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37 views

Where to find BRDF textures

I've read about measured BDRFs and models like cook-torrance have parameters that need to be set. It isn't hard to imagine that these parameters and the measured properties would vary from point to ...
2
votes
1answer
61 views

Offline path tracer produces a darker image than expected

I've been going though Peter Shirley's beginner raytracing books. Upon building the Cornell box and rendering an image, I get a much darker / dimmer image than expected. The color values are ...
0
votes
0answers
40 views

Moving a sphere in a basic ray tracer

I have written a really basic ray tracer. It generates primary rays and sets the colour of the pixel to the colour of the object that I have set myself. The code for which can be seen below. ...
1
vote
0answers
21 views

Mitsuba builds targets with scons but throws “undefined symbol” error when trying to render scene

I am trying to implement a custom add-on for Mitsuba, but when I use the Heightfield I have defined in another function call(WaveBrdfAccel) in main.cpp it compiles without any problems but when I try ...
3
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0answers
24 views

What expectations should I have of large (> 2 GB) file support in common mesh workflow tools?

I have an experimental workflow that involves very finely subdivided meshes, above the 2 GB limit where signed 32-bit integers stop working, which often causes problems for various tools. I would need ...
1
vote
1answer
58 views

light probe (for global illumination) placement techniques?

I'm learning light probes used for dynamic global illumination. I have a question regarding the placement of light probes, as based on most of the pictures I have seen, they seem to be placed ...
2
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0answers
39 views

Communication between vertex shader executions

Look at this vertex shader: ...
1
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0answers
38 views

Reddish tint with spectral renderer

I'm trying to implement a spectral path tracer and comparing results from my program with renders of the same scene done with pbrt and ...
0
votes
0answers
19 views

Visualize a mesh with sparse vertex counts

I have a mesh that records some integer information for its vertices. I expect this information to be quite sparse, with possible large variations. How could I visualize this on a colorscheme (e.g. ...
1
vote
0answers
153 views

Volume Rendering - Dataset not rendered correctly

So Im trying to implement a Volume Renderer mainly for medical images like CT-scans and MRI images using GPU raymarching. I'm using the book "Real Time Volume Graphics" and this tutorial as a refernce....
5
votes
3answers
95 views

What is the purpose of the projected solid angle $dA^\perp$ term in the definition of Radiance?

In the definition of Radiance, which according to PBRT is defined as flux per unit solid angle $d\omega$ per unit projected area $dA^\perp$ $$L_i=\frac{d\Phi}{d\omega\ dA^\perp}$$ My original ...
1
vote
0answers
39 views

Path tracing best materials to learn

i want some of your advices. To begin with i ve never studied computer graphics and i want to do a project with Path tracing which i didnt find the right materials to begin with. Is it recomeneded to ...
0
votes
0answers
14 views

how apply edge collapsing within selected surface

I'm using CGAL edge collapsing to remove edges on mesh and it's working successfully . But I want to run the edge collapsing process within selected surface on mesh viewer . I preview the Geomview (....
2
votes
1answer
75 views

Strange dark spot when lighting in deferred rendering PBR shaders

It's probably something obvious but there seems to be a strange issue with lighting in my pipeline. I'm trying to keep everything in world space at the moment for simplicity but cannot figure out what'...
0
votes
0answers
24 views

How to calculate rotational irradiance gradient vector?

I am reading the irradiance gradient on Greg Ward Radiance book and also this web page: Quoting from this web page: For normalized spherical coordinates the gradient is: The irradiance ...
2
votes
1answer
93 views

Downscaling texture via mipmap [DirectX 11]

I am implementing a post-processing effect in my DirectX 11 pet renderer. The post-processing pass is implemented by rendering a full-screen quad covered with texture containing original rendered ...
0
votes
0answers
44 views

Which method does the painting software use to deform the image so fast?

