[wagcbjr]

What and why

Fixes #12.

Pokémon Legends: Z-A built from this fork leaves parts of Lumiose invisible: the walkways beside the buildings' ladders are not drawn, while the ladders float and the walkways' collision still holds (#12 reports building walls with floating window frames). Two upstream fixes made after the fork's last sync (2026-10-27) are missing, and this backports both:

• seedds/nxnative 8fa9b2d1, the base instance from Metal. GLSLC's vertex shaders read the draw's base instance from c0 + 0x644, which the host fills from the draw command. An indirect draw's base instance is in GPU memory, so it was 0 and every GPU-culled instance took the first one's transform. dmsh_build.py's vs_base_instance now reads Metal's [[base_instance]].
• seedds/nxnative e4e5ff6, -fwrapv. Translated shaders compile with -fwrapv, because signed overflow wraps on the Switch's GPUs and Metal's front end folded around it (dmsh_build.py, ios_metal.py, vk_shaders.py, gl_shaders.py).

Chain 764aff238713 → 8a1b56655ae9 (dmsh_chain.py --header).

Checked

• Shaders: 775 of Z-A's 28,603 translated shaders read c0 + 0x644 in the form vs_base_instance looks for. Rewritten, all 775 compile with Metal Developer Tools for Windows (metal.exe, air64-apple-ios18.0, with -fwrapv), 0 failures. The full build then made 28,603 of 28,603 iOS libraries, and all 775 read as_type<float>(gl_BaseInstance) with none left on the old form.
• Games run, with title ID and version: Pokémon Legends: Z-A (0100F43008C44000) 2.0.2 + Mega Dimension DLC, split data build. The walkways beside the ladders in Lumiose, invisible on chain 764aff238713, are drawn on 8a1b56655ae9.
• Devices and OS: built on Windows 11 (10.0.26300), played on an iPhone with an A18 Pro, iOS 27.2.
• Not checked: other games, the Mac, Linux builds. The -fwrapv part was not checked on its own in Z-A.
• A full sync with upstream would bring many more fixes made after 2026-10-27. This PR takes only these two.

Docs

• No docs changed. The upstream commits' reference entries are not copied.
• No game files, keys or data extracted from a game in the change or the attachments.

🤖 Generated with Claude Code

https://claude.ai/code/session_01VDGHF5LyEKSqoK23EvYr6W