(function () {
  class MaskPass extends THREE.Pass {
    constructor(scene, camera) {
      super();
      this.scene = scene;
      this.camera = camera;
      this.clear = true;
      this.needsSwap = false;
      this.inverse = false;
    }

    render(
      renderer,
      writeBuffer,
      readBuffer
      /*, deltaTime, maskActive */
    ) {
      const context = renderer.getContext();
      const state = renderer.state; // don't update color or depth

      state.buffers.color.setMask(false);
      state.buffers.depth.setMask(false); // lock buffers

      state.buffers.color.setLocked(true);
      state.buffers.depth.setLocked(true); // set up stencil

      let writeValue, clearValue;

      if (this.inverse) {
        writeValue = 0;
        clearValue = 1;
      } else {
        writeValue = 1;
        clearValue = 0;
      }

      state.buffers.stencil.setTest(true);
      state.buffers.stencil.setOp(context.REPLACE, context.REPLACE, context.REPLACE);
      state.buffers.stencil.setFunc(context.ALWAYS, writeValue, 0xffffffff);
      state.buffers.stencil.setClear(clearValue);
      state.buffers.stencil.setLocked(true); // draw into the stencil buffer

      renderer.setRenderTarget(readBuffer);
      if (this.clear) renderer.clear();
      renderer.render(this.scene, this.camera);
      renderer.setRenderTarget(writeBuffer);
      if (this.clear) renderer.clear();
      renderer.render(this.scene, this.camera); // unlock color and depth buffer for subsequent rendering

      state.buffers.color.setLocked(false);
      state.buffers.depth.setLocked(false); // only render where stencil is set to 1

      state.buffers.stencil.setLocked(false);
      state.buffers.stencil.setFunc(context.EQUAL, 1, 0xffffffff); // draw if == 1

      state.buffers.stencil.setOp(context.KEEP, context.KEEP, context.KEEP);
      state.buffers.stencil.setLocked(true);
    }
  }

  class ClearMaskPass extends THREE.Pass {
    constructor() {
      super();
      this.needsSwap = false;
    }

    render(
      renderer
      /*, writeBuffer, readBuffer, deltaTime, maskActive */
    ) {
      renderer.state.buffers.stencil.setLocked(false);
      renderer.state.buffers.stencil.setTest(false);
    }
  }

  THREE.ClearMaskPass = ClearMaskPass;
  THREE.MaskPass = MaskPass;
})();