# All Questions

2,224 questions
43 views

### fastest way to bucket triangles into a grid?

What is the fastest known method for bucketing triangles into an unbounded regular 3D grid? Specifically, I need an array of buckets. Random queries (which bucket is here) are not necessary, as this ...
69 views

### Understanding of Camera Up Vector

Assume eye position e, gaze direction g, view-up vector t, right-handed base. As the graphs shows: $w=-\frac{g}{||g||}$ $u=\frac{t\times w}{||t\times w||}$ $v=w\times u$ I am really confused ...
85 views

### How to simulate elastic material with restoring shape

I'd like to simulate a rubber-like material. This material if deformed would experience a restoring force to its original shape, a bit like a school rubber ereaser. I tried with a spring-mass system ...
26 views

### How to apply SSRT to an existing image with associated depth map?

I have the following image and depth map from a CV paper: I want to know if there is an existing way to apply screen space rendering to a pre-existing image. Before someone yells ate me saying "Why ...
260 views

### Can i compile my shaders to SPIR-V without using glslangValidator?

I'm making a cross-platform application, and i need my shaders to be compiled to SPIR-V for both Opengl and Vulkan. It seems that the only way to do so is to call a separate program, called "...
53 views

### Merging/Clipping Signed Distance Fields

I have multiple separate shapes for which I have generated signed distance fields by merging and clipping them against each other. Is there a generic analytical solution for merge and clip operations ...
78 views

### Is it possible to emulate Vulkan on a non Vulkan compatible gpu?

I don't think there is much to explain here, since the question is pretty much in the title, but i'll try to explain myself better: My current laptop's gpu does not support Vulkan, so i was wondering ...
64 views

### How to raytrace triangular faces when camera is not at origin?

I've watched the Pixar In A Box, Maths of Rendering Tutorial on Khan Academy. I've started writing a raytracing program and have come to the point where I must solve for ...
177 views

### PBR and Specular Aliasing

I have been following LearnOpenGL.com's tutorials on PBR. Everything makes sense and I wrote up a shader for my physically based renderer. I noticed that the results look great, however all of my ...
37 views

### Has anybody extended parametric surfaces to volume density representations usefully?

Current mainstream technology does not really model the density functions very well. Yeah, we can use volumetric grids, FEM, voxel representations and particle clouds that define densities. But these ...
78 views

### Z-buffering implementation with small triangles

For research purpose, I have to implement z-buffering algorithm to render 3D face models. But I got a problem that the triangles are too small to be rendered (i.e. there is no pixel covered completely ...
101 views

### Difference in pixels between different monitors' sizes

If I have an image of x/y resolution and display it on a monitor, does this mean that between a 15-inch monitor and a 42-inch, the same amount of pixels (x/y) will be displayed, only that each pixel ...
113 views

### How to compute normal of surface from implicit equation for ray-marching?

I want to represent ovaloids with ray-marching. I have ovaloids defined with an implicit equation. For instance, we can consider the equation of an ellipsoid given as:  \frac{x^2}{a^2} + \frac{y^2}...
61 views

### Compute emitted importance of a pinhole camera

In section 16.1.1 of Physically Based Rendering the authors describe how we can check, if a given ray $r$ corresponds to one starting from the film area. They implement this check such that it works ...
76 views

### Are MMORPGs, specifically WoW, limited by their latency in terms of FPS?

It sounds crazy, but I've been doing a lot of reading on exactly why WoW performs very poorly, even on a 1080Ti / 8700k OC'd and overall, a high-end machine. Overclocking the CPU yielded great ...
35 views

### Translate vtkCellLocator

I would need to translate a vtkCellLocator, without rebuilding it entirely. I suppose that it should be possible to apply an offset to all the buckets in the octree. Do you know if is it possible to ...
47 views

### Evenly distributed point cloud for a grass renderer on a sphere

I'm trying to add some details like grass, rocks, trees, etc. to my little procedurally-generated planet. The meshes for the terrain are created from a spherified cube which is split in chunks (...
65 views

### Sample color calculation in rotated grid supersampling

I'm rendering a scene using scanline method. In order to get rid of aliasing we need to render a scene with higher resolution (2x, for example). I'm trying to figure out how to calculate the color of ...
43 views

### Is “generative art” the best term for describing graphical techniques like ASCII art or photo mosaics?

I'm researching generative art using computers, and I'm looking to see if there's a more specific term for types of image manipulation techniques like ASCII art or photo mosaics that can narrow down ...
184 views

### Procedural terrain: What's the best approach to calculate noise in the GPU?

A few years ago I started creating a procedural planet engine/renderer for a game in Unity, which after a couple of years I had to stop developing due to lack of time. At the time i didn't know too ...
131 views

### Why are depth buffer values clamped to (0, 1)?

This is a simple question. I know that in OpenGL or other graphics API, the values stored in the depth buffer are automatically clamped to (0,1). I just want to know why people do this instead of ...
25 views

### How can I register an articulated model to noisy predictions?

Given point sets $Y$ and $M$, I'd like to register articulated $M$ to $Y$ without changing the edge distances of $M$. The point correspondences between $Y$ and $M$ are known and points have a fixed ...
77 views

### How to handle GUI in a path traced renderer?

This isn't a pure CG question but it's more of a programming one related to CG. The main problem that occurs is both the GUI and the rendered scene need to be drawn regularly by swapping buffers. If ...
224 views

