Questions tagged [artifacts]

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AMD GPU specific triangles disappearing by subsequent draw calls in same frame

we have a Windows/DirectX11 2D Renderer that paints textured triangles to the screen from back to front. There is no face-culling or depth test activated. Now on AMD GPUs it happens randomly that an ...
user20154's user avatar
0 votes
2 answers
372 views

How to avoid curvature artifact in raytracer?

I have a pretty simple raytracer that is rendering some SDFs, but when my camera is close to the object I see curves: I am not entirely sure where they are coming from, as I am using nothing but ...
Makogan's user avatar
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How widespread are T-vertex artifacts nowadays?

As far as I know, OpenGL specifies that you cannot rely on precise rounding of vertex and edge coordinates for rasterization - which means that T-vertices may cause small artifacts: a continuous and a ...
Tau's user avatar
  • 121
3 votes
0 answers
114 views

ray racing (Whitted) bad shadow on far objects (artifact)

situation: I've implemented a Whitted style ray tracing in C. Everything appear to works except the shadow cast by small object on big far objects The problem : red sphere have radius 0.5 orange ...
LesChats's user avatar
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1 answer
107 views

What can be the cause of some strange ray shadows artefacts on a perfectly flat surface?

First of all I have to say that I am really new in the world of Computer Graphics. I apologise if some of my questions may appear trivial. I am currently using a non-commercial ray tracing and ...
Balfar's user avatar
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4 votes
1 answer
122 views

Reducing artificial rings in mean curvature of mesh

I have an isosurface/mesh (generated via marching cubes) of a micro-CT scan. Originally the surface looks very noisy, which becomes prevalent when the mean curvature is visualized: To reduce the ...
Steven's user avatar
  • 141
4 votes
3 answers
644 views

Visual Artifact in Wireframe Grid/Plane

I have a simplistic shader program that adds reference coordinate planes to a scene. These planes are drawn as intersecting lines. When viewed at a distance, a visual artifact is created; there is ...
user avatar
2 votes
1 answer
451 views

Strange sphere reflection effects in ray tracing project. I cannot figure out what causes them

I started a ray tracing project in Python. I made a CUDA kernel and a trace() function for each pixel. It works perfectly when calculating intersections, shadows and lambert shading, however when I ...
Speterius's user avatar
0 votes
1 answer
125 views

Microfacet BRDF artifacts

I've been trying to implement a microfacet specular BRDF based on the equations in Real Shading in UE4, but I'm getting weird ring-shaped artifacts in the highlights of rough surfaces: Here's the ...
Sam's user avatar
  • 198
1 vote
2 answers
464 views

Ghosting in volumetric lighting

Does anyone know any method to remove ghosting in volumetric lighting? When light move it leaves trail behind, i would like to remove it. Volumetrics are Bart Wronski style (in frustum) with ...
Derag's user avatar
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1 vote
1 answer
396 views

Normal Artifacts On Grazing Angles

I am currently experiencing a very obvious artifact that occurs when looking at objects on very grazing angles Here is a picture of the artifact: I noticed that the issue was coming from my ...
Brady Jessup's user avatar
3 votes
1 answer
973 views

How to solve Z buffer artifacts

I am currently rendering a scene in the most standard fashion possible (triangle projection and Blinn-Phong for shading) However I am getting some artifacts: As you can see the lion head is not ...
Makogan's user avatar
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1 answer
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What remedies are there for percieved color artifacts due to pixel geometry?

I have a white line on black background. Because of the pixel geometry the line does not look really white; one edge looks red-isch, the other blue-isch. Other fore- and background yield other ...
Andreas's user avatar
  • 359
2 votes
1 answer
692 views

What might be causing these artifacts in 5D & 6D simplex noise?

I've been working on writing functions for 5 and 6 dimensional simplex noise, working off FastNoise's 4D function as a base. 2D, 3D and 4D noise all follow a very similar and recognizable pattern ...
Mark A. Ropper's user avatar
0 votes
1 answer
122 views

Ringlike artifacts produced by rays bouncing off a light source

I recently set up a (very basic) ray-marched path-tracer, and I'm getting strange surface patterns on my area light [link]. I'm using known-valid analytical normals for the light's surface, and the ...
Paul Ferris's user avatar
6 votes
0 answers
619 views

Avoiding Mach band effect when using multiple lights

I wrote a simple Phong shader with two directional lights for a project, and noticed an unpleasant artifact in the lighting. Where both lights are illuminating the same region, dark bands appear at ...
russ's user avatar
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4 votes
1 answer
367 views

Tesselation sine distortion?

I am experimenting on a simple wave tessellation shader. I ported it from a working vertex shader. When my frequency is higher than 1, I get strange "saw-tooth" artifacting at peaks of the wave. Here ...
scx's user avatar
  • 169
6 votes
1 answer
3k views

Ray Tracing Shadows: The Shadow Line Artifact

By using smooth shading (i.e. interpolation of normals), an object can have a smooth look despite low polygon count. A nasty artifact that can happen when casting shadow rays is the Shadow Line ...
David Kuri's user avatar
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2 votes
0 answers
77 views

Vectorizing half tone images

Vectorizing continuous tone images is often met with color palette reduction and visual artifacts. Half-tone images, on the hand, have constant patterns in their tones, which would intuitively lead to ...
Danyil Bee's user avatar
5 votes
1 answer
483 views

Artifacts when gamma correcting

Doing post-process gamma correction is showing texture artifacts, here is a small example on a skybox: The first image is gamma correcting on the skybox shader and seems correct, the lower is doing ...
V.M.'s user avatar
  • 53
1 vote
1 answer
67 views

Compression-friendly PNG files

How to create PNG files optimized for being compression-friendly? I.e. would it help if image is created (mostly) from 8x8 unicolor blocks?
tomash's user avatar
  • 111
4 votes
1 answer
216 views

Weird rendering in rectangle mesh shader AKA Why has my basic shader become a modern art generator?

I am trying to translate an old (2013) bit of code from Apple from objective C to Swift with some modifications I need for my simulation. The code I am translating can be found here To make ...
J.Doe's user avatar
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22 votes
1 answer
4k views

Why does my Perlin Noise look "blocky"?

I tried to implement Perlin Noise by myself using just the theory (following flafla2.github.io/2014/08/09/perlinnoise.html). Unfortunately I was unable to achieve the look of the "original" Perlin ...
sarasvati's user avatar
  • 323
8 votes
2 answers
1k views

Moires patterns despite using mipmaps

I am working on Silverlight app. I am trying to render floor covered with tiles. Although I am using mip maps I am still getting awful Moire patterns, when trying to render big area. What I am doing ...
bartosz.baczek's user avatar
6 votes
1 answer
444 views

Texture glitch when using simple pixel shader

I have an issue with rendering my textures in Silverlight. When I look at it from above everything looks fine: But if I only change angle of watching it it looks terrible: I am using very simple ...
bartosz.baczek's user avatar
11 votes
1 answer
379 views

When creating a JPEG, how can I minimize the occurence of artifacts?

There are 2 main factors that seem to lead to digital artifacts when creating JPEG images: Aliasing and Compression. Example: Converting a PNG with characters on it to a JPEG or placing vector ...
Armfoot's user avatar
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