var check = require('./util/check')
var extend = require('./util/extend')
var values = require('./util/values')
var isTypedArray = require('./util/is-typed-array')
var isNDArrayLike = require('./util/is-ndarray')
var pool = require('./util/pool')
var convertToHalfFloat = require('./util/to-half-float')
var isArrayLike = require('./util/is-array-like')
var flattenUtils = require('./util/flatten')
var isPow2 = require('./util/is-pow2')

var dtypes = require('./constants/arraytypes.json')
var arrayTypes = require('./constants/arraytypes.json')

var GL_COMPRESSED_TEXTURE_FORMATS = 0x86A3

var GL_TEXTURE_2D = 0x0DE1
var GL_TEXTURE_CUBE_MAP = 0x8513
var GL_TEXTURE_CUBE_MAP_POSITIVE_X = 0x8515

var GL_RGBA = 0x1908
var GL_ALPHA = 0x1906
var GL_RGB = 0x1907
var GL_LUMINANCE = 0x1909
var GL_LUMINANCE_ALPHA = 0x190A

var GL_RGBA4 = 0x8056
var GL_RGB5_A1 = 0x8057
var GL_RGB565 = 0x8D62

var GL_UNSIGNED_SHORT_4_4_4_4 = 0x8033
var GL_UNSIGNED_SHORT_5_5_5_1 = 0x8034
var GL_UNSIGNED_SHORT_5_6_5 = 0x8363
var GL_UNSIGNED_INT_24_8_WEBGL = 0x84FA

var GL_DEPTH_COMPONENT = 0x1902
var GL_DEPTH_STENCIL = 0x84F9

var GL_SRGB_EXT = 0x8C40
var GL_SRGB_ALPHA_EXT = 0x8C42

var GL_HALF_FLOAT_OES = 0x8D61

var GL_COMPRESSED_RGB_S3TC_DXT1_EXT = 0x83F0
var GL_COMPRESSED_RGBA_S3TC_DXT1_EXT = 0x83F1
var GL_COMPRESSED_RGBA_S3TC_DXT3_EXT = 0x83F2
var GL_COMPRESSED_RGBA_S3TC_DXT5_EXT = 0x83F3

var GL_COMPRESSED_RGB_ATC_WEBGL = 0x8C92
var GL_COMPRESSED_RGBA_ATC_EXPLICIT_ALPHA_WEBGL = 0x8C93
var GL_COMPRESSED_RGBA_ATC_INTERPOLATED_ALPHA_WEBGL = 0x87EE

var GL_COMPRESSED_RGB_PVRTC_4BPPV1_IMG = 0x8C00
var GL_COMPRESSED_RGB_PVRTC_2BPPV1_IMG = 0x8C01
var GL_COMPRESSED_RGBA_PVRTC_4BPPV1_IMG = 0x8C02
var GL_COMPRESSED_RGBA_PVRTC_2BPPV1_IMG = 0x8C03

var GL_COMPRESSED_RGB_ETC1_WEBGL = 0x8D64

var GL_UNSIGNED_BYTE = 0x1401
var GL_UNSIGNED_SHORT = 0x1403
var GL_UNSIGNED_INT = 0x1405
var GL_FLOAT = 0x1406

var GL_TEXTURE_WRAP_S = 0x2802
var GL_TEXTURE_WRAP_T = 0x2803

var GL_REPEAT = 0x2901
var GL_CLAMP_TO_EDGE = 0x812F
var GL_MIRRORED_REPEAT = 0x8370

var GL_TEXTURE_MAG_FILTER = 0x2800
var GL_TEXTURE_MIN_FILTER = 0x2801

var GL_NEAREST = 0x2600
var GL_LINEAR = 0x2601
var GL_NEAREST_MIPMAP_NEAREST = 0x2700
var GL_LINEAR_MIPMAP_NEAREST = 0x2701
var GL_NEAREST_MIPMAP_LINEAR = 0x2702
var GL_LINEAR_MIPMAP_LINEAR = 0x2703

var GL_GENERATE_MIPMAP_HINT = 0x8192
var GL_DONT_CARE = 0x1100
var GL_FASTEST = 0x1101
var GL_NICEST = 0x1102

var GL_TEXTURE_MAX_ANISOTROPY_EXT = 0x84FE

var GL_UNPACK_ALIGNMENT = 0x0CF5
var GL_UNPACK_FLIP_Y_WEBGL = 0x9240
var GL_UNPACK_PREMULTIPLY_ALPHA_WEBGL = 0x9241
var GL_UNPACK_COLORSPACE_CONVERSION_WEBGL = 0x9243

var GL_BROWSER_DEFAULT_WEBGL = 0x9244

var GL_TEXTURE0 = 0x84C0

var MIPMAP_FILTERS = [
  GL_NEAREST_MIPMAP_NEAREST,
  GL_NEAREST_MIPMAP_LINEAR,
  GL_LINEAR_MIPMAP_NEAREST,
  GL_LINEAR_MIPMAP_LINEAR
]

var CHANNELS_FORMAT = [
  0,
  GL_LUMINANCE,
  GL_LUMINANCE_ALPHA,
  GL_RGB,
  GL_RGBA
]

var FORMAT_CHANNELS = {}
FORMAT_CHANNELS[GL_LUMINANCE] =
FORMAT_CHANNELS[GL_ALPHA] =
FORMAT_CHANNELS[GL_DEPTH_COMPONENT] = 1
FORMAT_CHANNELS[GL_DEPTH_STENCIL] =
FORMAT_CHANNELS[GL_LUMINANCE_ALPHA] = 2
FORMAT_CHANNELS[GL_RGB] =
FORMAT_CHANNELS[GL_SRGB_EXT] = 3
FORMAT_CHANNELS[GL_RGBA] =
FORMAT_CHANNELS[GL_SRGB_ALPHA_EXT] = 4

var formatTypes = {}
formatTypes[GL_RGBA4] = GL_UNSIGNED_SHORT_4_4_4_4
formatTypes[GL_RGB565] = GL_UNSIGNED_SHORT_5_6_5
formatTypes[GL_RGB5_A1] = GL_UNSIGNED_SHORT_5_5_5_1
formatTypes[GL_DEPTH_COMPONENT] = GL_UNSIGNED_INT
formatTypes[GL_DEPTH_STENCIL] = GL_UNSIGNED_INT_24_8_WEBGL

function objectName (str) {
  return '[object ' + str + ']'
}

var CANVAS_CLASS = objectName('HTMLCanvasElement')
var OFFSCREENCANVAS_CLASS = objectName('OffscreenCanvas')
var CONTEXT2D_CLASS = objectName('CanvasRenderingContext2D')
var BITMAP_CLASS = objectName('ImageBitmap')
var IMAGE_CLASS = objectName('HTMLImageElement')
var VIDEO_CLASS = objectName('HTMLVideoElement')

var PIXEL_CLASSES = Object.keys(dtypes).concat([
  CANVAS_CLASS,
  OFFSCREENCANVAS_CLASS,
  CONTEXT2D_CLASS,
  BITMAP_CLASS,
  IMAGE_CLASS,
  VIDEO_CLASS
])