### Generate mesh from pointcloud data

Given point-cloud data : For example. position + color and normal. What will you use to generate mesh of this data and keep reasonable quality for real time cases ? Additional info to consider: ...
2k views

### Why normal map is blue and purple in color?

I am learning about normal mapping I understood that RGB values converted into XYZ,but my question is how it is converted, and why the normal map is blue and purple in color ?
56 views

### Which of these 2 general designs for a game engine is better?

I have roughly seen 2 different ways rendering engines are commonly handled (there could be more). And was wondering which general design is better for a general purpose engine. Central Handler ...
177 views

### PBR missing rim darkening on non metallic rough surfaces

If you have a dielectric (non metallic) sphere with a large roughness value (say, 0.95), and put it in a lighting environment that has a constant onmidirectional lighting value (such as 0.5) Cook-...
35 views

### Why the interval for which there are more number of steps is chosen while implementing DDA Algorithm?

I was studying the DDA Algorithm and learnt that initially we calculate both the x-difference and the y-difference between the start and the end points of the given line, and if dx > dy, we choose ...
227 views

### Why does graphics speak of “dielectrics” rather than insulators?

For example, Filament's documentation at https://google.github.io/filament/Filament.md.html uses the term "dielectrics" when contrasting nonconductors to conductors, which it calls "metallics". And ...
46 views

### What does “region to be shaded” mean in the PCF paper?

I am reading the percentage closer filtering (PCF) paper by Reeves, W. et al. (https://graphics.pixar.com/library/ShadowMaps/paper.pdf). At at section 3.2, it mentioned that "each shading calculation ...
48 views

### CPU load in games - what is the GPU/DirectX doing to make CPU load higher?

More of a question about what's possible in DX. Some people have reported that when running games on higher settings they get less CPU load but when dropping the settings the CPU load increases. ...
61 views

### How do we approximate the integral of the measurement contribution function in Metropolis Light Transport?

In Metropolis Light Transport, we need to approximate the integral of the measurement contribution function. I've read that this can be done using a traditional approach like path tracing. However, ...
64 views

### Deciphering Affine/Projective Transformation Code

I've spent about 2 days trying to understand this piece of code (from here) that applies an affine/projective transformation to an image. I will link bits of the code that I'm struggling to understand ...
60 views

### Repeating alpha over/under operation multiple times

I have two RGBA colors in linear [0..1] space, src and dst and I want to alpha blender src ...
141 views

### How to visualize and programmatically work with huge point cloud

I have created a quite large point cloud with about 800M RGB points. The exported .ply file is about 12GB large. The commercial software I used to create it can render the cloud very smoothly on my ...
147 views

### Non real-time rendering on Unity3D

I made an audio visualizer using Unity3D (you can see it here) but I am not satisfied on the video quality, as the compression destroys the graphics. I recorded the screen during a real-time rendering....
100 views

### How can we convert a probability density according to solid angle to a density according to area?

In Chapter 14.5.3 of Physically Based Rendering - From Theory to Implementation (3rd edition), the authors claim that a probability density $p_\omega$ according to solid angle can be converted to a ...
206 views

### Best way to clear a framebuffer image without drawing?

So I have a framebuffer image which later acts as input to a compute shader, and some frames there is geometry drawn to the framebuffer, but some frames this is not necessary. The thing is, in my ...
95 views

### Generating Mip Maps For A Cube Map

Let's say I have a cube map that has a resolution of 256x256 for each face and I want to generate mip maps for it using a box filter. It's tempting to just mip each face individually, cutting the ...
35 views

### Difference between using + and * operator after tex2D to add albedo color?

I have a two different codes with a little difference Case 1. I used a + operator before _myColor. ...
430 views

### Why do GPUs divide clip space Z by W, for position?

Background: I found that it is very easy to use a linear depth buffer, using only a slight modification to the canonical vertex transformation. The simplest method is found at the bottom of https://...
87 views

### How does Primary Sample Space Metropolis Light Transport work?

For simplicity, assume we're only dealing with surfaces which have either a Lambertian or perfectly specular material. Morever, assume that the only type of lights are area lights (i.e. surfaces with ...
130 views

### PBR - How to handle multiple BSDFs and material type

So I am in the midst of writing my own path traced renderer and right now I have only implemented the old Blinn-Phong models where we separately calculated the diffuse and specular components of the ...
75 views

### Infinitely long 3D model

Let's say that I want to render something like Dimmadome's hat, a hat which has the height of infinity. A quick answer to this would be to place the top side of the hat high enough for the crown(...
66 views

### Can gl_WorkGroupSize be set outside the compute shader?

I am migrating code from CUDA to OpenGL compute shaders. I could not find a way to set the local workgroup size outside the shader; is there a way to set gl_WorkGroupSize in the calling program like ...
33 views

### Are the benefits of a Metal early depth test limited to one draw call

I should preface with currently this question is mostly asking about Metal and iOS GPUs. That being said if this is GPU or OS specific and you can go into detail about other platforms that would be ...
39 views

### Will sRGB color space get replaced by wider gamut [closed]

in future, will sRGB which is a common standard monitor color space nowadays be taken the place by the wider gamut color spaces? since wide gamut monitor keep publishing in the market and may be ...
123 views

### Light field rendering for 3d software?

Is there any 3d software that supports rendering an artificial scene to a light field image? With that I mean an image capturing light from more than one point in a scene, more lika a spherical ...