# All Questions

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### Is there a mathematical (as opposed to iterative/SDF) test for ray intersection with a grid of circles?

My actual problem is considerably more complex, but can be solved if there is a cheap way to compute the intersection of a ray with a regular grid of circles. If I had a circle centered at every ...
21 views

### Transfer parameterisation between one mesh to another [closed]

I have two similar looking meshes which are not geometrically identical but topologically equivalent. I carefully parameterised one in blender and want to reuse my parameterisation on another(or more ...
31 views

### Graphics APIs: read/write the same texture

I know we can't bind the same texture as an input resource to a shader and as a render target within a single draw call, Direct3D just forces unbinding of such a texture SRV, OpenGL says it's ...
39 views

### OpenGL transparency - object behind is not rendered

I'm trying to implement voxel world using OpenGL (Core 3.3). I've come across a problem with transparency. It looks like sometimes GPU decides to not render stuff that would be important. Can you help ...
48 views

### ACES tonemapping confusion

In different sources I see ACES tonemapping, but I see one of two possible sets of formulas: https://www.shadertoy.com/view/XsGfWV this one https://www.shadertoy.com/view/tdffDl or this I compared ...
42 views

### SSR - ray origin and ray direction

I'm implementing SSR, specifically HZCT (Hi-Z Cone Tracing, based on article in GPU Pro 5 name "Hi-Z Screen-Space Cone-Traced Reflections"). What I'm trying to do right now is to determine ...
34 views

### Deriving formula for perspective correct texture interpolation

I am trying to derive the formula for perspective correct texture interpolation on my own while implementing my own software rasterizer (projecting an arbitrarily rotated triangle in camera space on ...
37 views

### Reorder mesh triangles

Good Morning! My problem is: I need to get the vertices of a mesh and send them to a shader. Inside the shader I will reassemble the mesh from its vertices. So far so good, I send the information and ...
45 views

### Purpose and workflow of wireframe models

I am more less familiarized with the major computer graphics concepts up to certain dregree of "low-levelness". So I know how models, vertices, polygons etc. and how these works. Also how is ...
55 views

### Why does a game at 1080p look better on a 1080p display than 1440p display of the same size

So this is something i recently noticed. I have a 27inch 1440p monitor. And a game in 1080p looks pixelated on that. My friend has a 27 inch 1080p monitor and the same game on 1080p with all same ...
23 views

### glsl passing data array from vertex to tessellation control shader

I am trying to pass a vec3 array from vertex shader to tessellation shader. passing just one value works fine, but how to pass an array? Vertex shader ...
60 views

### What's The Math Behind This Cloth Animation?

I progammed a simple cloth animation. Initially I tried to implement Hooke's law, but it wasn't numerically stable, presumably because I used explicit Euler. Anyway, I came up with something (WebGL2 ...
35 views

I am looking for an easy solution for passing information between shader stages when adding additional shader stages. Right now I am using the "out" keyword to pass data from for example ...
11 views

### How to add a second calculation to an already working transform feedback webgl2 code?

I'm doing a project that involves transform feedback and WebGL2. I was able to make a transform feedback work using two buffers, to calculate an update in 3d positions of particles. But now I'd like ...
120 views

### Rendering Hypercentric Perspective

I came across some Non-Euclidean Games which involve Hyperbolic Spaces, Spherical Spaces, Portals, etc. And, I noticed that they give quite deep feel of what Non-Euclidean Spaces feel like. So, I was ...
70 views

### Stripping unnecessary data from C++ data structures before sending to GPU

I've recently been working on a particle system in my renderer and I've encountered a situation where my particle class on the C++ side has data I need to maintain my particle on that end, but that I ...
26 views

### Efficient algorithm for mesh scale adjustment based on the scale of another mesh

I have a mesh (Mesh-A) with a bounding box of some arbitrary size defined by X,Y,Z scale. In runtime I import another mesh (Mesh-B),which has an overall topology similar to the Mesh-A, but it can have ...
39 views

In the usual pipeline (vertex, tessellation, geometry and fragment shaders) the geometry can be deformed and in the geometry shader it is possible to copy the generated and deformed geometry in order ...
43 views

### Which geometry file format is the most similar to our geometry file format?

To represent a 3D geometry in our software we use this format below: Material-1 Material-2 P1(X1,Y1,Z1) P2(X2,Y2,Z2) P3(X3,Y3,Z3) This 11 point gives us a triangle with the description of what is ...
51 views

### Examples of cases where you write depth value in Fragment Shader?

I've very less knowledge when it comes to rasterization and typical rendering in games and other applications. So I was reading up on the rendering pipeline and found that the hardware could do early ...
55 views

### Is BSP the right tool for my game?

I am brushing up on the fundamentals of OpenGL. Things are going great. I am looking at BSP for maps/levels. I understand that Doom uses BSP, but I worry. Can BSP be used with complete 3D world and ...
36 views

### Generate Hi-Z buffer using single PSO and single UAV

I'm currently implementing SSR in my engine and I've created Hi-Z buffer using multiple PSOs in way presented below: Create descriptor table with multiple UAV entries (this case - 3 entries for Mip 0,...
49 views

### How is the maximum value for alpha (roughness == 1) decided for microfacet models?

Recently I have been looking at pbrt, and was looking at their remapping from roughness to $\alpha$ values: https://github.com/mmp/pbrt-v3/blob/master/src/core/microfacet.h#L86 I understand that it is ...
69 views