// for every texture type, store
// the size in bytes.
var TYPE_SIZES = []
TYPE_SIZES[GL_UNSIGNED_BYTE] = 1
TYPE_SIZES[GL_FLOAT] = 4
TYPE_SIZES[GL_HALF_FLOAT_OES] = 2

TYPE_SIZES[GL_UNSIGNED_SHORT] = 2
TYPE_SIZES[GL_UNSIGNED_INT] = 4

var FORMAT_SIZES_SPECIAL = []
FORMAT_SIZES_SPECIAL[GL_RGBA4] = 2
FORMAT_SIZES_SPECIAL[GL_RGB5_A1] = 2
FORMAT_SIZES_SPECIAL[GL_RGB565] = 2
FORMAT_SIZES_SPECIAL[GL_DEPTH_STENCIL] = 4

FORMAT_SIZES_SPECIAL[GL_COMPRESSED_RGB_S3TC_DXT1_EXT] = 0.5
FORMAT_SIZES_SPECIAL[GL_COMPRESSED_RGBA_S3TC_DXT1_EXT] = 0.5
FORMAT_SIZES_SPECIAL[GL_COMPRESSED_RGBA_S3TC_DXT3_EXT] = 1
FORMAT_SIZES_SPECIAL[GL_COMPRESSED_RGBA_S3TC_DXT5_EXT] = 1

FORMAT_SIZES_SPECIAL[GL_COMPRESSED_RGB_ATC_WEBGL] = 0.5
FORMAT_SIZES_SPECIAL[GL_COMPRESSED_RGBA_ATC_EXPLICIT_ALPHA_WEBGL] = 1
FORMAT_SIZES_SPECIAL[GL_COMPRESSED_RGBA_ATC_INTERPOLATED_ALPHA_WEBGL] = 1

FORMAT_SIZES_SPECIAL[GL_COMPRESSED_RGB_PVRTC_4BPPV1_IMG] = 0.5
FORMAT_SIZES_SPECIAL[GL_COMPRESSED_RGB_PVRTC_2BPPV1_IMG] = 0.25
FORMAT_SIZES_SPECIAL[GL_COMPRESSED_RGBA_PVRTC_4BPPV1_IMG] = 0.5
FORMAT_SIZES_SPECIAL[GL_COMPRESSED_RGBA_PVRTC_2BPPV1_IMG] = 0.25

FORMAT_SIZES_SPECIAL[GL_COMPRESSED_RGB_ETC1_WEBGL] = 0.5

function isNumericArray (arr) {
  return (
    Array.isArray(arr) &&
    (arr.length === 0 ||
    typeof arr[0] === 'number'))
}

function isRectArray (arr) {
  if (!Array.isArray(arr)) {
    return false
  }
  var width = arr.length
  if (width === 0 || !isArrayLike(arr[0])) {
    return false
  }
  return true
}

function classString (x) {
  return Object.prototype.toString.call(x)
}

function isCanvasElement (object) {
  return classString(object) === CANVAS_CLASS
}

function isOffscreenCanvas (object) {
  return classString(object) === OFFSCREENCANVAS_CLASS
}

function isContext2D (object) {
  return classString(object) === CONTEXT2D_CLASS
}

function isBitmap (object) {
  return classString(object) === BITMAP_CLASS
}

function isImageElement (object) {
  return classString(object) === IMAGE_CLASS
}

function isVideoElement (object) {
  return classString(object) === VIDEO_CLASS
}

function isPixelData (object) {
  if (!object) {
    return false
  }
  var className = classString(object)
  if (PIXEL_CLASSES.indexOf(className) >= 0) {
    return true
  }
  return (
    isNumericArray(object) ||
    isRectArray(object) ||
    isNDArrayLike(object))
}

function typedArrayCode (data) {
  return arrayTypes[Object.prototype.toString.call(data)] | 0
}

function convertData (result, data) {
  var n = data.length
  switch (result.type) {
    case GL_UNSIGNED_BYTE:
    case GL_UNSIGNED_SHORT:
    case GL_UNSIGNED_INT:
    case GL_FLOAT:
      var converted = pool.allocType(result.type, n)
      converted.set(data)
      result.data = converted
      break

    case GL_HALF_FLOAT_OES:
      result.data = convertToHalfFloat(data)
      break

    default:
      check.raise('unsupported texture type, must specify a typed array')
  }
}

function preConvert (image, n) {
  return pool.allocType(
    image.type === GL_HALF_FLOAT_OES
      ? GL_FLOAT
      : image.type, n)
}

function postConvert (image, data) {
  if (image.type === GL_HALF_FLOAT_OES) {
    image.data = convertToHalfFloat(data)
    pool.freeType(data)
  } else {
    image.data = data
  }
}

function transposeData (image, array, strideX, strideY, strideC, offset) {
  var w = image.width
  var h = image.height
  var c = image.channels
  var n = w * h * c
  var data = preConvert(image, n)

  var p = 0
  for (var i = 0; i < h; ++i) {
    for (var j = 0; j < w; ++j) {
      for (var k = 0; k < c; ++k) {
        data[p++] = array[strideX * j + strideY * i + strideC * k + offset]
      }
    }
  }

  postConvert(image, data)
}

function getTextureSize (format, type, width, height, isMipmap, isCube) {
  var s
  if (typeof FORMAT_SIZES_SPECIAL[format] !== 'undefined') {
    // we have a special array for dealing with weird color formats such as RGB5A1
    s = FORMAT_SIZES_SPECIAL[format]
  } else {
    s = FORMAT_CHANNELS[format] * TYPE_SIZES[type]
  }

  if (isCube) {
    s *= 6
  }

  if (isMipmap) {
    // compute the total size of all the mipmaps.
    var total = 0

    var w = width
    while (w >= 1) {
      // we can only use mipmaps on a square image,
      // so we can simply use the width and ignore the height:
      total += s * w * w
      w /= 2
    }
    return total
  } else {
    return s * width * height
  }
}

module.exports = function createTextureSet (
  gl, extensions, limits, reglPoll, contextState, stats, config) {
  // -------------------------------------------------------
  // Initialize constants and parameter tables here
  // -------------------------------------------------------
  var mipmapHint = {
    "don't care": GL_DONT_CARE,
    'dont care': GL_DONT_CARE,
    'nice': GL_NICEST,
    'fast': GL_FASTEST
  }

  var wrapModes = {
    'repeat': GL_REPEAT,
    'clamp': GL_CLAMP_TO_EDGE,
    'mirror': GL_MIRRORED_REPEAT
  }

