export default class GLHook {
	public drawPasses:number = 0;
	public isInit:boolean = false;
	private realGLDrawElements:Function = function(){};

	private gl:any;

	constructor(_gl?:any) {

		if(_gl){

			if(_gl.__proto__.drawElements){
				this.gl = _gl;
				this.realGLDrawElements = _gl.__proto__.drawElements;

				//replace to new function
				_gl.__proto__.drawElements = this.fakeGLdrawElements.bind(this);
				this.isInit = true;

				console.log("[GLHook] GL was Hooked!");
			}

		} else {
			console.error("[GLHook] GL can't be NULL");
		}
	}

	private fakeGLdrawElements(mode:any, count:any, type:any, offset:any):void {

		this.drawPasses ++;
		this.realGLDrawElements.call(this.gl, mode, count, type, offset);

	}
	public reset():void{

		this.drawPasses = 0;

	}

	public release():void{

		if(this.isInit){

			this.gl.__proto__.drawElements = this.realGLDrawElements;
			console.log("[GLHook] Hook was removed!");
		}

		this.isInit = false;
	}
}