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2
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1answer
31 views

Implementing the example of Walter et al. (2007) paper

As the title suggests I'm trying to implement the last images of the "Microfacet Models for Refraction through Rough Surfaces" Paper by Walter et al. in OpenGL I "think" (I had to put that into ...
1
vote
0answers
25 views

Convert a polygon mesh to a bspline surface

Problem: Getting a polygon mesh as input, I have to construct a surface that looks exactly to the given input. My task is to generate a b-spline surface that exactly looks like the connected polygon ...
0
votes
1answer
22 views

Trouble using Open Image Denoise

I'm trying to use open image denoise. Here's the code: ...
0
votes
0answers
26 views

How to Pan Zoom a spherical camera?

I asked this in regular SO but I think people are not understanding the question so i will try here: So, for anyone familiar with Google Maps, when you zoom, it does it around the cursor. That is to ...
3
votes
0answers
57 views

How to calculate subsurface scattering weights for fast skin shading

This question is in reference to the method described in ShaderX7 section 2.4 "Fast Skin Shading" by Hable et. al. The part I do not understand is how they derived the weights for the individual ...
0
votes
1answer
45 views

Why is the z direction away from the screen/viewer?

I wonder what is the reason that when z increase, the objects appear far away and when z is negative, the object is behind the camera?
0
votes
1answer
53 views

Should ray throughput always decrease when bouncing?

In the accepted answer for the question What is Importance Sampling?, in the example code there is this line: ...
2
votes
0answers
38 views

Importance Sampling path tracer, Different pdfs result in different luminance?

I'm having a lot of trouble implementing Importance Sampling path tracer. If I understand it correctly, what I need to evaluate for a path tracer is this: $\int_\Omega L_{in}(L) * fr(L, V) * \cos(\...
0
votes
1answer
23 views

How do you add text dynamically to an image and export it?

Apologize for crossposting, but I posted this in Stack Overflow and thought it might be a better post here. Recently, Spotify released their 2019 Spotify wrapped web application, which is essentially ...
2
votes
0answers
70 views

Why there are calculation differences in WebGL and OpenGL

I am currently implementing the Mandelbrot fractal on the GPU. I wrote two programs: the first in OpenGL (desktop C++ application) and the second in WebGL (static webpage). The two programs use almost ...
0
votes
0answers
22 views

Algorithms used in Wrap3?

I've just downloaded Wrap 3, and I'm playing a bit with it. I can't find any documentation about the specifics geometry algorithms used in the software. Does anyone happen to know where I can find a ...
1
vote
0answers
28 views

Apply transformation to single vertices in OpenGL in order to deform mesh

I'm making a 2D cell simulation game. The mesh for my cell is basically just a manually-generated triangle fan that looks like this. I would like to reproduce the wobbling/vibration effect on the ...
-1
votes
0answers
62 views

What is wrong with my path tracer?

I've already tried implementing the RL-based path tracer. The path tracer was buggy. Today after running one of my path tracers for hours I realized that even those path tracers show the same problem. ...
2
votes
1answer
31 views

How to decide which child of BVH to visit based on sign of ray's direction vector?

I'm reading about BVH from PBRT. According to the book, in the linear bvh part using morton encoding: An efficient way to perform a front-to-back traversal without incurring the expense of ...
2
votes
0answers
35 views

Calculating Luminance From Y'CbCr

I have a video feed generating a stream of of Y'CbCr frames (specifically 8-bit component Y'CbCr 4:2:0, luma range of 16-235, chroma range of 16-240) from which I'd like to calculate relative ...
2
votes
1answer
35 views

Can D3D12 resource barriers be used to synchronize between the compute and 3D engine?

What is the best way to synchronize resource access between the (async) compute engine and the 3d engine (aka. direct engine) in D3D 12? I found this paragraph about multi-engine synchronization on ...
0
votes
0answers
46 views

Understanding lighting for physically based rendering

i wanted to ask if you know the best books or resources to understand light physics. I have heard that Subrahmanyan Chandrasekhar's book "Radiance Transfer" is very good. Any other books or ...
2
votes
1answer
48 views

Is there a way to perform calculations of Mandelbrot set using only integer numbers?

