder, Sphere, IndexedFaceSet,
+    IndexedLineSet, PointSet, Coordinate3, and Normal
+  * All material nodes including Material, TextureCoordinate2, and Texture2
+  * DEF and USE constructs to share subtrees
+
 ## Usage
 
 From an es6 module under Node (for example)
@@ -44,8 +59,8 @@ Currently this package exports just two functions:
    actually check that its input is VRML 1, so its behavior is undefined
    if given anything but valid VRML 1 syntax). Returns VRML 97 syntax for
    the same scene, as nearly as it can translate. Note that not all of
-   VRML 1 is recognized, and some of the translations may be somewhat
-   approximate.
+   VRML 1 is recognized (see above for a list of constructs that should
+   be handled), and some of the translations may be somewhat approximate.
 
    If the optional second argument `source` is supplied, `convert` adds
    a comment indicating that the original vrml1 came from the specified
@@ -66,10 +81,12 @@ Currently this package exports just two functions:
 ## Conversion notes
 
 One sort of geometry common to VRML 1 and VRML97 is the IndexedFaceSet. These
-often used to render solids. Indeed, the default in VRML97 is to assume they
-do represent a solid, with the normals pointing outward. Unusual visual effects
-ensue if the normals are not properly directed (basically, you see through the
-"front" of the solid and see the "backs" of the faces on the opposite side).
+entities are often used to render solids. Indeed, the default in VRML97 is to
+assume they do represent a solid, with the normals pointing outward. Unusual
+visual effects ensue if the normals are not properly directed (basically, you
+see through the "front" of the solid and see the "backs" of the faces on the
+opposite side).
+
 As a result, unless the input VRML 1 explicitly includes an explicit
 vertexOrdering of CLOCKWISE or COUNTERCLOCKWISE, the default solid treatment
 will be turned off in the VRML97 output, meaning that all faces will be

package.json5

@@ -1,6 +1,6 @@
 {
   name: 'vrml1to97',
-  version: '0.2.4',
+  version: '0.4.0',
   description: 'JavaScript converter from VRML 1 to VRML97',
   scripts: {
     test: 'echo "Error: no test specified" && exit 1',
@@ -40,7 +40,7 @@
   },
   type: 'module',
   devDependencies: {
-    '@danielx/civet': '^0.6.71',
+    '@danielx/civet': '^0.6.72',
     '@types/moo': '^0.5.9',
     'http-server': '^14.1.1',
     json5: '^2.2.3',

pnpm-lock.yaml

@@ -11,8 +11,8 @@ dependencies:
 
 devDependencies:
   '@danielx/civet':
-    specifier: ^0.6.71
-    version: 0.6.71(typescript@5.3.3)
+    specifier: ^0.6.72
+    version: 0.6.72(typescript@5.3.3)
   '@types/moo':
     specifier: ^0.5.9
     version: 0.5.9
@@ -35,8 +35,8 @@ packages:
       '@jridgewell/trace-mapping': 0.3.9
     dev: true
 
-  /@danielx/civet@0.6.71(typescript@5.3.3):
-    resolution: {integrity: sha512-piOoHtJARe6YqRiXN02Ryb+nLU9JwU8TQLknvPwmlaNm6krdKN+X9dM+C9D4LRoAnAySC2wVshR0wf7YDIUV1Q==}
+  /@danielx/civet@0.6.72(typescript@5.3.3):
+    resolution: {integrity: sha512-jumnIbXbdFs0ZiKN62fmD+p8QGi+E0jmtc02dKz9wIIoPkODsa4XXlBrS5BRR5fr3w5d3ah8Vq7gWt+DL9Wa0Q==}
     engines: {node: '>=19 || ^18.6.0 || ^16.17.0'}
     hasBin: true
     peerDependencies:

src/index.civet

@@ -2,6 +2,7 @@ moo from ../deps/moo.js
 import type {Lexer, Token} from ../deps/moo.d.ts
 
 type Tree = {[key:string]: (string | Tree)[]}
+type DefTree = {_definitions?: Tree} & Tree
 
 lexer := moo.compile
    comment:    /#.*?$/
@@ -86,30 +87,196 @@ function addWorldParameter(name: string, value: string, tree: Tree): void
      children.push world
   world.WorldInfo.push(` ${name}`, ` ${value}`)
 
