code: function setupFrameBuffer ( framebuffer, renderTarget, textureTarget ) {
  
  		_gl.bindFramebuffer( _gl.FRAMEBUFFER, framebuffer );
  		_gl.framebufferTexture2D( _gl.FRAMEBUFFER, _gl.COLOR_ATTACHMENT0, textureTarget, renderTarget.__webglTexture, 0 );
  
  	}
docs: Render targets