;(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
})()