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# Questions tagged [frustum]

In computer graphics - the part of the 3D scene that is visible on the screen, also called the viewing frustum. The shape of the viewing frustum is a pyramid defined by the viewing angle, and that is "clipped" between the near and the far clipping planes.

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### Unity how to make raycaster test only against collider in frustum

I'm working on a scene with thousands of object wich have all a collider associated. I'm just testing if my mouse is on top of any collider in a 2D space. The raycasting operation is taking a lot of ...
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### Why is the vieweing field a frustum instead of a pyramid?

In 3D games, why would the viewing field be a frustum? Why not a pyramid? You would still have to do culling to figure out what's in the field, and to me it seems a pyramid field is no harder to do ...
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### Why are clipping planes... plane?

A frustum is used to clip geometry, deciding which parts of it are visible. It seems that most cameras use a frustum shaped as a pyramid segment, i.e. a box between two rects of equal alignment on ...
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### Cubic Voxel Game, Calculate What Chunks are in the Player's View, using 3D chunks?

I need to calculate what chunks are in the player's view, meaning I need the 3D positions (the bottom, back, left corner in world space) of each chunk that is in the player's view. I'm not worried ...
1 vote
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### How can I reduce a frustum to the subset that passes through a portal AABB?

I'm trying to implement portal based occlusion culling: There are sectors and portals. When a portal is visible, the sector it is connected to is rendered. The sector is made of polygons and ...
1 vote
44 views

### Can I get world-space z-near-plane vertices from projection matrix + z-near distance?

I'm trying to port ShaderToy VR shaders to WebXR (the new browser API for AR/VR devices). ShaderToy VR shaders expect two extra parameters: ray origin (view translation) and ray direction (unit vector ...
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### Calculate the near clip plane distance in meters from a certain object - Unity

How do you convert the near clip plane and far clip planes to position units, to be able to find out its distance to a game object?
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### What´s wrong with my Frustum Culling implementation?

I´m struggling with a weird problem since hours. Ive implemented frustum culling with the help of online articles and a book. The problem is that the objects are not culled correctly. I´m using ...
83 views

### Having some trouble with my frustum checking code

I'm trying to check if a bounding sphere is either within or intersecting my frustum. It mostly works but there are cases where it should and it doesn't. The frustum is made up of 6 planes which have ...
1 vote
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### How and where to transform a Camera Frustum onto a tilted screen?

In rendering tutorials for perspective projection the assumption is that the rendering surface is perpendicular to the sight line. As shown here: How to accommodate for a screen that is tilted ...
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1 vote
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### OpenGL frustum extraction

I'm trying to extract frustum planes from the camera. The algorithm is simple: create clip to world space matrix (inversed projection * inversed view) multiply clip point by clip to world matrix ...
• 108
1 vote
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### Frustum Culling bug in program

I did Frustum Culling in my engine, but it does not work correctly. All shown in the video: Video If the approximation is too close, the model disappears. On the right in the console you can see ...
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### OBB vs Frustrum collision detection

Some definitions: An oriented bounding box (OBB) is a rectangular block which can be represented in many ways, as a collection of eight vertices, a collection of six planes or others, for this ...
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1 vote
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### How to get a camera's frustum information?

I have a local coordinate system with three camera normalised directions, D, U and R. I ...
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### How do you handle large triangles with frustum?

I am rendering the Sponza scene ato test my frustum implementation. My current approach is simply, test if the vertices of the triangle are within the frustum (angle between the camera looking ...
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2k views

### Finding the normals of the planes of a View Frustum

Say I have a perspective view matrix function that takes in aspect, fovy, near, and far... Transforming the view into a frustum. Typical OpenGL stuff, right. But say then, that I would like to find ...
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1 vote
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### Given the size of far and near plane, find other parameters of a frustum

I am trying to find the correct parameters for setting up my perspective camera. But I don't know the mathematics involved in that. Can somebody point me to the right direction? My near plane should ...
262 views

### What is the near plane equation in NDC?

I'm trying to compute the line intersecting my plane (transformed to NDC) and the near plane. I have troubles to get a correct result and I think it is coming from the near plane equation. I ...
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1 vote
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### Choosing size of frustum based on objects

I would like to show camera frames using OpenGL and rotate the frame in 3D. The frame is placed at (0,0,-frameDepth), and will rotate about the origin. Should I decide the size of frustum based on ...
• 111
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### Same dimension feel no matter what FOV

Does anyone know a formula, way, ... to make a FPS player feel like an object has the same size on different FOVs (given that it's at the same distance of the player, of course)? I know that this can'...
• 111
1 vote
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### Tiled deferred rendering frustum calculation problem

I know there are plenty of tutorials how to create tiled frustum with compute shaders, but I`m trying to understand the steps and want to build it on the cpu with pure C# code. I translated a lof of ...
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### What's the difference between Camera::getPosition() and Camera::getPositionForViewUpdate()?

In Ogre3d, what's the difference between methods Camera::getPosition() and Camera::getPositionForViewUpdate(), official ...
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### Testing spheres without extracting planes

I am currently a bit stuck. On OpenGL I am attempting to do view frustum culling, so far I managed to do it by using a PCM. Where center is the world position of the mesh. ...
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1 vote
40 views

### Show icon at screen edge when corresponding object is out of view frustum

If an object moves out of the view frustum of the camera, I want to display an icon on one of the edges of the screen to indicate the rough direction where it is. Unfortunately I have not come up ...
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### How do you make a camera look at a box and ensure all of it is visible?

