Fix: Not safe to remove vector constructor if argument doesn't fully-define the type.

E.g.
Good: vec2(v.xy)
Bad: vec2(v.x)

Author: DeanEdisGG

README.md

@@ -2,6 +2,8 @@
 ## What Is It For?
 GLSL Shader Shrinker is a Windows GUI tool that attempts to reduce the size of GLSL fragment shader code, whilst keeping it _readable_ and understandable.
 
+It is written in C# using WPF and Visual Studio 2019, and has several hundred NUnit-powered unit tests.
+
 ![Main UI](img/ED209.png?raw=true "Main UI")
 
 It is designed to work primarily with code from [Shadertoy](https://www.shadertoy.com/), but has limited support for other styles of GLSL too (E.g. [Bonzomatic](https://github.com/Gargaj/Bonzomatic))

ShaderShrinker/Shrinker.Parser/Optimizations/SimplifyVectorConstructorsExtension.cs

@@ -88,6 +88,9 @@ public static void RemoveUnnecessaryVectorConstructors(this SyntaxNode rootNode)
                             continue; // Can't find what type of 'vec' we have, or different types.
                     }
 
+                    if (lhsRhs.Length >= 2 && lhsRhs[1].Length != vectorLength)
+                        continue; // RHS does not define the entire vector.
+
                     // They match - Remove the surrounding vecN keyword.
                     brackets.Remove();
                     vectorNode.ReplaceWith(vecParam);

ShaderShrinker/Shrinker.WpfApp/Properties/AssemblyInfo.cs

@@ -49,5 +49,5 @@
 // You can specify all the values or you can default the Build and Revision Numbers
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion("0.1.0.0")]
-[assembly: AssemblyFileVersion("0.1.0.0")]
+[assembly: AssemblyVersion("0.2.0.0")]
+[assembly: AssemblyFileVersion("0.2.0.0")]

ShaderShrinker/UnitTests/ShrinkerTests.cs

@@ -1085,6 +1085,7 @@ public void CheckSimplifyingVec4ConstructionFromVecComponents(
                     "vec2 ab; vec4 v = vec4(ab, ab.x, ab.y);",
                     "vec2 ab; vec4 v = vec4(ab, .1, .2);",
                     "vec3 ab; vec2 v = vec2(ab.x, ab.z);",
+                    "vec3 ab; vec2 v = vec2(ab.x);",
                     "struct S{ float A, B, C; }; S s; vec3 v = vec3(s.A, s.B, s.C);")] string code,
             [Values("vec3 ab; vec4 v = vec4(ab, 1);",
                     "vec3 ab; vec4 v = vec4(1, ab);",
@@ -1096,6 +1097,7 @@ public void CheckSimplifyingVec4ConstructionFromVecComponents(
                     "vec2 ab; vec4 v = vec4(ab, ab);",
                     "vec2 ab; vec4 v = vec4(ab, .1, .2);",
                     "vec3 ab; vec2 v = ab.xz;",
+                    "vec3 ab; vec2 v = vec2(ab.x);",
                     "struct S { float A, B, C; }; S s; vec3 v = vec3(s.A, s.B, s.C);")] string expected)
         {
             var lexer = new Lexer();