init()

in packages/layers/flyline/src/FlyLine.ts [113:215]
85 lines of code
14 McCabe index (conditional complexity)

	init(timeline) {
		if (!timeline) {
			throw new Error('FlyLine::缺少必要参数 timeline')
		}

		this.timeline = timeline

		// @TODO not safe
		this.trackID = '' + Math.random() * 999999

		// 飞行部分的点数 = 总点数 * 飞行比例
		this.flySegments = Math.floor(this.props.lineSegments * this.props.flyPercent)
		// 飞行总长度, 避免大量重复计算
		this.flightLength = this.props.lineSegments + this.flySegments
		this.flightLength_1 = this.flightLength - 1
		this.flightLength_2 = this.flightLength - 2

		// 着地时间
		this.landingP = this.props.lineSegments / this.flightLength

		this.useColors = !!this.props.useColors && !!this.props.colors && this.props.colors.length > 0

		this.sampler = {
			anisotropy: 8,
			minFilter: 'LINEAR_MIPMAP_NEAREST',
		}

		// 优先使用image属性
		if (this.props.image) {
			this.props.texture = specifyTexture({
				image: {
					uri: this.props.image,
					extensions: {
						EXT_image: {
							flipY: !!this.props.flipY,
						},
					},
				},
				sampler: this.sampler,
			})
		} else if (this.props.texture && this.props.texture.image && this.props.texture.image.uri) {
			this.props.texture = specifyTexture({
				image: this.props.texture.image,
				sampler: this.sampler,
			})
		}

		const glineConfig = {
			level: this.props.level,
			lineWidth: this.props.lineWidth,
			pointSize: this.props.pointSize,
			color: new Color(this.props.color),
			opacity: this.props.opacity,
			texture: this.props.useColors ? undefined : this.props.texture,
			resolution: this.props.resolution,
			usePerspective: this.props.usePerspective,
			useColors: this.useColors,
			dynamic: true,
			u: !(this.props.texture === undefined),
		}

		this.updateColors(this.props.colors, glineConfig)

		this.gline = this.props.gline || new GLine(glineConfig)
		this.mesh = this.gline
		this.mesh.name = 'FlyLine-' + this.trackID
		this.matr = this.gline.material
		this.matr.alphaMode = this.props.transparent ? 'BLEND' : 'OPAQUE'

		// 缓冲池
		// this.bufferLength = this.config.pool * this.config.segment;
		// const posBuffers = new Float32Array(this.bufferLength * 3);
		const posBuffers: Float32Array[] = []
		for (let i = 0; i < this.props.pool; i++) {
			const b = new Float32Array(this.flySegments * 3)
			this.props.usePoint && b.fill(this.props.infinity)
			posBuffers.push(b)
		}

		this.pointer = 0

		this.gline.geometry.updateData({
			positions: posBuffers,
			colors: this.colorBuffer,
		})

		// 主动降帧率
		this.frameCounting = 0
		this.frameValid = true
		this.timeline.addTrack({
			startTime: this.timeline.currentTime,
			duration: Infinity,
			onUpdate: () => {
				this.frameCounting++
				if (this.frameCounting > this.props.frameDropping) {
					this.frameValid = true
					this.frameCounting = 0
				} else {
					this.frameValid = false
				}
			},
		})
	}