func (this *textureManager) Update(filename string) {
	outer := gl.Texture(getEnum(BindingMap[this.target]))
	this.texture.Bind(this.target)
	LoadTexture(filename, this.target)
	gl.GenerateMipmap(this.target)
	outer.Bind(this.target)
}
func TexturesTest() {
	out := make([]int32, 1)
	gl.GetIntegerv(gl.MAX_TEXTURE_IMAGE_UNITS, out)
	maxUnits := int(out[0])

	for i := 0; i < maxUnits; i++ {
		gl.ActiveTexture(gl.GLenum(gl.TEXTURE0 + i))

		gl.GetIntegerv(gl.TEXTURE_BINDING_1D, out)
		texture := gl.Texture(out[0])
		if texture != 0 {
			fmt.Println("unit: ", i, " texture1d: ", texture)
		}

		gl.GetIntegerv(gl.TEXTURE_BINDING_2D, out)
		texture = gl.Texture(out[0])
		if texture != 0 {
			fmt.Println("unit: ", i, " texture2d: ", texture)
		}

		gl.GetIntegerv(gl.TEXTURE_BINDING_RECTANGLE, out)
		texture = gl.Texture(out[0])
		if texture != 0 {
			fmt.Println("unit: ", i, " textureRect: ", texture)
		}

		gl.GetIntegerv(gl.TEXTURE_BINDING_CUBE_MAP, out)
		texture = gl.Texture(out[0])
		if texture != 0 {
			fmt.Println("unit: ", i, " textureCube: ", texture)
		}

		gl.GetIntegerv(gl.TEXTURE_BINDING_3D, out)
		texture = gl.Texture(out[0])
		if texture != 0 {
			fmt.Println("unit: ", i, " texture3d: ", texture)
		}
	}

	gl.ActiveTexture(gl.TEXTURE0)
}
func LoadTextureWatched(filename string, target gl.GLenum) {
	i, _, _, _ := gl.GetInteger4(BindingMap[target])
	Manage(&textureManager{gl.Texture(i), target}, filename)
	LoadTexture(filename, target)
}