9.3 KiB
title = "Crops"
date = "2016-05-29 10:29:00 -0400"
Preparation
Before we get started making our corn crop, we'll need to make a couple of changes to the base item/block infrastructure we've already created. Specifically what we need to change has to do with item models. Currently, BlockBase and ItemBase have their own registerItemModel methods. We're going to move this into the ItemModelProvider interface so that blocks and items we create that don't extend BlockBase or ItemBase can still use our system for registering item models.
Create a new ItemModelProvider interface and add one method to it:
package net.shadowfacts.tutorial.item;
import net.minecraft.item.Item;
public interface ItemModelProvider {
void registerItemModel(Item item);
}
This interface functions exactly the same as the registerItemModel methods in BlockBase and ItemBase.
Next, we'll change BlockBase to implement ItemModelProvider. Just add the implements ItemModelProvider after the class declaration, change the reigsterItemModel method to accept an Item instead of an ItemBlock and add @Override to the registerItemModel method.
We'll repeat a similar process for ItemBase. Add implements ItemModelProvider, change registerItemModel to accept an Item, and add @Override to it.
Now that we've changed our BlockBase and ItemBase classes, we'll need to make some changes to our ModItems and ModBlocks classes to ensure that ItemModelProvider#registerItemModel is called even if the block or item isn't a subclass of our block or item base classes.
In ModBlocks, simply change block instanceof BlockBase to block instanceof ItemModelProvider and change the cast from BlockBase to ItemModelProvider. Do the same for the ModItems class, replacing ItemBase with ItemModelProvider in the appropriate section of the code.
Due to the way we are going to implement our crop, we'll need to make another modification to our ModBlocks class. Before we make this modification, let me explain why it's necessary.
Our crop is going to have 3 important parts:
- The crop block
- The seed item
- The food item
Because we have a separate seed item, the crop block won't have an ItemBlock to go along with it.
In our register(T block, ItemBlock itemBlock) method, we'll need to add a null check to itemBlock so we don't attempt to register itemBlock if it's null.
Lastly, we'll need to make one change in our main TutorialMod class. Due to the way Minecraft's ItemSeed works, our blocks need to be initialized before we can call the constructor of our seed. Simply move the ModItems.init call in TutorialMod.preInit to after the ModBlocks.init call.
Crop
The crop we are going to create will be corn.
As I mentioned before, our crop will be divded into 3 main parts:
- The crop block (corn crop)
- The seed item (corn seed)
- The food item (corn)
We're going to create these one at a time. At the intermediate stages, our code will contain errors because we are referencing things we haven't created yet, but everything should be fine at the end.
Corn Crop
Let's create a class called BlockCropCorn that extends Minecraft's BlockCrops. The crop block won't have an ItemBlock so this class won't implement ItemModelProvider and it is why we need that null check in ModBlocks.register.
In this class, we'll need to override 2 methods to return our own items instead of the vanilla ones. getSeed should return ModItems.cornSeed and getCrop should return ModItems.corn.
package net.shadowfacts.tutorial.block;
import net.minecraft.block.BlockCrops;
import net.minecraft.item.Item;
import net.shadowfacts.tutorial.item.ModItems;
public class BlockCropCorn extends BlockCrops {
public BlockCropCorn() {
setUnlocalizedName("crop_corn");
setRegistryName("crop_corn");
}
@Override
protected Item getSeed() {
return ModItems.cornSeed;
}
@Override
protected Item getCrop() {
return ModItems.corn;
}
}
Minecraft will use the seed and crop we specified to determine what to drop when our crop block is broken. Let's register our block in the ModBlocks class:
// ...
public static BlockCropCorn cropCorn;
public static init() {
// ...
cropCorn = register(new BlockCropCorn(), null);
}
// ...
The last thing we'll need to do is create a model. Download the textures from here and save them into src/main/resources/assets/tutorial/textures/blocks/corn/ and have there filenames the 0.png through 7.png.
Let's create a blockstate for our crop. Create src/main/resources/assets/tutorial/blockstates/crop_corn.json. We're once again going to be using the Forge blockstates format because this is a fairly complicated blockstate.
