ParticleSystem.LightsModule.alphaAffectsIntensity

Description

切换在计算最终光强度时，是否将粒子 Alpha 乘以光强度。

可用于使光源与粒子同时淡出，以避免弹出。

using UnityEngine;
using System.Collections;

// For best results, use Deferred Rendering (see Camera settings)
public class ExampleClass : MonoBehaviour
{
    private ParticleSystem ps;
    public Light lightPrefab;     // Provide a light Prefab in the inspector (eg a default Point Light)
    public float hSliderValueA = 1.0f;
    public bool alphaAffectsIntensity = true;

    void Start()
    {
        ps = GetComponent<ParticleSystem>();
        ps.transform.localRotation = Quaternion.Euler(0.0f, 0.0f, 45.0f);

        var shape = ps.shape;
        shape.shapeType = ParticleSystemShapeType.Circle;

        var lights = ps.lights;
        lights.enabled = true;
        lights.light = lightPrefab;
        lights.ratio = 1.0f;
        lights.maxLights = 1000;

        // plane to receive lights
        var plane = GameObject.CreatePrimitive(PrimitiveType.Plane);
        plane.transform.parent = ps.transform;
        plane.transform.localPosition = new Vector3(0.0f, 0.0f, 3.0f);
        plane.transform.localScale = new Vector3(20.0f, 20.0f, 20.0f);
        plane.transform.localRotation = Quaternion.Euler(-90.0f, 0.0f, 0.0f);

        var material = new Material(Shader.Find("Standard"));
        material.color = new Color(0.1f, 0.1f, 0.1f, 1.0f);
        plane.GetComponent<MeshRenderer>().material = material;
    }

    void Update()
    {
        var lights = ps.lights;
        lights.alphaAffectsIntensity = alphaAffectsIntensity;

        var main = ps.main;
        main.startColor = new Color(1.0f, 1.0f, 1.0f, hSliderValueA);
    }

    void OnGUI()
    {
        GUI.Label(new Rect(25, 40, 100, 30), "Alpha");

        hSliderValueA = GUI.HorizontalSlider(new Rect(95, 45, 100, 30), hSliderValueA, 0.0f, 1.0f);
        alphaAffectsIntensity = GUI.Toggle(new Rect(25, 85, 200, 30), alphaAffectsIntensity, "Particle Alpha Affects Light Intensity");
    }
}