java - 如何用java记录Minecraft玩家的视线位置

Question

我知道这个标题很令人困惑。我正在用java制作一个我的世界模组。我制作了一个元素，当你右键单击时，它会爆炸并产生闪电。目前，它会在玩家所在位置爆炸并产生闪电。我怎样才能让它在玩家看到的位置爆炸？我的元素类别目前如下所示:

package com.mod.elliotmod;

import net.minecraft.creativetab.CreativeTabs;
import net.minecraft.entity.effect.EntityLightningBolt;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.world.World;
import net.minecraftforge.fml.common.registry.GameRegistry;

public class ItemMyTNT extends Item {

    public ItemMyTNT(String name, int stackSize) {
        GameRegistry.registerItem(this, name);
        setUnlocalizedName(ElliotMod.MODID + "_" + name);
        setCreativeTab(CreativeTabs.tabMisc);
        setMaxStackSize(stackSize);
    }

    public ItemStack onItemRightClick(ItemStack item, World world, EntityPlayer player) {

        world.spawnEntityInWorld(new EntityLightningBolt(world, player.posX, player.posY, player.posZ));
        world.createExplosion(player, player.posX, player.posY, player.posZ, 5.0F, true);

        return item;
    }
}

编辑:这是我现在拥有的:

package com.mod.elliotmod;

import net.minecraft.creativetab.CreativeTabs;
import net.minecraft.entity.effect.EntityLightningBolt;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.world.World;
import net.minecraftforge.fml.common.registry.GameRegistry;

public class ItemMyTNT extends Item {

    public ItemMyTNT(String name, int stackSize) {
        GameRegistry.registerItem(this, name);
        setUnlocalizedName(ElliotMod.MODID + "_" + name);
        setCreativeTab(CreativeTabs.tabMisc);
        setMaxStackSize(stackSize);
    }

    public ItemStack onItemRightClick(ItemStack item, World world, EntityPlayer player) {

        double x = player.getLookVec().xCoord;
        double y = player.getLookVec().yCoord;
        double z = player.getLookVec().zCoord; 

        world.spawnEntityInWorld(new EntityLightningBolt(world, x, y, z));
        world.createExplosion(player, x, y, z, 5.0F, true);

        return item;
    }
}

我在实体播放器类中找到了这个。可能会有所帮助

        Vec3 vec3 = new Vec3(((double)this.rand.nextFloat() - 0.5D) * 0.1D, Math.random() * 0.1D + 0.1D, 0.0D);
        vec3 = vec3.rotatePitch(-this.rotationPitch * (float)Math.PI / 180.0F);
        vec3 = vec3.rotateYaw(-this.rotationYaw * (float)Math.PI / 180.0F);
        double d0 = (double)(-this.rand.nextFloat()) * 0.6D - 0.3D;
        Vec3 vec31 = new Vec3(((double)this.rand.nextFloat() - 0.5D) * 0.3D, d0, 0.6D);
        vec31 = vec31.rotatePitch(-this.rotationPitch * (float)Math.PI / 180.0F);
        vec31 = vec31.rotateYaw(-this.rotationYaw * (float)Math.PI / 180.0F);
        vec31 = vec31.addVector(this.posX, this.posY + (double)this.getEyeHeight(), this.posZ);

我使用了这个类，我的代码看起来像这样，但不起作用:

public ItemStack onItemRightClick(ItemStack item, World world, EntityPlayer player) {
         Random rand = new Random();
         Vec3 vec3 = new Vec3(((double)rand.nextFloat() - 0.5D) * 0.1D, Math.random() * 0.1D + 0.1D, 0.0D);
         vec3 = vec3.rotatePitch(-player.rotationPitch * (float)Math.PI / 180.0F);
         vec3 = vec3.rotateYaw(-player.rotationYaw * (float)Math.PI / 180.0F);
         double d0 = (double)(rand.nextFloat()) * 0.6D - 0.3D;
         Vec3 vec31 = new Vec3(((double)rand.nextFloat() - 0.5D) * 0.3D, d0, 0.6D);
         vec31 = vec31.rotatePitch(-player.rotationPitch * (float)Math.PI / 180.0F);
         vec31 = vec31.rotateYaw(-player.rotationYaw * (float)Math.PI / 180.0F);
         vec31 = vec31.addVector(player.posX, player.posY + (double)player.getEyeHeight(), player.posZ);

