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Per Erin Catto (Box2D GDC talks), collision pipelines split into BROAD phase and NARROW phase. The broad phase does which?
ARender debug shapes for the editor only
BCompute exact penetration depths each frame
CSolve velocity constraints at every contact
DQuickly cull pairs that cannot possibly collide
Answer & Solution
Correct answer: D. Quickly cull pairs that cannot possibly collide
Catto Box2D: broad phase (sweep+prune or dynamic AABB tree) reduces O(n²) pairs to O(n log n). Narrow phase does exact tests on the survivors.
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