Project

https://graphics.cs.utah.edu/research/projects/shortest-path-to-boundary/

Build and Debug

Fork:(在Win10上）
https://github.com/chunleili/Shortest-Path-to-Boundary-for-Self-Intersecting-Meshes

commit hash
d3160168d2b6a58188d12e6cd959da0ac9b56e95

./vscode/launch.json
{
“version”: “0.2.0”,
“configurations”: [
{
“name”: “(msvc) Launch”,
“type”: “cppvsdbg”,
“request”: “launch”,
// Resolved by CMake Tools:
“program”: “$workspaceFolder/build/Debug/Shortest?Path?Test.exe","args":["TestData/Parameters.json","TestData/IntersectingShape.t"],"stopAtEntry":true,"cwd":"${workspaceFolder}”,
“environment”: [
{
// add the directory where our target was built to the PATHs
// it gets resolved by CMake Tools:
“name”: “PATH”,
“value”: “$env:PATH:${command:cmake.getLaunchTargetDirectory}”
},
],
“console”: “internalConsole”,
}
]
}

Code Explain

Test.cpp中是入口main函數
40行之前是初始化（mesh和param)
在這個for loop當中查找每個Vert的最近點。

關鍵的函數
dcd.vertexCollisionDetection(iV, meshId, &colDecResult);
用BVH做碰撞檢測。（Broad Phase)

dcd.closestPointQuery(&colDecResult, &queryResult);
用碰撞檢測后的結果查找最近點。(Narrow Phase)

Broad Phase：vertexCollisionDetection

核心就rtcPointQuery，調用的是intel embree的API

D:\Dev\Shortest-Path-to-Boundary-for-Self-Intersecting-Meshes\ShortestPath\CollisionDetector\DiscreteCollisionDetector.cpp
L598

https://github.com/chunleili/Shortest-Path-to-Boundary-for-Self-Intersecting-Meshes/blob/5be890b7775dc92cde410895d124c81162bee978/ShortestPath/CollisionDetector/DiscreteCollisionDetector.cpp#L598

Narrow Phase: closestPointQuery

https://github.com/chunleili/Shortest-Path-to-Boundary-for-Self-Intersecting-Meshes/blob/5be890b7775dc92cde410895d124c81162bee978/ShortestPath/CollisionDetector/DiscreteCollisionDetector.cpp#L621

其中較為關鍵的是idTetIntersected，表示相交的四面體的id。intersectedTets則是所有相交四面的的array。

執行查詢最近點：
rtcPointQuery(surfaceMeshScenes[idTMIntersected], &query, &context, nullptr, (void*)pClosestPtResult); 仍然是用API來查詢點。目的是針對某個表面網格（surfaceMeshScenes[idTMIntersected]），找到距離查詢點最近的表面點，并把結果存儲在 pClosestPtResult 中。

接下來是存儲找到的最近點的信息：其face id, 坐標， barycentric coord.

另外，rtc是根據注冊機制自動調用一些hook函數的例如比較關鍵的是

其中checkTetTraverse這個flag表示檢查四面體的遍歷，正是文中提到的連接性檢測（valid path)