Questions tagged [antialiasing]

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Ray tracing Supersampling patterns : pre-computing them?

This wikipedia page explains the principle of patterning in Supersampling. However, I have a question: should the pattern be constant for every pixel? Of course, the pattern will be constant for a &...
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1 vote
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32 views

Algorithm for transforming PNG anti-aliasing to smooth paths

I read the pixels of PNG files via libpng and creates an array of alpha channels (showing visible pixels for a monochromatic image). int pixels[height][width]; <...
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How big is a multi-sampled FBO than a regular FBO with the same resolution?

Is it proportional to the samples count? Whats the performance difference between binding a multi-sampler and a regular sampler?
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2 votes
1 answer
93 views

How can I implement subpixel antialiasing for font rasterization in Vulkan?

As a hobby project I am creating text rendering application that renders text directly from glyph outlines. Currently I am trying to find info on how to implement subpixel antialiasing. I know that ...
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3 votes
1 answer
59 views

Is a simple circle gradient enough to make an anti-aliased brush?

I'm new to programming raster graphics and trying to build a simple app, and I want to make sure lines have a smooth anti-aliased look. I am wondering if this can be achieved simply by having a brush ...
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1 vote
1 answer
262 views

glBlitFramebuffer does not copy all textures

The setup I have a working bloom shader implemented which creates a fbo with two textures attached to it. The first texture holds the entire scene The other only displays objects which are supposed ...
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0 answers
57 views

What are the limitations and benefits of anti-aliasing and subpixel rendering respectively?

Just like the question, I am wondering are there any limitations and benefits for these two techniques?
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1 answer
142 views

Is anti-aliasing color processing correct in this image?

I have the impression that there is a problem with anti-aliasing in a 2D GUI framework using opengl. To demonstrate the problem I made a program that draws gray ramps. The result is shown below. The ...
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1 answer
134 views

Rotate a Bitmap with Shearing

I am rotating a bitmap using the three shear algorithm documented in these articles [1][2]. From about 0-90°, the quality is acceptable, but beyond that it gets progressively more distorted until it's ...
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1 answer
241 views

Screen Space anti aliasing?

I have the following challenge. I am given a black and white image with rasterized lines. Given this input, I want to extend the edges to cover more than one pixel and antialias the edges. My first ...
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1 vote
1 answer
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Why is the image from the CUDA version not as sharp as the CPU version?

I am extending Roger Allen's Ray Tracing in One Weekend in CUDA (and also here) by following Peter Shirley's Ray Tracing: The Next Week; specifically Image Texture Mapping. The image I obtain from ...
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0 answers
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How can i understand the algorithm wu line?

I have Wu's line algorithm but I don't understand all the lines of code very well. ...
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1 answer
280 views

Multiple samples per pixel and texture blurring

As far as I know path tracers (or super-sampling antialiasing) typically calculate the final color of a single pixel by averaging the result of all samples taken inside that pixel. This gives a nice ...
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Temporal anti-alliasing breaks the entire image

I'm kind of lost here as I'm faced with a graphical bug the origin of which I don't even know. In an attempt to recreate a shadertoy I saw that had TXAA, I made a function TemporalAA that takes in 3 ...
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What is the difference between post-/pre- sampling, aliasing, filtering and processing?

What is the difference between post-/pre- sampling, aliasing, filtering and processing? How do the terms post-/pre-aliasing, post-/pre-processing, post-/pre-sampling and post-/pre-filtering relate to ...
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1 vote
2 answers
2k views

FXAA vs MSAA on modern hardware

looking for suggestion whether it is worth implementing a post process FXAA pass on modern mobile GPU's (mainly looking at apple A Series chip), or should i simply use the MSAA. Did a basic test with ...
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Pixelated /aliased /blurry edges in volumetric rendering

I have been trying to implement a simple GPU based volumetric renderer, somewhat similar to described here. I conceptually understand most of the stuff, and implemented some code, but my results are ...
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1 answer
95 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 ...
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1 vote
0 answers
57 views

Anti aliasing thin features in textures

Assume I have a texture with a repeating line pattern. The lines are exactly 2 texels wide (really thin). Ans very spaced out (50 texels in between each line). I am now struggling with the ...
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3 votes
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Sample color calculation in rotated grid supersampling

I'm rendering a scene using scanline method. In order to get rid of aliasing we need to render a scene with higher resolution (2x, for example). I'm trying to figure out how to calculate the color of ...
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0 votes
1 answer
519 views

Self intersection artifacts in 3D image raytracing

I am developping a voxel raytracer for global illumination. I have been successful in multiple aspects but there is a problem I am not sure how to solve. The model works as most other Voxelization ...
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3 votes
0 answers
273 views

Circular pattern aliasing in voxel ray tracer

I am doing a voxel based raytracer. In other words, I first voxelize the scene using rasterization and I proceed to raytrace the volume in a 3D image to generate a final frame. Currently I noticed ...
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3 votes
1 answer
711 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 ...
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1 vote
0 answers
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Anisotropic filtering and multisample anti-aliasing

Anisotropic filtering and multisample anti-aliasing both imply supersampling. In EWA and (derived) Feline AF algorithms a non-uniform weighted average is used. But in case of MSAA not. Why this is ...
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76 views

