All Questions
3,964
questions
0
votes
1
answer
90
views
Parametric equation for Catenary curve between two Points
I have two points in 3D space, A and B. I need to have a parametric equation of the catenary curve such that:
Cat(0) = A,
Cat(1) = B,
Cat(t)= f(t, A, B)
How can I derive the function f
0
votes
1
answer
64
views
Why can't I get fog on OpenGL?
I am creating a cylinder, and there is fog around it. I can't handle two things:
the inner surface of the cylinder, realized as a smaller diameter cylinder, actually gives me just a second cylinder ...
- 103
0
votes
0
answers
60
views
What is this method of interpolation / blending?
I am reverse-engineering two classes from a game. The two classes are responsible for generating sets of t values for interpolating / blending between two points through the formula:
...
- 1
0
votes
1
answer
108
views
Can dxf Files Represent a Parametric Design?
dxf files emerge from various applications, for example Autocad, LibreCAD and so on.
Sometimes a design should be flexible, e.g. one should be able to change one dimension of it and keep everything ...
1
vote
1
answer
102
views
Why do texture samplers seem to bleed into other instances when rendering multiple instances of the same mesh with differing textures
I originally asked this question on the gamdev stack exchange but was told by a friend I would be better served here.
Original Question
So I will start off by laying out the relevant structure of my ...
1
vote
0
answers
186
views
DDS BC7 Thumbnails on Windows 10
Is it possible to enable accurate thumbnail previews for DDS files that use the newer DX10 headers (DirectX 10 headers)? It seems there is very limited information about this.
I did find a couple ...
- 111
2
votes
2
answers
110
views
drawing ellipse with rotation cause inaccurate result
i'am a junior in computer graphics , currently i learn how to draw ellipses with rotation .
when i preform rotation with 90deg or 180deg nothing unusual happened ,
but when i try to rotate with any ...
- 23
1
vote
2
answers
138
views
Is there a canonical way to convert G1 continuity to C1 continuity for splines
I understand what C1 and G1 continuity are (e.g. this is not Continuity of parametric and geometric continuity).
But let's say I have a list of cubic splines that are, together, G1 continuous. Is ...
3
votes
0
answers
92
views
What vergence angle is commonly used for "infinitely far away" objects in stereoscopic displays?
I think that VR / AR experts will know the answer to this.
At what vergence angle are "infinitely far away" objects such as star field textures drawn in head-mounted VR / AR displays ?
I ...
- 163
1
vote
0
answers
56
views
LOD/culling algorithms with procedural meshes
I am experimenting with procedural meshes. Those are generated at runtime in a compute shader. I'm getting to the point where those geometries are big enough to require some sort of culling/LODing ...
- 161
0
votes
2
answers
139
views
Whats the best way to render (2D) parametric curves with uniform stroke width?
I want to create a rendering engine that mostly renders parametric curves on a 2d screen. As far as it seems, todays graphics are all dependent on vertices and matrices, so not sure where to start or ...
user19809
0
votes
0
answers
18
views
How does denoising factor into most render engines + practical question
I'm a student working on an experimental animation.
The animation has been selected to be screened at a festival, but they would like a resolution that is beyond what my single graphics card can ...
- 1
1
vote
0
answers
33
views
How to encode UTF inside an Encapsulated PostScript
Twenty years ago I made a descriptive illustration program whose output was the industrial standard Encapsulated PostScript, which is also compatible with the LaTeX system. In order to write accented ...
- 41
2
votes
1
answer
115
views
How to properly use the BRDF from glTF 2.0 specification in path tracing while using metallic/roughness materials?
I've built a renderer which should render glTF materials, as they are defined in their specification. So I should be able to render satisfying (similar to Cycles and Ospray) results just from the base ...
1
vote
1
answer
64
views
Unknown array of floating point numbers. View matrix?
I want to control the camera in an old game using head tracking (TrackIR, opentrack, etc.), such control was not provided by the game engine. I'm trying to find the camera coordinates and rotation ...
- 13
2
votes
0
answers
45
views
Optimal Command Ordering for CPU/GPU concurrency
I am writing a renderer that uses a deferred clustered shading technique.
On the CPU I group lights, decals, and environment maps into 3 seperate clustered structures (functionally, arrays of unsigned ...
- 21
1
vote
1
answer
191
views
Having trouble rendering entire sphere
I'm working on a program where I need to draw spheres. The method I'm using is creating an octahedron
And using tessellation shaders to subdivide it into a sphere, however there is a patch of the ...
