WalkScreenClip ports PrimD3DRender::xformStart @0x0059b990 (homogeneous
viewport coords, y-flip, no divide) and ACRender::polyClipFinish
@0x006b6d00 (w>=cdstW plane then last-to-first edge passes, inside =
side<=0 homogeneous 2D cross, reverse-scan passes with original-winding
restore, <3 early-outs). WalkViews ports the view_type/portal_view_type
data model and Render::copy_view @0x0054dfc0 exactly: in-place divide,
the keep/last/stl/second pruning bookkeeping with all three closing
wrap checks, <3 reject leaving dest untouched, cap 31, pool-base reset
at view_count==0, retail fabs on copy, and edge planes
N=normalize(cross(ray[k+1],ray[k])), d=-dot(N,eye) behind an
IWalkRayCaster seam. Thirteen new tests; Walk namespace 85/85.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
