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CHAPTER 9: User Interface
1.0f, 1.0f,
1.0f, 0.0f, 0.0f, 1.0f,
0.2f, 0.2f, 0.2f, 1.0f,
0.0f, 0.0f, 1.0f, 0.0f,
1.0f, 0.0f,
1.0f, 0.0f, 0.0f, 1.0f,
-0.2f, 0.2f, 0.2f, 1.0f,
0.0f, 0.0f, 1.0f, 0.0f,
0.0f, 0.0f,
1.0f, 0.0f, 0.0f, 1.0f
)
val drawOrder = shortArrayOf( //
vertices order
0, 1, 2, 0, 2, 3
)
}
Inside the init block, the buffers
get defined and initialized, and we also load a texture image.
init {
// initialize vertex byte buffer for shape
//
coordinates
vertexBuffer = ByteBuffer.allocateDirect(
coords.size * BYTES_PER_FLOAT).apply{
order(ByteOrder.nativeOrder())
}.asFloatBuffer().apply {
put(coords)
position(0)
}
// initialize byte buffer for the draw list
drawListBuffer = ByteBuffer.allocateDirect(
drawOrder.size * BYTES_PER_SHORT).apply {
order(ByteOrder.nativeOrder())
}.asShortBuffer().apply {
put(drawOrder)
position(0)
}
if (vertBuf > 0 && idxBuf > 0) {
GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER,
vertBuf)
GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER,
vertexBuffer.capacity() * BYTES_PER_FLOAT,
vertexBuffer, GLES20.GL_STATIC_DRAW)
GLES20.glBindBuffer(
GLES20.GL_ELEMENT_ARRAY_BUFFER, idxBuf)
GLES20.glBufferData(
GLES20.GL_ELEMENT_ARRAY_BUFFER,
drawListBuffer.capacity() *
BYTES_PER_SHORT,
drawListBuffer, GLES20.GL_STATIC_DRAW)
