All Questions

0
votes
0answers
11 views

Why do animated CG characters always feel fake?

Why do animated CG characters always feel fake? Usually if a CG character is an animal (or humanoid creature), they tend too look kinda off. Their movement tends to look oddly smooth or lightweight, ...
0
votes
2answers
14 views

How to create 2D (directional) noise?

I'm just getting started trying to understand noise generation algorithms. What I'm trying to achieve is to get a 2D (or 3D) grid of random directional vectors (again, 2D or 3D) according to a noise ...
1
vote
1answer
44 views

kinematics and dynamics of a sphere in a spring mass system?

I am attempting to code a simple spring mass system simulation in which a sphere pendulus hangs from a string (a spring) by the top and then another sphere (controlled by the user) can move and ...
8
votes
1answer
137 views

Conserving Mass in Liquid Simulation

I am trying to implement a 2D version of Foster and Fedkiw's paper, "Practical Animation of Liquids" here: http://physbam.stanford.edu/~fedkiw/papers/stanford2001-02.pdf Mostly everything works, ...
1
vote
1answer
64 views

Deciphering Affine/Projective Transformation Code

I've spent about 2 days trying to understand this piece of code (from here) that applies an affine/projective transformation to an image. I will link bits of the code that I'm struggling to understand ...
3
votes
1answer
200 views

Multiple Importance Sampling in Path tracer produces Dark Images

So I recently implemented Multiple Importance Sampling in my path tracer which was based on next event estimation. The problem is without MIS I get images like, This is obtained by setting ...
0
votes
0answers
21 views

What would be the best app to test my gpu for hardware problems? [on hold]

I have a GeForce GT 540M and id like to run a test to find hardware issues before trying to figure out why my game keeps crashing. What app would you recomend? thanks
0
votes
2answers
39 views

An algorithms for covering a 2d polygon with a prefixed number of rectangles?

I am looking for an algorithm that is able to cover with non-overlapping rectangles in a pre-defined number and minimum area a generic 2d-polygon. Polygons are usually free-hand draws, so they can be ...
1
vote
1answer
19 views

Is it possible to bind dynamic texture samplers to a shader in DX12?

So usually texture samplers are set directly in the D3D12_ROOT_SIGNATURE_DESC structure in DX12, at least that's how I've been setting them. I was wondering if it's ...
0
votes
0answers
33 views

Weirdly looking diffuse irradiance map

I have problem with creating diffuse irradiance map. As reference I am using https://learnopengl.com/PBR/IBL/Diffuse-irradiance and https://github.com/TheEvilBanana/PhysicallyBasedRendering/blob/...
0
votes
0answers
41 views

Prefered gpu for deep learning

Im planning to buy a custom build pc for computer vision because I want to make a career switch in it. So Im still confused about the choice of gpu. Should I go with nvdia(cuda) or amd(opencl)? Also ...
1
vote
0answers
49 views

Why don't discretization errors occur with compute-shaded kernel filters?

An efficient compute-shaded image filter would be emitted with (screenX / [kernel width], screenY / [kernel height], 1) groups and one kernel in each group, allowing texels to pass into groupshared ...
1
vote
1answer
57 views

How can I control memory for command allocators and command queues in D3D12?

The D3D12 programming guide suggests specific allocation strategies for command queues and allocators, but the creation methods for those objects operate directly on queue/allocator pointers without ...
2
votes
0answers
51 views

How to use Photometric Units with Rendering Equation?

So I was just reading up on how to create more Physically Based Lights and wandered into the realm of photometry. I read the paper "Moving FrostBite to PBR" and in it the author claims he decided to ...
0
votes
1answer
81 views

Ray tracing in One weeked: issue with metal reflection

Problem I am following the book Ray tracing in one weekend , and I got stuck after the implementation of the material Metal. I checked my code many times, and it looks exactly like the code ...
1
vote
1answer
32 views

GBuffer: Framebuffer with different texture format types?

