截屏获取image base64字符串

ImgBase64.js

// 返回 image base64
getImgBase64() {
    let sp = cc.find('Canvas/New Sprite(Splash)').getComponent(cc.Sprite);
    let target = cc.find('Canvas');
    let width = 960,
    height = 640;
    let renderTexture = new cc.RenderTexture(width, height);
    renderTexture.begin();
    target._sgNode.visit();
    renderTexture.end();
    //
    let canvas = document.createElement('canvas');
    let ctx = canvas.getContext('2d');
    canvas.width = width;
    canvas.height = height;
    if (cc.renderType === cc.game.RENDERTYPE_CANVAS) {
        let texture = renderTexture.getSprite().getTexture();
        let image = texture.getHtmlElementObj();
        ctx.drawImage(image, 0, 0);
    } else if (cc.renderType === cc.game.RENDERTYPE_WEBGL) {
        let buffer = gl.createFramebuffer();
        gl.bindFramebuffer(gl.FRAMEBUFFER, buffer);
        let texture = renderTexture.getSprite().getTexture()._glID;
        gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, 0);
        let data = new Uint8Array(width * height * 4);
        gl.readPixels(0, 0, width, height, gl.RGBA, gl.UNSIGNED_BYTE, data);
        gl.bindFramebuffer(gl.FRAMEBUFFER, null);
        let rowBytes = width * 4;
        for (let row = 0; row < height; row++) {
            let srow = height - 1 - row;
            let data2 = new Uint8ClampedArray(data.buffer, srow * width * 4, rowBytes);
            let imageData = new ImageData(data2, width, 1);
            ctx.putImageData(imageData, 0, row);
        }
    }
    return canvas.toDataURL('image/png');
}