package br.carinha.rosto;

import java.nio.ByteBuffer;

/** Converts Camera2 planes to NV21, respecting padding and interleaved chroma. */
public final class YuvFrame {
    public static byte[] nv21(int w, int h, ByteBuffer[] planes, int[] rows, int[] pixels) {
        if (w <= 0 || h <= 0 || (w & 1) != 0 || (h & 1) != 0)
            throw new IllegalArgumentException("YUV requires positive even dimensions");
        byte[] out = new byte[w * h * 3 / 2];
        int at = 0;
        for (int y = 0; y < h; y++)
            for (int x = 0; x < w; x++)
                out[at++] = planes[0].get(planes[0].position() + y * rows[0] + x * pixels[0]);
        for (int y = 0; y < h / 2; y++)
            for (int x = 0; x < w / 2; x++) {
                out[at++] = planes[2].get(planes[2].position() + y * rows[2] + x * pixels[2]);
                out[at++] = planes[1].get(planes[1].position() + y * rows[1] + x * pixels[1]);
            }
        return out;
    }
}