b3dPickedNY

Returns Y component of surface normal at pick hit point from last pick operation (0.0 if no hit). Takes no parameters. Returns normal Y component (Double) from g_lastPickResult.normal.y. Reads result from last b3dCameraPick, b3dEntityPick, or b3dLinePick call. World-space surface normal Y component at intersection point.

This function retrieves hit normal Y. Pick sequence: (1) Call b3dCameraPick/EntityPick/LinePick to perform ray-cast, (2) Call b3dPickedNY (and NX/NZ) to get surface normal components. Surface normal: unit-length vector perpendicular to surface at hit point (for sphere picks: vector from sphere center to hit point normalized, for box picks: face normal, for polygon picks: triangle normal or interpolated vertex normal). Y-axis convention: returned value in user space (+Y up), normal calculated in world coordinates. Use cases: (1) Impact orientation (align bullet impact decal to surface), (2) Reflection (reflect projectiles off surface using normal), (3) Slope detection (check if surface is walkable using normal Y component), (4) Standing detection (check if standing on floor, normal Y near 1.0), (5) Physics simulation (bounce objects off surface). Common pattern: if b3dPickedEntity() > 0 then nx=b3dPickedNX(), ny=b3dPickedNY(), nz=b3dPickedNZ(), if ny > 0.7 then walkable surface. Typical usage: retrieve surface normal after successful pick (entity > 0), use for aligning decals or checking surface slope. Normal Y interpretation: ny near 1.0 = horizontal surface facing up (floor), ny near -1.0 = horizontal surface facing down (ceiling), ny near 0.0 = vertical surface (wall). No hit: returns 0.0 if no entity picked (check b3dPickedEntity first), normal is undefined if pick missed. Result storage: g_lastPickResult.normal populated by pick functions with surface normal at hit point. Performance: O(1) read (simple global variable access, instant). Related: b3dPickedNX/NZ retrieve X and Z normal components, b3dPickedX/Y/Z retrieve hit position, b3dPickedEntity checks if hit occurred, b3dCameraPick/EntityPick/LinePick perform picking.