Packet Play Client Update Light

1.16.2

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x25 0x23	Play	Client	Chunk X		VarInt		Chunk coordinate (block coordinate divided by 16, rounded down)
			Chunk Z		VarInt		Chunk coordinate (block coordinate divided by 16, rounded down)
			Trust Edges		Boolean		If edges should be trusted for light updates.
			Sky Light Mask		VarInt		Mask containing 18 bits, with the lowest bit corresponding to chunk section -1 (in the void, y=-16 to y=-1) and the highest bit for chunk section 16 (above the world, y=256 to y=271)
			Block Light Mask		VarInt		Mask containing 18 bits, with the same order as sky light
			Empty Sky Light Mask		VarInt		Mask containing 18 bits, which indicates sections that have 0 for all their sky light values. If a section is set in both this mask and the main sky light mask, it is ignored for this mask and it is included in the sky light arrays (the notchian server does not create such masks). If it is only set in this mask, it is not included in the sky light arrays.
			Empty Block Light Mask		VarInt		Mask containing 18 bits, which indicates sections that have 0 for all their block light values. If a section is set in both this mask and the main block light mask, it is ignored for this mask and it is included in the block light arrays (the notchian server does not create such masks). If it is only set in this mask, it is not included in the block light arrays.
			Sky Light arrays	Length	Array	VarInt	Length of the following array in bytes (always 2048)
				Sky Light array		Array of 2048 bytes	There is 1 array for each bit set to true in the sky light mask, starting with the lowest value. Half a byte per light value.
			Block Light arrays	Length	Array	VarInt	Length of the following array in bytes (always 2048)
				Block Light array		Array of 2048 bytes	There is 1 array for each bit set to true in the block light mask, starting with the lowest value. Half a byte per light value.





1.16

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x25 0x24	Play	Client	Chunk X		VarInt		Chunk coordinate (block coordinate divided by 16, rounded down)
			Chunk Z		VarInt		Chunk coordinate (block coordinate divided by 16, rounded down)
			Trust Edges		Boolean		If edges should be trusted for light updates.
			Sky Light Mask		VarInt		Mask containing 18 bits, with the lowest bit corresponding to chunk section -1 (in the void, y=-16 to y=-1) and the highest bit for chunk section 16 (above the world, y=256 to y=271)
			Block Light Mask		VarInt		Mask containing 18 bits, with the same order as sky light
			Empty Sky Light Mask		VarInt		Mask containing 18 bits, which indicates sections that have 0 for all their sky light values. If a section is set in both this mask and the main sky light mask, it is ignored for this mask and it is included in the sky light arrays (the notchian server does not create such masks). If it is only set in this mask, it is not included in the sky light arrays.
			Empty Block Light Mask		VarInt		Mask containing 18 bits, which indicates sections that have 0 for all their block light values. If a section is set in both this mask and the main block light mask, it is ignored for this mask and it is included in the block light arrays (the notchian server does not create such masks). If it is only set in this mask, it is not included in the block light arrays.
			Sky Light arrays	Length	Array	VarInt	Length of the following array in bytes (always 2048)
				Sky Light array		Array of 2048 bytes	There is 1 array for each bit set to true in the sky light mask, starting with the lowest value. Half a byte per light value.
			Block Light arrays	Length	Array	VarInt	Length of the following array in bytes (always 2048)
				Block Light array		Array of 2048 bytes	There is 1 array for each bit set to true in the block light mask, starting with the lowest value. Half a byte per light value.





1.15.2

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x25	Play	Client	Chunk X		VarInt		Chunk coordinate (block coordinate divided by 16, rounded down)
			Chunk Z		VarInt		Chunk coordinate (block coordinate divided by 16, rounded down)
			Sky Light Mask		VarInt		Mask containing 18 bits, with the lowest bit corresponding to chunk section -1 (in the void, y=-16 to y=-1) and the highest bit for chunk section 16 (above the world, y=256 to y=271)
			Block Light Mask		VarInt		Mask containing 18 bits, with the same order as sky light
			Empty Sky Light Mask		VarInt		Mask containing 18 bits, which indicates sections that have 0 for all their sky light values. If a section is set in both this mask and the main sky light mask, it is ignored for this mask and it is included in the sky light arrays (the notchian server does not create such masks). If it is only set in this mask, it is not included in the sky light arrays.
			Empty Block Light Mask		VarInt		Mask containing 18 bits, which indicates sections that have 0 for all their block light values. If a section is set in both this mask and the main block light mask, it is ignored for this mask and it is included in the block light arrays (the notchian server does not create such masks). If it is only set in this mask, it is not included in the block light arrays.
			Sky Light arrays	Length	Array	VarInt	Length of the following array in bytes (always 2048)
				Sky Light array		Array of 2048 bytes	There is 1 array for each bit set to true in the sky light mask, starting with the lowest value. Half a byte per light value.
			Block Light arrays	Length	Array	VarInt	Length of the following array in bytes (always 2048)
				Block Light array		Array of 2048 bytes	There is 1 array for each bit set to true in the block light mask, starting with the lowest value. Half a byte per light value.





1.14.4

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x24	Play	Client	Chunk X		VarInt		Chunk coordinate (block coordinate divided by 16, rounded down)
			Chunk Z		VarInt		Chunk coordinate (block coordinate divided by 16, rounded down)
			Sky Light Mask		VarInt		Mask containing 18 bits, with the lowest bit corresponding to chunk section -1 (in the void, y=-16 to y=-1) and the highest bit for chunk section 16 (above the world, y=256 to y=271)
			Block Light Mask		VarInt		Mask containing 18 bits, with the same order as sky light
			Empty Sky Light Mask		VarInt		Mask containing 18 bits, which indicates sections that have 0 for all their sky light values. If a section is set in both this mask and the main sky light mask, it is ignored for this mask and it is included in the sky light arrays (the notchian server does not create such masks). If it is only set in this mask, it is not included in the sky light arrays.
			Empty Block Light Mask		VarInt		Mask containing 18 bits, which indicates sections that have 0 for all their block light values. If a section is set in both this mask and the main block light mask, it is ignored for this mask and it is included in the block light arrays (the notchian server does not create such masks). If it is only set in this mask, it is not included in the block light arrays.
			Sky Light arrays	Length	Array	VarInt	Length of the following array in bytes (always 2048)
				Sky Light array		Array of 2048 bytes	There is 1 array for each bit set to true in the sky light mask, starting with the lowest value. Half a byte per light value.
			Block Light arrays	Length	Array	VarInt	Length of the following array in bytes (always 2048)
				Block Light array		Array of 2048 bytes	There is 1 array for each bit set to true in the block light mask, starting with the lowest value. Half a byte per light value.