- 11
1
vote
0
answers
26
views
How to get back project point cloud from rendered rgbd images by rgbd?
Given a sequence of RGB-D images rendered by blender and the camera parameters for the blender camera(Perspective Projection camera).
How can I back project the RGB images with depth map to a RGB ...
- 11
1
vote
0
answers
53
views
Term confusion about volume scattering
We have two different terms, for example, let's talk about scattering only.
Scattering coefficient
Scattering cross-section
These two terms are supposed to have different physical meaning. I read it ...
- 575
1
vote
0
answers
40
views
how to fix this strange effect when editing image?
G'day,
I have this strange effect when editing my image. It seems to happen a lot on photos with the sky in it, but in the CR2 file it doesn't show, only when i open it in the software i am using does ...
- 11
1
vote
0
answers
57
views
Normal Map Under rotation Issue
I have been trying to apply normal maps to a rotating sphere with light shining directing from above the sphere (0,1,0). but lighting does not look correct under rotation as one side of the sphere ...
- 61
0
votes
1
answer
116
views
Creating a UV Map for a 3D Cone
I have the following problem I am currently facing.
I am creating the vertices for a cone based on the number of segments and the radius of the base and top.
This is done as follows:
...
- 167
0
votes
1
answer
70
views
OpenGL get default depthbuffer
I have an application that uses only the default opengl framebuffer. It is initialized with color and depth buffer.
I want to use the depth buffer as a uniform within a shader to access the current ...
- 1,136
0
votes
0
answers
13
views
What is the color space of Luminosity blend mode and other three blend modes that photoshop use , HSB HSL or LCH
Here is what I have tried:
I create a base layer and a blend layer and I choose Luminosity blend mode, so the result suppose to have the hue and Saturation of the blend layer and the Luminosity of the ...
0
votes
1
answer
139
views
want bokeh blur with custom shapes
I have a 2d texture and a shape matte, the matte could be any shape, like a star, heart, and so on, and I want to use this matte to generate different-shaped bokeh blur, how can I do it? and normally, ...
1
vote
0
answers
58
views
How does changes in vertex data work?
I have been learning computer graphics and for some time and can't seem to wrap my head around one concept. How to handle vertex data changes?
Ex. 1. I have a text rendering on a screen. And up on ...
- 11
3
votes
0
answers
82
views
I need to implement a CPU Rasterizer but am unsure how to parallelize rasterization
I have a rendering engine that has CPU path tracing support, as well as GPU (Vulkan) rasterization and path tracing support. It uses a rasterization pre-processing step to identify the resolution of ...
- 215
0
votes
0
answers
87
views
Ray light color at distance
I am obviously not understanding something related to light for a ray tracer.
Reading Spectral representation
and Point light calculation
A bit of a context:
My question is: in room at X degrees ...
- 23
2
votes
1
answer
277
views
How does Unreal Engine 5's Lumen (most likely) implement reflections?
In this YouTube video, the creator mentions that reflections in Unreal Engine 5's Lumen "work by tracing the path of light as it bounces off of surfaces in the game world." Does this mean ...
- 159
2
votes
0
answers
33
views
Optimized 3D rendering using dots and/or line segments of different sizes in Scratch
I'm developing a 3D rendering engine in Scratch, which is a block-based visual programming language. It does not have any support for bitmap rendering, but there is a "pen" plugin that lets ...
-1
votes
1
answer
62
views
Converting ACES ap0 color space into srgb?
I'd like to know the correct when of converting ACES AP0 color space into sRGB. Let's say artists decide to pick colors outside of sRGB in AP0, will ACES handle this situation correctly, meaning no ...
0
votes
1
answer
132
views
Rendering light balls: Where to do perspective calculations?
After rewatching Bisqwit's starfield renderer video, I've decided to try to rewrite the program in order to learn more about compute shaders and shader programming in general. My knowledge at this ...
- 109
0
votes
1
answer
138
views
undefined reference to `SDL_setRenderDrawColor'
I am getting
C:\Users\rasmu\AppData\Local\Temp\ccwOn3mM.o:main.c:(.text+0x11f): undefined reference to `SDL_setRenderDrawColor'
C:\Users\rasmu\AppData\Local\Temp\ccwOn3mM.o:main.c:(.text+0x155): ...
- 1
2
votes
0
answers
51
views
Fresnel and light reflection/refraction
I keep reading about fresnel and there is one thing I don't fully understand.
