add pie graph shading style

src/main/java/net/pixaurora/janerator/shade/method/PieShading.java

@@ -0,0 +1,51 @@
+package net.pixaurora.janerator.shade.method;
+
+import java.util.List;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+
+import net.minecraft.util.Mth;
+import net.pixaurora.janerator.config.SerialType;
+import net.pixaurora.janerator.graphing.Coordinate;
+
+public class PieShading implements SimpleShadingMethod {
+    public static final Codec<PieShading> CODEC = RecordCodecBuilder.create(
+        instance -> instance.group(
+            Codec.STRING.listOf().fieldOf("generator_keys").forGetter(PieShading::involvedGeneratorKeys)
+        ).apply(instance, PieShading::new)
+    );
+    public static final SerialType<ShadingMethod> TYPE = new SerialType<>("pie", CODEC);
+
+    private final List<String> generatorKeys;
+
+    private final double stepAmount;
+    private final int maxSlice;
+
+    public PieShading(List<String> generatorKeys) {
+        this.generatorKeys = generatorKeys;
+
+        this.stepAmount = 2 * Math.PI / (generatorKeys.size());
+        this.maxSlice = generatorKeys.size() - 1;
+    }
+
+    @Override
+    public SerialType<? extends ShadingMethod> type() {
+        return TYPE;
+    }
+
+    @Override
+    public List<String> involvedGeneratorKeys() {
+        return this.generatorKeys;
+    }
+
+    private int getSlice(Coordinate pos) {
+        int slice = Mth.floor((pos.angle() + Math.PI) / this.stepAmount);
+        return Math.min(slice, maxSlice); // Because there is a straight 1-thick line that is out of bounds otherwise
+    }
+
+	@Override
+	public String getShade(Coordinate pos) {
+		return this.generatorKeys.get(this.getSlice(pos));
+	}
+}

src/main/java/net/pixaurora/janerator/shade/method/ShadingMethod.java

@@ -13,7 +13,7 @@
 import net.pixaurora.janerator.graphing.Coordinate;
 
 public interface ShadingMethod extends SpecifiesType<ShadingMethod> {
-    public static final List<SerialType<ShadingMethod>> TYPES = new ArrayList<>(List.of(NormalShading.TYPE));
+    public static final List<SerialType<ShadingMethod>> TYPES = new ArrayList<>(List.of(NormalShading.TYPE, PieShading.TYPE));
     public static final Codec<ShadingMethod> BASE_CODEC = new SerialType.Group<>("Shading method", TYPES).dispatchCodec();
     public static final Codec<ShadingMethod> CODEC = Codec.either(
         Codec.STRING,