Code/net/minecraft/client/particle/FireflyParticle.java

package net.minecraft.client.particle;

import net.minecraft.client.multiplayer.ClientLevel;
import net.minecraft.core.BlockPos;
import net.minecraft.core.particles.SimpleParticleType;
import net.minecraft.util.Mth;
import net.minecraftforge.api.distmarker.Dist;
import net.minecraftforge.api.distmarker.OnlyIn;

@OnlyIn(Dist.CLIENT)
public class FireflyParticle extends TextureSheetParticle {
    private static final float PARTICLE_FADE_OUT_LIGHT_TIME = 0.3F;
    private static final float PARTICLE_FADE_IN_LIGHT_TIME = 0.1F;
    private static final float PARTICLE_FADE_OUT_ALPHA_TIME = 0.5F;
    private static final float PARTICLE_FADE_IN_ALPHA_TIME = 0.3F;
    private static final int PARTICLE_MIN_LIFETIME = 36;
    private static final int PARTICLE_MAX_LIFETIME = 180;

    FireflyParticle(ClientLevel p_392461_, double p_395781_, double p_397251_, double p_392758_, double p_391215_, double p_396621_, double p_394403_) {
        super(p_392461_, p_395781_, p_397251_, p_392758_, p_391215_, p_396621_, p_394403_);
        this.speedUpWhenYMotionIsBlocked = true;
        this.friction = 0.96F;
        this.quadSize *= 0.75F;
        this.yd *= 0.8F;
        this.xd *= 0.8F;
        this.zd *= 0.8F;
    }

    @Override
    public ParticleRenderType getRenderType() {
        return ParticleRenderType.PARTICLE_SHEET_TRANSLUCENT;
    }

    @Override
    public int getLightColor(float p_391946_) {
        return (int)(255.0F * getFadeAmount(this.getLifetimeProgress(this.age + p_391946_), 0.1F, 0.3F));
    }

    @Override
    public void tick() {
        super.tick();
        if (!this.level.getBlockState(BlockPos.containing(this.x, this.y, this.z)).isAir()) {
            this.remove();
        } else {
            this.setAlpha(getFadeAmount(this.getLifetimeProgress(this.age), 0.3F, 0.5F));
            if (Math.random() > 0.95 || this.age == 1) {
                this.setParticleSpeed(-0.05F + 0.1F * Math.random(), -0.05F + 0.1F * Math.random(), -0.05F + 0.1F * Math.random());
            }
        }
    }

    private float getLifetimeProgress(float p_391220_) {
        return Mth.clamp(p_391220_ / this.lifetime, 0.0F, 1.0F);
    }

    private static float getFadeAmount(float p_392433_, float p_396209_, float p_393676_) {
        if (p_392433_ >= 1.0F - p_396209_) {
            return (1.0F - p_392433_) / p_396209_;
        } else {
            return p_392433_ <= p_393676_ ? p_392433_ / p_393676_ : 1.0F;
        }
    }

    @OnlyIn(Dist.CLIENT)
    public static class FireflyProvider implements ParticleProvider<SimpleParticleType> {
        private final SpriteSet sprite;

        public FireflyProvider(SpriteSet p_391324_) {
            this.sprite = p_391324_;
        }

        public Particle createParticle(
            SimpleParticleType p_392220_,
            ClientLevel p_392739_,
            double p_395400_,
            double p_396183_,
            double p_392361_,
            double p_397702_,
            double p_393784_,
            double p_397769_
        ) {
            FireflyParticle fireflyparticle = new FireflyParticle(
                p_392739_,
                p_395400_,
                p_396183_,
                p_392361_,
                0.5 - p_392739_.random.nextDouble(),
                p_392739_.random.nextBoolean() ? p_393784_ : -p_393784_,
                0.5 - p_392739_.random.nextDouble()
            );
            fireflyparticle.setLifetime(p_392739_.random.nextIntBetweenInclusive(36, 180));
            fireflyparticle.scale(1.5F);
            fireflyparticle.pickSprite(this.sprite);
            fireflyparticle.setAlpha(0.0F);
            return fireflyparticle;
        }
    }
}