  var magFilters = {
    'nearest': GL_NEAREST,
    'linear': GL_LINEAR
  }

  var minFilters = extend({
    'mipmap': GL_LINEAR_MIPMAP_LINEAR,
    'nearest mipmap nearest': GL_NEAREST_MIPMAP_NEAREST,
    'linear mipmap nearest': GL_LINEAR_MIPMAP_NEAREST,
    'nearest mipmap linear': GL_NEAREST_MIPMAP_LINEAR,
    'linear mipmap linear': GL_LINEAR_MIPMAP_LINEAR
  }, magFilters)

  var colorSpace = {
    'none': 0,
    'browser': GL_BROWSER_DEFAULT_WEBGL
  }

  var textureTypes = {
    'uint8': GL_UNSIGNED_BYTE,
    'rgba4': GL_UNSIGNED_SHORT_4_4_4_4,
    'rgb565': GL_UNSIGNED_SHORT_5_6_5,
    'rgb5 a1': GL_UNSIGNED_SHORT_5_5_5_1
  }

  var textureFormats = {
    'alpha': GL_ALPHA,
    'luminance': GL_LUMINANCE,
    'luminance alpha': GL_LUMINANCE_ALPHA,
    'rgb': GL_RGB,
    'rgba': GL_RGBA,
    'rgba4': GL_RGBA4,
    'rgb5 a1': GL_RGB5_A1,
    'rgb565': GL_RGB565
  }

  var compressedTextureFormats = {}

  if (extensions.ext_srgb) {
    textureFormats.srgb = GL_SRGB_EXT
    textureFormats.srgba = GL_SRGB_ALPHA_EXT
  }

  if (extensions.oes_texture_float) {
    textureTypes.float32 = textureTypes.float = GL_FLOAT
  }

  if (extensions.oes_texture_half_float) {
    textureTypes['float16'] = textureTypes['half float'] = GL_HALF_FLOAT_OES
  }

  if (extensions.webgl_depth_texture) {
    extend(textureFormats, {
      'depth': GL_DEPTH_COMPONENT,
      'depth stencil': GL_DEPTH_STENCIL
    })

    extend(textureTypes, {
      'uint16': GL_UNSIGNED_SHORT,
      'uint32': GL_UNSIGNED_INT,
      'depth stencil': GL_UNSIGNED_INT_24_8_WEBGL
    })
  }

  if (extensions.webgl_compressed_texture_s3tc) {
    extend(compressedTextureFormats, {
      'rgb s3tc dxt1': GL_COMPRESSED_RGB_S3TC_DXT1_EXT,
      'rgba s3tc dxt1': GL_COMPRESSED_RGBA_S3TC_DXT1_EXT,
      'rgba s3tc dxt3': GL_COMPRESSED_RGBA_S3TC_DXT3_EXT,
      'rgba s3tc dxt5': GL_COMPRESSED_RGBA_S3TC_DXT5_EXT
    })
  }

  if (extensions.webgl_compressed_texture_atc) {
    extend(compressedTextureFormats, {
      'rgb atc': GL_COMPRESSED_RGB_ATC_WEBGL,
      'rgba atc explicit alpha': GL_COMPRESSED_RGBA_ATC_EXPLICIT_ALPHA_WEBGL,
      'rgba atc interpolated alpha': GL_COMPRESSED_RGBA_ATC_INTERPOLATED_ALPHA_WEBGL
    })
  }

  if (extensions.webgl_compressed_texture_pvrtc) {
    extend(compressedTextureFormats, {
      'rgb pvrtc 4bppv1': GL_COMPRESSED_RGB_PVRTC_4BPPV1_IMG,
      'rgb pvrtc 2bppv1': GL_COMPRESSED_RGB_PVRTC_2BPPV1_IMG,
      'rgba pvrtc 4bppv1': GL_COMPRESSED_RGBA_PVRTC_4BPPV1_IMG,
      'rgba pvrtc 2bppv1': GL_COMPRESSED_RGBA_PVRTC_2BPPV1_IMG
    })
  }

  if (extensions.webgl_compressed_texture_etc1) {
    compressedTextureFormats['rgb etc1'] = GL_COMPRESSED_RGB_ETC1_WEBGL
  }

  // Copy over all texture formats
  var supportedCompressedFormats = Array.prototype.slice.call(
    gl.getParameter(GL_COMPRESSED_TEXTURE_FORMATS))
  Object.keys(compressedTextureFormats).forEach(function (name) {
    var format = compressedTextureFormats[name]
    if (supportedCompressedFormats.indexOf(format) >= 0) {
      textureFormats[name] = format
    }
  })

  var supportedFormats = Object.keys(textureFormats)
  limits.textureFormats = supportedFormats

  // associate with every format string its
  // corresponding GL-value.
  var textureFormatsInvert = []
  Object.keys(textureFormats).forEach(function (key) {
    var val = textureFormats[key]
    textureFormatsInvert[val] = key
  })

  // associate with every type string its
  // corresponding GL-value.
  var textureTypesInvert = []
  Object.keys(textureTypes).forEach(function (key) {
    var val = textureTypes[key]
    textureTypesInvert[val] = key
  })

  var magFiltersInvert = []
  Object.keys(magFilters).forEach(function (key) {
    var val = magFilters[key]
    magFiltersInvert[val] = key
  })

  var minFiltersInvert = []
  Object.keys(minFilters).forEach(function (key) {
    var val = minFilters[key]
    minFiltersInvert[val] = key
  })

  var wrapModesInvert = []
  Object.keys(wrapModes).forEach(function (key) {
    var val = wrapModes[key]
    wrapModesInvert[val] = key
  })

  // colorFormats[] gives the format (channels) associated to an
  // internalformat
  var colorFormats = supportedFormats.reduce(function (color, key) {
    var glenum = textureFormats[key]
    if (glenum === GL_LUMINANCE ||
        glenum === GL_ALPHA ||
        glenum === GL_LUMINANCE ||
        glenum === GL_LUMINANCE_ALPHA ||
        glenum === GL_DEPTH_COMPONENT ||
        glenum === GL_DEPTH_STENCIL ||
        (extensions.ext_srgb &&
                (glenum === GL_SRGB_EXT ||
                 glenum === GL_SRGB_ALPHA_EXT))) {
      color[glenum] = glenum
    } else if (glenum === GL_RGB5_A1 || key.indexOf('rgba') >= 0) {
      color[glenum] = GL_RGBA
    } else {
      color[glenum] = GL_RGB
    }
    return color
  }, {})

  function TexFlags () {
    // format info
    this.internalformat = GL_RGBA
    this.format = GL_RGBA
    this.type = GL_UNSIGNED_BYTE
    this.compressed = false

    // pixel storage
    this.premultiplyAlpha = false
    this.flipY = false
    this.unpackAlignment = 1
    this.colorSpace = GL_BROWSER_DEFAULT_WEBGL