-function parse(stream: Lexer, tree: Tree = {}): Tree
-   held .= filtered stream // for lookahead
+// Current best way to re-use a pattern
+matches := (str: string, pat: RegExp) => pat.test(str)
+operator matches
+GroupNode := /(?:Transform)?Separator|Group|Switch|WWWAnchor/
+TransformNode := /^(?:Rotation|Scale|Transform|Translation)$/
+SetNode := /IndexedFaceSet|IndexedLineSet|PointSet/
+LightNode := /Light$/
+
+function parse(stream: Lexer, tree: DefTree = {}): DefTree
+   held .= filtered stream  // for lookahead
+   currentDefinition .= ''  // if we have just started a DEF
 
    while next := filtered stream
       unless held then break
+      // May need to know the current definition, but it clears each round
+      lastDefinition := currentDefinition
+      currentDefinition = ''
+
       switch data :=
             {nt: next.type, nv: next.value, ht: held.type, hv: held.value}
+         {ht: 'word', hv: 'Info'}
+            // Here the meaning is entirely dependent on what DEF we are in
+            if next.type !== 'obrace'
+               // Not sure what this construct is, so ignore it
+               held = next
+               continue
+            contents := toksUntilClose stream
+            held = filtered stream
+            switch lastDefinition
+               'BackgroundColor'
+                  // Find the first string token and assume it is the color
+                  stok := contents.find .type[0] === 'string'
+                  colorString := stok?.value[0]
+                  if colorString and typeof colorString === 'string'
+                     color := colorString.replace /^"|"$/g, ''
+                     addChild `Background {
+                        groundColor [ ${color} ]
+                        skyColor [ ${color} ]
+                     }\n`, tree
+               'Title'
+                  // Find the first string token and assume it is the title
+                  stok := contents.find .type[0] === 'string'
+                  titleString := stok?.value[0]
+                  if titleString and typeof titleString === 'string'
+                     addWorldParameter 'title', titleString, tree
+               'SceneInfo'
+                  // Filter all the strings and add them as info
+                  info := contents
+                     |> .filter .type[0] === 'string'
+                     |> .map .value[0]
+                     |> .join ' '
+                  addWorldParameter 'info', `[ ${info} ]`, tree
+               'Viewer'
+                  // Filter all of the strings, and translate them into
+                  // current viewer names
+                  tr: Record<string, string> := {'"examiner"': '"EXAMINE"'}
+                  viewers := contents
+                     |> .filter .type[0] === 'string'
+                     |> .map .value[0] as string
+                     |> .map((x) => x in tr ? tr[x] : x.toUpperCase())
+                     |> .join ' '
+                  addChild `NavigationInfo { type [ ${viewers} ] }\n`, tree
+         {ht: 'word', hv: 'DEF'}
+            unless next.type is 'word'
+               // Don't understand this construction, ignore the DEF
+               held = next
+               continue
+            currentDefinition = next.value
+            held = filtered stream
+            // Special case from VRML 1: DEF Cameras Switch { ... }
+            // needs to be hoisted to a list of viewpoints at this level
+            if currentDefinition is 'Cameras' and held?.value is 'Switch'
+               held = filtered stream
+               unless held?.type is 'obrace'
+                  console.error
+                     `DEF Cameras Switch followed by ${held?.value}, ignoring`
+                  continue
+               {children, ...context} := tree
+               subTree := parse stream, context
+               addChild renderList(subTree.children), tree
+               held = filtered stream
+               continue
+            if held?.type is 'word'
+               clause := `DEF ${currentDefinition}`
+               role .= held.value
+               switch role
+                  matches GroupNode
+                     role = 'Child'
+                  matches TransformNode
+                     role = 'Transform'
+                  'Coordinate3'
+                     role = 'Coordinate'
+                  /Cube|Cone|Cylinder|Sphere/
+                     role = 'Shape'
+                  'PerspectiveCamera'
+                     role = 'Viewpoint'
+                  'ShapeHints'
+                     role = 'Dummy' // will fill in when we parse the ShapeHints
+                  'Texture2'
+                     role = 'Texture'
+                  'TextureCoordinate2'
+                     role = 'TextureCoordinate'
+                  matches SetNode
+                     role = 'Shape'
+                  matches LightNode
+                     role = 'Child'
+               (tree._definitions ??= {})[currentDefinition] = [role]
+               unless role is 'Info'
