meta-next/src/resources/Texture.js

import Engine from "../Engine"
import { isPowerOf2 } from "../Utils"
import Resource from "./Resource"

const greenPixel = new Uint8Array([ 0, 255, 0, 255 ])

class Texture extends Resource
{
	constructor(config) 
	{
		super(config)

		this.instance = Engine.gl.createTexture()
		this.width = 0
		this.height = 0

		if(config) {
			this.setup(config)
		}
	}

	setup(config) {
		this.loadFromPath(config.path)
	}

	loadFromPath(path) 
	{
		this.loading = true

		const image = new Image()
		image.onload = () => {
			this.loadFromImage(image)
		}
		image.onfailed = () => {
			this.loadEmpty()
		}
		image.src = path
	}

	loadEmpty() 
	{
		const gl = Engine.gl

		this.width = 1
		this.height = 1
		
		gl.bindTexture(gl.TEXTURE_2D, this.instance)
		gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, this.width, this.height, 0, gl.RGBA, gl.UNSIGNED_BYTE, greenPixel)
		gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
		gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
		gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
		
		this.loaded = true
	}

	loadFromImage(image) 
	{
		const gl = Engine.gl

		this.width = image.width
		this.height = image.height

		gl.bindTexture(gl.TEXTURE_2D, this.instance)
		gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, image)

		if(isPowerOf2(image.width) && isPowerOf2(image.height)) {
			gl.generateMipmap(gl.TEXTURE_2D)
		}
		else {
			gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
			gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
			gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
		}

		this.loading = false
	}

	loadFromCanvas(canvas)
	{
		const gl = Engine.gl

		this.width = canvas.width
		this.height = canvas.height

		gl.bindTexture(gl.TEXTURE_2D, this.instance)
		gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, canvas)

		if(isPowerOf2(canvas.width) && isPowerOf2(canvas.height)) {
			gl.generateMipmap(gl.TEXTURE_2D)
		}
		else {
			gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
			gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
			gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
		}

		this.loaded = true
	}

	frame() {
		return this.frameData
	}

	use() {
		const gl = Engine.gl
		gl.bindTexture(gl.TEXTURE_2D, this.instance)
	}
}

export default Texture