1 files changed, 89 insertions, 0 deletions
diff --git a/subprojects/pixpat/pixpat-native/src/io/packed_yuv.h b/subprojects/pixpat/pixpat-native/src/io/packed_yuv.h
new file mode 100644
index 0000000..90c8b2f
--- /dev/null
+++ b/subprojects/pixpat/pixpat-native/src/io/packed_yuv.h
@@ -0,0 +1,89 @@
+#pragma once
+
+// Packed YUV 4:2:2 (YUYV / YVYU / UYVY / VYUY): two pixels per 32-bit
+// word, one shared chroma pair. The Layout uses two C::Y entries plus
+// one each of C::U / C::V; we resolve the duplicate Y via
+// find_pos<C::Y>(n).
+
+#include <array>
+
+#include "../layout.h"
+#include "detail.h"
+
+namespace pixpat
+{
+
+template <typename L>
+struct PackedYUVSource {
+	using Layout = L;
+	using Pixel  = YUV16;
+
+	static_assert(L::kind == ColorKind::YUV);
+	static_assert(L::num_planes == 1);
+	static_assert(L::h_sub == 2 && L::v_sub == 1);
+
+	using P = typename L::template plane<0>;
+	static constexpr size_t y0_idx = P::template find_pos<C::Y>(0);
+	static constexpr size_t y1_idx = P::template find_pos<C::Y>(1);
+	static constexpr size_t u_idx  = P::template find_pos<C::U>();
+	static constexpr size_t v_idx  = P::template find_pos<C::V>();
+
+	static YUV16 read(const Buffer<1>& buf, size_t x, size_t y,
+	                  [[maybe_unused]] size_t W,
+	                  [[maybe_unused]] size_t H) noexcept
+	{
+		const uint8_t* p = buf.data[0] + y * buf.stride[0]
+		                   + (x / 2) * P::bytes_per_pixel;
+		const auto vals = P::unpack(detail::load_word<P>(p));
+		const size_t y_pick = (x & 1) ? y1_idx : y0_idx;
+		// Both Y components share the same bit width, so the bit-width
+		// for y0 and y1 is identical — pick either.
+		return YUV16{
+		        detail::decode_norm(P::comps[y0_idx].bits, vals[y_pick]),
+		        detail::decode_norm(P::comps[u_idx].bits, vals[u_idx]),
+		        detail::decode_norm(P::comps[v_idx].bits, vals[v_idx]),
+		        uint16_t(0),
+		};
+	}
+};
+
+template <typename L>
+struct PackedYUVSink {
+	using Layout = L;
+	using Pixel  = YUV16;
+
+	static_assert(L::kind == ColorKind::YUV);
+	static_assert(L::num_planes == 1);
+	static_assert(L::h_sub == 2 && L::v_sub == 1);
+
+	using P = typename L::template plane<0>;
+	static constexpr size_t y0_idx = P::template find_pos<C::Y>(0);
+	static constexpr size_t y1_idx = P::template find_pos<C::Y>(1);
+	static constexpr size_t u_idx  = P::template find_pos<C::U>();
+	static constexpr size_t v_idx  = P::template find_pos<C::V>();
+
+	static constexpr size_t block_h = 1;
+	static constexpr size_t block_w = 2;
+
+	static void write_block(Buffer<1>& buf, size_t bx, size_t by,
+	                        const YUV16 (&block)[1][2]) noexcept
+	{
+		std::array<uint16_t, P::num_comps> v{};
+		v[y0_idx] = detail::encode_norm(P::comps[y0_idx].bits, block[0][0].y);
+		v[y1_idx] = detail::encode_norm(P::comps[y1_idx].bits, block[0][1].y);
+		// Integer chroma averaging in normalized-16 space. Truncates
+		// (no round-half-up).
+		v[u_idx]  = detail::encode_norm(P::comps[u_idx].bits, uint16_t(
+							(uint32_t(block[0][0].u) +
+							 uint32_t(block[0][1].u)) / 2));
+		v[v_idx]  = detail::encode_norm(P::comps[v_idx].bits, uint16_t(
+							(uint32_t(block[0][0].v) +
+							 uint32_t(block[0][1].v)) / 2));
+
+		uint8_t* p = buf.data[0] + by * buf.stride[0]
+		             + (bx / 2) * P::bytes_per_pixel;
+		detail::store_word<P>(p, P::pack(v));
+	}
+};
+
+} // namespace pixpat