+                  // Info nodes don't directly generate a node in translation
+                  addChild clause, tree
+         {ht: 'word', hv: 'USE'}
+            unless next.type is 'word'
+               // Don't understand this construction, ignore the USE
+               held = next
+               continue
+            known := tree._definitions
+            if known and next.value in known
+               role := known[next.value][0]
+               clause := `USE ${next.value}`
+               switch role
+                  'Child'
+                     addChild clause, tree
+                  'Shape'
+                     addShape clause, [], tree
+                  'Transform'
+                     // VRML97 doesn't allow just the transform part of
+                     // a Transform to be USEd (the whole node must be), so
+                     // we have to recreate the transform. FIXME: dedupe code
+                     content := known[next.value][1..]
+                     {children, ...context} := tree
+                     restOfTree := parse stream, context
+                     if remainingKids := restOfTree.children
+                        newChild := `Transform {\n   ${renderList content}\n   `
+                           + `children [\n      ${renderList remainingKids}`
+                           + "] }\n"
+                        addChild newChild, tree
+                     return tree
+                  {}
+                     mergeTree role, tree
+                  else
+                     tree[role] = [clause]
+            else
+               console.error 'USE of unDEFined identifier', next.value
+            held = filtered stream
          {ht: 'word', nt: 'obrace'}
             switch held.value
-               /(?:Transform)?Separator|Group|Switch|WWWAnchor/
-                  parent :=
-                     held.value.endsWith('Separator') ? 'Transform' : 'Group'
+               matches GroupNode
                   {children, ...context} := tree
                   subTree := parse stream, context
                   if newKids := subTree.children
-                     addChild `${parent} { children [
-                        ${renderList newKids} ] }\n`, tree
+                     newChild .= ''
+                     if held.value is 'Switch'
+                        newChild = "Switch {\n  "
+                        if 'whichChoice' in subTree
+                           newChild += `whichChoice ${subTree.whichChoice[0]}\n   `
+                        newChild += `choice [\n     ${renderList newKids} ] }\n`
+                     else newChild =
+                        `Group { children [\n   ${renderList newKids} ] }\n`
+                     addChild newChild, tree
+               matches TransformNode
+                  content := toksUntilClose stream
+                  if (lastDefinition
+                      and tree._definitions?[lastDefinition][0] is 'Transform')
+                     tree._definitions[lastDefinition].push ...content
+                  {children, ...context} := tree
+                  restOfTree := parse stream, context
+                  if remainingKids := restOfTree.children
+                     newChild := `Transform {\n   ${renderList content}\n   `
+                        + `children [\n      ${renderList remainingKids} ] }\n`
+                     addChild newChild, tree
+                  return tree // used the rest of the tree, so done
                'ShapeHints'
                   subTree := parse stream
+                  hints: Tree := {}
                   if 'vertexOrdering' in subTree
-                     tree.ccw = [
-                        subTree.vertexOrdering[0] is 'ccw' ? 'true' : 'false']
+                     hints.ccw = [
+                        subTree.vertexOrdering[0] is 'ccw' ? 'TRUE' : 'FALSE']
                   if 'creaseAngle' in subTree
-                     tree.creaseAngle = subTree.creaseAngle
+                     hints.creaseAngle = subTree.creaseAngle
+                  mergeTree hints, tree
+                  if lastDefinition and tree._definitions
+                     tree._definitions[lastDefinition] = [hints]
+               'PerspectiveCamera'
+                  contents := toksUntilClose stream
+                  hasDescription := contents.find (e) =>
+                     e.type?[0] is 'word' and e.value?[0] is 'description'
+                  if lastDefinition and hasDescription is undefined
+                     contents.push type: ['word'], value: ['description']
+                     contents.push type: ['word'], value: [`"${lastDefinition}"`]
+                  addChild {Viewpoint: contents}, tree
                'Coordinate3'
                   tree.Coordinate = toksUntilClose stream
                'Normal'
@@ -140,7 +307,7 @@ function parse(stream: Lexer, tree: Tree = {}): Tree
                   dims := radius: ''
                   findNumbersAtTopLevel stream, dims
                   addShape 'Sphere', [`radius ${dims.radius}`], tree
-               /IndexedFaceSet|IndexedLineSet|PointSet/
