Feature: Consecutive assignments of the same vector component can now be combined.

E.g.
vec2 v;
v.x = 1.0;
v.x = v.x + 1.0;
...changes to...
vec2 v;
v.x = 1.0 + 1.0;

Author: DeanEdisGG

ShaderShrinker/Shrinker.Parser/Optimizations/CombineConsecutiveAssignmentsExtension.cs

@@ -33,18 +33,23 @@ public static void CombineConsecutiveAssignments(this SyntaxNode rootNode)
                             // Find consecutive assignment of same variable.
                             var assignment = braces.Children.OfType<VariableAssignmentSyntaxNode>()
                                 .Where(o => o.HasValue && o.Parent is not VariableDeclarationSyntaxNode)
-                                .Where(o => o.Next is VariableAssignmentSyntaxNode)
-                                .Where(o => o.Name == localVariable.Name &&
-                                            o.Next is VariableAssignmentSyntaxNode ass2 &&
-                                            ass2.Name == localVariable.Name &&
-                                            o.FullName == ass2.FullName)
+                                .Where(o => o.Name.StartsWith(localVariable.Name) &&
+                                            o.FullName == (o.Next as VariableAssignmentSyntaxNode)?.FullName)
                                 .FirstOrDefault(o => o.Next.TheTree.OfType<GenericSyntaxNode>().Count(n => n.StartsWithVarName(localVariable.Name)) == 1);
 
                             if (assignment == null)
                                 continue;
 
+                            // If assigning to a component of the variable (E.g. v.x or v[1]), there must be no other references to
+                            // the variable in the second assignment.
+                            if (assignment.FullName.IndexOfAny(new[] { '.', '[' }) > 0)
+                            {
+                                if (((VariableAssignmentSyntaxNode)assignment.Next).TheTree.Any(o => o.HasNodeContent(localVariable.Name)))
+                                    continue;
+                            }
+
                             // Inline the definition (adding (...) if necessary).
-                            var usage = assignment.Next.TheTree.OfType<GenericSyntaxNode>().Single(o => o.IsVarName(localVariable.Name));
+                            var usage = assignment.Next.TheTree.OfType<GenericSyntaxNode>().Single(o => o.HasNodeContent(assignment.FullName));
                             var addBrackets = assignment.Children.Any(o => o.Token is SymbolOperatorToken);
                             if (addBrackets)
                                 usage.ReplaceWith(new RoundBracketSyntaxNode(assignment.Children));

ShaderShrinker/UnitTests/ShrinkerTests.cs

@@ -1106,6 +1106,55 @@ public void CheckCombiningAssignmentsRecognizesArrayAccessors()
             Assert.That(rootNode.ToCode().ToSimple(), Is.EqualTo(Code));
         }
 
+        [Test]
+        public void CheckCombiningAssignmentsRecognizesCommonVectorAccessors()
+        {
+            var lexer = new Lexer();
+            lexer.Load("void main() { vec2 v; v.x = 1.0; v.x = v.x + 1.0; }");
+
+            var options = CustomOptions.None();
+            options.CombineConsecutiveAssignments = true;
+            var rootNode = new Parser(lexer)
+                .Parse()
+                .Simplify(options);
+
+            Assert.That(rootNode.ToCode().ToSimple(), Is.EqualTo("void main() { vec2 v; v.x = 1.0 + 1.0; }"));
+        }
+
+        [Test]
+        public void CheckCombiningAssignmentsIgnoresCommonVectorAccessorsIfWholeVariableIsUsed()
+        {
+            const string Code = "void main() { vec2 v; v.x = 1.0; v.x = v.x + 1.0 + f(v); }";
+
+            var lexer = new Lexer();
+            lexer.Load(Code);
+
+            var options = CustomOptions.None();
+            options.CombineConsecutiveAssignments = true;
+            var rootNode = new Parser(lexer)
+                .Parse()
+                .Simplify(options);
+
+            Assert.That(rootNode.ToCode().ToSimple(), Is.EqualTo(Code));
+        }
+
+        [Test]
+        public void CheckCombiningAssignmentsIgnoresDifferentVectorAccessors()
+        {
+            const string Code = "void main() { vec2 v; v.x = 1.0; v.y = v.x + 1.0; }";
+
+            var lexer = new Lexer();
+            lexer.Load(Code);
+
+            var options = CustomOptions.None();
+            options.CombineConsecutiveAssignments = true;
+            var rootNode = new Parser(lexer)
+                .Parse()
+                .Simplify(options);
+
+            Assert.That(rootNode.ToCode().ToSimple(), Is.EqualTo(Code));
+        }
+
         [Test, Sequential]
         public void GivenVectorReferencingAllComponentsCheckSimplifyingToJustVariableName(
             [Values("vec4 a = vec4(1, 2, 3, 4), b = a.rgba;",