My understanding :
Here is my understanding so far, so please correct me where I am wrong.
Fresnel is related to ior (eta)...
- 23
0
votes
1
answer
106
views
Do GL compute shaders trigger TDR if they crash. Not just timeout?
I'm getting a TDR trigger after 4ms with a GL4.3 compute shader. tdrDelay is currently set to 30 secs, this obviously isn't long enough to get a timeout with the default Windows 11 tdrDelay value let ...
- 411
5
votes
0
answers
57
views
Facetted look when using SampleBias
I am writing a simple material system for a game.
Each material can have a specular value (phong) that is translated into "smoothness" via environment map.
Similar to PBR, I compute a ...
- 171
1
vote
1
answer
94
views
How to compute discrete partial derivatives in 3D
I'm supposed to compute partial derivatives for 3D volume rendering (in ray tracing). I'm bad at math and so I can't understand what $f$ is in my case. In reviewing examples, I'm seeing the $f$ ...
- 111
1
vote
0
answers
45
views
How to display real time 3-D orthogonal vector rotations?
I'm an embedded developer here with very little experience in computer graphics. I'm currently working on a GUI that can display a calculated inertial solution at run time. I have hardware that can ...
0
votes
1
answer
68
views
OpenGL 3.0 is not supported by the OpenGL driver - RizomUV
I have a problem with RizomUV 2022.0. When the program starts, it comes up with pop-up "OpenGL 3.0 is not supported by the OpenGL driver", so I can't import any geometry and work. I'm ...
- 1
0
votes
0
answers
25
views
What happens when we select lower resolutions on a high-resolution monitor?
I have a monitor with a resolution of 1360x768 (16:9), When I set the resolution to 1280x768 (5:3), 1024x768 (4:3), 800x600 (4:3), even 1920x1080 (16:9) it completely covers the screen and the monitor ...
- 1
-1
votes
2
answers
64
views
How does one construct a 3D file format from pixels and vertices? [closed]
I have searched around in a lot of places but I have yet to find some place that explains 3D file formats in a way that aligns with the model I have right now. I have a simple problem (I think) but it'...
- 99
1
vote
1
answer
149
views
How to get the boundary of delaunay triangulation
I'm implementing tunnel detection algorithm in the paper "Computing Geometry-aware Handle and Tunnel Loops in 3D Models".
Before the actual tunnel detection, the input needs to be ...
- 31
2
votes
0
answers
60
views
Non Uniform Scaling vs Shear in Image Transformation
I am reading computer graphics. I am unable to distinguish between Non-uniform Scaling and Shear. Can someone explain the difference with two different examples?
- 121
0
votes
1
answer
294
views
Raytracing in OpenGL or Vulkan?
I was looking at this glass ball rendering with an image inside of it (zoom out to see the glass ball), and noticed that it looks like they simulate the refraction of light as it crosses from inside ...
- 159
1
vote
0
answers
41
views
replace IBL with single color - the lighting equation
I want to avoid IBL (image based lighting), however my scenes are way too dark - especially close-to-mirror like surfaces, which get little contributions from other direct light sources in the scene.
...
- 41
0
votes
0
answers
22
views
models used for verifying standard PBR shaders
I know this collection of models: https://casual-effects.com/data/
I am looking for something similar, but with models with standard PBR materials (roughness + metallic). I want to verify that my ...
- 41
1
vote
1
answer
357
views
Which coding strategies exist to handle opengl texture size limit?
I recently hit the roof for maximum texture size for my opengl implementation (GL_MAX_TEXTURE_SIZE contains $3379$) when I wanted to create a texture for a 4k resolution video frame ($3840 \times 2160$...
- 125
0
votes
1
answer
59
views
Does OpenGL allocate on glBegin/glEnd?
You can enclose arbitrary amount of vertices within glBegin/glEnd statements. Does OpenGL limit the number of vertices you create or it allocates memory for more?
user19644
0
votes
2
answers
73
views
Why an object becomes larger when drawn in perspective
I am following David Salomon's book "Transformations and Projections in Computer Graphics" where it is explained how to project a 3d object to the 2d canvas in perspective:
Define a point ...
- 103
0
votes
1
answer
55
views
What technique can I use to swap thousands of models per frame?
I need to render a lot of objects that swap their model from frame to frame.
Currently, I am putting every model into a single vertex buffer and giving every vertex an id. I store the same id in the ...
- 103