I rely on this answer from Nathan Reed: How much precision do I need in my G-Buffer? It is proposed to use two different texture formats for one Gbuffer. However as far as I know, color texture ...
0
votes
1answer
42 views

Inconsistent behavior involving VkPhysicalDeviceFeatures.fillModeNonSolid

I departed slightly from the Vulkan tutorial I was following and decided to draw a wireframe instead of a solid triangle. As soon as I call ...
2
votes
1answer
57 views

Blur with alpha transparency

I'm writing a simple box blur for a graphics library. The formula makes the average of a range of pixels by adding the ARGB amounts and then dividing by the blur range For example, with a blur range ...
3
votes
1answer
69 views

Data fitting SVBRDF with L-M

I am reading two shot svbrdf capture . I want to understand the data fitting. For example, I have my input image 3000x2000 pixels, and I divide it to create my source tiles of 192x192 pixels. The way ...
0
votes
1answer
34 views

OpenGL Unable to retrieve the values of data sent to shader using textures

I've been following these tutorials and i can't figure out how to send data to shaders using textures. https://en.wikibooks.org/wiki/OpenGL_Programming/Scientific_OpenGL_Tutorial_02 In this tutorial ...
2
votes
0answers
39 views

How to implement explicit light sampling when implementing path tracing?

I implemented a path tracer and got a similar result like this one. Sample: 4096, time used: 537.05s The algorithm is exactly the same as the one in wikipedia, where only the Gathering Path is ...
-1
votes
2answers
55 views

How do I use texture coordinates of a .obj file in OpenGL?

I have an obj file, with texture coordinates (indicated by vt). How would I use this to load textures in OpenGL?
0
votes
2answers
52 views

transformation from cartesian coordinates to spherical coordinates without calculations

Given this graph in the 3d cartesian coordinates i should figure out the spherical coordinates representation but without the use of calculations . I've been trying to solve this the whole day but i ...
1
vote
1answer
118 views

Get intersection Ray with square

I have a class Ray and Square public class Rayo { public Point origen; public Vector direction; Square{ X,Y,Widht, height; } I need intersection between this ...
0
votes
0answers
44 views

Access YUV inside a Glsl Shader

I have a video texture which is in YUV format, I need to access Y,U,V individually inside a Glsl shader as we access R,G,B. How can I do that?
5
votes
1answer
5k views

GLSL. Can someone explain why gl_FragCoord.xy / screenSize is performed and for what reason?

I'm new to shaders and know that you can color pixels with gl_FragColor but sometimes there is this thing: ...
0
votes
2answers
63 views

Using transformations to get from A to B image

I try to solve this, First, I used scaling: $Scale(S_x,S_y)=S(\sqrt 5,\sqrt 5)$ So, I enlarge the bottom of the house and the sides, to the same size of B image. Later, I used rotation: $R(\theta)=...
0
votes
0answers
39 views

Optimizing sphere tracing, ray-traced hulls vs. gradient volumes

My rendering engine uses sphere-traced SDFs for surface representation and path-tracing for shading, so fast intersection times are important. I'm creating lots of organic/procedural surfaces, so I ...
0
votes
2answers
66 views

How to set equivalent PDFs for cosine-weighted and uniform-sampled hemispheres?

I'm trying to add BRDFs to a very basic path tracer. Starting out, I'd like to convert just the Lambertian material, with two different sampling methods, to ensure that everything is working right. ...
0
votes
0answers
44 views

Rectifying the Environment Map (How it works)

Hello everyone I am currently reading a paper of Disney research, Zurich, for my exam, and I really don't understand a thing in this paper... The main issue of this paper is to create a ...
0
votes
1answer
24 views

Can you generate your own HDRI maps without using photos?

For example, preparing a scene in Maya using standard lights and rendering out a panorama? Could they also be made from scratch in photoshop using 32bit color? Is there a reason why people don’t ...
2
votes
1answer
65 views

What is the oldest hardware able to feasibly support Vulkan?

