Introduction
In the expansive and endlessly customizable world of Minecraft, modding offers an unparalleled opportunity to tailor the game to your specific visions. Imagine the possibilities: custom tools that interact uniquely with targeted blocks, spells that affect only the block a player is focusing on, or even advanced mechanics that rely on precisely knowing what a user is looking at. Getting the block a player is looking at within the Minecraft world is crucial for achieving such immersive and interactive modding goals.
Specifically, this guide targets Minecraft Forge version one point seven point two. This version, while not the most recent, remains a favorite among many modders due to its stability, well-documented APIs, and the sheer volume of existing mods built for it. If you’re embarking on a project with this particular version, or perhaps looking to update an older mod, then understanding how to accurately determine the targeted block is absolutely essential. You may also be aiming to revisit and enhance an old project, around version one point seven point two, and need a simple, effective solution. This article aims to provide that solution. This simple mechanism can be a cornerstone of how the mod works.
The Problem: Targeting the Illusive Block
The challenge lies in translating a player’s gaze into precise coordinates within the three-dimensional Minecraft world. It’s not as simple as just grabbing the player’s position and assuming they’re looking straight ahead. Players can look up, down, and all around, and the distance to the block they’re targeting can vary greatly. The Minecraft world does not tell which block player is looking at easily, we need to implement a way to get the block a player is looking at.
This is where the concept of ray tracing comes into play. Ray tracing, in essence, simulates a beam of light (or a ray) emanating from the player’s eyes and extending outwards until it collides with a block in the game world. However, achieving accurate ray tracing within Minecraft requires careful consideration. We need to account for the player’s viewing angle, their current position, and the limitations of the game engine. In order to get the block a player is looking at, this process needs to be implemented correctly.
Moreover, in one point seven point two, the Forge API isn’t always as straightforward as it could be in later versions. This means we need to carefully navigate the available methods to get the information we need and construct the ray tracing logic ourselves. There is many sources that are not up to date, and it becomes the main problem to tackle.
We also need to consider EntityPlayer and World objects to get the player and the surrounding blocks.
EntityPlayer: Represents the player in the game. We can get the player’s position, looking direction, and other related information from this object.World: Represents the world the player is in. This object contains the information of all the blocks, entities, and other environmental properties.
Implementing the Solution: Code Snippet
Here’s a code snippet, crafted specifically for Minecraft Forge version one point seven point two, that demonstrates how to get the block a player is looking at.
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.util.Vec3;
import net.minecraft.util.MovingObjectPosition;
import net.minecraft.world.World;
public class BlockLooker {
public static MovingObjectPosition getTargetBlock(World world, EntityPlayer player, double range) {
float pitch = player.rotationPitch;
float yaw = player.rotationYaw;
double x = player.posX;
double y = player.posY + (double)player.getEyeHeight();
double z = player.posZ;
Vec3 vec3 = Vec3.createVectorHelper(x, y, z);
float yawCos = (float)Math.cos(-yaw * 0.017453292F - (float)Math.PI);
float yawSin = (float)Math.sin(-yaw * 0.017453292F - (float)Math.PI);
float pitchCos = (float)(-Math.cos(-pitch * 0.017453292F));
float pitchSin = (float)Math.sin(-pitch * 0.017453292F);
Vec3 vec31 = Vec3.createVectorHelper((double)(yawSin * pitchCos), (double)pitchSin, (double)(yawCos * pitchCos));
double multiplier = range;
Vec3 vec32 = vec3.addVector(vec31.xCoord * multiplier, vec31.yCoord * multiplier, vec31.zCoord * multiplier);
return world.rayTraceBlocks(vec3, vec32);
}
}
This code provides a method called getTargetBlock that takes the World object, the EntityPlayer object, and a range (in blocks) as input. It returns a MovingObjectPosition object, which contains information about the block that was hit by the ray trace, or null if no block was hit within the specified range.
Understanding the Code: A Step-by-Step Explanation
Let’s break down the code snippet and understand how it works:
Import Statements
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.util.Vec3;
import net.minecraft.util.MovingObjectPosition;
import net.minecraft.world.World;
These lines import the necessary classes from the Minecraft Forge API. EntityPlayer represents the player, Vec3 represents a three-dimensional vector, MovingObjectPosition represents the result of a ray trace, and World represents the Minecraft world.
getTargetBlock Method
public static MovingObjectPosition getTargetBlock(World world, EntityPlayer player, double range) {
This method is the heart of the solution. It takes the world, the player, and the maximum range of the ray trace as input. It returns a MovingObjectPosition object.
