How to prevent Line Renderer from deleting lines after rendering them?-CodePudding

how can I make it so that the lines I am rendering do not disappear when it spawns a new one? I am creating lines from one point to another in the correct position moving along the screen on the correct interval but the lines disappear one after another? I am trying to create a gamified graphical simulation of a stock chart. Thank you to anyone who helps.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class line_rend : MonoBehaviour
{
    private LineRenderer lineRend;
    float candle_y;
    public float stop_running;
    public float candle_speed;
    public float candle_delay;
    public float candle_rate;
    public float candle_volat;
    float candle_x;
    // Start is called before the first frame update
    void Awake()
    {
        candle_y = Random.Range(-4.5f, 4.5f);
        lineRend = GetComponent<LineRenderer>();
        candle_x = -11.0f;
        InvokeRepeating("Spawn_Candle", candle_speed, candle_delay);
    }

    public void Spawn_Candle()
    {
        lineRend.startWidth = 0.1f;
        lineRend.endWidth = 0.1f;
        lineRend.SetPosition(0, new Vector3(candle_x, candle_y, 0f));
        candle_y  = Random.Range((0f - candle_volat), candle_volat);
        candle_x  = candle_rate;
        lineRend.SetPosition(1, new Vector3(candle_x, candle_y, 0f));
    }
}

CodePudding user response：

I think you are reusing the same line repeatedly.

Instead, save the line as a prefab and instantiate a new one when you need them.

A every brief example:

    public Transform linePrefab; <--Configurate the prefab in Inspector
    GameObject lineObj;
    LineRenderer lineRend;

    public void Spawn_Candle()
    {
        lineObj = Instantiate(linePrefab);
        lineRend = lineObj.GetComponent<LineRenderer>();
        lineRend.startWidth = 0.1f;
        lineRend.endWidth = 0.1f;
        lineRend.SetPosition(0, new Vector3(candle_x, candle_y, 0f));
        candle_y  = Random.Range((0f - candle_volat), candle_volat);
        candle_x  = candle_rate;
        lineRend.SetPosition(1, new Vector3(candle_x, candle_y, 0f));
    }

CodePudding user response：

As mentioned in this answer you are currently always overwriting your existing line with new coordinates.

However, a stock chart is a continuous line and you definitely do not want to spawn a new linerenderer for each stroke.

You rather simply want to add more points.

public class line_rend : MonoBehaviour
{
    private LineRenderer lineRend;
    // Personal choice but if I have coordinates I'd rather store them in a single field
    Vector2 candle;
    public float stop_running;
    public float candle_speed;
    public float candle_delay;
    public float candle_rate;
    public float candle_volat;

    // Start is called before the first frame update
    void Awake()
    {
        candle.y = Random.Range(-4.5f, 4.5f);
        lineRend = GetComponent<LineRenderer>();
        lineRend.startWidth = 0.1f;
        lineRend.endWidth = 0.1f;
        candle.x = -11.0f;
        // Use nameof it prevents trouble when you rename the method later
        InvokeRepeating(nameof(Spawn_Candle), candle_speed, candle_delay);
    }

    public void Spawn_Candle()
    {
        // Add a new position
        lineRend.positionCount  = 1;

        candle.y  = Random.Range(-candle_volat, candle_volat);
        candle.x  = candle_rate;

        // only set the new position
        // It already is connected to the previous one
        lineRend.SetPosition(lineRend.positionCount - 1, candle);
    }
}