VertexAttribute
fun VertexAttribute( usage: VertexAttrUsage, numComponents: Int, alias: String, type: VertexAttrType = if (usage == VertexAttrUsage.COLOR_PACKED) VertexAttrType.UNSIGNED_BYTE else VertexAttrType.FLOAT, normalized: Boolean = usage == VertexAttrUsage.COLOR_PACKED, unit: Int = 0, asInt: Boolean = false)