specified conditions for creative fly controls

src/main/java/carpet/mixins/LivingEntity_creativeFlyMixin.java

@@ -0,0 +1,50 @@
+package carpet.mixins;
+
+import carpet.CarpetSettings;
+import net.minecraft.entity.Entity;
+import net.minecraft.entity.EntityType;
+import net.minecraft.entity.LivingEntity;
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.world.World;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Constant;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.ModifyConstant;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+@Mixin(LivingEntity.class)
+public abstract class LivingEntity_creativeFlyMixin extends Entity
+{
+    @Shadow public float flyingSpeed;
+
+    public LivingEntity_creativeFlyMixin(EntityType<?> type, World world)
+    {
+        super(type, world);
+    }
+
+    @ModifyConstant(method = "travel", constant = @Constant(floatValue = 0.91F), expect = 2)
+    private float drag(float original)
+    {
+        if (CarpetSettings.creativeFlyDrag != 0.91D && (Object)this instanceof PlayerEntity)
+        {
+            PlayerEntity self = (PlayerEntity)(Object)(this);
+            if (self.abilities.flying && ! onGround )
+                return (float)CarpetSettings.creativeFlyDrag;
+        }
+        return original;
+    }
+
+
+    @Inject(method = "getMovementSpeed(F)F", at = @At("HEAD"), cancellable = true)
+    private void flyingAltSpeed(float slipperiness, CallbackInfoReturnable<Float> cir)
+    {
+        if (CarpetSettings.creativeFlySpeed != 1.0D && (Object)this instanceof PlayerEntity)
+        {
+            PlayerEntity self = (PlayerEntity)(Object)(this);
+            if (self.abilities.flying && !onGround)
+                cir.setReturnValue(flyingSpeed* (float)CarpetSettings.creativeFlySpeed);
+        }
+    }
+}