+               matches SetNode
                   isFaces := held.value is 'IndexedFaceSet'
                   contents := translatedToksUntilClose stream
                   params := []
@@ -157,69 +324,34 @@ function parse(stream: Lexer, tree: Tree = {}): Tree
                      params.push `creaseAngle ${tree.creaseAngle[0]}`
                   if isFaces
                      if 'ccw' in tree then params.push `ccw ${tree.ccw[0]}`
-                     else params.push 'solid false'
+                     else params.push 'solid FALSE'
                   params.push ...contents
                   addShape held.value, params, tree
-               /Light$/
+               matches LightNode
                   contents := toksUntilClose stream
                   addChild {[held.value]: contents}, tree
                else
                   parse stream // discard the subgroup
             held = filtered stream
-         {ht: 'word', hv: 'vertexOrdering', nt: 'word', nv: 'COUNTERCLOCKWISE'}
-            tree.vertexOrdering = ['ccw']
-            held = filtered stream
-         {ht: 'word', hv: 'vertexOrdering', nt: 'word', nv: 'CLOCKWISE'}
-            tree.vertexOrdering = ['cw']
+         {ht: 'word', hv: 'vertexOrdering', nt: 'word'}
+            switch next.value
+               'COUNTERCLOCKWISE'
+                  tree.vertexOrdering = ['ccw']
+               'CLOCKWISE'
+                  tree.vertexOrdering = ['cw']
             held = filtered stream
          {ht: 'word', hv: 'creaseAngle', nt: 'number'}
             tree.creaseAngle = [ next.value ]
             held = filtered stream
-         {ht: 'word', nt: 'word', nv: 'Info'}
-            opener := filtered stream
-            if opener and opener.type === 'obrace'
-               contents := toksUntilClose stream
-               switch held.value
-                  'BackgroundColor'
-                     // Find the first string token and assume it is the color
-                     stok := contents.find .type[0] === 'string'
-                     colorString := stok?.value[0]
-                     if colorString and typeof colorString === 'string'
-                        color := colorString.replace /^"|"$/g, ''
-                        addChild `Background {
-                           groundColor [ ${color} ]
-                           skyColor [ ${color} ]
-                        }\n`, tree
-                  'Title'
-                     // Find the first string token and assume it is the title
-                     stok := contents.find .type[0] === 'string'
-                     titleString := stok?.value[0]
-                     if titleString and typeof titleString === 'string'
-                        addWorldParameter 'title', titleString, tree
-                  'SceneInfo'
-                     // Filter all the strings and add them as info
-                     info := contents
-                        |> .filter .type[0] === 'string'
-                        |> .map .value[0]
-                        |> .join ' '
-                     addWorldParameter 'info', `[ ${info} ]`, tree
-                  'Viewer'
-                     // Filter all of the strings, and translate them into
-                     // current viewer names
-                     tr: Record<string, string> := {'"examiner"': '"EXAMINE"'}
-                     viewers := contents
-                        |> .filter .type[0] === 'string'
-                        |> .map .value[0] as string
-                        |> .map((x) => x in tr ? tr[x] : x.toUpperCase())
-                        |> .join ' '
-                     addChild `NavigationInfo { type [ ${viewers} ] }\n`, tree
-               held = filtered stream
-            else held = opener
+         {ht: 'word', hv: 'whichChild'}
+            tree.whichChoice = [ next.value ]
+            held = filtered stream
          else
+            console.error 'Ignoring unparseable token', held
             held = next // ignore unknown words
       if not held or held.type === 'cbrace' then break
    if held and held.type !== 'cbrace'
-      console.log 'Oddly ended up with held', held
+      console.error 'Incomplete parse, symbol at end:', held
    tree
 
 function addShape(nodeType: string, params: (string | Tree)[], tree: Tree): void
@@ -233,9 +365,15 @@ function addShape(nodeType: string, params: (string | Tree)[], tree: Tree): void
          shape.Shape.push "texture ImageTexture {\n",
             ...tree.Texture, " }\n"
       shape.Shape.push " }\n"
-   shape.Shape.push `geometry ${nodeType} {\n`, ...params, " }\n"
+   geometry: (string|Tree)[] := [`geometry ${nodeType}`]
+   if params.length then geometry.push "  {\n", ...params, " }\n"
+   shape.Shape.push ...geometry
    addChild shape, tree
 
+function mergeTree(subtree: Tree, tree: Tree): void
+   for key, value in subtree
+      tree[key] = value
+
 function render(t: string | Tree): string
    if typeof t is 'string' then return t
    if 'children' in t then return renderList t.children