src/game/java/net/minecraft/client/model/BannerModel.java

package net.minecraft.client.model;

import net.minecraft.client.model.geom.ModelPart;
import net.minecraft.client.model.geom.PartPose;
import net.minecraft.client.model.geom.builders.CubeListBuilder;
import net.minecraft.client.model.geom.builders.LayerDefinition;
import net.minecraft.client.model.geom.builders.MeshDefinition;
import net.minecraft.client.model.geom.builders.PartDefinition;
import net.minecraft.client.renderer.RenderType;
import net.minecraftforge.api.distmarker.Dist;
import net.minecraftforge.api.distmarker.OnlyIn;

@OnlyIn(Dist.CLIENT)
public class BannerModel extends Model {
    public static final int BANNER_WIDTH = 20;
    public static final int BANNER_HEIGHT = 40;
    public static final String FLAG = "flag";
    private static final String POLE = "pole";
    private static final String BAR = "bar";

    public BannerModel(ModelPart p_376011_) {
        super(p_376011_, RenderType::entitySolid);
    }

    public static LayerDefinition createBodyLayer(boolean p_375508_) {
        MeshDefinition meshdefinition = new MeshDefinition();
        PartDefinition partdefinition = meshdefinition.getRoot();
        if (p_375508_) {
            partdefinition.addOrReplaceChild(
                "pole", CubeListBuilder.create().texOffs(44, 0).addBox(-1.0F, -42.0F, -1.0F, 2.0F, 42.0F, 2.0F), PartPose.ZERO
            );
        }

        partdefinition.addOrReplaceChild(
            "bar",
            CubeListBuilder.create().texOffs(0, 42).addBox(-10.0F, p_375508_ ? -44.0F : -20.5F, p_375508_ ? -1.0F : 9.5F, 20.0F, 2.0F, 2.0F),
            PartPose.ZERO
        );
        return LayerDefinition.create(meshdefinition, 64, 64);
    }
}