I would like to create program in JavaScript (JS) which draws Mandelbrot set with arbitrary precision (zoom). In JS there is build in integer type BigInt which support simple operations like +,*,/,...
1
vote
1answer
116 views

Why is Russian Roulette used in ray tracing?

Why should we use Russian Roulette? Does it reduce ray tracing artifacts?
1
vote
1answer
47 views

Value range of normal distribution function

Is the normal distribution term D in the Cook-Torrance BRDF supposed to be between 0 and 1? What does this number actually represent?
1
vote
1answer
86 views

Multiple samples per pixel and texture blurring

As far as I know path tracers (or super-sampling antialiasing) typically calculate the final color of a single pixel by averaging the result of all samples taken inside that pixel. This gives a nice ...
1
vote
0answers
33 views

Projective Texture / Shadow Mapping — Why is the perspective division performed in the fragment shader?

I've just worked my way through this OpenGL shadow mapping tutorial. While I understand the basic algorithm, one thing puzzles me: During the 2nd render pass all vertices are transformed into the clip ...
0
votes
1answer
31 views

Stumped on GLSL error C5041 (cannot located suitable resources to bind variable… possibly large array

I have an OpenGL based graphics engine coming along quite nicely, but I'm currently stumped on a problem that arose after adding a new vertex shader output array. The vertex shader is outputing the ...
1
vote
2answers
71 views

Why are reflections in a spherical surface sharp, regardless of depth of field?

A question has come up recently in Blender SE, remarking on the absence of blur due to depth of field in reflections in a spherical surface. This is a real-life effect.. can anyone come up with a nice ...
1
vote
0answers
40 views

Path tracing: How to do tone mapping and gamma correction?

I am not sure what is the correct way to do tone mapping and gamma correction in a Monte-Carlo Path Tracer. Should I apply tone mapping before or after averaging the samples?
1
vote
0answers
57 views

UV mapping on triangles

After watching some Youtube tutorials I thought I had understood the concept of UV mapping: I have a net of triangles, and I have an image representing my texture. Now I tell the GPU which point of ...
0
votes
0answers
36 views

Is it possible to draw horizontal and vertical line with Bresenham's line drawing algorithm?

In computer graphics Bresenham's line drawing algorithm used to draw line . But i want to know the properties why i can't draw vertical and horizontal line by this algorithm.
1
vote
0answers
27 views

Question about simple estimation of the discrete curvature at vertices of a mesh

In this post, Nathan-Reed gave a simple, neat, "heuristic" estimation for the discrete curvature at vertices of a mesh. In a nutshell, it computes a curvature along each edge incident to the vertex, ...
2
votes
2answers
51 views

Visualize the interpolated unit quaternion on the surface of the unit sphere

My major is mechanical, please forgive me for asking questions that may seem trivial to you. First, I'm reading the following paper: Dam, Erik B., Martin Koch, and Martin Lillholm. Quaternions, ...
0
votes
1answer
68 views

Compute Speed of Spheres in 3D animation

I have created two animations: One where a "camera" moves towards the spheres creating an optic flow (1st GIF).The code can be found here. One where spheres move randomly in a 3D coordinates space (...
0
votes
0answers
35 views

What’s the most efficient way to compute shadow from depth map?

Suppose we are given the depth map in the form of an image of fixed resolution. And suppose the point light source is not too far from the camera. Is it possible to compute the shadow map from ONLY ...
0
votes
0answers
20 views

invcdf for spherical function

There are recent papers on theme of analytic solution of integrals on 2-sphere over polygonal domains. For importance sampling (sample warping) it is attractive to use the analytic solution to derive ...
2
votes
1answer
122 views

Rendering equation for spherical lights

I am currently implementing spherical lights in my DirectX game engine. I decided to build the shading formula from the classical rendering equation. Here is what I get: The simplifications show that ...
0
votes
1answer
34 views

How to change a picture to fail comparison algorithms?

