# All Questions

2,221 questions
8 views

### Is it possible to bind dynamic texture samplers to a shader in DX12?

So usually texture samplers are set directly in the D3D12_ROOT_SIGNATURE_DESC structure in DX12, at least that's how I've been setting them. I was wondering if it's ...
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### Weirdly looking diffuse irradiance map

I have problem with creating diffuse irradiance map. As reference I am using https://learnopengl.com/PBR/IBL/Diffuse-irradiance and https://github.com/TheEvilBanana/PhysicallyBasedRendering/blob/...
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### Prefered gpu for deep learning

Im planning to buy a custom build pc for computer vision because I want to make a career switch in it. So Im still confused about the choice of gpu. Should I go with nvdia(cuda) or amd(opencl)? Also ...
43 views

### Why don't discretization errors occur with compute-shaded kernel filters?

An efficient compute-shaded image filter would be emitted with (screenX / [kernel width], screenY / [kernel height], 1) groups and one kernel in each group, allowing texels to pass into groupshared ...
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### How can I control memory for command allocators and command queues in D3D12?

The D3D12 programming guide suggests specific allocation strategies for command queues and allocators, but the creation methods for those objects operate directly on queue/allocator pointers without ...
66 views

### Ray tracing in One weeked: issue with metal reflection

Problem I am following the book Ray tracing in one weekend , and I got stuck after the implementation of the material Metal. I checked my code many times, and it looks exactly like the code ...
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### GBuffer: Framebuffer with different texture format types?

I rely on this answer from Nathan Reed: How much precision do I need in my G-Buffer? It is proposed to use two different texture formats for one Gbuffer. However as far as I know, color texture ...
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### How to implement explicit light sampling when implementing path tracing?

I implemented a path tracer and got a similar result like this one. Sample: 4096, time used: 537.05s The algorithm is exactly the same as the one in wikipedia, where only the Gathering Path is ...
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### OpenGL Unable to retrieve the values of data sent to shader using textures

I've been following these tutorials and i can't figure out how to send data to shaders using textures. https://en.wikibooks.org/wiki/OpenGL_Programming/Scientific_OpenGL_Tutorial_02 In this tutorial ...
51 views

### Blur with alpha transparency

I'm writing a simple box blur for a graphics library. The formula makes the average of a range of pixels by adding the ARGB amounts and then dividing by the blur range For example, with a blur range ...
52 views

### How do I use texture coordinates of a .obj file in OpenGL?

I have an obj file, with texture coordinates (indicated by vt). How would I use this to load textures in OpenGL?
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### An algorithms for covering a 2d polygon with a prefixed number of rectangles?

I am looking for an algorithm that is able to cover with non-overlapping rectangles in a pre-defined number and minimum area a generic 2d-polygon. Polygons are usually free-hand draws, so they can be ...
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### Access YUV inside a Glsl Shader

I have a video texture which is in YUV format, I need to access Y,U,V individually inside a Glsl shader as we access R,G,B. How can I do that?
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### How to use Photometric Units with Rendering Equation?

So I was just reading up on how to create more Physically Based Lights and wandered into the realm of photometry. I read the paper "Moving FrostBite to PBR" and in it the author claims he decided to ...
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### transformation from cartesian coordinates to spherical coordinates without calculations

Given this graph in the 3d cartesian coordinates i should figure out the spherical coordinates representation but without the use of calculations . I've been trying to solve this the whole day but i ...
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### Optimizing sphere tracing, ray-traced hulls vs. gradient volumes

My rendering engine uses sphere-traced SDFs for surface representation and path-tracing for shading, so fast intersection times are important. I'm creating lots of organic/procedural surfaces, so I ...
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### How to set equivalent PDFs for cosine-weighted and uniform-sampled hemispheres?

I'm trying to add BRDFs to a very basic path tracer. Starting out, I'd like to convert just the Lambertian material, with two different sampling methods, to ensure that everything is working right. ...
63 views

### Using transformations to get from A to B image

I try to solve this, First, I used scaling: $Scale(S_x,S_y)=S(\sqrt 5,\sqrt 5)$ So, I enlarge the bottom of the house and the sides, to the same size of B image. Later, I used rotation: \$R(\theta)=...
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### Can you generate your own HDRI maps without using photos?

For example, preparing a scene in Maya using standard lights and rendering out a panorama? Could they also be made from scratch in photoshop using 32bit color? Is there a reason why people don’t ...
64 views

### What is the oldest hardware able to feasibly support Vulkan?

What is the oldest hardware or minimum requirements conceptually able to support a fully hardware-accelerated Vulkan implementation? I am not referring to what implementations are currently available ...
24 views

### Using Hough Transform to detect lines in an image

I am using hough transform on the following image after canny edge detection ...
43 views

### Rectifying the Environment Map (How it works)

Hello everyone I am currently reading a paper of Disney research, Zurich, for my exam, and I really don't understand a thing in this paper... The main issue of this paper is to create a ...
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### Consistent animation speed across systems

I recently noticed that in all games, no matter what system you play on or what specs you have, your character will always move at the same speed even if there is no frame rate limit. I was wondering ...
33 views

### Define position and orientation in a local coordinate system

Suppose we have a world coordinate system W and a 3D model m1 defined in W. ...
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### How to convert from Object space into World space (exercise from 3D Math Primer book)

This is not homework. I'm self studying Computer Graphics, using the book "3D Math Primer for Graphics and Game Development" (2nd edition). So there is the exercise 6 in chapter 3 which I can't figure ...
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### Strange stripes on the gradient

On the picture below you can see mathematically perfect smooth transition from black to white. But I noticed that on all gradient picture I see strange strips and the color transition doesn't feel ...
60 views

### Skybox is rendered on the model instead of surroundings

I'm trying to implement Skybox in DirectX 11 (DirectXTK) but when I'm rendering skybox, then texture is rendered to my sphere model instead of showing skybox outside. Rendering code: ...
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### Anisotropic GGX BRDF implementation. How is it related to isotropic GGX BRDF?

