Structs: allow field names that look like vec4 fields in some cases

src/parse.fs

@@ -159,15 +159,7 @@ type private ParseImpl() =
 
     // A type block, like struct or interface blocks
     let blockSpecifier prefix =
-
-        // Restriction on field names
-        let check ((_,l) as arg : Ast.Decl) =
-            for decl in l do
-                if decl.name.Name <> Rewriter.renameField decl.name.Name then
-                    failwithf "Record field name '%s' is not allowed by Shader Minifier,\nbecause it looks like a vec4 field name." decl.name.Name
-            arg
-
-        let decls = many (declaration .>> ch ';' |>> check)
+        let decls = many (declaration .>> ch ';')
         let name = opt ident
         pipe2 name (between (ch '{') (ch '}') decls)
             (fun n d ->

src/renamer.fs

@@ -4,6 +4,11 @@ open System.Collections.Generic
 open Ast
 open Options.Globals
 
+let renameField field =
+    if Builtin.isFieldSwizzle field then
+        field |> String.map (fun c -> options.canonicalFieldNames.[Builtin.swizzleIndex c])
+    else field
+
 module private RenamerImpl =
 
     // Environment for renamer
@@ -328,10 +333,24 @@ module private RenamerImpl =
             renList env renCase cl |> ignore<Env>
             env
 
+    let renStructElts (decls: Decl list) =
+        let allFields = Dictionary<string, string>()
+        for _, elts in decls do
+            for elt in elts do
+                let newName = renameField elt.name.Name
+                match allFields.TryGetValue(newName) with
+                | true, conflict ->
+                    failwithf "Field '%s' will conflict with field '%s' after renaming: both will be named '%s'" elt.name.Name conflict newName
+                | _ ->
+                    allFields.[newName] <- elt.name.Name
+                    elt.name.Rename(newName)
+
     // e.g. struct foo { int a; float b; }
     //   or uniform foo { int a; float b; }
     let renTyBlock (env: Env) = function
-        | TypeBlock("struct", _, _) -> env
+        | TypeBlock("struct", _, fields) ->
+            renStructElts fields
+            env
         | TypeBlock(_, _, fields) ->
             // treat the fields as if they were global variables
             renList env (renDecl Level.TopLevel) fields

src/rewriter.fs

@@ -6,11 +6,6 @@ open Builtin
 open Ast
 open Options.Globals
 
-let renameField field =
-    if isFieldSwizzle field then
-        field |> String.map (fun c -> options.canonicalFieldNames.[swizzleIndex c])
-    else field
-
 let private commaSeparatedExprs = List.reduce (fun a b -> FunCall(Op ",", [a; b]))
 
 let rec private sideEffects = function
@@ -336,7 +331,7 @@ module private RewriterImpl =
         | FunCall(Var constr, args) when constr.Name = "vec2" || constr.Name = "vec3" || constr.Name = "vec4" ->
             simplifyVec constr args
 
-        | Dot(e, field) when options.canonicalFieldNames <> "" -> Dot(e, renameField field)
+        | Dot(e, field) when options.canonicalFieldNames <> "" -> Dot(e, Renamer.renameField field)
 
         | Var s as e ->
             match env.vars.TryFind s.Name with

tests/commands.txt

@@ -33,6 +33,7 @@
 --no-remove-unused --format indented -o tests/unit/interface_block.frag.expected tests/unit/interface_block.frag
 --no-remove-unused --no-renaming --format indented -o tests/unit/ternary.frag.expected tests/unit/ternary.frag
 --no-remove-unused --no-renaming --format indented -o tests/unit/reuse-var.frag.expected tests/unit/reuse-var.frag
+--no-remove-unused --format indented -o tests/unit/struct.frag.expected tests/unit/struct.frag
 
 # Unused removal tests
 

tests/unit/struct.frag

@@ -0,0 +1,14 @@
+struct Foo {
+  int field1;
+  int field2;
+  int ab;
+  int st;
+};
+
+void main() {
+  Foo f;
+  f.field1 = 1;
+  f.field2 = 2;
+  f.ab = 3;
+  f.st = 4;
+}

tests/unit/struct.frag.expected

@@ -0,0 +1,9 @@
+struct Foo{int field1;int field2;int wz;int xy;};
+void main()
+{
+  Foo i;
+  i.field1=1;
+  i.field2=2;
+  i.wz=3;
+  i.xy=4;
+}