Remove the --smoothstep flag

README.md

@@ -1,6 +1,6 @@
 # Shader Minifier
 
-[![Build status](https://ci.appveyor.com/api/projects/status/chwlpnssgd5kdl4x/branch/master?svg=true)](https://ci.appveyor.com/project/laurentlb/shader-minifier/branch/master)
+[![Build status](https://ci.appveyor.com/api/projects/status/9sekrxuiway58su3?svg=true)](https://ci.appveyor.com/project/laurentlb/shader-minifier-r5gmt)
 
 Shader Minifier is a tool that minifies and obfuscates shader code (GLSL and
 HLSL) without affecting its behaviour. It is also suitable for reducing the size
@@ -100,7 +100,7 @@ USAGE: Shader Minifier [--help] [-o <string>] [-v] [--hlsl]
                        [--preserve-all-globals] [--no-inlining]
                        [--aggressive-inlining] [--no-renaming]
                        [--no-renaming-list <string>] [--no-sequence]
-                       [--smoothstep] [--no-remove-unused]
+                       [--no-remove-unused]
                        [--move-declarations] [<filename>...]
 
 FILENAMES:
@@ -134,7 +134,6 @@ OPTIONS:
     --no-renaming-list <string>
                           Comma-separated list of functions to preserve
     --no-sequence         Do not use the comma operator trick
-    --smoothstep          Use IQ's smoothstep trick
     --no-remove-unused    Do not remove unused code
     --move-declarations   Move declarations to group them
     --preprocess          Evaluate some of the file preprocessor directives
@@ -318,7 +317,6 @@ them all at the same time by listing them all on the command-line.
 - [Unused local variables](TRANSFORMATIONS.md#Unused-local-variables)
 - [Dead code removal](TRANSFORMATIONS.md#Dead-code-removal)
 - [Unused function removal](TRANSFORMATIONS.md#Unused-function-removal)
-- [Smoothstep transformation](TRANSFORMATIONS.md#Smoothstep-transformation)
 - [Renaming](TRANSFORMATIONS.md#Renaming)
 
 

TRANSFORMATIONS.md

@@ -468,17 +468,6 @@ default, this is the case for `main` and `mainImage`.
 **Note**: Use `--no-remove-unused` to disable this transformation.
 
 
-## Smoothstep transformation
-
-`smoothstep(a,b,x)` calls can be replaced with
-`smoothstep(0.0,1.0,(x-a)/(b-a))`. When `a` and `b` are constant, the expression
-will be simplified. In some cases, this might make the code more compressible,
-and this technique was [used in
-Elevated](https://www.pouet.net/topic.php?which=6751&page=1#c295695).
-
-However, in many cases this trick doesn't give good results. As a result, this
-is not enabled by default; use `--smoothstep` if you want to try it.
-
 ## Renaming
 
 There are two renaming strategies:

src/options.fs

@@ -35,7 +35,6 @@ type CliArguments =
     | [<CustomCommandLine("--no-renaming")>] NoRenaming
     | [<CustomCommandLine("--no-renaming-list")>] NoRenamingList of string
     | [<CustomCommandLine("--no-sequence")>] NoSequence
-    | [<CustomCommandLine("--smoothstep")>] Smoothstep
     | [<CustomCommandLine("--no-remove-unused")>] NoRemoveUnused
     | [<CustomCommandLine("--move-declarations")>] MoveDeclarations
     | [<CustomCommandLine("--preprocess")>] Preprocess
@@ -58,7 +57,6 @@ type CliArguments =
             | NoRenaming -> "Do not rename anything"
             | NoRenamingList _ -> "Comma-separated list of functions to preserve"
             | NoSequence -> "Do not use the comma operator trick"
-            | Smoothstep -> "Use IQ's smoothstep trick"
             | NoRemoveUnused -> "Do not remove unused code"
             | MoveDeclarations -> "Move declarations to group them"
             | Preprocess -> "Evaluate some of the file preprocessor directives"
@@ -70,7 +68,6 @@ type Options() =
     member val outputFormat = CVariables with get, set
     member val verbose = false with get, set
     member val debug = false with get, set
-    member val smoothstepTrick = false with get, set
     member val canonicalFieldNames = "xyzw" with get, set
     member val preserveExternals = false with get, set
     member val preserveAllGlobals = false with get, set
@@ -119,7 +116,6 @@ let private initPrivate argv needFiles =
         options.outputFormat <- args.GetResult(FormatArg, defaultValue = CVariables)
         options.verbose <- args.Contains(Verbose)
         options.debug <- args.Contains(Debug)
-        options.smoothstepTrick <- args.Contains(Smoothstep)
         options.canonicalFieldNames <- (sprintf "%A" (args.GetResult(FieldNames, defaultValue = XYZW))).ToLower()
         options.preserveExternals <- args.Contains(PreserveExternals) || args.Contains(PreserveAllGlobals)
         options.preserveAllGlobals <- args.Contains(PreserveAllGlobals)

src/rewriter.fs

@@ -117,8 +117,8 @@ module private RewriterImpl =
 
     // Expression that is equivalent to an assignment.
     let (|Assignment|_|) = function
-        | (FunCall (Op "=", [Var v; e])) -> Some (v, e)
-        | (FunCall (Op op, [Var name; e])) when Builtin.assignOps.Contains op ->
+        | FunCall (Op "=", [Var v; e]) -> Some (v, e)
+        | FunCall (Op op, [Var name; e]) when Builtin.assignOps.Contains op ->
             let baseOp = op.TrimEnd('=')
             if not (Builtin.augmentableOperators.Contains baseOp)
             then None
@@ -336,14 +336,6 @@ module private RewriterImpl =
         | FunCall(Var constr, args) when constr.Name = "vec2" || constr.Name = "vec3" || constr.Name = "vec4" ->
             simplifyVec constr args
 
-        // iq's smoothstep trick: http://www.pouet.net/topic.php?which=6751&page=1#c295695
-        | FunCall(Var var, [Float (0.M,_); Float (1.M,_); _]) as e when var.Name = "smoothstep" -> e
-        | FunCall(Var var, [a; b; x]) when var.Name = "smoothstep" && options.smoothstepTrick ->
-            let sub1 = FunCall(Op "-", [x; a])
-            let sub2 = FunCall(Op "-", [b; a])
-            let div  = FunCall(Op "/", [sub1; sub2]) |> mapExpr env
-            FunCall(Var (Ident "smoothstep"), [Float (0.M,""); Float (1.M,""); div])
-
         | Dot(e, field) when options.canonicalFieldNames <> "" -> Dot(e, renameField field)
 
         | Var s as e ->