# All Questions

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36 views

### Sampling glossy surface in Path tracing

I am working on a Bidirectional monte-carlo path tracer with importance sampling and light sampling and I have a problem with sampling glossy objects. First I will sum up what I understand and then ...
13 views

### How to calculate clip to device coordinates with matrix

I am trying to convert my points from Cartesian points (X,Y,Z) and run them through a clip to device pipeline. I do not know the specific matrix for this problem and was looking for some help. Thanks
12 views

### Render to framebuffer > output color components greater than 1 in fragment shader

I am trying to render a scene to a framebuffer, then use the resulting texture to render my final scene. In my first render step, I am trying to use the alpha channel of my texture to store depth ...
49 views

### What is the reason that a boolean operation between two almost identical 3D triangular meshes fails?

I have been trying to detect defects on "before-and-after" meshes, by finding the boolean difference between them, to no avail. I tried these two Python libraries(algorithms run in C++) but their ...
17 views

### Interpolating HSV color with black

I'm interpolating RGB values by transforming them into HSV space and then back into RGB. I have trouble figuring out how to achieve ...
33 views

### How do I produce a metallic surface in ray tracing?

I can't manage to produce a metallic looking sphere despite trying many things. I have the basics working, i.e shadows, refraction etc. but I'm not sure what combination of these will allow me to ...
43 views

I am relatively new to compute shaders and gpgpu in general so bear with me if i am missing the point somewhere. The main thing i do not yet understand / see is how to get memory from a compute ...
32 views

I am learning about fragment shaders and have seen how by setting the colours of each vertex a triangle can be coloured via interpolation. However what if we want to use our own function to manually ...
64 views

I'm a noob to the OpenGL world and am picking up ideas through practice. I've been writing some code to build retro-arcade games recently and need to load textures to provide the graphic interface. I'...
25 views

### Write CPP program, DFA and NFA diagram for DFA accepting string with length 5 and starting at 0 , ending at 1 input(0, 1)

I am having trouble in making this program and DFA:- Write CPP program, DFA and NFA diagram for DFA accepting string with length 5 and starting at 0 , ending at 1 input(0, 1).
41 views

### Techniques for making tesselated shapes appear smoother?

What are some common techniques for making the edges on a tesselated shape less apparent without increasing the amount of tesselation which is actually carried out? As an example, I followed along ...
20 views

### Perlin Noise implementation looks blocky in WebGL2

I'm trying to implement Perlin Noise. Earlier I implemented it using HTML Canvas and then converted it to WebGL2 since I wanted a faster implementation. But the WebGL2 code has obvious edge artifacts ...
15 views

### Projective Texture Mapping when Texture Comes from a Framebuffer? Incorrect Texture Coordinates?

I am trying to perform a projective texture mapping using a texture which I generate by first drawing it to a framebuffer, so that I can dynamically generate a reflection which interacts with the ...
19 views

### Alpha part of color class or shape class

I am designing a 2D drawing library (it is its very early stages) and I was wondering what to do with Alpha (transparency). I have two trains of thought: A. Implement Alpha in the Color class ...
31 views

### How to handle negative reflection directions in raytracing?

I got a function that generates samples from a GGX visible normal distribution function. When I use it to calculate reflection directions obviously some of these intersect with the surface agin (...
14 views

### Homographic equation

I need some help : I have here the homographic equation that transform an object point M(X, Y, Z) to a point projected on an image m(x, y) I'm searching for the plan of points that are projected to ...
16 views

### Help needed with AI generated texture

I need to process sets of pictures (1 to 10 real life photos) from mammals to produce 3d models. I need to automate this process: 1. normalise colors among the set; 2. turn the set of real photos ...
33 views

### glBindImageTexture returning INVALID_VALUE

I am currently having an issue with OpenGL as I am trying to load some vector information into a 3D texture. Currently, I am developing in OpenGL 4.6 which should support Image bindings. this my ...
19 views

### How are 2D graphics rendered in HTML canvas

I was making some circles in the HTML Canvas element and the circles were so smooth. In a sense that you cant see any vertices. I normally work in unity and I you make a shape in 3d you most of the ...
23 views

### (Desperately) Need help using Compute Buffers with GLSL and Unity C#

I am currently working on implementing parametric curve based dynamic tessellation using GLSL. I have scanned the entire internet and I cannot find even a single good example of a GLSL shader which ...
41 views

### Mathematics in Computer Graphics

Can you please recommend some topic for research work related to mathematics in CG? (Maybe something like "Affine transformations in CG")
26 views

### Controlling “zoom” and “position” of a cubemap in shaders

I am trying to mimic reflections in image composition using shaders. I have gotten this far: In this image the floor is "reflecting" the back wall, however the reflection is uncanny because the ...
31 views

### nearest neighbour search structure with multithreaded build

I need a c/c++ lib to perform nearest neighbour search (2d or 3d only). I tried some kdTree implementations, but all of them are single-threaded when building the tree. Because of interactive nature ...
28 views

### Why the gradients generated in original Perlin Noise causing axis-aligned clumping?

I am learning Perlin Noise, the original version and the improved version. In the paper which Ken Perlin wrote in 2002. He said "The second deficiency is that whereas the gradients in G are ...
41 views

### Considering a path generated by bidirectional path tracing under a different strategy

Say I have constructed a path, using bidirectional path tracing (BDPT), consisting of a light subpath $y$ with $s=2$ vertices and a camera subpath $z$ with $t=3$ camera vertices. Now I want to ...
63 views

