routefinder: name loc approach bits, add rotation tests - #156
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Rotations.rotate masks its input to 4 bits (7cd2d93). The mask is correct but hides the reason: forceApproachFlags is a 5-bit mask, not 4. Every non-zero value in the rev 240 cache is 0b11111 with exactly one bit cleared - the single permitted approach. Bits 0-3 are N/E/S/W; bit 4 is a fifth position used by 59 locs and unmodelled server-side. Unmasked, only 0x1e broke: its stray bit wraps into the low nibble giving 0x0f, blocking every side. The other three rotate correctly by coincidence. No behaviour change.
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Follow-up to #123. No behaviour change.
Rotations.rotatemasks to 4 bits (7cd2d93). The mask is right — this makes the reason explicit and adds tests.forceApproachFlagsis a 5-bit mask. Every non-zero value at rev 240 is0b11111with exactly one bit cleared — the permitted approach:0x1e111100x1d111010x1b110110x17101110x0f01111Bits 0–3 are N/E/S/W. Bit 4 is a fifth position, used only by 59 locs — all 1×1 and non-solid. Not modelled server-side.
Why only north broke: unmasked,
0x1e shr 3wraps two bits instead of one and gives0x0f— every side blocked. The other three land the stray bit where the shift already set one.Adds the first tests to
engine/routefinder, covering every value in the cache across all four angles.