    // shape info
    this.width = 0
    this.height = 0
    this.channels = 0
  }

  function copyFlags (result, other) {
    result.internalformat = other.internalformat
    result.format = other.format
    result.type = other.type
    result.compressed = other.compressed

    result.premultiplyAlpha = other.premultiplyAlpha
    result.flipY = other.flipY
    result.unpackAlignment = other.unpackAlignment
    result.colorSpace = other.colorSpace

    result.width = other.width
    result.height = other.height
    result.channels = other.channels
  }

  function parseFlags (flags, options) {
    if (typeof options !== 'object' || !options) {
      return
    }

    if ('premultiplyAlpha' in options) {
      check.type(options.premultiplyAlpha, 'boolean',
        'invalid premultiplyAlpha')
      flags.premultiplyAlpha = options.premultiplyAlpha
    }

    if ('flipY' in options) {
      check.type(options.flipY, 'boolean',
        'invalid texture flip')
      flags.flipY = options.flipY
    }

    if ('alignment' in options) {
      check.oneOf(options.alignment, [1, 2, 4, 8],
        'invalid texture unpack alignment')
      flags.unpackAlignment = options.alignment
    }

    if ('colorSpace' in options) {
      check.parameter(options.colorSpace, colorSpace,
        'invalid colorSpace')
      flags.colorSpace = colorSpace[options.colorSpace]
    }

    if ('type' in options) {
      var type = options.type
      check(extensions.oes_texture_float ||
        !(type === 'float' || type === 'float32'),
      'you must enable the OES_texture_float extension in order to use floating point textures.')
      check(extensions.oes_texture_half_float ||
        !(type === 'half float' || type === 'float16'),
      'you must enable the OES_texture_half_float extension in order to use 16-bit floating point textures.')
      check(extensions.webgl_depth_texture ||
        !(type === 'uint16' || type === 'uint32' || type === 'depth stencil'),
      'you must enable the WEBGL_depth_texture extension in order to use depth/stencil textures.')
      check.parameter(type, textureTypes,
        'invalid texture type')
      flags.type = textureTypes[type]
    }

    var w = flags.width
    var h = flags.height
    var c = flags.channels
    var hasChannels = false
    if ('shape' in options) {
      check(Array.isArray(options.shape) && options.shape.length >= 2,
        'shape must be an array')
      w = options.shape[0]
      h = options.shape[1]
      if (options.shape.length === 3) {
        c = options.shape[2]
        check(c > 0 && c <= 4, 'invalid number of channels')
        hasChannels = true
      }
      check(w >= 0 && w <= limits.maxTextureSize, 'invalid width')
      check(h >= 0 && h <= limits.maxTextureSize, 'invalid height')
    } else {
      if ('radius' in options) {
        w = h = options.radius
        check(w >= 0 && w <= limits.maxTextureSize, 'invalid radius')
      }
      if ('width' in options) {
        w = options.width
        check(w >= 0 && w <= limits.maxTextureSize, 'invalid width')
      }
      if ('height' in options) {
        h = options.height
        check(h >= 0 && h <= limits.maxTextureSize, 'invalid height')
      }
      if ('channels' in options) {
        c = options.channels
        check(c > 0 && c <= 4, 'invalid number of channels')
        hasChannels = true
      }
    }
    flags.width = w | 0
    flags.height = h | 0
    flags.channels = c | 0

    var hasFormat = false
    if ('format' in options) {
      var formatStr = options.format
      check(extensions.webgl_depth_texture ||
        !(formatStr === 'depth' || formatStr === 'depth stencil'),
      'you must enable the WEBGL_depth_texture extension in order to use depth/stencil textures.')
      check.parameter(formatStr, textureFormats,
        'invalid texture format')
      var internalformat = flags.internalformat = textureFormats[formatStr]
      flags.format = colorFormats[internalformat]
      if (formatStr in textureTypes) {
        if (!('type' in options)) {
          flags.type = textureTypes[formatStr]
        }
      }
      if (formatStr in compressedTextureFormats) {
        flags.compressed = true
      }
      hasFormat = true
    }

    // Reconcile channels and format
    if (!hasChannels && hasFormat) {
      flags.channels = FORMAT_CHANNELS[flags.format]
    } else if (hasChannels && !hasFormat) {
      if (flags.channels !== CHANNELS_FORMAT[flags.format]) {
        flags.format = flags.internalformat = CHANNELS_FORMAT[flags.channels]
      }
    } else if (hasFormat && hasChannels) {
      check(
        flags.channels === FORMAT_CHANNELS[flags.format],
        'number of channels inconsistent with specified format')
    }
  }

  function setFlags (flags) {
    gl.pixelStorei(GL_UNPACK_FLIP_Y_WEBGL, flags.flipY)
    gl.pixelStorei(GL_UNPACK_PREMULTIPLY_ALPHA_WEBGL, flags.premultiplyAlpha)
    gl.pixelStorei(GL_UNPACK_COLORSPACE_CONVERSION_WEBGL, flags.colorSpace)
    gl.pixelStorei(GL_UNPACK_ALIGNMENT, flags.unpackAlignment)
  }

  // -------------------------------------------------------
  // Tex image data
  // -------------------------------------------------------
  function TexImage () {
    TexFlags.call(this)

    this.xOffset = 0
    this.yOffset = 0

    // data
    this.data = null
    this.needsFree = false

    // html element
    this.element = null

    // copyTexImage info
    this.needsCopy = false
  }

  function parseImage (image, options) {
    var data = null
    if (isPixelData(options)) {
      data = options
    } else if (options) {
      check.type(options, 'object', 'invalid pixel data type')
      parseFlags(image, options)
      if ('x' in options) {
        image.xOffset = options.x | 0
      }
      if ('y' in options) {
        image.yOffset = options.y | 0
      }
      if (isPixelData(options.data)) {
        data = options.data
      }
    }

    check(
      !image.compressed ||
      data instanceof Uint8Array,
      'compressed texture data must be stored in a uint8array')

