Added Vectors and Vector component swizzling

2026-09-05 21:01:52 +00:00 · 2021-02-20 13:38:05 +01:00
parent 64e9cc1613
commit 9ae376f572
6 changed files with 887 additions and 4 deletions
@@ -0,0 +1,88 @@
+using System;
+
+namespace GlitchyEngine.Math
+{
+	/**
+	 * Generates component swizzle operators for a vector.
+	 */
+	[AttributeUsage(.Struct | .Class)]
+	struct SwizzleVectorAttribute : Attribute, IComptimeTypeApply
+	{
+		private int _vectorSize;
+
+		public int VectorSize => _vectorSize;
+
+		this(int vectorSize)
+		{
+			_vectorSize = vectorSize;
+		}
+
+		/**
+		 * Determines whether or not a swizzle operator can have a valid setter (e.g. no component assigned twice)
+		*/
+		static bool invalidSetter(int[4] cmp, int vecSize)
+		{
+			return cmp[0] == cmp[1] || (vecSize >= 3 && cmp[0] == cmp[2]) || (vecSize == 4 && cmp[0] == cmp[3]) ||
+				(vecSize >= 3 && cmp[1] == cmp[2]) || (vecSize == 4 && cmp[1] == cmp[3]) ||
+				(vecSize == 4 && cmp[2] == cmp[3]);
+		}
+
+		[Comptime]
+		public void ApplyToType(Type type)
+		{
+			// TODO: report bug... sized array not working
+			String[] componentNames = scope String[]("X", "Y", "Z", "W");
+
+			for(int swizzleCount = 2; swizzleCount <= 4; swizzleCount++)
+			{
+				int[4] cmp = .();
+
+				int cmp2max = swizzleCount > 2 ? _vectorSize : 1;
+				int cmp3max = swizzleCount > 3 ? _vectorSize : 1;
+
+				for(cmp[0] = 0; cmp[0] < _vectorSize; cmp[0]++)
+				for(cmp[1] = 0; cmp[1] < _vectorSize; cmp[1]++)
+				for(cmp[2] = 0; cmp[2] < cmp2max; cmp[2]++)
+				for(cmp[3] = 0; cmp[3] < cmp3max; cmp[3]++)
+				{
+					String swizzleName = scope String(swizzleCount);
+					String swizzleConstructor = scope String(swizzleCount * 3);
+					String setter = scope String(128);
+
+					bool setterInvalid = invalidSetter(cmp, swizzleCount);
+
+					for(int c = 0; c < swizzleCount; c++)
+					{
+						swizzleName.Append(componentNames[cmp[c]]);
+
+						if(c != 0)
+						{
+							swizzleConstructor.Append(", ");
+						}
+						swizzleConstructor.Append(componentNames[cmp[c]]);
+
+						if(!setterInvalid && c < _vectorSize) //
+						{
+							setter.AppendF($"\n\t\t{componentNames[cmp[c]]} = value.{componentNames[c]};");
+						}
+					}
+
+					//{(setterInvalid ? "[Error(\"Cannot assign multiple values to same component.\")]" : String.Empty)}		
+
+					String swizzleString = scope $"""
+						public Vector{swizzleCount} {swizzleName}
+						{{
+							get => .({swizzleConstructor});
+							set mut
+							{{{setter}
+							}}
+						}}
+
+						""";
+
+					Compiler.EmitTypeBody(type, swizzleString);
+				}
+			}
+		}
+	}
+}