I tried to make my own painting software. I used OpenCV in my job so I use openCV here. I want to make a image deformation function like the following : use mouse click on GUI to deform the image. I ...
4
votes
1answer
61 views

Adding two fogs

When calculating fog along the ray we have two main part- transmittance and scattering. What happens when we have two different fogs? With different extinction and color? Both extinction and color ...
0
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0answers
26 views

Software Rendering Display Latency

I've been doing some reading as to how to reduce input delay on modern computing devices. A lot of my understanding from this comes from the VR research paper by Carmack explaining the numerous ...
3
votes
2answers
190 views

Triangle - Why is it the basic building block for complex shapes

I was recently learning about OpenGL and computer graphics development. I have a question regarding the usage of triangle as the basic building block, or basic shape to develop complex shapes. Is ...
1
vote
1answer
67 views

How was computer graphics libraries or gtk,qt programmed?

I am wondering how was first graphic or image libraries created,I know C and Python ,I want to create plotting application,and I cant imagine these libraries(QT,OpenGL,Vulkan) written by C,how can I ...
3
votes
0answers
70 views

How to separate, modulate, and reassemble spatial frequencies?

Background I am trying to create a node in Blender that would allow me to do what you would do with an audio equalizer but on the spatial frequencies of an image: A sort of panel with eight ...
2
votes
0answers
79 views

Can I use Path tracing together with Ray Marching?

So I'm trying to render participating media like clouds/sky/fog (Sky is the first step) etc. I had already implemented a normal pathtracer and I was thinking of extending it. But I heard terms like ...
0
votes
0answers
9 views

How do I set proper local rotation axis for A-posed arm joints?

I am currently teaching myself in character rigging while working on an educational project. So far I’ve been following the official character rigging tutorial from the maya learning channel on ...
0
votes
1answer
49 views

What are the i,j,k components of a 3d mesh on plot.ly (online)?

A 3d Mesh on plot.ly online graph maker (https://plot.ly/create/#/) takes 3 mandatory variables (X, Y, Z) and 3 optional variables (I, J, K). I understand that if I want to draw a cube that I then ...
0
votes
1answer
41 views

How to triangulate a simple 2d surface to generate a constrained surface trimesh

I want to split a couple of simple 2d forms into tri meshes. The meshes should conserve the original geometry and ideally I'd like a possibility to influence refinement vs. tris count. I have the 2d ...
3
votes
1answer
76 views

Origin of blurring and colour distortion in monochrome diagrams

I am analysing a large number of PDF files from scientific articles, all of which contain images which (I think) were originally monochrome ( black/white). The images have been extracted with Apache ...
1
vote
2answers
75 views

Techniques for rendering high polycount models

I would like to know what common techniques are used for rendering large models, when using rasterisation within a graphics API, for example OpenGL or Vulkan. For example if I had a model with >10 ...
-1
votes
2answers
62 views

Why does Cubemap have 6 individual textures?

I am learning about Cubemap and I learned that A cubemap is basically a texture that contains 6 individual 2D textures but my question is Why does it contain 6 individual texture ? and also I've read ...
0
votes
0answers
19 views

Newby - which computer language for video to video &/or 4-D to video

First post on forum. What's the simplest language / package for computer graphics that will do what i need? I have two projects in mind: One is to input a video (eg. from youtube) and process it ...
2
votes
1answer
36 views

What do the OpenGL version strings from glxinfo actually mean?

Note: I wasn't 100% certain if this question belonged here or in Ask Ubuntu. I figured since it was about OpenGL programming I'd put it here, but if I should move it to Ask Ubuntu, please let me know. ...
0
votes
0answers
27 views

Custom background color

I am exporting an OpenSCAD file with OpenSCAD with: openscad model.scad -o model.png --imgsize=1920,1080 --camera 400,300,150,74,0,0,8000 I can set the image ...
5
votes
2answers
100 views

Why do identical polygons not z-fight in OpenGL?

Typically when coplanar or nearly coplanar polygons are rendered in OpenGL, the textures of each polygon mix together in a non-deterministic way. My understanding is that this is caused by the limited ...
1
vote
1answer
34 views

Description of the process involved in displaying digital images

Could someone please provide me with/point me to a description of the process involved in displaying a digital image? Starting from reading the data from a file to displaying the image on the screen. ...
1
vote
0answers
18 views

What is the mathematics behind inkscape's power stroke path effect interpolator_type and interpolator_beta attributes?