    if (options.copy) {
      check(!data, 'can not specify copy and data field for the same texture')
      var viewW = contextState.viewportWidth
      var viewH = contextState.viewportHeight
      image.width = image.width || (viewW - image.xOffset)
      image.height = image.height || (viewH - image.yOffset)
      image.needsCopy = true
      check(image.xOffset >= 0 && image.xOffset < viewW &&
            image.yOffset >= 0 && image.yOffset < viewH &&
            image.width > 0 && image.width <= viewW &&
            image.height > 0 && image.height <= viewH,
      'copy texture read out of bounds')
    } else if (!data) {
      image.width = image.width || 1
      image.height = image.height || 1
      image.channels = image.channels || 4
    } else if (isTypedArray(data)) {
      image.channels = image.channels || 4
      image.data = data
      if (!('type' in options) && image.type === GL_UNSIGNED_BYTE) {
        image.type = typedArrayCode(data)
      }
    } else if (isNumericArray(data)) {
      image.channels = image.channels || 4
      convertData(image, data)
      image.alignment = 1
      image.needsFree = true
    } else if (isNDArrayLike(data)) {
      var array = data.data
      if (!Array.isArray(array) && image.type === GL_UNSIGNED_BYTE) {
        image.type = typedArrayCode(array)
      }
      var shape = data.shape
      var stride = data.stride
      var shapeX, shapeY, shapeC, strideX, strideY, strideC
      if (shape.length === 3) {
        shapeC = shape[2]
        strideC = stride[2]
      } else {
        check(shape.length === 2, 'invalid ndarray pixel data, must be 2 or 3D')
        shapeC = 1
        strideC = 1
      }
      shapeX = shape[0]
      shapeY = shape[1]
      strideX = stride[0]
      strideY = stride[1]
      image.alignment = 1
      image.width = shapeX
      image.height = shapeY
      image.channels = shapeC
      image.format = image.internalformat = CHANNELS_FORMAT[shapeC]
      image.needsFree = true
      transposeData(image, array, strideX, strideY, strideC, data.offset)
    } else if (isCanvasElement(data) || isOffscreenCanvas(data) || isContext2D(data)) {
      if (isCanvasElement(data) || isOffscreenCanvas(data)) {
        image.element = data
      } else {
        image.element = data.canvas
      }
      image.width = image.element.width
      image.height = image.element.height
      image.channels = 4
    } else if (isBitmap(data)) {
      image.element = data
      image.width = data.width
      image.height = data.height
      image.channels = 4
    } else if (isImageElement(data)) {
      image.element = data
      image.width = data.naturalWidth
      image.height = data.naturalHeight
      image.channels = 4
    } else if (isVideoElement(data)) {
      image.element = data
      image.width = data.videoWidth
      image.height = data.videoHeight
      image.channels = 4
    } else if (isRectArray(data)) {
      var w = image.width || data[0].length
      var h = image.height || data.length
      var c = image.channels
      if (isArrayLike(data[0][0])) {
        c = c || data[0][0].length
      } else {
        c = c || 1
      }
      var arrayShape = flattenUtils.shape(data)
      var n = 1
      for (var dd = 0; dd < arrayShape.length; ++dd) {
        n *= arrayShape[dd]
      }
      var allocData = preConvert(image, n)
      flattenUtils.flatten(data, arrayShape, '', allocData)
      postConvert(image, allocData)
      image.alignment = 1
      image.width = w
      image.height = h
      image.channels = c
      image.format = image.internalformat = CHANNELS_FORMAT[c]
      image.needsFree = true
    }

    if (image.type === GL_FLOAT) {
      check(limits.extensions.indexOf('oes_texture_float') >= 0,
        'oes_texture_float extension not enabled')
    } else if (image.type === GL_HALF_FLOAT_OES) {
      check(limits.extensions.indexOf('oes_texture_half_float') >= 0,
        'oes_texture_half_float extension not enabled')
    }

    // do compressed texture  validation here.
  }

  function setImage (info, target, miplevel) {
    var element = info.element
    var data = info.data
    var internalformat = info.internalformat
    var format = info.format
    var type = info.type
    var width = info.width
    var height = info.height

    setFlags(info)

    if (element) {
      gl.texImage2D(target, miplevel, format, format, type, element)
    } else if (info.compressed) {
      gl.compressedTexImage2D(target, miplevel, internalformat, width, height, 0, data)
    } else if (info.needsCopy) {
      reglPoll()
      gl.copyTexImage2D(
        target, miplevel, format, info.xOffset, info.yOffset, width, height, 0)
    } else {
      gl.texImage2D(target, miplevel, format, width, height, 0, format, type, data || null)
    }
  }

  function setSubImage (info, target, x, y, miplevel) {
    var element = info.element
    var data = info.data
    var internalformat = info.internalformat
    var format = info.format
    var type = info.type
    var width = info.width
    var height = info.height

    setFlags(info)

    if (element) {
      gl.texSubImage2D(
        target, miplevel, x, y, format, type, element)
    } else if (info.compressed) {
      gl.compressedTexSubImage2D(
        target, miplevel, x, y, internalformat, width, height, data)
    } else if (info.needsCopy) {
      reglPoll()
      gl.copyTexSubImage2D(
        target, miplevel, x, y, info.xOffset, info.yOffset, width, height)
    } else {
      gl.texSubImage2D(
        target, miplevel, x, y, width, height, format, type, data)
    }
  }

  // texImage pool
  var imagePool = []

  function allocImage () {
    return imagePool.pop() || new TexImage()
  }

  function freeImage (image) {
    if (image.needsFree) {
      pool.freeType(image.data)
    }
    TexImage.call(image)
    imagePool.push(image)
  }

  // -------------------------------------------------------
  // Mip map
  // -------------------------------------------------------
  function MipMap () {
    TexFlags.call(this)

    this.genMipmaps = false
    this.mipmapHint = GL_DONT_CARE
    this.mipmask = 0
    this.images = Array(16)
  }

  function parseMipMapFromShape (mipmap, width, height) {
    var img = mipmap.images[0] = allocImage()
    mipmap.mipmask = 1
    img.width = mipmap.width = width
    img.height = mipmap.height = height
    img.channels = mipmap.channels = 4
  }

  function parseMipMapFromObject (mipmap, options) {
    var imgData = null
    if (isPixelData(options)) {
      imgData = mipmap.images[0] = allocImage()
      copyFlags(imgData, mipmap)
      parseImage(imgData, options)
      mipmap.mipmask = 1
    } else {
      parseFlags(mipmap, options)
      if (Array.isArray(options.mipmap)) {
        var mipData = options.mipmap
        for (var i = 0; i < mipData.length; ++i) {
          imgData = mipmap.images[i] = allocImage()
          copyFlags(imgData, mipmap)
          imgData.width >>= i
          imgData.height >>= i
          parseImage(imgData, mipData[i])
          mipmap.mipmask |= (1 << i)
        }
      } else {
        imgData = mipmap.images[0] = allocImage()
        copyFlags(imgData, mipmap)
        parseImage(imgData, options)
        mipmap.mipmask = 1
      }
    }
    copyFlags(mipmap, mipmap.images[0])

    // For textures of the compressed format WEBGL_compressed_texture_s3tc
    // we must have that
    //
    // "When level equals zero width and height must be a multiple of 4.
    // When level is greater than 0 width and height must be 0, 1, 2 or a multiple of 4. "
    //
    // but we do not yet support having multiple mipmap levels for compressed textures,
    // so we only test for level zero.