Getting Player Data
float pitch = player.rotationPitch;
float yaw = player.rotationYaw;
double x = player.posX;
double y = player.posY + (double)player.getEyeHeight();
double z = player.posZ;
These lines retrieve the player’s pitch (up/down rotation), yaw (left/right rotation), and position (x, y, z coordinates). The getEyeHeight() method is added to the player’s Y position to start the ray trace from the player’s eye level.
Creating Vectors
Vec3 vec3 = Vec3.createVectorHelper(x, y, z);
This line creates a Vec3 object representing the starting point of the ray trace (the player’s eye position).
float yawCos = (float)Math.cos(-yaw * 0.017453292F - (float)Math.PI);
float yawSin = (float)Math.sin(-yaw * 0.017453292F - (float)Math.PI);
float pitchCos = (float)(-Math.cos(-pitch * 0.017453292F));
float pitchSin = (float)Math.sin(-pitch * 0.017453292F);
These lines calculate the cosine and sine of the player’s yaw and pitch angles. These values are used to determine the direction vector of the ray trace.
The magic number 0.017453292F is the value of pi/one hundred eighty.
Vec3 vec31 = Vec3.createVectorHelper((double)(yawSin * pitchCos), (double)pitchSin, (double)(yawCos * pitchCos));
double multiplier = range;
Vec3 vec32 = vec3.addVector(vec31.xCoord * multiplier, vec31.yCoord * multiplier, vec31.zCoord * multiplier);
This section calculates the end point of the ray trace based on the player’s orientation. vec31 is a vector that shows where the player is looking at.
vec32 is a vector that has been increased by range.
Ray Tracing
return world.rayTraceBlocks(vec3, vec32);
This is the most important line of code. It uses the rayTraceBlocks method of the World object to perform the ray trace. This method takes the starting point (vec3) and the ending point (vec32) of the ray trace as input and returns a MovingObjectPosition object containing information about the block that was hit.
Using the Code
To use this code, you’ll need to call the getTargetBlock method from your mod’s code. You can do this in a variety of ways, depending on your specific needs. For example, you could call it every tick to continuously update the targeted block, or you could call it only when the player presses a certain key.
Here’s an example of how to call the getTargetBlock method from a tick event:
import cpw.mods.fml.common.eventhandler.SubscribeEvent;
import cpw.mods.fml.common.gameevent.TickEvent;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.util.MovingObjectPosition;
public class MyTickHandler {
@SubscribeEvent
public void onClientTick(TickEvent.ClientTickEvent event) {
if (event.phase == TickEvent.Phase.END) {
EntityPlayer player = Minecraft.getMinecraft().thePlayer;
if (player != null) {
MovingObjectPosition mop = BlockLooker.getTargetBlock(player.worldObj, player, 5.0);
if (mop != null && mop.typeOfHit == MovingObjectPosition.MovingObjectType.BLOCK) {
// Do something with the targeted block
int x = mop.blockX;
int y = mop.blockY;
int z = mop.blockZ;
System.out.println("Player is looking at block at: " + x + ", " + y + ", " + z);
}
}
}
}
}
In this example, the onClientTick method is called every client tick. It first checks if the player is not null. If the player is not null, it calls the getTargetBlock method to get the targeted block. If a block was hit, it prints the coordinates of the block to the console.
You also need to register MyTickHandler class to get the tick event.
Optimizing the Code for Performance
While the provided code is functional, there are several ways to optimize it for better performance, especially if you’re calling it frequently:
- Reduce Object Creation: Avoid creating new
Vec3objects every tick. Reuse existing objects whenever possible. - Limit the Range: The
rangeparameter significantly impacts performance. Keep it as small as is practically possible for your mod’s functionality. - Conditional Execution: Only perform the ray trace when necessary. For example, only when the player is holding a specific item or when a certain game condition is met.
- Profiling: Use a profiler to identify performance bottlenecks in your code and optimize accordingly.
Conclusion: Mastering the Art of Targeting
Successfully getting the block a player is looking at in Minecraft Forge version one point seven point two opens up a world of possibilities for modding. By understanding the principles of ray tracing and utilizing the provided code, you can create more immersive, interactive, and engaging experiences for your players.
You have managed to get the targeted block from player.
Remember to adapt and refine the code to suit your specific needs. Experiment with different ranges, implement additional checks, and explore the full potential of the MovingObjectPosition object to extract even more information about the targeted block.
If you have any questions, alternative solutions, or insights to share, please don’t hesitate to leave a comment below. Your contributions can help others in the Minecraft modding community!