{
"forge_marker": 1,
"defaults": {
"model": "cross"
},
"variants": {
"age": {
"0": {
"textures": {
"cross": "tutorial:blocks/corn/0"
}
},
"1": {
"textures": {
"cross": "tutorial:blocks/corn/1"
}
},
"2": {
"textures": {
"cross": "tutorial:blocks/corn/2"
}
},
"3": {
"textures": {
"cross": "tutorial:blocks/corn/3"
}
},
"4": {
"textures": {
"cross": "tutorial:blocks/corn/4"
}
},
"5": {
"textures": {
"cross": "tutorial:blocks/corn/5"
}
},
"6": {
"textures": {
"cross": "tutorial:blocks/corn/6"
}
},
"7": {
"textures": {
"cross": "tutorial:blocks/corn/7"
}
}
}
}
}
The model specified in the defaults section is Minecraft's cross model which is just the same texture rendered twice. You can see what this model looks like by looking at the various flowers in vanilla.
The age property is the age of the crop. All the objects inside the age object are for one value of the property. In our case, age can have a value 0 through 7 so we'll need separate JSON objects for each of those. For each value of age, we'll have a different texture that is specified in the textures object with the name cross.
Corn Seed
Now let's make our corn seed item. Create a new class called ItemCornSeed that extends ItemSeeds and implements ItemModelProvider.
In our constructor, we'll need to pass a couple of things to the ItemSeeds constructor, ModBlocks.cropCorn and Blocks.FARMLAND. The first parameter of the ItemSeeds constructor is the crop block and the second is the soil block. Since we implemented ItemModelProvider, we'll need to provide an implementation for registerItemModel which will just use our registerItemRenderer proxy method.
package net.shadowfacts.tutorial.item;
import net.minecraft.init.Blocks;
import net.minecraft.item.Item;
import net.minecraft.item.ItemSeeds;
import net.shadowfacts.tutorial.TutorialMod;
import net.shadowfacts.tutorial.block.ModBlocks;
public class ItemCornSeed extends ItemSeeds implements ItemModelProvider {
public ItemCornSeed() {
super(ModBlocks.cropCorn, Blocks.FARMLAND);
setUnlocalizedName("corn_seed");
setRegistryName("corn_seed");
}
@Override
public void registerItemModel(Item item) {
TutorialMod.proxy.registerItemRenderer(item, 0, "corn_seed");
}
}
Let's register our corn seed in ModItems.
// ...
public static ItemCornSeed cornSeed;
public static void init() {
// ...
cornSeed = register(new ItemCornSeed());
}
// ...
Lastly, we'll create a simple JSON model for the corn seed. First you'll want to download the texture from here and save it to src/main/resources/assets/tutorial/textures/items/cornSeed.png. Now create a JSON file in the models/item folder called cornSeed.json. This model with be fairly similar to our copper ingot model, it will just have a parent of item/generated and a layer 0 texture of tutorial:items/corn_seed.
{
"parent": "item/generated",
"textures": {
"layer0": "tutorial:items/corn_seed"
}
}
Corn Item
For now, our corn item is going to be a simple instance of our ItemBase class which means you won't be able to eat it (yet!). Let's add our corn item to our ModItems class.
// ...
public static ItemBase corn;
public static void init() {
// ...
corn = register(new ItemBase("corn").setCreativeTab(CreativeTabs.FOOD));
}
// ...
Now let's also make a simple model for our corn item. Download the texture from here and save it as corn.png in the textures/items folder. Now let's create a corn.json file for our model. This model will also be very simple, with a parent of item/generated and a layer 0 texture of tutorial:items/corn.
{
"parent": "item/generated",
"textures": {
"layer0": "tutorial:items/corn"
}
}
Localization
Now let's quickly add localization for new items:
# ...
item.corn.name=Corn
item.corn_seed.name=Corn Seed
# ...
Finished
Now, you should be able to launch game from inside the IDE and see our corn seed in the materials creative tab, plant it, grow it with bone meal, and break it to get corn and more seeds.