### What is the Viewport?

Can someone please explain to me what the Viewport is. I've read the OpenGL wiki and doc.gl but they give me a definition that I don't understand at all. The definition they gave me is "...
32 views

### glTexImage2d from bytebuffer

I want to create a single-channel 2d texture with bytebuffer which contain each float for each pixel (let say it is an alpha value) to use further in shader Btw, I've tried this ...
38 views

### Mapping an image from one camera pose to another given a planar scene

I'm trying to map an image of a 3D object to another one from a different camera position. My assumption is that the pose change between two cameras is so small and the object is far enough from the ...
54 views

### Understanding how gradient noise generation works

When attempting to compute the gradient noise derivatives I've seen the use of a function named "hash" and I don't understand its purpose (nor why they have commented that it should be ...
42 views

### PDF of BRDF respecting the spherical coordinates

I'm reading the article Sampling microfacet BRDF. The GGX function is $D(h)$, the articles says the PDF respecting the spherical coordinates is $P_1(\theta)=D(h)Cos(\theta)Sin(\theta)$. But I think ...
21 views

### Missing from cmake QT project

I'm attempting to create a basic QT cmake (either in VS or QTCreator) project but I'm getting a rather larger linker error. I imagine I'm missing something in the cmake as I'm getting a lot of ...
57 views

### OpenGL state management

I am working on a software with lots of different shaders, which require different states in OpenGL. My problem is the following: The different models with different shaders are not rendered in the ...
38 views

### Are vertices of each LOD version always loaded into VRAM

Are vertices of each LOD version always loaded into VRAM? I know many game engines have a LOD feature for mesh vertices and textures. I'm just wondering if all vertices and textures of all(each) LOD ...
32 views

### opengl and glxinfo

I have a question about reading glxinfo. I'm running a Fedora 31 virtual machine. When I look at glxinfo (using softpipe) with this command: ...
102 views
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### Cubic Splines - Do Parametric and Explicit representation give different curves?

I asked a similar question here before but since the previous post original question was different, I think it was confusing people. So I've voted to close that and asking the new question here. I'm ...
70 views

### What is this glitch where objects get stretched to infinity?

I've encountered this glitch a few times in various video games and other apps with 3D graphics. It causes things to get stretched all the way to the vanishing point of the scene, usually towards the ...
66 views

### Ray-Marching: Rendering a Voxel Grid with Proper Normals

Dear Computer Graphics SE, I have a RAYMARCHING renderer, that looks up voxel data from a 3D texture. Each cell in the texture can be 0 or 1. I have a very simple algorithm for calculating the signed ...
62 views

### Is it possible to change pixel brightness programmatically?

So, I've been learning 3D rendering for more than a year now, and I've read a lot about various rendering techniques and theories, such as PBR, deferred shading, real-time raytracing, BRDF, all that ...
19 views

### Unexpected INVALID_OPERATION on glClearNamedBufferData

Under OpenGL 4.5 on AMD RENOIR (DRM 3.40.0, 5.10.56-1-lts, LLVM 12.0.1), running ...
28 views

While I am not looking for a method to render soft stencil shadows, I am trying to achieve hard shadow rendering that is extended to include the penumbra regions of a shadow for omni-directional ...
18 views

### raycasting in opentk: size of projection plane / direction of rays

I found my error! The solution was as posted for example here: How to avoid curvature artifact in raytracer? ; just multiply the forward vector with cos(angle) before adding the vectors. i want to ...
35 views

### How to dynamically calculate the Partial Derivative of any vector?

I have a problem that requires Partial Derivative of X and Partial Derivative of Y (Like OpenGL's dFdx() and dFdy() functions.. OpenGL Registry dFdx) However, the issue is, I dont have access to these ...
24 views

### How to troubleshoot GPU card that fails after weeks and works well after restart?

A computer "Controller" that controls several screens has separate GPU Cards attached. after weeks of running smooth screens attached to "a card" will fail showing no signal and ...
32 views

### Zebra-Like Patterns Generated By Linear PDE

I wrote some code which basically computes the color value $c_{t+1,x,y}$ of a pixel at time $t+1$ and position $(x,y)$ by taking adding linear transformations of the values $c_{t,x,y}-c_{t-1,x,y}$, \$...
54 views

### Motivation behind tesselation

This question is NOT about the hardware difficulties and shortcomings of tesselation shaders I am trying to understand the motivation behind tesselation shaders. Why/when/where tesselation is a good ...
57 views

### Is it possible that a superior, undiscovered 3D rendering method exists?

As far as I know, the only options we have for true 3D rendering are polygonal rendering, ray-marching and raytracing/casting. Why is that? Surely there must be other ways? Is there some paper ...
15 views

### openGL plotting point to window not using glutDisplayFunc(your_func)

I want to plot complex data points to a window to display. I know how to do it all in one go: ...
18 views

### Why RGB value bigger than 1 when convert from spectrum in PBRT-V3

In PBRT-V3, the light has following spectrum in scene file(Note that the scene file is not come from PBRT itself): ...
15 views

### D3D11 How to re-use queries?

I'm trying to use queries in D3D11 to profile my program. Here is how I do it: ...
67 views

### Opengl geometry shader input point to output point doesn't show any ouput

I am trying a simple passthrough just to get a feel for the geometry shader. I am taking in a single point and trying to output that point from the geometry shader, it works with the vertex and ...