Is there a way to change a picture so it would fail to match against existing copy of the same picture on the big social networks such as Facebook, Twitter, Instagram, Tinder and others? Desired ...
1
vote
1answer
43 views

Latency difference between texture copy on GPU vs CPU?

Does anyone happen to know the latency difference between copying a texture on cpu (using, say, memcpy) compared to gpu (using, say, ...
1
vote
0answers
28 views

Optimizing texture fetches with higher mip levels

Let's say I have some shader program in DirectX or OpenGL rendering a full screen quad. And in a pixel/fragment shader I sample some huge textures at random texture coordinates. That is one same ...
0
votes
0answers
35 views

Questions in Veach path-space formulation

http://graphics.stanford.edu/papers/veach_thesis/chapter8.ps In chapter 8 of his thesis which he talks about the three-point form of the transport equations, equation (8.1) in particular, it seems ...
1
vote
0answers
55 views

Least squares for uniform scale and translation

I have two meshes that I want to align, I'll call the reference mesh the template mesh and the other is the target mesh. I have 1 point-to-point correspondence between my template and target mesh. I ...
0
votes
1answer
48 views

Compute normal based on Voronoi pattern

I am applying a 3D Voronoi pattern on a mesh. Using those loops, I am able to compute the cell position, an id and the distance. But I would like to compute a normal based on the generated pattern. ...
0
votes
1answer
46 views

How to calculate the PDF of a multi-lobe BSDF

In PBRT, a BSDF is represented as an array of BxDF lobes. Each lobe sets a bitflag representing what kind of lobe it is. (Specular, Diffuse, Reflection, Transmission, etc.) I'm investigating how PBRT ...
1
vote
1answer
56 views

Strange VSync issues on a GTX 1060

I'm out of my wits. I've been working an a voxel game for the last couple of years, written in C# and OpenTK (=OpenGL backend) I've been struggling to achieve a stable frame rate and one of the major ...
1
vote
1answer
25 views

convert image pixel dimensions to UV

Hi i am rather new to computergraphics but i am trying to map an equirectangular image (360 video) to the inside of a sphere now i found the following formula to do this. ...
0
votes
2answers
63 views

How to handle different data types (uint8, uint16, float) in Volume Datasets?

So I've written a personal volume renderer which currently visualizes datasets (CT-Scans mostly) that have a .raw extension and the values are in the range ...
1
vote
0answers
134 views

Strange behaviour when tracing rays through hemisphere patches

I have implemented a ray tracer using reinforcement learning. But I see some problems. I tried to divide the planes into rectangular grids. I searched the moire effect and realized that I can solve my ...
1
vote
0answers
32 views

How to use MTLLoader in THREE.js

I'm a student in computer science and I have a project where I need to create a 3d scene with a train. I loaded the model correctly but the texture is a .mtl file. So I looked the official ...
0
votes
0answers
18 views

Unlit shader emulation in usdz

How do you "emulate" an unlit shader in the .usdz file format?
0
votes
0answers
42 views

Infinite 2D Coordinate Space

I am working with a 1 dimensional array of an RGBA struct composed of unsigned 8-bit integers. I have implemented a very basic line algorithm, and can draw lines from one point to another accurately, ...
0
votes
1answer
44 views

What is a 0 “null” normal map? Or Unlit shader

Does anyone understand normal maps and what would color a uniformly 0 normal map be? I'd like to convert a standard shader into an unlit shader, so (I think?) the idea is that the normal map should ...
1
vote
1answer
88 views

A pseudocode to parallelize a path tracer?

Where can I find a pseudocode to parallelize a path tracer using multiple cpu threads? How should I change the normal path tracer to be capable of parallelization?
1
vote
0answers
48 views

gBuffer view/eye space missing z (depth) value?

I need some help understanding whats happening to my view space. I have the following colour buffers coming out of my deffered renderer... My concern is with the view space buffer (third image), ...

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