ShaderShrinker/UnitTests/TestFiles/SimplifiedReference/ED209.glsl

@@ -1,4 +1,4 @@
-// Processed by 'GLSL Shader Shrinker' (Shrunk by 904 characters)
+// Processed by 'GLSL Shader Shrinker' (Shrunk by 946 characters)
 // (https://github.com/deanthecoder/GLSLShaderShrinker)
 
 float stretch, gunsUp, gunsForward, edWalk, edTwist, edDown, edShoot, doorOpen, glow;
@@ -94,8 +94,7 @@ float headSphere(vec3 p) { return (length(p / vec3(1, .8, 1)) - 1.) * .8; }
 MarchData headVisor(vec3 p, float h, float bump) {
 	bump *= sin(p.x * 150.) * sin(p.y * 150.) * .002;
 	MarchData result;
-	result.d = sdBox(p, vec3(1, h, 2));
-	result.d = max(mix(result.d, headSphere(p), .57), -p.y) - bump;
+	result.d = max(mix(sdBox(p, vec3(1, h, 2)), headSphere(p), .57), -p.y) - bump;
 	result.mat = vec3(.05);
 	result.specPower = 30.;
 	return result;
@@ -126,8 +125,7 @@ MarchData gunPod(vec3 p) {
 	p.yz += vec2(.1, .45);
 	vec3 pp = p;
 	pp.z = abs(pp.z) - .5;
-	r.d = sdCappedCone(pp, vec3(0), vec3(0, 0, -.1), .35 - .1, .35);
-	r.d = min(r.d, sdCappedCylinder(p, .35, .4));
+	r.d = min(sdCappedCone(pp, vec3(0), vec3(0, 0, -.1), .35 - .1, .35), sdCappedCylinder(p, .35, .4));
 	pp = vec3(p.x, .28 - p.y, p.z);
 	r.d = min(r.d, sdTriPrism(pp, vec2(.1, .5)));
 	pp = p;
@@ -205,8 +203,7 @@ MarchData waist(vec3 p) {
 	pp.x = abs(pp.x);
 	pp.yz *= rot(-.58525 + legAngle * sign(p.x));
 	pp.x -= .98;
-	r.d = min(r.d, max(sdCappedCylinder(pp.zyx, .4, .24), -pp.y));
-	r.d = min(r.d, sdBox(pp, vec3(.24, .2, .14 + .2 * pp.y)));
+	r.d = min(min(r.d, max(sdCappedCylinder(pp.zyx, .4, .24), -pp.y)), sdBox(pp, vec3(.24, .2, .14 + .2 * pp.y)));
 	p = pp;
 	pp.xz = abs(pp.xz) - vec2(.12, .25);
 	r.d = min(r.d, max(min(sdCappedCylinder(pp.xzy, .1, .325), sdCappedCylinder(pp.xzy, .05, .5)), pp.y));
@@ -246,8 +243,7 @@ MarchData legs(vec3 p) {
 	cp -= vec3(0, -.7, 0);
 	r.d = sdBox(cp - vec3(0, 0, 1.15), vec3(.17, .17, .07)) - .04;
 	cp.z++;
-	r.d = min(r.d, sdChamferedCube(cp.xzy, vec2(.28 - sign(abs(cp.z) - .3) * .01, .5).xyx, .18));
-	r.d = min(r.d, foot(cp));
+	r.d = min(min(r.d, sdChamferedCube(cp.xzy, vec2(.28 - sign(abs(cp.z) - .3) * .01, .5).xyx, .18)), foot(cp));
 	if (silver < r.d) {
 		r.d = silver;
 		r.mat = vec3(.8);