How to prevent multiple spawns from a single spawn point?

Question

Hey everyone,

I'm working on an endless runner style game where the player has to dodge blocks w$$anonymous$$le collecting coins. I'm using four spawn points to spawn three blocks and one coin using the code below:

 void SpawnBlocks()
     {
         int randomIndex = Random.Range(0, spawnPoints.Length);
 
         for (int i = 0; i < spawnPoints.Length; i++)
         {
             if (randomIndex != i)
             {
 
                 Instantiate(blockPrefab, spawnPoints[i].position, Quaternion.identity);
 
                 Instantiate(coinPrefab, spawnPoints[randomIndex].position, Quaternion.identity);
                
             }
 
         }
     }

Initially, I started the project by randomly spawning three blocks among four spawn points, so there would always be a gap for the player to go through. To make the game more engaging, I decided to spawn a collectable coin wit$$anonymous$$n the gap using w$$anonymous$$chever spawn point is not being used to spawn a block.

According to t$$anonymous$$s script, i = all of the spawn points that are being activated in each instance. I had to figure out w$$anonymous$$ch spawn point was not being activated so that I could use that spawn point to spawn a coin. After simply realizing that the randomIndex != i, I figured out that I could use spawnPoints[randomIndex].position to spawn the coin because the randomIndex number is the number that is never being used for the block spawn points.

T$$anonymous$$s worked flawlessly, or so I thought. When I tried implementing the score system, w$$anonymous$$ch would +1 for every coin that the player collected, I noticed that each time the player collected a coin, the score would +3 instead. That's when I realized that, instead of spawning just one coin, I was spawning three coins on top of each other.

I would like to prevent the spawn point from spawning three coins at once and, instead, just spawn one coin, but I can't wrap my head around how to do that with my current script.

I've also seen people utilize a check function to see if an object is already in the location before spawning another, w$$anonymous$$ch would work if these coins weren't spawning at the exact same time.

My last idea is to change the score value from +1 per coin to +0.3 per coin, and then round the 0.9 from the stacked coins into a 1. T$$anonymous$$s might be my best option, but I can't quite figure out how to add the decimals together and then round to a whole number (I'm basically one DNA molecule away from a c$$anonymous$$mp, after all).

Apologies for the reading assignment, I thought it'd be best to fully explain my situation to receive proper assistance. If anybody knows of a solution/workaround then I would greatly appreciate it!

Answer 1

Answer by losingisfun · Mar 17, 2021 at 03:17 AM

What you could do is create a pool and then remove the last used spawn point. Here's an example:

 public void SpawnBlocks() {
 
         // Create a pool
         List<Vector3> pool = new List<Vector3>();
         foreach (Vector3 v in spawnPoints) { pool.Add(v); }
 
         for (int i = 0; i < spawnPoints.Length-1; i++) {
             int randomIndex = Random.Range(0, pool.Count);
 
             Instantiate(blockPrefab, pool[randomIndex], Quaternion.identity);
 
             pool.RemoveAt(randomIndex);
         }
 
         // Now add the coin with the last remaining spawn point in the pool
         Instantiate(coinPrefab, pool[0], Quaternion.identity);
     }

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DiamondPaws · Mar 17, 2021 at 06:05 PM 0

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Really fascinating method! Its implementation is above my pay grade but that just provides the motivation to read into it more. I'll check in with you if I can get this to work. I appreciate you sharing your thought process!

How to prevent multiple spawns from a single spawn point?

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