0
votes
0answers
27 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 ...
2
votes
1answer
48 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 ...
1
vote
0answers
13 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 ...
0
votes
1answer
26 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 ...
1
vote
1answer
55 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: ...
0
votes
0answers
22 views

Speed of different access methods reading a picture

Suppose there is a cpu with a cache line of 64 Bytes. Now you need to access all the data of a 2D image stored in the main sequence of the line by pixel. The image size is 1024*1024, of which there ...
0
votes
0answers
22 views

Targeted pixel updating in Java GUI

What’s the best approach for targeting specific pixels of a displayed GUI image in Java? For example writing a real-time mouse highlighter, editing certain pixels without refreshing the entire frame.
5
votes
2answers
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 ?
0
votes
0answers
42 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 ...
5
votes
2answers
137 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-...
1
vote
0answers
32 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 ...
9
votes
2answers
177 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 ...
0
votes
1answer
36 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 ...
0
votes
1answer
43 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. ...
2
votes
1answer
47 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, ...
1
vote
0answers
41 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 ...
0
votes
0answers
42 views

What is wrong with this GGX sampling function?

I wrote a small Shadertoy path-tracer a few days ago to teach myself PBR transmission/reflection, and I decided to use Heitz's microfacet sampling model since it's cleaner than the one in PBRT. I'm ...
3
votes
1answer
52 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 ...
3
votes
1answer
53 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 ...
3
votes
1answer
63 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....
2
votes
1answer
78 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 ...
0
votes
1answer
50 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 ...
1
vote
0answers
39 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 ...
0
votes
0answers
29 views

What's the definition of the “emitted importance” in the measurement equation?

Let $M$ denote the set of all surfaces in the scene $\nu_M(x)$ denote the unit outer normal$^1$ at $x\in M$ $\Omega_x$ denote the upper unit hemisphere at $x\in M$ oriented according to $\nu_M(x)$ $\...
1
vote
1answer
25 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. ...
4
votes
2answers
125 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://...
0
votes
1answer
26 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 ...
2
votes
1answer
73 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 ...
2
votes
1answer
62 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(...
3
votes
2answers
35 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 ...
1
vote
1answer
27 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 ...
2
votes
1answer
31 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 ...
2
votes
1answer
59 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 ...
0
votes
0answers
19 views

Precomputated rendering for isotropic microfacet BRDF

I am looking for a suitable precomputing rederings for isotropic microfacet brdf (say GGX) given an environment lighting. I was using ward brdf before which is radially symmetric so I was able to use ...
0
votes
0answers
32 views

Simulating vanishing points shader

How do I create a vertex shader that allows to choose 3 non aligned direction vectors and then allows to morph all vectors positions such that every vertex is remapped so that two vertices that are ...
0
votes
0answers
46 views

Reading Z-buffer with glReadPixels always return 1.0 (OpenGL 3.3)

I'm trying to use glm::unProject (), however, it gives wrong results. I discovered that it is caused by wrong depth returned by ...
0
votes
1answer
38 views

OpenCL ray tracer: which is better, geometry code on device side or on host side?

I am writing a ray tracer using openCL, and following this tutorial http://raytracey.blogspot.com/2016/11/opencl-path-tracing-tutorial-2-path.html However, I find that the author has two copies of the ...
2
votes
0answers
40 views

What is wrong with my deformation gradient calculation?

I created two ellipses,$\hspace{150px}$,where the red ellipsis is as the blue one, except translated to the right and rotated by ${30}^{\circ} .$ Using rotation matrix, $$ \left[ \begin{array}{cc} ...
6
votes
1answer
99 views

Same draw call causing extremely different GPU usage under different triangle orders

So I have a bit of a predicament I am trying to solve. I have 10,000 triangle strips I am trying to draw. Each one has a z-order for the entire strip and within each strip the most recent triangles ...
4
votes
1answer
42 views

How do I calculate average hue, since the numbers loop around?

If I calculate the average (mean) hue of a set of colours naively, I will get silly answers sometimes. For example, in HSB/HSL, the average of hue=10 (slightly orange red) and hue=350 (slightly blue ...
0
votes
1answer
23 views

How to blend a segment of an image with another image

I want to put a segment of an image to another image. But to make it realistic I applied poisson blending. But the output is not good at all. Output without poisson blending. The kid was cropped ...
3
votes
2answers
369 views

Ambient occlusion of a sole object in a scene

So, the german wikipedia states about ambient occlusion:The ambient occlusion method is based on the assumption that an object, a set of objects or an entire scene is surrounded by a unit sphere of ...
5
votes
1answer
172 views

Problems rendering a plane via `drawElements`

I am generating plane vertices where the y values are generated by a heightmap (noise) algorithm. This is how I produce my vertex array: ...
0
votes
1answer
37 views

Multiple VAO share a EBO (OpenGL 3.3)

As mentioned here, multiple VAOs can share a single VBO. However, can multiple VAOs share a single EBO? For example, I want to create 2 rectangles. So, I do the following: ...
1
vote
1answer
127 views

Problem of understanding the coordinate systems involved in ray tracing

This picture depicts my current immagination of the coordinate systems involved in ray tracing: Explanation: So the green rectangle is the [-0.5, nx-0.5] x [-0.5, ny-0.5] coordinate system and you ...
1
vote
0answers
36 views

Sorting my geometry for alpha testing

Here is my predicament. I am trying to draw a multitude of dots that leave trails behind them real time. Heres the difficulty, that line fades. Each dot line has a defined z position and the goal ...
0
votes
1answer
79 views

SSAO random noise vector generation

I am currently trying to implement SSAO on my graphics engine. I am following John Chapman's tutorial here. This is a pretty popular article that is used as reference in many SSAO articles. The part ...
2
votes
2answers
66 views

How to perform additive blending in Metal. What do these terms mean?

Forgive me, I dont really understand the basis of alpha blending. Like I know the formula but when it comes to the terms blending operation, source blend factor, and destination blend factor I am ...
1
vote
1answer
45 views

Equation for camera projection

I am trying to find an equation for a camera projection. The goal is to map the point $P(P_x, P_y, P_z)$ from the world coordinates onto the window coordinates $Q(Q_x, Q_y)$. The eye of viewing is ...
4
votes
1answer
89 views

Using multiply and accumulate of 4x4 matrices for ray-triangle intersection tests on GPU

Is it possible to gain performance boost using new 4x4 MAD from NVIDIA'a tensor cores for ray-triangle intersection tests? Really there are two questions: Is it possible to modify some of the ray-...

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