Inkscape has a feature called Power Stroke which is a form of path effect. When you apply it to a stroke you gain 3 control points that allow you to adjust the thickness of the stroke. (I have not ...
0
votes
0answers
25 views

How to find matrix that projects 3d points into 2d plane centered in the origin?

I have a list of 3D points defined by Cartesian coordinates, i.e. [(x1,y1,z1), (x2,y2,z2), ..., (xn,yn,zn)]. I want to project them to a 2D plane which has origin in the center (0,0,0) but which is ...
2
votes
0answers
19 views

How to open and render in a second window with OpenGL / JOGL with NEWT

I have a working renderer implemented with Java in JOGL with NEWT. Now I want to implement a Material Editor which should run in a second window. However I can't get a second window up and render in ...
3
votes
1answer
36 views

What are affine covariant regions

I am trying to understand this seminal paper. I read this post on what affine transformations and my understanding is that affine transformations are transformations that preserve parallelism of lines ...
0
votes
0answers
16 views

How can you use a rectangular object in an image and use its edges as a new coordinate system?

As a quality inspection vision application, we have images of printed circuit boards. The PCBs are rectangular in shape and the distance from the camera to the PCB is fixed. The relative location of ...
0
votes
1answer
51 views

Inflate 3D mesh into sphere

I am after a simple (not necessarily efficient) algorithm to "continuously" transform a closed surface mesh into a sphere. It seems that Blender is able to do this quite well: https://docs.blender....
0
votes
0answers
16 views

Specular error - wrong TBN transformations

I have a problem with TBN matrices due to their transformation in world space. In .cpp I am trasforming my worldMatrix based on rotation: ...
2
votes
1answer
46 views

Non jagged line algorithm for javascript canvas

I'm trying to draw a line between two specified points, by updating values in an array which is heightxWidth with each element a set of four bytes (r,g,b,a). In my naive implementation I get the top ...
0
votes
0answers
26 views

sdl2: Compiler throws “Undefined Reference”

I'm trying to learn computer graphics, but when I tried to get this very simple windower running with c ...
0
votes
0answers
92 views

Sub pixel rendered white text on black background changes color when resized to a very small size

download: https://upload.wikimedia.org/wikipedia/commons/5/57/Subpixel-rendering-RGB.png The above picture is an example for sub pixel rendering. I tried resizing the image to very small size in ...
1
vote
0answers
46 views

Why cache working set per multiprocessor for texture memory in Nvidia has a variable size?

I saw it here https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#features-and-technical-specifications__technical-specifications-per-compute-capability , I don't know if it also happens ...
1
vote
0answers
80 views

Why don't I see tile-based 3D graphics?

As we know, tiles can make it quicker to update large portions of the display at once, as compared with a bitmap. To put, say a letter, on the screen, the Commodore 64 typically does two writes (the ...
1
vote
1answer
92 views

What is the difference between world coordinate, viewing coordinate and device coordinate in computer graphics?

The 2D pipeline involves with the construction of world coordinate scene followed by converting world coordinate to viewing coordinate, then transforming viewing coordinate to normalized coordinate ...
0
votes
0answers
46 views

How to rotate an object in OpenGL on the X, Y and Z axis on its local coordinates?

I've read multiple tutorials, but I still can't understand how do I properly rotate an object in 3D space on all 3 axis at once. For example, I'd like to give the object a pitch of 60 degrees, yaw of ...
1
vote
2answers
91 views

Multiple swapchains in Vulkan app with ImGui

I am integrating imgui into my app using glfw + vulkan example. The function vkCreateSwapchainKHR() is also called by imgui setup logic in addition to my app on the same device and it fails with "...
0
votes
1answer
91 views

shaderc compile through api with #include

I'm using shaderc to compile glsl code in to spirv module and pass to pipelie in REAL-TIME. I want to use #include to reuse some of the shader code but shaderc is having problems recognizing it. Any ...

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