pbrtools/bindatastruct.ts

laya pbr tools

/**
 * 根据描述创建一个buffer或者描述一个buffer
 * 通过描述中的属性来访问或者修改buffer的内容。
 */
class binDataStruct{
    buff:ArrayBuffer;
    desc:string[];
    static typeinfo={
        u8:[1,Uint8Array],    //size,class
        u16:[2,Uint16Array],
        u32:[4,Uint32Array],
        f32:[4,Float32Array]
        //不要扩展vec2,3,4,mat之类的，不是一个层级的
    }
    constructor(desc:string[]){
        this.desc=desc;
        var sz = this.calcBufSz(desc);
        this.buff = new ArrayBuffer(sz);
        this.cook(desc,this.buff,0);
    }
    /**
     * 返回[type，num]
     */
    _gettype(str:string):[string,number]{
        var st=str.indexOf('[');
        var ed=str.indexOf(']');
        if(st<0){
            return [str,1];
        }
        if(ed<0)throw 'error no ]'+str;
        return [str.substr(0,st), parseInt( str.substr(st+1,ed-st-1))];
    }
    cook(desc:string[],buff:ArrayBuffer,off:number){
        var off=off;
        desc.forEach((v)=>{
            var av = v.split(',');if(av.length<2)throw 'error '+v;
            var ti = this._gettype(av[1]);
            var cls = binDataStruct.typeinfo[ti[0]][1];
            var num = ti[1];
            var isarr=num>1;
            //问题：如果某个uint32或者f32没有按照4对齐会报错。
            if(!isarr){
                var dt = new cls(buff,off,1);
                Object.defineProperty(this,av[0],{
                    set:function(v){dt[0]=v;},
                    get:function(){return dt[0];},
                    enumerable: true,
                    configurable:true
                });
            }else{
                this[av[0]]=new cls(buff,off,num);
            }
            off+=binDataStruct.typeinfo[ti[0]][0]*num;;
        });
    }
    calcBufSz(desc:string[]){
        var sz =0;
        desc.forEach((v)=>{
            var av = v.split(',');if(av.length<2)throw 'error '+v;
            var ti = this._gettype(av[1]);
            var tp = ti[0];
            var num = ti[1];
            sz += binDataStruct.typeinfo[tp][0]*num;
        });
        return sz;
    }
    attachBuff(buff:ArrayBuffer,off:number){
        this.cook(this.desc,buff,off);
    }
}

/**
 * 根据描述字符串读写数据
 */
class strDataStruct{
    constructor(){

    }
    desc(str:string){

    }
    size():number{
        return 0;
    }
    fromBuff(buff:ArrayBuffer, off:number){

    }
    toBuff(buff:ArrayBuffer,off:number){

    }
}
/*
//var，type，defvalue
var bf = new binDataStruct(['id,u16','padd,u16','dataoff,u32','datasize,u32']) as any;
bf.datasize=22;

//test
bf = new binDataStruct(['id,u32','dt,u32[4]']) as any;
bf.dt[0]=10;
bf.dt[1]=11;

var bb = new Uint8Array([1,2,3]);
var c=new binDataStruct(['a,u8','b,u8','c,u8'])
c.attachBuff(bb.buffer,0)
*/