- BVH with SAH (Bounding Volume Hierarchy  with Surface Area Heuristic) -      0. Overview 包围层次盒(BVH)是一种基于"物体“(object, 区别于“空间”,spatial )的场景管理技术,广泛应用于碰撞检测.射线相交测试之类的应用场合中. 一般情况下BVH的性能都比较不错,起码比基于格子(Grid)的场景管理技术要高.   BVH的数据结构其实就是一棵二叉树(Binary Tree).它有两种…
Bounding Volume Hierarchy BVH in OpenCASCADE eryar@163.com Abstract. Bounding Volume Hierarchy(BVH) organizes geometric objects in the tree based on spatial relationships. Each node in the tree contains an axis-aligned bounding box of all the objects…
背景   光线与物体求交是光线追踪的主要时间瓶颈.   如果不进行优化,则对每条光线,我们都需要遍历场景中的全部物体并求交.而现在想建模一个小物体的表面,往往要几千甚至几万个三角形,一个商业级产品,屏幕内甚至可能同时存在几亿个三角形.   想要提升效率,我们需要加速结构的帮助.   类似于二分查找的思想,我们先判断光线是否与较大的集合相交,如果不相交,则该集合内的所有物体都无需求交,减少了原有的计算量.   加速结构一般有两种:     一种是划分空间:如K-D Tree     一种是划分物体…
On a N * N grid, we place some 1 * 1 * 1 cubes. Each value v = grid[i][j] represents a tower of v cubes placed on top of grid cell (i, j). Return the total surface area of the resulting shapes. Example 1: Input: [[2]] Output: 10 Example 2: Input: [[1…
题目要求 On a N * N grid, we place some 1 * 1 * 1 cubes. Each value v = grid[i][j] represents a tower of v cubes placed on top of grid cell (i, j). Return the total surface area of the resulting shapes. 题目分析及思路 给定一个N*N网格,在其上放置1*1*1的小方块,二维数组的值即为当前位置的高度,要求…
On a N * N grid, we place some 1 * 1 * 1 cubes. Each value v = grid[i][j] represents a tower of v cubes placed on top of grid cell (i, j). Return the total surface area of the resulting shapes.   Example 1: Input: [[2]] Output: 10 Example 2: Input: […
here were various changes to memory related DMVs, DBCC memory status, and Perfmon counters in SQL Server 2012 as part of the redesign of the Memory Manager component of SQLOS. The Memory Manager redesign resulted in being able to more accurately size…
On a N * N grid, we place some 1 * 1 * 1 cubes. Each value v = grid[i][j] represents a tower of v cubes placed on top of grid cell (i, j). Return the total surface area of the resulting shapes. Example 1: Input: [[2]] Output: 10 Example 2: Input: [[1…
problem 892. Surface Area of 3D Shapes 题意:感觉不清楚立方体是如何堆积的,所以也不清楚立方体之间是如何combine的.. Essentially, compute the surface area of each grid but substract the overlapping areas. All areas = surface + combined area so we have surface = * total_count - * combi…
问题 该文章的最新版本已迁移至个人博客[比特飞],单击链接 https://www.byteflying.com/archives/4136 访问. 在 N * N 的网格上,我们放置一些 1 * 1 * 1  的立方体. 每个值 v = grid[i][j] 表示 v 个正方体叠放在单元格 (i, j) 上. 返回结果形体的总表面积. 输入:[[2]] 输出:10 示例 2: 输入:[[1,2],[3,4]] 输出:34 示例 3: 输入:[[1,0],[0,2]] 输出:16 示例 4: 输…