        MovingObjectPosition movingobjectposition = world.rayTraceBlocks(vec3, vec31, false, true, false);
        if (movingobjectposition == null) {
            //nothing was under the player's gaze
            return item;
        }
        if (movingobjectposition.typeOfHit == MovingObjectPosition.MovingObjectType.BLOCK) {
            int ix = movingobjectposition.getBlockPos().getX();
            int iy = movingobjectposition.getBlockPos().getY();
            int iz = movingobjectposition.getBlockPos().getZ();
            if (!world.isBlockNormalCube(movingobjectposition.getBlockPos(), true)) {
                --iy;
            }
            world.spawnEntityInWorld(new EntityLightningBolt(world, ix, iy, iz));
        }
        if (movingobjectposition.typeOfHit == MovingObjectPosition.MovingObjectType.ENTITY) {
            double ix = movingobjectposition.hitVec.xCoord;
            double iy = movingobjectposition.hitVec.yCoord;
            double iz = movingobjectposition.hitVec.zCoord;
            world.spawnEntityInWorld(new EntityLightningBolt(world, ix, iy, iz));
        }

        return item;


    }

Answer 1

因此，您的第一次尝试(使用玩家的位置)只正确了一半，但没有到达玩家正在寻找的地方。

您正确地确定需要使用播放器的 LookVec 但是您没有正确实现它。实体的 LookVec 是一个标准化 vector ，它不是一个位置。

所以你的第二次尝试仍然只正确了一半(并且在 (0,0,0) 的 1 block 内产生闪电。

因此，要纠正错误，您需要将这两个值相加:

public ItemStack onItemRightClick(ItemStack item, World world, EntityPlayer player) {

    double x = player.posX + player.getLookVec().xCoord;
    double y = player.posY + player.getLookVec().yCoord;
    double z = player.posZ + player.getLookVec().zCoord; 

    world.spawnEntityInWorld(new EntityLightningBolt(world, x, y, z));
    world.createExplosion(player, x, y, z, 5.0F, true);

    return item;
}

但这仍然只是部分正确，因为它没有获得玩家正在查看的 block :它在玩家的脸前面创建了闪电 1 block (好吧，实际上是他们的脚，我们没有添加玩家的眼睛高度)。

唯一的方法就是进行一些光线追踪。

注释:

• world.rayTraceBlocks_do_do 的名称可能会有所不同，具体取决于您的 Forge 版本。我从 old project 中提取了这段代码并且需要一些按摩。

• vec3:玩家眼睛位置的 vector

• vec31:玩家的注视方向(按照上面的示例)

  MovingObjectPosition movingobjectposition = world.rayTraceBlocks_do_do(vec3, vec31, false, true, false);
  if (movingobjectposition == null) {
      //nothing was under the player's gaze
      return item;
  }
  if (movingobjectposition.typeOfHit == MovingObjectPosition.MovingObjectType.BLOCK) {
      int ix = movingobjectposition.blockX;
      int iy = movingobjectposition.blockY;
      int iz = movingobjectposition.blockZ;
      if (!world.getBlock(ix, iy, iz).isNormalCube()) {
          --iy;
      }
      //spawn lightning (ix, iy, iz)
  }
  if (movingobjectposition.typeOfHit == MovingObjectPosition.MovingObjectType.ENTITY) {
      double ix = movingobjectposition.hitVec.xCoord;
      double iy = movingobjectposition.hitVec.yCoord;
      double iz = movingobjectposition.hitVec.zCoord;
      //spawn lightning (ix, iy, iz)
  }