    if (
      mipmap.compressed &&
      (
        mipmap.internalformat === GL_COMPRESSED_RGB_S3TC_DXT1_EXT ||
        mipmap.internalformat === GL_COMPRESSED_RGBA_S3TC_DXT1_EXT ||
        mipmap.internalformat === GL_COMPRESSED_RGBA_S3TC_DXT3_EXT ||
        mipmap.internalformat === GL_COMPRESSED_RGBA_S3TC_DXT5_EXT
      )
    ) {
      check(mipmap.width % 4 === 0 && mipmap.height % 4 === 0,
        'for compressed texture formats, mipmap level 0 must have width and height that are a multiple of 4')
    }
  }

  function setMipMap (mipmap, target) {
    var images = mipmap.images
    for (var i = 0; i < images.length; ++i) {
      if (!images[i]) {
        return
      }
      setImage(images[i], target, i)
    }
  }

  var mipPool = []

  function allocMipMap () {
    var result = mipPool.pop() || new MipMap()
    TexFlags.call(result)
    result.mipmask = 0
    for (var i = 0; i < 16; ++i) {
      result.images[i] = null
    }
    return result
  }

  function freeMipMap (mipmap) {
    var images = mipmap.images
    for (var i = 0; i < images.length; ++i) {
      if (images[i]) {
        freeImage(images[i])
      }
      images[i] = null
    }
    mipPool.push(mipmap)
  }

  // -------------------------------------------------------
  // Tex info
  // -------------------------------------------------------
  function TexInfo () {
    this.minFilter = GL_NEAREST
    this.magFilter = GL_NEAREST

    this.wrapS = GL_CLAMP_TO_EDGE
    this.wrapT = GL_CLAMP_TO_EDGE

    this.anisotropic = 1

    this.genMipmaps = false
    this.mipmapHint = GL_DONT_CARE
  }

  function parseTexInfo (info, options) {
    if ('min' in options) {
      var minFilter = options.min
      check.parameter(minFilter, minFilters)
      info.minFilter = minFilters[minFilter]
      if (MIPMAP_FILTERS.indexOf(info.minFilter) >= 0 && !('faces' in options)) {
        info.genMipmaps = true
      }
    }

    if ('mag' in options) {
      var magFilter = options.mag
      check.parameter(magFilter, magFilters)
      info.magFilter = magFilters[magFilter]
    }

    var wrapS = info.wrapS
    var wrapT = info.wrapT
    if ('wrap' in options) {
      var wrap = options.wrap
      if (typeof wrap === 'string') {
        check.parameter(wrap, wrapModes)
        wrapS = wrapT = wrapModes[wrap]
      } else if (Array.isArray(wrap)) {
        check.parameter(wrap[0], wrapModes)
        check.parameter(wrap[1], wrapModes)
        wrapS = wrapModes[wrap[0]]
        wrapT = wrapModes[wrap[1]]
      }
    } else {
      if ('wrapS' in options) {
        var optWrapS = options.wrapS
        check.parameter(optWrapS, wrapModes)
        wrapS = wrapModes[optWrapS]
      }
      if ('wrapT' in options) {
        var optWrapT = options.wrapT
        check.parameter(optWrapT, wrapModes)
        wrapT = wrapModes[optWrapT]
      }
    }
    info.wrapS = wrapS
    info.wrapT = wrapT

    if ('anisotropic' in options) {
      var anisotropic = options.anisotropic
      check(typeof anisotropic === 'number' &&
         anisotropic >= 1 && anisotropic <= limits.maxAnisotropic,
      'aniso samples must be between 1 and ')
      info.anisotropic = options.anisotropic
    }

    if ('mipmap' in options) {
      var hasMipMap = false
      switch (typeof options.mipmap) {
        case 'string':
          check.parameter(options.mipmap, mipmapHint,
            'invalid mipmap hint')
          info.mipmapHint = mipmapHint[options.mipmap]
          info.genMipmaps = true
          hasMipMap = true
          break

        case 'boolean':
          hasMipMap = info.genMipmaps = options.mipmap
          break

        case 'object':
          check(Array.isArray(options.mipmap), 'invalid mipmap type')
          info.genMipmaps = false
          hasMipMap = true
          break

        default:
          check.raise('invalid mipmap type')
      }
      if (hasMipMap && !('min' in options)) {
        info.minFilter = GL_NEAREST_MIPMAP_NEAREST
      }
    }
  }

  function setTexInfo (info, target) {
    gl.texParameteri(target, GL_TEXTURE_MIN_FILTER, info.minFilter)
    gl.texParameteri(target, GL_TEXTURE_MAG_FILTER, info.magFilter)
    gl.texParameteri(target, GL_TEXTURE_WRAP_S, info.wrapS)
    gl.texParameteri(target, GL_TEXTURE_WRAP_T, info.wrapT)
    if (extensions.ext_texture_filter_anisotropic) {
      gl.texParameteri(target, GL_TEXTURE_MAX_ANISOTROPY_EXT, info.anisotropic)
    }
    if (info.genMipmaps) {
      gl.hint(GL_GENERATE_MIPMAP_HINT, info.mipmapHint)
      gl.generateMipmap(target)
    }
  }

  // -------------------------------------------------------
  // Full texture object
  // -------------------------------------------------------
  var textureCount = 0
  var textureSet = {}
  var numTexUnits = limits.maxTextureUnits
  var textureUnits = Array(numTexUnits).map(function () {
    return null
  })

  function REGLTexture (target) {
    TexFlags.call(this)
    this.mipmask = 0
    this.internalformat = GL_RGBA

    this.id = textureCount++

    this.refCount = 1

    this.target = target
    this.texture = gl.createTexture()

    this.unit = -1
    this.bindCount = 0

    this.texInfo = new TexInfo()

    if (config.profile) {
      this.stats = { size: 0 }
    }
  }

  function tempBind (texture) {
    gl.activeTexture(GL_TEXTURE0)
    gl.bindTexture(texture.target, texture.texture)
  }

  function tempRestore () {
    var prev = textureUnits[0]
    if (prev) {
      gl.bindTexture(prev.target, prev.texture)
    } else {
      gl.bindTexture(GL_TEXTURE_2D, null)
    }
  }

  function destroy (texture) {
    var handle = texture.texture
    check(handle, 'must not double destroy texture')
    var unit = texture.unit
    var target = texture.target
    if (unit >= 0) {
      gl.activeTexture(GL_TEXTURE0 + unit)
      gl.bindTexture(target, null)
      textureUnits[unit] = null
    }
    gl.deleteTexture(handle)
    texture.texture = null
    texture.params = null
    texture.pixels = null
    texture.refCount = 0
    delete textureSet[texture.id]
    stats.textureCount--
  }

