[1.16.4] Change Biome RainType through Reflections Casting error

[than00ber1]

I am trying to change all biome's RainType from RAIN to SNOW.

 

Following this (old but most recent) post, I figured I should use reflections but I am having some trouble cast from Biome.Builder to Biome with this casting error:

 

java.lang.ClassCastException: net.minecraft.world.biome.Biome cannot be cast to net.minecraft.world.biome.Biome$Builder

 

Here is my code:

 

        @SubscribeEvent
        public static void onBiomeRegistry(final RegistryEvent.Register<Biome> event) {
            Set<Map.Entry<RegistryKey<Biome>, Biome>> biomes = event.getRegistry().getEntries();

            for (Map.Entry<RegistryKey<Biome>, Biome> biome : biomes) {
                String name = biome.getValue().getRegistryName().getPath();
                String method = String.format("make%sBiome", CaseFormat.LOWER_UNDERSCORE.to(CaseFormat.UPPER_CAMEL, name));
                System.out.println(method);
                Method builder = null;
                Biome.Builder biome$builder = null;

                try {
                    builder = ObfuscationReflectionHelper.findMethod(BiomeMaker.class, method);
                    biome$builder = (Biome.Builder) builder.invoke(BiomeMaker.class);
                }
                catch (Exception e) {
                    LOGGER.error("Could not get biome builder: %s", e);
                }

                if (builder != null && biome$builder != null) {
                    Biome newBiome = biome$builder.precipitation(Biome.RainType.SNOW).build();
                    event.getRegistry().register(newBiome);
                    LOGGER.info("NEW BIOME " + newBiome.getPrecipitation());
                }
            }
        }

 

[lupicus]

A Biome object and Biome.Builder object can't be cast to the other type.

The easier way to do this is by using the BiomeLoadingEvent, then you can do:

event.getClimate().precipitation = RainType.SNOW;

 

Edited February 23, 2021 by lupicus

[than00ber1]

Alright, I've made some changes to my code and noticed that the precipitation field in the Biome class is final and had to change its modifiers from public final to just public.

 

        private static Field precipitation;

        @SubscribeEvent
        public static void onBiomeLoad(BiomeLoadingEvent event) {
            try {
                precipitation.set(event.getClimate().precipitation, Biome.RainType.SNOW);
            }
            catch (Exception e) {
                LOGGER.error(e);
            }
        }

        static {
            try {
                precipitation = Biome.Climate.class.getDeclaredField("precipitation");
                Field mf = Field.class.getDeclaredField("modifiers");
                mf.setAccessible(true);
                mf.setInt(precipitation, precipitation.getModifiers() & ~Modifier.FINAL);

                System.out.println(precipitation.getModifiers()); // prints 1 -> public

            }
            catch (Exception e) {
                LOGGER.error(e);
            }
        }

 

 However, an IllegalArgumentException is thrown with message:

 

Can not set net.minecraft.world.biome.Biome$RainType field net.minecraft.world.biome.Biome$Climate.precipitation to net.minecraft.world.biome.Biome$RainType

 

I honestly don't understand why this happens. My code seems to make sense (atleast to me)...

 

Any ideas why that is or how to fix this?

[lupicus]

You don't need to use reflection for this.

Sorry my code wasn't good.

Try this:

        Climate climate = event.getClimate();
        event.setClimate(new Climate(RainType.SNOW, climate.temperature, climate.temperatureModifier, climate.downfall));

 

FYI: you will not see snow in higher temperature biomes

Edited February 25, 2021 by lupicus

[than00ber1]

Oh wow that really did the trick. Thanks!