What is the oldest hardware or minimum requirements conceptually able to support a fully hardware-accelerated Vulkan implementation? I am not referring to what implementations are currently available ...
0
votes
0answers
25 views

Using Hough Transform to detect lines in an image

I am using hough transform on the following image after canny edge detection ...
9
votes
1answer
257 views

The most performant way to organize vertex data on modern GPUs

Say I have a model made up of vertices, each with position, normal, tangent, and ...
1
vote
1answer
30 views

Consistent animation speed across systems

I recently noticed that in all games, no matter what system you play on or what specs you have, your character will always move at the same speed even if there is no frame rate limit. I was wondering ...
0
votes
1answer
48 views

How to convert from Object space into World space (exercise from 3D Math Primer book)

This is not homework. I'm self studying Computer Graphics, using the book "3D Math Primer for Graphics and Game Development" (2nd edition). So there is the exercise 6 in chapter 3 which I can't figure ...
2
votes
1answer
41 views

Is there an analogue of OpenGL's ImageLoadStore in DirectX 12?

I'm trying to port part of an OpenGL program into an existing DirectX 12 software, at some point in their shaders they use OpenGL ImageLoadStore in order to store information in 3D Textures without ...
1
vote
1answer
34 views

How does a GLSL Sampler2D read a Vec2 UV coordinate to determine UV range

I am working with an atlas shader that steps through various sprite tiles within a single png atlas page to playback an animation with sampler2D. Looking at the shader code, I would expect to have to ...
2
votes
3answers
101 views

Strange stripes on the gradient

On the picture below you can see mathematically perfect smooth transition from black to white. But I noticed that on all gradient picture I see strange strips and the color transition doesn't feel ...
0
votes
1answer
33 views

Define position and orientation in a local coordinate system

Suppose we have a world coordinate system W and a 3D model m1 defined in W. ...
3
votes
1answer
49 views

Getting contrast color to a given color in RGB or ARGB or HEX

I am looking for a stable way to find a contrast/inverted/opposite color to a given one. Application of this is to find best possible color for foreground to give background.
0
votes
1answer
60 views

Skybox is rendered on the model instead of surroundings

I'm trying to implement Skybox in DirectX 11 (DirectXTK) but when I'm rendering skybox, then texture is rendered to my sphere model instead of showing skybox outside. Rendering code: ...
0
votes
0answers
51 views

State-of-the-art human extraction from image

What are the state-of-the-art algorithms for single human extraction from image? I am looking for algorithms able to extract from a picture only the person, reulting in a picture of the person with ...
4
votes
0answers
65 views

Anisotropic GGX BRDF implementation. How is it related to isotropic GGX BRDF?

Introduction I am implementing anisotropic GGX BRDF and have encountered strange behaviour of my implementation. I thought that if I compare the microfacet distribution function I have with the one ...
2
votes
1answer
49 views

My 2D translation matrix causes the box to be off screen when it shouldnt be

Now I know this isn't the way this is normally done so please bear with me. I am doing this this way so I know I have a solid conceptual understanding of everything that goes beyond example code. I ...
2
votes
1answer
55 views

Should animations be locked to FPS or Fixed time

I have been working on a 3D engine and I am now implementing animations, but I can't find out whether or not to use the FPS of the engine or a fixed time method for the transformation's speed. Could ...
3
votes
1answer
65 views

Adding noise to gradient

I found this picture When you zoom in to any part of the image, the background looks a bit noisy/grainy. See pixels around "violent violet" label: I'm trying to understand how to achieve the same ...
1
vote
0answers
24 views

How to capture frames in a MacOS MTKView for recording to a video

I have created a 3D model of a local outdoor performance space and I have an app that uses Metal on MacOS 10.14.2 to display the model. I want to create an animation by flying the camera around the ...
2
votes
2answers
143 views

Physically Based Shading for Diffuse surfaces

So I am currently in the process of implementing Physically based Shading in my pathtracer using microfacet models and I'm quite stuck at comprehending light interaction with diffuse surfaces. First ...
8
votes
2answers
957 views

In a physically based BRDF, what vector should be used to compute the Fresnel coefficient?

The well known Schlick approximation of the Fresnel coefficient gives the equation: $F=F_0+(1 - F_0)(1 - cos(\theta))^5$ And $cos(\theta)$ is equal to the dot product of the surface normal vector ...

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