QuadRender.kt

private val quadVertices: FloatBuffer

init {
   // set array of Quad vertices
   val quadVerticesData = floatArrayOf(
       // [x,y,z, U,V]
       -1.0f, -1.0f, 0f, 0f, 1f,
       1.0f, -1.0f, 0f, 1f, 1f,
       -1.0f, 1.0f, 0f, 0f, 0f,
       1.0f, 1.0f, 0f, 1f, 0f
   )

   quadVertices = ByteBuffer
       .allocateDirect(quadVerticesData.size * FLOAT_SIZE_BYTES)
       .order(ByteOrder.nativeOrder())
       .asFloatBuffer()
       .apply {
           put(quadVerticesData).position(0)
       }
}