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77 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
71 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 ...
3
votes
0answers
88 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
84 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
47 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
77 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
78 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
94 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
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0answers
20 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
70 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
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0answers
29 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
109 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
38 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. ...
2
votes
0answers
21 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
22 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 ...
4
votes
1answer
45 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
58 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
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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
54 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
32 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
105 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
47 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
83 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
224 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
54 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
131 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
111 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 ...
0
votes
0answers
51 views

RGB map into numerical data

the image below uses an RGB scale (the values of the scale are displayed on the image) to show the magnetic field strength at each point on the map. I've been struggling to find a way to convert this ...
3
votes
1answer
56 views

Mesh Simplification Algorithms

I'm currently looking into Mesh Simplification to batch-simplify a large amount of .obj files. It is necessary for these algorithms to preserve the visual representation of a mesh as well as possible. ...
2
votes
1answer
130 views

Is vkCmdPushDescriptorSetKHR efficient?

I am new to Vulkan. Compared to DX12, the resource binding procedure seems a little bit complicated. In terms of per draw call uniform buffers, I currently have two approaches in mind, and they both ...
0
votes
0answers
31 views

Clarification about Phong lighting model

I've read some tutorials about Phong and Blinn lighting models and tried to implement a rendered myself. To my knowledge, the basic approach consists of the following steps: calculate the vector from ...
1
vote
1answer
108 views

Tone Mapping in a physically based rendering ray tracer

I'm implementing a pbr ray tracer. Let's say that I'm at the end of the process: for each pixel pi, I accumulated the radiance value in vector pi = (radR, radG, radB). At this point, these values are ...
0
votes
1answer
66 views

how to update my scene graph?

I am updating my scene graph in response to user input and the network. What is the best way to do this? The updating threads are separate. Some approaches I am thinking about: double buffer. There ...
0
votes
0answers
27 views

How to pass an SAH based BVH to the GPU using OpenCL

So I'm in the midst of implementing an SAH based BVH (the one implemented in PBRT) for my pathtracer. The whole path tracer is written inside an OpenCL kernel. Now I need to build the BVH on the CPU ...
0
votes
0answers
31 views

Confused on GPU Voxelization

I am learning how to voxelize a scene using GPU. In OpenGL Insights, there is a algorithm doing this on page 6. However, I am confused on the last step: Convert 2D fragment to 3d voxel. In the book, ...
1
vote
0answers
32 views

Algorithm for randomly generating polyhedrons?

I want to randomly generate polyhedrons which need not be convex. What is the most efficient way for doing so? I can think of an algorithm for generating random convex polyhedrons, but am unable to ...
0
votes
1answer
63 views

Unity: Pass texture pointer from OpenGL to Unity

I'm working on a scene in Unity where I have textures loaded at runtime. As a result of that, the scene is being slowed down (even with co-routines), so I thought maybe I could move the texture ...
0
votes
1answer
54 views

WebGL Can't render anything, wrong projection?

I'm trying to understand and learn WebGL and computer graphics from button up, that is why I started to work on my own little library for that. I've spent couple of days looking for right answer and I ...
0
votes
1answer
41 views

Are non manifold meshes problematic for Virtual Reality?

A simple question. I know that non-manifold meshes are problematic for physics simulations, boolean operations, and 3D printing. I was wondering if they can be problematic for a virtual reality ...
1
vote
2answers
282 views

How are colors really mixed?

I'm kind of stuck on this one. When following a conventional, high-level shading tutorial, you'll come across these images that are like ambient + diffuse + specular = result, but I can tell that it's ...
3
votes
2answers
161 views

Programmatically generating bin files for GLTF models

I have a need to generate a series of GLB files. I have a base template for a GLTF file which I have to derive off of. The models thus generated will only have varying textures on them. The base mesh ...
0
votes
0answers
60 views

Using octree for cheking intersection of ray and meshes

I wrote the code for checking intersection of ray and meshes on scene. It consist of two parts - broad phase and narrow phase. In broad phase I build an oriented bounding box around each mesh and ...
2
votes
1answer
135 views

gl_FragCoord and glViewport

I've been scanning the specifications for both OpenGL and GLSL, and I can't find a definitive answer as to how exactly are gl_FragCoord's ...
0
votes
1answer
121 views

Vulkan: efficient way to update VBO mesh vertices?

I would like to change/add/remove some mesh vertices in existing VBO's (while deforming and remeshing 3D objects) . With OpenGL I would have to reload whole vertex VBO's. I suppose with Vulkan there ...
0
votes
1answer
32 views

How to make the lines of a (binary) image dotted or dashed?

Let's say I had a binary image (i.e. only contains black and white pixels). For example, this one: How would I make all the lines in this image dotted or dashed? In other words, the eyes would be ...
0
votes
0answers
20 views

Export images in sketchup models

I built a model on Sketchup and imported png images in it to fill some faces. At first time, I tried to fill with a texture pointing to the desired image but it wasn't centered. Then when I export my ...
2
votes
0answers
50 views

How to project an image on spherical surface with least possible distortion

I did not know where to ask, I will try it here. I work in a local planetarium and I wonder if it is possible to edit an image in such way, that when projected on spherical cupola (diameter 8 m), it ...

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