FA-87818 / Collision detection broadphase / Member archive

Rotated proxy uses signed cosine and sine · case 03

Boxes rotated into the second quadrant get inverted, too small bounds.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

solve(cx, cy, hx, hy, angle, margin): broadphase proxy for a box with centre, half extents and rotation in degrees. Half sizes ex=|cos|hx+|sin|hy, ey=|sin|hx+|cos|hy; fatten by margin on every side. Return [minx, miny, maxx, maxy] rounded to 6.

Why this case matters

Broadphase stages decide which object pairs ever reach narrowphase; a wrong boundary, ordering or bookkeeping rule silently drops real contacts or floods the solver with false candidates.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
case 0	`[0.770193, 4.592936, -0.650193, 2.527064]`	`[-0.650193, 2.527064, 0.770193, 4.592936]`	Failed

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