三渲二 Cocos Creator-轻识

分享把3D动画输出成序列帧图片的一种方法，希望对大家有所帮助，代码工程将整理到 Cocos 论坛。

实现效果

配置环境

Cocos Creator 3.6.2 编辑器
Chrome 浏览器

实现

原理

相机渲染成一张纹理
读取纹理数据传给 Canvas 绘制
Canvas 生成纹理数据传给 HTML <a> 标签

步骤

将动画的模型放入场景中
调整相机视角，修改相机参数
引入脚本组件，填充参数

讲解视频

https://www.bilibili.com/video/BV1g8411u7Pp

工程代码

ScreenCapture.ts

面向网络编程，拼凑起来的代码，在此感谢各路神仙

    import {
    _decorator, Component, log, Camera
    , math, view, RenderTexture, Animation
} from 'cc';
const { ccclass, property } = _decorator;

@ccclass('ScreenCapture')
export class ScreenCapture extends Component {
    @property(Camera)
    camera: Camera = null!

    @property(Animation)
    animation: Animation = null!

    @property
    count = 3

    start() {
        log('欢迎关注微信公众号【白玉无冰】 https://mp.weixin.qq.com/s/4WwCjWBtZNnONh8hZ7JVDA')
const defaultState = this.animation.getState(this.animation.defaultClip!.name)
let count = this.count;
if (count < 2) count = 2;
        defaultState.stop();
const stepTime = defaultState.duration / count;
const doAfterCap = () => {
            count--;
if (count > 0) {
                defaultState.update(stepTime);
this.doCapture(doAfterCap)
            }
        }
        defaultState.update(0);
this.doCapture(doAfterCap);
    }

    private doCapture(doAfterCap = () => {

    }) {
let vSize = new math.Size
        vSize.width = view.getVisibleSize().width
        vSize.height = view.getVisibleSize().height
let texture = new RenderTexture();
        texture.reset(vSize);
this.camera.targetTexture = texture;
this.scheduleOnce(() => {
this.saveCapture(texture)
this.camera.targetTexture = null;
            doAfterCap()
        }, 0)
    }

    private index = 0
    private timestamp = Date.now()
    private saveCapture(rt: RenderTexture) {
let data: string = this.getImgBase(rt)
this.saveAs(`${this.timestamp}_${++this.index}`, data)
    }

    private getImgBase(texture: RenderTexture) {
const rtW = Math.floor(texture.width);
const rtH = Math.floor(texture.height);
const texPixels = new Uint8Array(rtW * rtH * 4);
let data = texture.readPixels(0, 0, rtW, rtH, texPixels)!

let canvas = document.createElement('canvas')
let ctx = canvas.getContext('2d')!

        canvas.width = texture.width
        canvas.height = texture.height

let width = texture.width
let height = texture.height

let rowBytes = width * 4
for (let row = 0; row < height; row++) {
let srow = height - 1 - row
let imgData = ctx.createImageData(width, 1)
let start = srow * width * 4
for (let i = 0; i < rowBytes; i++) {
                imgData.data[i] = data[start + i]
            }
            ctx.putImageData(imgData, 0, row)
        }
let dataUrl = canvas.toDataURL('image/png')
console.log(dataUrl)
return dataUrl
    }

    private saveAs(fileName: string, data: any | string) {
var element = document.createElement('a');
if (typeof data === "string") {
            element.setAttribute('href', data);
        }
else {
            element.setAttribute('href', 'data:text/plain;charset=utf-8,' + encodeURIComponent(data));
        }

        element.setAttribute('download', fileName);
        element.style.display = 'none';
document.body.appendChild(element);
        element.click();
document.body.removeChild(element);
    }
}

示例工程

capture-ccc3.6.2.zip (488.2 KB)

https://forum.cocos.org/uploads/short-url/9Q24VrBnMKyybOaKQM8SwRYtZkw.zip

文末阅读原文可下载

参考资料

https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement
https://developer.mozilla.org/en-US/docs/Web/API/HTMLAnchorElement
https://developer.mozilla.org/en-US/docs/web/api/htmlelement/click

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