Do a bit of cleanup

src/main/java/com/minelittlepony/unicopia/client/render/PlayerPoser.java

@@ -23,7 +23,10 @@ import net.minecraft.util.math.Vec3f;
 public class PlayerPoser {
     public static final PlayerPoser INSTANCE = new PlayerPoser();
 
-    public void applyPosing(MatrixStack matrices, PlayerEntity player, BipedEntityModel<?> model) {
+    private static final float HEAD_NOD_DURATION = 15F;
+    private static final float HEAD_NOD_GAP = HEAD_NOD_DURATION / 3F;
+
+    public void applyPosing(MatrixStack matrices, PlayerEntity player, BipedEntityModel<?> model, Context context) {
         Pony pony = Pony.of(player);
         float progress = pony.getAnimationProgress(MinecraftClient.getInstance().getTickDelta());
         Animation animation = pony.getAnimation();
@@ -34,34 +37,25 @@ public class PlayerPoser {
         ModelPart head = model.getHead();
 
         if (glasses.hasCustomName() && "Cool Shades".equals(glasses.getName().getString())) {
-
+            final float bop = AnimationUtil.beat(player.age, HEAD_NOD_DURATION, HEAD_NOD_GAP) * 3F;
-            float duration = 15F;
-            float gap = duration / 3F;
-
-            float prog = (player.age % duration);
-            if (prog <= gap) {
-                prog = 0;
-            } else if (prog > (duration - gap)) {
-                prog = 1;
-            } else {
-                prog = (prog - gap) / (duration - 2 * gap);
-            }
-            prog *= Math.PI;
-
-            float bop = (float)Math.sin(prog) * 3F;
             head.pitch += bop / 10F;
 
-            if (isPony) {
+            float beat30 = bop / 30F;
-                model.leftArm.roll -= bop / 50F;
-                model.rightArm.roll += bop / 50F;
 
-                model.leftLeg.roll -= bop / 30F;
+            if (isPony) {
-                model.leftLeg.pitch -= bop / 20F;
+                float beat50 = bop / 50F;
-                model.rightLeg.roll += bop / 30F;
+                float beat20 = bop / 20F;
-                model.rightLeg.pitch += bop / 20F;
+
+                model.leftArm.roll -= beat50;
+                model.rightArm.roll += beat50;
+
+                model.leftLeg.roll -= beat30;
+                model.leftLeg.pitch -= beat20;
+                model.rightLeg.roll += beat30;
+                model.rightLeg.pitch += beat20;
             } else {
-                model.leftArm.roll -= bop / 30F;
+                model.leftArm.roll -= beat30;
-                model.rightArm.roll += bop / 30F;
+                model.rightArm.roll += beat30;
             }
         }
 
@@ -251,4 +245,10 @@ public class PlayerPoser {
             return sound;
         }
     }
+
+    public enum Context {
+        FIRST_PERSON_LEFT,
+        FIRST_PERSON_RIGHT,
+        THIRD_PERSON
+    }
 }

src/main/java/com/minelittlepony/unicopia/mixin/client/MixinLivingEntityRenderer.java

@@ -37,7 +37,7 @@ abstract class MixinLivingEntityRenderer<T extends LivingEntity, M extends Entit
             int light,
             CallbackInfo into) {
         if (entity instanceof PlayerEntity player) {
-            PlayerPoser.INSTANCE.applyPosing(matrices, player, (BipedEntityModel<?>)getModel());
+            PlayerPoser.INSTANCE.applyPosing(matrices, player, (BipedEntityModel<?>)getModel(), PlayerPoser.Context.THIRD_PERSON);
         }
         if (entity instanceof MobEntity mob) {
             AnimalPoser.INSTANCE.applyPosing(matrices, mob, getModel());

src/main/java/com/minelittlepony/unicopia/mixin/client/MixinPlayerEntityRenderer.java

@@ -51,6 +51,6 @@ abstract class MixinPlayerEntityRenderer extends LivingEntityRenderer<AbstractCl
                 target = "Lnet/minecraft/client/render/entity/model/PlayerEntityModel;setAngles(Lnet/minecraft/entity/LivingEntity;FFFFF)V",
                 shift = Shift.AFTER))
     private void onPoseArm(MatrixStack matrices, VertexConsumerProvider vertexConsumers, int light, AbstractClientPlayerEntity player, ModelPart arm, ModelPart sleeve, CallbackInfo info) {
-        PlayerPoser.INSTANCE.applyPosing(matrices, player, getModel());
+        PlayerPoser.INSTANCE.applyPosing(matrices, player, getModel(), arm == getModel().leftArm ? PlayerPoser.Context.FIRST_PERSON_LEFT : PlayerPoser.Context.FIRST_PERSON_RIGHT);
     }
 }

src/main/java/com/minelittlepony/unicopia/util/AnimationUtil.java

@@ -16,4 +16,17 @@ public interface AnimationUtil {
     static float seeSitSaw(float progress, float clipRatio) {
         return Math.min(1, seesaw(progress) * clipRatio);
     }
+
+    /**
+     * Generates a beat at regular intervals
+     */
+    static float beat(float progress, float duration, float gap) {
+        progress %= duration;
+
+        if (progress <= gap || progress > (duration - gap)) {
+            return 0;
+        }
+
+        return (float)Math.sin(((progress - gap) / (duration - 2 * gap)) * Math.PI);
+    }
 }