russell@unturf.com
1b98cac200
cocos2d-0001: EventDispatcher _toRemovedListeners std::find O(L*R) MEDIUM 2.4x cocos2d-0002: PhysicsWorld collisionBeginCallback std::find O(J_body*J_world) MEDIUM 11.6x cocos2d-0003: BoneNode::visit _boneSkins.contains O(C*S) per frame MEDIUM 7.3x MOAD-0002 (Intertangle): heavy singleton pattern (Director, etc.) but architectural, not patchable MOAD-0003 (Leaked Context): no thread_local usage, CLEAN MOAD-0004 (Logged Secret): no credential logging, CLEAN MOAD-0005 (Thundering Herd): TextureCache uses unordered_map, CLEAN 6/6 unit tests PASS.
90 lines
3.1 KiB
C++
90 lines
3.1 KiB
C++
// Unit test for cocos2d-0003: BoneNode::visit _boneSkins.contains O(C*S) per frame
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// Defect: In the per-frame render traversal (visit), for each child node,
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// _boneSkins.contains(node) does O(S) linear scan of the skins vector.
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// With C children and S skins per bone, this is O(C*S) per bone per frame.
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// Fix: Maintain an std::unordered_set<Node*> _boneSkinSet alongside the vector
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// for O(1) membership test.
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#include <vector>
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#include <unordered_set>
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#include <chrono>
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#include <cstdio>
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#include <cassert>
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#include <algorithm>
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struct Node { int id; };
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// Defect: linear scan of skins vector for each child
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int defectVisit(const std::vector<Node*>& children,
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const std::vector<Node*>& boneSkins) {
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int rendered = 0;
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for (auto* node : children) {
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// O(S) linear scan
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if (std::find(boneSkins.begin(), boneSkins.end(), node) != boneSkins.end())
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continue;
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rendered++;
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}
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return rendered;
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}
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// Fixed: hash set for O(1) lookup
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int fixedVisit(const std::vector<Node*>& children,
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const std::unordered_set<Node*>& boneSkinSet) {
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int rendered = 0;
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for (auto* node : children) {
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if (boneSkinSet.count(node) > 0)
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continue;
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rendered++;
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}
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return rendered;
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}
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int main() {
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const int C = 500; // children per bone (complex character)
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const int S = 200; // skins per bone
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const int FRAMES = 1000; // per-frame render traversal
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std::vector<Node> pool(C);
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for (int i = 0; i < C; i++) pool[i].id = i;
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std::vector<Node*> children;
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for (int i = 0; i < C; i++) children.push_back(&pool[i]);
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// First S children are skins
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std::vector<Node*> boneSkins;
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std::unordered_set<Node*> boneSkinSet;
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for (int i = 0; i < S; i++) {
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boneSkins.push_back(&pool[i]);
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boneSkinSet.insert(&pool[i]);
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}
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// === Defect ===
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auto t0 = std::chrono::high_resolution_clock::now();
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int defectTotal = 0;
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for (int f = 0; f < FRAMES; f++)
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defectTotal += defectVisit(children, boneSkins);
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auto t1 = std::chrono::high_resolution_clock::now();
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double defectUs = std::chrono::duration<double, std::micro>(t1 - t0).count();
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// === Fixed ===
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auto t2 = std::chrono::high_resolution_clock::now();
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int fixedTotal = 0;
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for (int f = 0; f < FRAMES; f++)
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fixedTotal += fixedVisit(children, boneSkinSet);
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auto t3 = std::chrono::high_resolution_clock::now();
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double fixedUs = std::chrono::duration<double, std::micro>(t3 - t2).count();
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assert(defectTotal == fixedTotal);
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int expectedRendered = (C - S) * FRAMES;
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assert(defectTotal == expectedRendered);
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double ratio = defectUs / fixedUs;
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printf("cocos2d-0003: BoneNode::visit _boneSkins.contains O(C*S) per frame\n");
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printf(" C=%d children, S=%d skins, FRAMES=%d\n", C, S, FRAMES);
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printf(" defect: %.1f us\n", defectUs);
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printf(" fixed: %.1f us\n", fixedUs);
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printf(" ratio: %.1fx\n", ratio);
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printf(" PASS: %s\n", (defectTotal == expectedRendered) ? "true" : "false");
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return (defectTotal == expectedRendered) ? 0 : 1;
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}
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