frustum

[3D图形学]视锥剔除入门(翻译)

由 允我心安 提交于 2021-02-12 22:32:25
原文: http://www.flipcode.com/archives/Frustum_Culling.shtml 时至今日,许多刚刚下海的3D引擎程序员仍不了解视锥剔除(Frustum Culling)的重要性和益处,这让我和我的小伙伴们感到很震♂惊.我在Flipcode的论坛中发现尽管网络上有海量的相关资料,仍有许多人提出对视锥剔除实现的问题.因此我决定撰写这篇文档,简单描绘出我现在所使用的四叉树剔除引擎(Quad-tree Culled Engine)的工作方式.诚然,市面上有许多种成熟且高效的视锥剔除算法,但我认为这个算法足以用来学习视锥剔除的理论基础.在正式开始前我还想说明一件事,以前我一直把Frustum(平截头体)打成Frustrum(截头锥),为此我没少被论坛上的人喷.在这里我承认Frustum是正确的拼写.对那些以前被我冒犯的人我表示抱歉...你们这群吹毛求疵的傻[哔-]... 大多数人已经知道什么是视锥剔除了(译者:如果你是手滑误点进来的...视锥剔除是一个图形渲染前的步骤,用于剔除掉不需要绘制的部分).视锥(准确说是平截头体Frustum)的形状酷似一个塔尖被削平了的金字塔,更准确地说,是一个四棱锥的顶点偏下位置被一个裁面(Clipping Plane,见图1)裁断.事实上,视锥本身就是由6个面所组成.这6个面被称为近裁面,远裁面,上裁面,下裁面,左裁面

SceneKit stucks for a few frames, when SCNGeometry asset gets inside frustum of SCNCamera

由 孤街浪徒 提交于 2021-01-28 11:15:35
问题 I am working on a game in which a character runs along the screen and the camera is following the character. For each scene I add all the required assests and place them on scene. I do this behind a loading screen, because SceneKit needs some time to put all the stuff on scene. After like 5 seconds I fade out the screen (which is basically a black UIImage that lays in front of everything) and the game starts. Depending on the current scene, the amout of memory required is between 200MB and

How can I make the glOrtho parallelepiped rotating?

由 佐手、 提交于 2020-01-06 10:40:44
问题 I have my world rendered. Based on some specific requirements it includes (some time) some lights on the floor. I am rendering these lights using triangle primitives. Right now I have the following code to zoom and limit the rendering area: if(aspect>1) gl.glOrtho(-scale*aspect, scale*aspect, -scale, scale, 0, 2); else gl.glOrtho(-scale, scale, -scale/aspect, scale/aspect, 0, 2); As you can see in this image, the far plane is cutting the light throught a line (parallel to the line on the

How to detect all GameObjects within the Camera FOV? Unity3D

由 穿精又带淫゛_ 提交于 2019-12-22 20:06:10
问题 I would like to detect all gameobjects tagged by "Wall_ [0-24] ", which are within the camera FOV. I already tried Raycasting, but as it is only one ray, it doesn't catch multiple objects at the same time. I tried this one: void Update() { GameObject walls = GameObject.FindGameObjectWithTag ("Wall"); Renderer[] renders = walls.GetComponentsInChildren<Renderer> (); for (int i = 1; i < renders.Length; i++) { if (walls.GetComponentInChildren<Renderer> ().isVisible) { Debug.Log (renders[i] + " is

THREE.js check if object is in frustum

由 ￣綄美尐妖づ 提交于 2019-12-13 15:05:55
问题 i've been tinkering around with three.js and i have a canvas i'd like to use as kind of a GUI. for that i have to check if an object is in the camera frustum. my current code: camera.updateMatrix(); camera.updateMatrixWorld(); var frustum = new THREE.Frustum(); var projScreenMatrix = new THREE.Matrix4(); projScreenMatrix.multiplyMatrices( camera.projectionMatrix, camera.matrixWorldInverse ); frustum.setFromMatrix( camera.projectionMatrix ); if(frustum.containsPoint( mesh.position )){ //stuff

Determine if point is in frustum

由 六月ゝ 毕业季﹏ 提交于 2019-12-11 04:15:08
问题 I'm trying to work out the best way to determine whether a point is inside a frustum. I have something working, but not sure whether it is too cumbersome, and perhaps there is a more elegant / efficient way I should be doing this. Suppose I want to find out whether point 'x' is inside a frustrum: Once I have the locations of the 8 points of the frustrum (4 near points, four far points), I am calculating the normal for each plane of the frustum based on a triangle made from three of the points

Placing an object 30 meters above a person

由 旧巷老猫 提交于 2019-12-07 07:05:28
问题 Is it possible to place an object right above a person that is 30 or 50 meters higher? When I try to place an object linked to anchor it is visible in 20 meters and not visible in 40 meters? Why this happens and how can I configure this? 回答1: It is frustum culling issue in ARCore – objects that aren't within the viewable area of camera frustum won't be rendered. Typically FoV (field of view) in Android devices is around 60 degrees horizontally (vertical aperture depends on aspect ratio).

Finding a minimum bounding sphere for a frustum

由 丶灬走出姿态 提交于 2019-12-06 20:33:21
问题 I have a frustum (truncated pyramid) and I need to compute a bounding sphere for this frustum that's as small as possible. I can choose the centre to be right in the centre of the frustum and the radius be the distance to one of the "far" corners, but that usually leaves quite a lot of slack around the narrow end of the frustum This seems like simple geometry, but I can't seem to figure it out. Any ideas? 回答1: This is probably not the answer you're looking for, but you could compute all the

How to detect all GameObjects within the Camera FOV? Unity3D

由 僤鯓⒐⒋嵵緔 提交于 2019-12-06 09:53:48
I would like to detect all gameobjects tagged by "Wall_ [0-24] ", which are within the camera FOV. I already tried Raycasting, but as it is only one ray, it doesn't catch multiple objects at the same time. I tried this one: void Update() { GameObject walls = GameObject.FindGameObjectWithTag ("Wall"); Renderer[] renders = walls.GetComponentsInChildren<Renderer> (); for (int i = 1; i < renders.Length; i++) { if (walls.GetComponentInChildren<Renderer> ().isVisible) { Debug.Log (renders[i] + " is detected!"); } else { Debug.Log ("Nothing's detecetd!"); } } } All I get is every wall again and again

How to compute the size of the rectangle that is visible to the camera at a given coordinate? [duplicate]

由 一个人想着一个人 提交于 2019-12-05 01:01:19
问题 This question already has an answer here : Three.js - Width of view (1 answer) Closed 2 years ago . I made a small three.js app that moves a bunch of circles from the bottom of the canvas to the top: let renderer, scene, light, circles, camera; initialize(); animate(); function initialize() { renderer = new THREE.WebGLRenderer({ alpha: true, antialias: true }); renderer.setSize(window.innerWidth, window.innerHeight); document.body.appendChild(renderer.domElement); scene = new THREE.Scene();
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