nx_raycast_voxel.nx

nx_raycast_voxel.nx -- DDA voxel ray traversal. Per user 2026-05-19 session 1: "we want to build minecraft equivalent on the lowest possible hardware." THE rendering core for that vision. Digital Differential Analyzer ray traversal walks a ray from camera through nx_tissue voxel grid, returning the first non-empty voxel + distance + which face was hit. Fixed-point math throughout — NO floating point. Per cardinals minimum-hardware-floor + bits-up-exceed-never-match: this primitive runs on Cortex-M0+ (no FPU) without modification. Q14 fixed point: 16384 = 1.0; range ~ -131072 to +131071 (covers 32x32x32 worlds with headroom for camera + direction vectors). Composes: nx_tissue -- the voxel world being traversed nx_palette -- voxel palette indices returned on hit nx_fb_1bpp -- caller renders the hit results into framebuffer nx_metabolism -- raycast is the canonical hot path that metabolism promotes through tier ladder V1 ships: - sealed enum NxRayFace (which face of voxel was hit) - struct NxRay + NxRayHit - cast: DDA walk; returns first non-empty voxel or MISS - normalize_q14: caller-helper to scale a direction to Q14