  extend(REGLTexture.prototype, {
    bind: function () {
      var texture = this
      texture.bindCount += 1
      var unit = texture.unit
      if (unit < 0) {
        for (var i = 0; i < numTexUnits; ++i) {
          var other = textureUnits[i]
          if (other) {
            if (other.bindCount > 0) {
              continue
            }
            other.unit = -1
          }
          textureUnits[i] = texture
          unit = i
          break
        }
        if (unit >= numTexUnits) {
          check.raise('insufficient number of texture units')
        }
        if (config.profile && stats.maxTextureUnits < (unit + 1)) {
          stats.maxTextureUnits = unit + 1 // +1, since the units are zero-based
        }
        texture.unit = unit
        gl.activeTexture(GL_TEXTURE0 + unit)
        gl.bindTexture(texture.target, texture.texture)
      }
      return unit
    },

    unbind: function () {
      this.bindCount -= 1
    },

    decRef: function () {
      if (--this.refCount <= 0) {
        destroy(this)
      }
    }
  })

  function createTexture2D (a, b) {
    var texture = new REGLTexture(GL_TEXTURE_2D)
    textureSet[texture.id] = texture
    stats.textureCount++

    function reglTexture2D (a, b) {
      var texInfo = texture.texInfo
      TexInfo.call(texInfo)
      var mipData = allocMipMap()

      if (typeof a === 'number') {
        if (typeof b === 'number') {
          parseMipMapFromShape(mipData, a | 0, b | 0)
        } else {
          parseMipMapFromShape(mipData, a | 0, a | 0)
        }
      } else if (a) {
        check.type(a, 'object', 'invalid arguments to regl.texture')
        parseTexInfo(texInfo, a)
        parseMipMapFromObject(mipData, a)
      } else {
        // empty textures get assigned a default shape of 1x1
        parseMipMapFromShape(mipData, 1, 1)
      }

      if (texInfo.genMipmaps) {
        mipData.mipmask = (mipData.width << 1) - 1
      }
      texture.mipmask = mipData.mipmask

      copyFlags(texture, mipData)

      check.texture2D(texInfo, mipData, limits)
      texture.internalformat = mipData.internalformat

      reglTexture2D.width = mipData.width
      reglTexture2D.height = mipData.height

      tempBind(texture)
      setMipMap(mipData, GL_TEXTURE_2D)
      setTexInfo(texInfo, GL_TEXTURE_2D)
      tempRestore()

      freeMipMap(mipData)

      if (config.profile) {
        texture.stats.size = getTextureSize(
          texture.internalformat,
          texture.type,
          mipData.width,
          mipData.height,
          texInfo.genMipmaps,
          false)
      }
      reglTexture2D.format = textureFormatsInvert[texture.internalformat]
      reglTexture2D.type = textureTypesInvert[texture.type]

      reglTexture2D.mag = magFiltersInvert[texInfo.magFilter]
      reglTexture2D.min = minFiltersInvert[texInfo.minFilter]

      reglTexture2D.wrapS = wrapModesInvert[texInfo.wrapS]
      reglTexture2D.wrapT = wrapModesInvert[texInfo.wrapT]

      return reglTexture2D
    }

    function subimage (image, x_, y_, level_) {
      check(!!image, 'must specify image data')

      var x = x_ | 0
      var y = y_ | 0
      var level = level_ | 0

      var imageData = allocImage()
      copyFlags(imageData, texture)
      imageData.width = 0
      imageData.height = 0
      parseImage(imageData, image)
      imageData.width = imageData.width || ((texture.width >> level) - x)
      imageData.height = imageData.height || ((texture.height >> level) - y)

      check(
        texture.type === imageData.type &&
        texture.format === imageData.format &&
        texture.internalformat === imageData.internalformat,
        'incompatible format for texture.subimage')
      check(
        x >= 0 && y >= 0 &&
        x + imageData.width <= texture.width &&
        y + imageData.height <= texture.height,
        'texture.subimage write out of bounds')
      check(
        texture.mipmask & (1 << level),
        'missing mipmap data')
      check(
        imageData.data || imageData.element || imageData.needsCopy,
        'missing image data')

      tempBind(texture)
      setSubImage(imageData, GL_TEXTURE_2D, x, y, level)
      tempRestore()

      freeImage(imageData)

      return reglTexture2D
    }

    function resize (w_, h_) {
      var w = w_ | 0
      var h = (h_ | 0) || w
      if (w === texture.width && h === texture.height) {
        return reglTexture2D
      }

      reglTexture2D.width = texture.width = w
      reglTexture2D.height = texture.height = h

      tempBind(texture)

      for (var i = 0; texture.mipmask >> i; ++i) {
        var _w = w >> i
        var _h = h >> i
        if (!_w || !_h) break
        gl.texImage2D(
          GL_TEXTURE_2D,
          i,
          texture.format,
          _w,
          _h,
          0,
          texture.format,
          texture.type,
          null)
      }
      tempRestore()

      // also, recompute the texture size.
      if (config.profile) {
        texture.stats.size = getTextureSize(
          texture.internalformat,
          texture.type,
          w,
          h,
          false,
          false)
      }

      return reglTexture2D
    }

    reglTexture2D(a, b)

    reglTexture2D.subimage = subimage
    reglTexture2D.resize = resize
    reglTexture2D._reglType = 'texture2d'
    reglTexture2D._texture = texture
    if (config.profile) {
      reglTexture2D.stats = texture.stats
    }
    reglTexture2D.destroy = function () {
      texture.decRef()
    }

    return reglTexture2D
  }

  function createTextureCube (a0, a1, a2, a3, a4, a5) {
    var texture = new REGLTexture(GL_TEXTURE_CUBE_MAP)
    textureSet[texture.id] = texture
    stats.cubeCount++

    var faces = new Array(6)

    function reglTextureCube (a0, a1, a2, a3, a4, a5) {
      var i
      var texInfo = texture.texInfo
      TexInfo.call(texInfo)
      for (i = 0; i < 6; ++i) {
        faces[i] = allocMipMap()
      }

      if (typeof a0 === 'number' || !a0) {
        var s = (a0 | 0) || 1
        for (i = 0; i < 6; ++i) {
          parseMipMapFromShape(faces[i], s, s)
        }
      } else if (typeof a0 === 'object') {
        if (a1) {
          parseMipMapFromObject(faces[0], a0)
          parseMipMapFromObject(faces[1], a1)
          parseMipMapFromObject(faces[2], a2)
          parseMipMapFromObject(faces[3], a3)
          parseMipMapFromObject(faces[4], a4)
          parseMipMapFromObject(faces[5], a5)
        } else {
          parseTexInfo(texInfo, a0)
          parseFlags(texture, a0)
          if ('faces' in a0) {
            var faceInput = a0.faces
            check(Array.isArray(faceInput) && faceInput.length === 6,
              'cube faces must be a length 6 array')
            for (i = 0; i < 6; ++i) {
              check(typeof faceInput[i] === 'object' && !!faceInput[i],
                'invalid input for cube map face')
              copyFlags(faces[i], texture)
              parseMipMapFromObject(faces[i], faceInput[i])
            }
          } else {
            for (i = 0; i < 6; ++i) {
              parseMipMapFromObject(faces[i], a0)
            }
          }
        }
      } else {
        check.raise('invalid arguments to cube map')
      }