Introduction I am implementing anisotropic GGX BRDF and have encountered strange behaviour of my implementation. I thought that if I compare the microfacet distribution function I have with the one ...
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### State-of-the-art human extraction from image

What are the state-of-the-art algorithms for single human extraction from image? I am looking for algorithms able to extract from a picture only the person, reulting in a picture of the person with ...
55 views

### Should animations be locked to FPS or Fixed time

I have been working on a 3D engine and I am now implementing animations, but I can't find out whether or not to use the FPS of the engine or a fixed time method for the transformation's speed. Could ...
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I found this picture When you zoom in to any part of the image, the background looks a bit noisy/grainy. See pixels around "violent violet" label: I'm trying to understand how to achieve the same ...
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### How to capture frames in a MacOS MTKView for recording to a video

I have created a 3D model of a local outdoor performance space and I have an app that uses Metal on MacOS 10.14.2 to display the model. I want to create an animation by flying the camera around the ...
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### My 2D translation matrix causes the box to be off screen when it shouldnt be

Now I know this isn't the way this is normally done so please bear with me. I am doing this this way so I know I have a solid conceptual understanding of everything that goes beyond example code. I ...
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### Getting contrast color to a given color in RGB or ARGB or HEX

I am looking for a stable way to find a contrast/inverted/opposite color to a given one. Application of this is to find best possible color for foreground to give background.
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### Specular/Diffuse light on an icosahedron opengl

I'm having a problem with my model here. I draw an icosahedron using GLUT, and the radius is set to 0.8. The info of the coordinates are listed below: (X and Z are calculated since our radius is 0.8) ...
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### GL_SAMPLE_ALPHA_TO_COVERAGE and depth testing

I am currently looking into alternatives to my current, somewhat slow but exact, OIT approach. Specifically, GL_SAMPLE_ALPHA_TO_COVERAGE to convert the alpha value into a per-sample mask. ...
127 views

### Iridescence/Thin-film interference integration as a layer

I'm trying to integrate the thin-film interference effect described in the paper "Belcour, L., & Barla, P. (2017). A practical extension to microfacet theory for the modeling of varying ...
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### Finding the normals of a tileable 2D surface extracted from 4D space

If I use a 4D noise function which returns a noise value and a four-part analytically derived gradient vector, I can create a 2D tile which is seamless (i.e. the opposite edges match) through ...
41 views

### Is there an analogue of OpenGL's ImageLoadStore in DirectX 12?

I'm trying to port part of an OpenGL program into an existing DirectX 12 software, at some point in their shaders they use OpenGL ImageLoadStore in order to store information in 3D Textures without ...
48 views

### Convert RGB image to YUV420 using a hlsl shader

I am new to shaders and I need to convert efficiently an RGB image to YUV420. I can convert the RGB image to YUV420 with a simple c++ program that uses the ...
143 views

### Physically Based Shading for Diffuse surfaces

So I am currently in the process of implementing Physically based Shading in my pathtracer using microfacet models and I'm quite stuck at comprehending light interaction with diffuse surfaces. First ...
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### debugging VGA signal timings for 640x480 @ 60hz

I am trying to get started with implementing a basic display (i.e a simple red screen) onto a VGA monitor by programming a Xilinx spartan3a fpga for the same. I have studied about the signal timings ...
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### Intersecting Frusta

I am trying to determine whether two frusta intersect in 3D space and to quantify this intersection as a percentage of one frustum volume (eg. 100% intersection meaning that the two frusta occupy the ...
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### what is the limit of Triangulation Matting?

I am studying triangulation matting in computer graphic. It seems very simple but very cool to identify the foregrouand and background. However, I didn't find what's the limit of it. Besides the ...
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### confused on isotropic BRDF

I am reading a paper and there is a part I don't understand: I am wondering why the isotropic BRDF only depends on the view direction and roughness? Why is the light direction not related?
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### How is lighting done in Rasterization based pipeline?

So I wanted to know how do Game Engines like Unity3D and Unreal do lighting. I'm familiar with Ray-tracing, pathtracing based renderers etc. But not much with rasterization based engines. I do know a ...
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The Unity Engine manual page Best Practice: Setting up the Lighting Pipeline has a section "Render pipelines" with an illustration of Tile Rendering and Cluster Rendering: The section then mentions:...
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### Insert an edges in a surface - CGAL error: assertion violation

'm creating an application using qt creator which read .off files as CGAL::Linear_cell_complex_for_combinatorial_map and preview it I want to make operations on the read mesh such as removing edge and ...