In most game engines (Unity, UE4) if we select a model and press F, the camera moves and focuses to the selected model. I want to implement that for my models. I have a perspective camera and world ...
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### How to clip cut-off using different frustrum than that of original camera? How to cut plane by pyramid shape?

SOURCE : http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2012/10/Mitchell_LightShafts.pdf This process is part of creating light draft effect. And I am suggested to do the described process in ...
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1 vote
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### Asymetric Perspectiv View

I am building a addon component that will show synthesized 3D view of the world (kind of FLIR camera simulation). The problem I am facing is that currently I am using Symmetric Perspective View with ...
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### Problem with Frustum Culling Right-Handed(LookAtRH GLM)

I am trying to do Frustum Culling based on Goemetric Approach, however don't matter how much i try, the frustrum rotate to opposite side, i tried to find a solution over all internet, but couldn't ...
1 vote
577 views

### Frustum culling takes ages c++

I have two ways of doing frustum culling taken from different web sources. First one takes 200ms to check 10k AABBs, second around 50ms for the same box count. I read some forum answers, people say 0....
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### Drawn frustum does not match with glm::perspective

I am working on a personal project and I got a 3d viewport with moving camera working nicely. Now I am working on being able to freeze the time and switch to a debug camera and move in the game freely....
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### Control frustum near and far clip plane sizes in a Projection Matrix

I'm trying to achieve a dolly zoom effect. My first try was the obvious one, the original "zoom in & dolly out" technique, which works nicely. Except that there are cases which this is not ...
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### Which three points to use to calculate a frustum plane?

So I have a view frustum I'm going to be using for frustum culling. I have a method that finds the cross-product of three points but since each side of the frustum has four corners I don't know which ...
226 views

### Frustum culling only working at certain angles

So how I'm doing this is a little sketchy but I plan on changing it to either AABBs or spheres once I get it working. So the problem I'm having right now is that the frustum culling I've implemented ...
411 views

### Frustum Culling: How to calculate if an angle is between another two angles

I am trying to implement frustum culling but got stuck on how to determine if the angle that the object is from the player is in the FOV of the player. So basically I have the following information: ...
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### Custom 3D Renderer: Frustum clipping

I have recently been toying with the idea of creating a 3D-renderer from scratch and, after looking into it, doesn't seem like such a behemoth of a task as it sounds. Last night, I was tossing and ...
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1 vote
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### Directional light view frustum stabilisation

Calculating directional light view frustum based on scene objects(bounding frustum) results in noticeable scene jittering on camera movement in CSM and non-CSM rendering code paths. What are the ...
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### Is Frustum culling still needed today?

I'm reading about efficient Frustum culling algorithms. I found an article about a smart method that first use the Frustum AABB (Axis Aligned Bounding Box) to eliminate most of the scene before check ...
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1 vote
2k views

### Stop rendering hidden objects libgdx

I currently am hiding objects that are not in the frustums view. However, some objects are still being rendered that are in the frustums view, but are hidden. My goal is to not render objects that won'...
• 113
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### Clip shadow frustum to scene bounds

I have a global light in my scene. It casts shadows using shadow mapping and has an associated camera (for rendering to the shadow map). I'm going to refer to it as my "shadow camera" from now on. I ...
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### OpenGL: How to map point inside frustrum to normal device coordinates (NDC)?

I read this article http://www.songho.ca/opengl/gl_projectionmatrix.html. It's explain how calculate projection matrix coefficients. But I completely can't understand how author perform mapping from ...
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1 vote
622 views

### How do I construct the planes for my camera's frustum?

I'm trying to get a handle on frustum culling, but I'm not quite there yet. I have a camera in three-dimensional space ...
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### Compute directional light frustum from view furstum points and light direction

I'm working on a friends engine project and my task is to construct a new frustum from the light direction that overlaps the view frustum and possible shadow casters. The project already has a ...
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### Rendering a mesh in image viewport

I have a mesh made of nearly half to a one million vertices. I also have some 6-DoF camera poses around this mesh. At these poses I'd like to find out which of the 3D points of this mesh get projected ...
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### Frustum culling - error evaluating a point in the plane of the frustum

I am trying to implement the following code: http://www.lighthouse3d.com/tutorials/view-frustum-culling/geometric-approach-implementation/ I need to use frustum culling in my graphics engine. my ...
7k views

### What dimensions should you use for a perspective projection frustum?

What dimensions should you use for a perspective projection frustum? Initially I created a perspective matrix based on the width and height of the screen, with a calculated zNear value based on a ...
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### How to set "near" value properly?

Usually, the camera's near value is set to sth like 0.1f. However, this (assuming ...
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1 vote
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### How Extract Frustum Planes from Clip Coordinates?

I'm having some problems with my Frustum Culling and I want to debug it, so I'm trying to render it's planes, to see exatly the Frustum. But I'm using the Clip Coordinates to do the culling (like ...
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### Deferred tiled shading, tile frusta calculation in OpenGL

I'm trying to do deferred tiled shading in OpenGL using the compute shader but I have hit a snag when trying to create the frustum for each tile. I'm using AMD's Forward+ demo (written in D3D) as a ...
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### Which parts to draw in an infinite world?

I have an infinite world (from Perlin Noise). The world is generated in sectors that are that are big cubes (each with a random colour, in the image above; my sectors are 10x10x10). I'm currently ...
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