      copyFlags(texture, faces[0])
      check.optional(function () {
        if (!limits.npotTextureCube) {
          check(isPow2(texture.width) && isPow2(texture.height), 'your browser does not support non power or two texture dimensions')
        }
      })

      if (texInfo.genMipmaps) {
        texture.mipmask = (faces[0].width << 1) - 1
      } else {
        texture.mipmask = faces[0].mipmask
      }

      check.textureCube(texture, texInfo, faces, limits)
      texture.internalformat = faces[0].internalformat

      reglTextureCube.width = faces[0].width
      reglTextureCube.height = faces[0].height

      tempBind(texture)
      for (i = 0; i < 6; ++i) {
        setMipMap(faces[i], GL_TEXTURE_CUBE_MAP_POSITIVE_X + i)
      }
      setTexInfo(texInfo, GL_TEXTURE_CUBE_MAP)
      tempRestore()

      if (config.profile) {
        texture.stats.size = getTextureSize(
          texture.internalformat,
          texture.type,
          reglTextureCube.width,
          reglTextureCube.height,
          texInfo.genMipmaps,
          true)
      }

      reglTextureCube.format = textureFormatsInvert[texture.internalformat]
      reglTextureCube.type = textureTypesInvert[texture.type]

      reglTextureCube.mag = magFiltersInvert[texInfo.magFilter]
      reglTextureCube.min = minFiltersInvert[texInfo.minFilter]

      reglTextureCube.wrapS = wrapModesInvert[texInfo.wrapS]
      reglTextureCube.wrapT = wrapModesInvert[texInfo.wrapT]

      for (i = 0; i < 6; ++i) {
        freeMipMap(faces[i])
      }

      return reglTextureCube
    }

    function subimage (face, image, x_, y_, level_) {
      check(!!image, 'must specify image data')
      check(typeof face === 'number' && face === (face | 0) &&
        face >= 0 && face < 6, 'invalid face')

      var x = x_ | 0
      var y = y_ | 0
      var level = level_ | 0

      var imageData = allocImage()
      copyFlags(imageData, texture)
      imageData.width = 0
      imageData.height = 0
      parseImage(imageData, image)
      imageData.width = imageData.width || ((texture.width >> level) - x)
      imageData.height = imageData.height || ((texture.height >> level) - y)

      check(
        texture.type === imageData.type &&
        texture.format === imageData.format &&
        texture.internalformat === imageData.internalformat,
        'incompatible format for texture.subimage')
      check(
        x >= 0 && y >= 0 &&
        x + imageData.width <= texture.width &&
        y + imageData.height <= texture.height,
        'texture.subimage write out of bounds')
      check(
        texture.mipmask & (1 << level),
        'missing mipmap data')
      check(
        imageData.data || imageData.element || imageData.needsCopy,
        'missing image data')

      tempBind(texture)
      setSubImage(imageData, GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, x, y, level)
      tempRestore()

      freeImage(imageData)

      return reglTextureCube
    }

    function resize (radius_) {
      var radius = radius_ | 0
      if (radius === texture.width) {
        return
      }

      reglTextureCube.width = texture.width = radius
      reglTextureCube.height = texture.height = radius

      tempBind(texture)
      for (var i = 0; i < 6; ++i) {
        for (var j = 0; texture.mipmask >> j; ++j) {
          gl.texImage2D(
            GL_TEXTURE_CUBE_MAP_POSITIVE_X + i,
            j,
            texture.format,
            radius >> j,
            radius >> j,
            0,
            texture.format,
            texture.type,
            null)
        }
      }
      tempRestore()

      if (config.profile) {
        texture.stats.size = getTextureSize(
          texture.internalformat,
          texture.type,
          reglTextureCube.width,
          reglTextureCube.height,
          false,
          true)
      }

      return reglTextureCube
    }

    reglTextureCube(a0, a1, a2, a3, a4, a5)

    reglTextureCube.subimage = subimage
    reglTextureCube.resize = resize
    reglTextureCube._reglType = 'textureCube'
    reglTextureCube._texture = texture
    if (config.profile) {
      reglTextureCube.stats = texture.stats
    }
    reglTextureCube.destroy = function () {
      texture.decRef()
    }

    return reglTextureCube
  }

  // Called when regl is destroyed
  function destroyTextures () {
    for (var i = 0; i < numTexUnits; ++i) {
      gl.activeTexture(GL_TEXTURE0 + i)
      gl.bindTexture(GL_TEXTURE_2D, null)
      textureUnits[i] = null
    }
    values(textureSet).forEach(destroy)

    stats.cubeCount = 0
    stats.textureCount = 0
  }

  if (config.profile) {
    stats.getTotalTextureSize = function () {
      var total = 0
      Object.keys(textureSet).forEach(function (key) {
        total += textureSet[key].stats.size
      })
      return total
    }
  }

  function restoreTextures () {
    for (var i = 0; i < numTexUnits; ++i) {
      var tex = textureUnits[i]
      if (tex) {
        tex.bindCount = 0
        tex.unit = -1
        textureUnits[i] = null
      }
    }

    values(textureSet).forEach(function (texture) {
      texture.texture = gl.createTexture()
      gl.bindTexture(texture.target, texture.texture)
      for (var i = 0; i < 32; ++i) {
        if ((texture.mipmask & (1 << i)) === 0) {
          continue
        }
        if (texture.target === GL_TEXTURE_2D) {
          gl.texImage2D(GL_TEXTURE_2D,
            i,
            texture.internalformat,
            texture.width >> i,
            texture.height >> i,
            0,
            texture.internalformat,
            texture.type,
            null)
        } else {
          for (var j = 0; j < 6; ++j) {
            gl.texImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + j,
              i,
              texture.internalformat,
              texture.width >> i,
              texture.height >> i,
              0,
              texture.internalformat,
              texture.type,
              null)
          }
        }
      }
      setTexInfo(texture.texInfo, texture.target)
    })
  }

  function refreshTextures () {
    for (var i = 0; i < numTexUnits; ++i) {
      var tex = textureUnits[i]
      if (tex) {
        tex.bindCount = 0
        tex.unit = -1
        textureUnits[i] = null
      }
      gl.activeTexture(GL_TEXTURE0 + i)
      gl.bindTexture(GL_TEXTURE_2D, null)
      gl.bindTexture(GL_TEXTURE_CUBE_MAP, null)
    }
  }

  return {
    create2D: createTexture2D,
    createCube: createTextureCube,
    clear: destroyTextures,
    getTexture: function (wrapper) {
      return null
    },
    restore: restoreTextures,
    refresh: refreshTextures
  }
}