211dc8cd2d
This PR adds a define BVH_EXPAND_LEAF_AABBS which is set, which stores expanded AABBs in the tree instead of exact AABBs. This makes the logic less error prone when considering reciprocal collisions in the pairing, as all collision detect is now taking place between expanded AABB against expanded AABB, rather than expanded AABB against exact AABB. The flip side of this is that the intersection tests will now be less exact when expanded margins are set. All margins are now user customizable via project settings, and take account of collision pairing density to adjust the margin dynamically.
72 lines
1.6 KiB
C++
72 lines
1.6 KiB
C++
public:
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// note .. maybe this can be attached to another node structure?
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// depends which works best for cache.
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struct ItemPairs {
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struct Link {
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void set(BVHHandle h, void *ud) {
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handle = h;
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userdata = ud;
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}
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BVHHandle handle;
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void *userdata;
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};
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void clear() {
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num_pairs = 0;
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extended_pairs.reset();
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expanded_aabb = BOUNDS();
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}
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BOUNDS expanded_aabb;
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// maybe we can just use the number in the vector TODO
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int32_t num_pairs;
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LocalVector<Link> extended_pairs;
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void add_pair_to(BVHHandle h, void *p_userdata) {
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Link temp;
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temp.set(h, p_userdata);
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extended_pairs.push_back(temp);
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num_pairs++;
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}
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uint32_t find_pair_to(BVHHandle h) const {
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for (int n = 0; n < num_pairs; n++) {
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if (extended_pairs[n].handle == h) {
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return n;
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}
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}
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return -1;
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}
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bool contains_pair_to(BVHHandle h) const {
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return find_pair_to(h) != BVHCommon::INVALID;
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}
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// return success
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void *remove_pair_to(BVHHandle h) {
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void *userdata = nullptr;
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for (int n = 0; n < num_pairs; n++) {
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if (extended_pairs[n].handle == h) {
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userdata = extended_pairs[n].userdata;
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extended_pairs.remove_unordered(n);
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num_pairs--;
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break;
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}
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}
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return userdata;
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}
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// experiment : scale the pairing expansion by the number of pairs.
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// when the number of pairs is high, the density is high and a lower collision margin is better.
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// when there are few local pairs, a larger margin is more optimal.
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real_t scale_expansion_margin(real_t p_margin) const {
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real_t x = real_t(num_pairs) * (1.0 / 9.0);
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x = MIN(x, 1.0);
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x = 1.0 - x;
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return p_margin * x;
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}
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};
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