ParticleSystem.ShapeModule.texture

描述

指定一个纹理来为粒子的起始颜色着色。

要为粒子的起始颜色着色，形状模块会在 CPU 上读取此纹理中的像素。这意味着您必须在分配的纹理的导入设置中启用读/写选项。

要为粒子着色，形状模块首先会将纹理拉伸到您指定的形状上。然后，当系统从形状上的某个点发射粒子时，形状模块会使用该位置处纹理的颜色作为粒子颜色。

要查看纹理如何在形状上拉伸，请在层次结构视图中选择粒子系统并展开形状模块。形状的场景视图可视化包含纹理预览。

using UnityEditor;
using UnityEngine;

[RequireComponent(typeof(ParticleSystem))]
public class ExampleClass : MonoBehaviour
{
    private ParticleSystem ps;
    public float alphaThreshold = 0.0f;
    public bool colorAffectsParticles = true;
    public bool alphaAffectsParticles = true;
    public bool bilinearFiltering = false;

    void Start()
    {
        ps = GetComponent<ParticleSystem>();

        var main = ps.main;
        main.startSpeed = 0.0f;
        main.startSize = 0.5f;
        main.startLifetime = 1.0f;

        var emission = ps.emission;
        emission.rateOverTime = 500.0f;

        var shape = ps.shape;
        shape.shapeType = ParticleSystemShapeType.Circle;
        shape.radius = 6.0f;
        shape.texture = AssetDatabase.GetBuiltinExtraResource<Texture2D>("Default-Particle.psd");
    }

    void Update()
    {
        var shape = ps.shape;
        shape.textureClipThreshold = alphaThreshold;
        shape.textureColorAffectsParticles = colorAffectsParticles;
        shape.textureAlphaAffectsParticles = alphaAffectsParticles;
        shape.textureBilinearFiltering = bilinearFiltering;
    }

    void OnGUI()
    {
        float y = 120.0f;
        float spacing = 40.0f;

        GUI.Label(new Rect(25, y, 140, 30), "Alpha Threshold");
        alphaThreshold = GUI.HorizontalSlider(new Rect(165, y + 5, 100, 30), alphaThreshold, 0.0f, 1.0f);
        y += spacing;

        colorAffectsParticles = GUI.Toggle(new Rect(25, y + 5, 200, 30), colorAffectsParticles, "Color Affects Particles");
        y += spacing;

        alphaAffectsParticles = GUI.Toggle(new Rect(25, y + 5, 200, 30), alphaAffectsParticles, "Alpha Affects Particles");
        y += spacing;

        bilinearFiltering = GUI.Toggle(new Rect(25, y + 5, 200, 30), bilinearFiltering, "Bilinear Filtering");
        y += spacing;
    }
}