### How to achieve higher FPS for my GPU pathtracer?

So I've written a GPU based pathtracer using OpenCL-GL interoperability. The system uses the Mega-Kernel Approach instead of a wavefront one as I was aiming it as an educational software for other ...
55 views

### Path tracing material system with OpenCL

I started developing my own path tracing program with OpenCL on GPU (for the speed). I had easily created a path tracer with a basic material with standard properties (as metallic, specular, ...
49 views

### OpenGL Compute Shader Shared Maximum

I'm working on an OpenGL compute shader in which each work item results in a single number output I'll call x, as well as a struct output with more information, I'll call y. What I would like is a ...
50 views

### Upscaling screenshots with subpixel rendered text

Upscaling a screenshot with subpixel antialiased text produces unpleasant color fringes, e.g. why does black text have orange and blue pixels This is especially annoying when trying to show an ...
60 views

### An API for drawing RGB pixels with a 4:4:4 sampling color? [closed]

I need to draw pixels on the screen and I don't know which API to study for my specific case, actually I don't want to master any video or image format, I just want to draw pixels on the screen, in ...
70 views

### What is the CMYK color profile used by pantone.com

Pantone spot colors are specified in the RGB and CMYK color models on the https://pantone.com website. For example, the Pantone 122 spot color as it appears when printed on coated paper is specified ...
29 views

### Extract object from image and apply it to different image

SHORT BACKGROUND: I am developing a neural network based model to differentiate benign and malignant ovarian tumors. I am working with transvaginal ultrasound images, some of which contains yellow ...
31 views

### How do you compute the winding number of a closed poly curve?

Pretty much the title, given a closed curve in 2D, defined by a set of points, and a point. What's the algorithm to calculate the winding number of that curve, point pair?
38 views

### Keep constant number of visible circles in 3D animation

I have created a 3D animation with a perspective projection of white circles moving randomly in a fake 3D space projected on a 2D computer screen (GIF 1). Since I need to keep the same number of ...
24 views

### What's the most efficient way to extract the information from Shipping Labels?

I'm currently using Google Cloud Vision API to extract shipping information from shipping labels. While, OCR accuracy is not the issue here, the problem is that the data extracted from the label is ...
56 views

### Wrong reflection

Here is a youtube video showing my problem: youtube.com/watch?v=y8J7VhS2pkM I think I'm either doing the texture lookup on the reflection texture wrong, or the reflection or view matrix is somehow ...
24 views

### RubberHose plugin distorts a shape

I'm trying to animate a shape in After Effects with RubberHose plugin. I'm creating a shape layer and placing it in pre-compose. Then placing a 3 pins on that pre-compose. After I select them and alt+...
47 views

### Terminology: Volumetric Model

I am reading a paper TileGAN: Synthesis of Large-Scale Non-Homogeneous Textures available here, and in the section entitled Selected Applications of GANS (i.e. applications of Generative Adversarial ...
24 views

### Looking for a compact file format for outputting 3D geometry with color support

I am looking for a file format to output some 3D geometry. In my case, it only needs to handle very simple shapes - uniformly spaced and sized cubes at points in space. So far I've ended up just ...
22 views

I try to implement GIMP's the Additional blending mode for layers in my application. I've found the formula: E = min((M+I), 255) I think, that if I blend ...
28 views

### constant pixel width for any scale

I have a standard 3d camera/projection/model setup that renders rectangles with a WebGL shader. Users can zoom out and fly anywhere. I want to make sure that regardless of the scale, width of the ...
117 views

### Looking for a cylinder / axis-aligned box volume intersection test

Given: An arbitrary circular cylinder (defined by startpoint, endpoint, and radius). An Infinite cylinder is acceptable as well, as long as it passes through those points and has the same radius. An ...
39 views

### How is the image reconstruction filter on the path space defined in terms of the filter on the raster space?

Say we have a image reconstruction filter $h:R\to\mathbb R$ defined on the raster space $[0,w]\times[0,h]$, where $w,h\in\mathbb N$ define the width and height of the image plane in pixels, ...
22 views

### Want to add strafe function

I’m trying add strafe function in my program, i tried everything i can but still i was unable to get desire output! Can anyone please tell me how can i add strafe function in my program?.. is there ...
52 views

### Is linear interpolation in a 2D texture possible (not quadratic like bilinear interpolation)?

I am currently studying for a computer graphics exam and on the slides about bilinear interpolation it is said that it is in reality quadratic interpolation. An (on the slides) unanswered question ...
39 views

### BDPT - How to handle deterministic ray PDF?

I'm trying to implement a simple BDPT without MIS as described in Lafortune's paper. I've used the weighting scheme defined in the paper in which they suggest that the weight be based on the surface ...
28 views

### Terminology Question: Temporal Stability

I am reading the paper Blockwise Multi-Order Feature Regression for Real-Time Path Tracing Reconstruction and the authors use a term several times which I am not sure what it means. This is in the ...
77 views

### Procedural Generation of 4D Shapes

I'm curious if anyone has any insight into how one might procedurally generate 4D objects, as showcased in Miegakure (or the developer's other game, 4D Toys ). I built a program a while back to do ...
Let $W_{\text e}$ denote the camera sensor responsivity (i.e. importance) and $h_j$ and $W_{\text e}^{(j)}$ denote the image reconstruction filter and sensor response associated with the $j$th pixel, ...