Per instance bbox culling for thin instance picking

kzhsw · March 19, 2025, 9:48am

Current code of picking thin instances checks directly into every vertex, but picking meshes are guarded by a bbox culling before checking vertices.
It might be possible to check bbox culling of each instance before checking vertices, if a instance have maybe more than 100 vertices, for better performance.

github.com/BabylonJS/Babylon.js

packages/dev/core/src/Culling/ray.core.ts

317f0a787


      
          

          if (mesh.hasThinInstances && (mesh as Mesh).thinInstanceEnablePicking) {

              // first check if the ray intersects the whole bounding box/sphere of the mesh

              const result = picker(pickingInfo, rayFunction, mesh, world, true, true, trianglePredicate);

              if (result) {

                  if (onlyBoundingInfo) {

                      // the user only asked for a bounding info check so we can return

                      return result;

                  }

                  const tmpMatrix = TmpVectors.Matrix[1];

                  const thinMatrices = (mesh as Mesh).thinInstanceGetWorldMatrices();

                  for (let index = 0; index < thinMatrices.length; index++) {

                      if (predicate && !predicate(mesh, index)) {

                          continue;

                      }

                      const thinMatrix = thinMatrices[index];

                      thinMatrix.multiplyToRef(world, tmpMatrix);

                      const result = picker(pickingInfo, rayFunction, mesh, tmpMatrix, fastCheck, onlyBoundingInfo, trianglePredicate, true);

          

                      if (result) {

                          pickingInfo = result;

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Per instance bbox culling for thin instance picking

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