    gl.clear(gl.DEPTH_BUFFER_BIT | gl.STENCIL_BUFFER_BIT);
        gl.useProgram(drawProgram);
        wtu.drawUnitQuad(gl);
        wtu.glErrorShouldBe(gl, gl.NO_ERROR, "no errors after drawing to the depth or depth stencil texture");

        // Detach the depth or depth stencil texture to avoid feedback loop
        gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_STENCIL_ATTACHMENT, gl.RENDERBUFFER, null);
        wtu.framebufferStatusShouldBe(gl, gl.FRAMEBUFFER, gl.FRAMEBUFFER_COMPLETE);

        co