Baked anisotropic filtering using spherical harmonics

I want to learn is it good or bad idea. Let's assume video RAM is not a problem. For source texture create a texture of texels: spherical functions. Spherical functions defined by small arrays of ...
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3 votes
1 answer
1k views

Unexpected results from Mitchell-Netravali

I recently implemented Mitchell-Netravali filtering in my path-tracer with 16x (4x4) temporal anti-aliasing. PBR's demonstration image shows it should give significantly better results than the box ...
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1 vote
1 answer
335 views

Structural artifacts in ray jitter

I recently set up temporal super-sampling in my path-tracer, and now I'm trying to improve early samples by adding random offsets between -[PIXEL_WIDTH] and +[PIXEL_WIDTH] to each initial ray position....
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0 answers
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How does anti-aliasing work, in general, for raytracing? [duplicate]

I am working on a raytracing Java program for fun. Here's one rendering: As you can see I still have to implement anti-aliasing (and there are huge geometry problems I won't get in to). How would ...
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6 votes
4 answers
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Algorithms to "anti-alias" (or somehow improve) binary 1-bit drawings and fonts

These days anti-aliasing uses gray scale pixel values on displays with high pixel counts. I'd like to take a step back in time and learn what is available for anti-aliasting or at least improving the ...
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0 votes
1 answer
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How to plot an input signal in image?

Given an input signal(ex. sine) how can one go about plotting an image like below ones(the stripped black and white image)? The images are from these slides on image processing. Or this one:
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1 vote
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How to eliminate line aliasing in an object made of cubes?

I have a big cube made of smaller cubes, but sometimes, due to the fact that each side of the cube has different colors, I get some ugly colored lines that I would like to get rid off. Any advice is ...
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2 votes
1 answer
759 views

How to compare anti-aliasing effects on images ?

I am trying out different anti-aliasing algorithms on my image to improve the image quality. I want to compare the differences between these generated images via some metric. I was checking online for ...
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3 votes
1 answer
201 views

Relationship between spatial frequency of an image and Aliasing

I was looking into measuring the amount of aliasing in an image. After reading through many papers and sites, I came to the conclusion that the best method to measure the amount of aliasing in an ...
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3 votes
1 answer
2k views

How can I remove aliasing in an image without introducing blur?

I am trying to reduce aliasing in an image using some filters. I tried the Gaussian variant of filters to remove the said high frequency patterns in the image, but I feel it's a bit too much of a blur....
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4 votes
1 answer
284 views

Main techniques to draw a point at non integer coordinates?

I've difficulties in looking for an answer by myself because I don't know the jargon. I need somebody who'll points me in the right direction. Assume I have 100000 points with coordinates in the unit ...
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6 votes
1 answer
413 views

Anti-aliasing - Controlling colour density of pixel that comes within the "rectangle" surrounding my line

I am currently a beginner when it comes to anti-aliasing. I have read some notes online that how anti-aliasing works is that you first draw the line using an algorithm such as Bresenham's algorithm. ...
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2 votes
2 answers
176 views

Points of a line given in global coordinates to calculate the pixels that are set using the midpoint algorithm without anti-aliasing

I've the following problem: Let the camera opening angle be $\frac{3}{4}\pi$ and the window be $15 \times 15$ pixels large. Which pixels does the midpoint algorithm (without anti-aliasing) set for ...
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15 votes
4 answers
15k views

How is Anti Aliasing Implemented in Ray Tracing?

After reading a few articles online I can confidently say I am clueless on how Anti-Aliasing works when using Ray Tracing. All I understand is that A Single Pixel/Ray is split into 4 sub-pixels and 4 ...
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6 votes
1 answer
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What is the relation between Aliasing and Flickering?

So in the class I've learned that Aliasing refers to the jagged edges resultant from the discrete nature of computer graphics way of representation. Also, I know that Anti-aliasing refers to a ...
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12 votes
2 answers
1k views

What is the fundamental reasoning for anti aliasing using multiple random samples within a pixel?

In graphics, it's common to take multiple samples within the bounds of a pixel and combine them together (most commonly just doing an average) for a final sample pixel color. This has the effect of ...
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3 votes
0 answers
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What does these FXAA settings do?

I been looking for a way to do anti-aliasing with deferred rendering with WebGL as my target platform. WebGL does not support multisampled FBOs. I found FXAA implmentations such as this https://github....
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7 votes
2 answers
2k views

What kind of anti-aliasing is used in font rasterization?

I'm writing my own TrueType font rasterizer as an exercise to improve my knowledge in computer graphics (along with a basic vector graphics engine). At this stage, I have implemented most of the TTF ...
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7 votes
1 answer
277 views

How to never draw "Jaggies" in the first place considering resolution and scale

Ok, I have a simulation I am trying to make. The entire simulation is drawn by circles (with gl_Point) and rectangles (gl_triangles with indices). It would be great to add some anti aliasing ...
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24 votes
1 answer
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Anti-aliasing / Filtering in Ray Tracing

In ray tracing / path tracing, one of the simplest way to anti-alias the image is to supersample the pixel values and average the results. IE. instead of shooting every sample through the center of ...
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16 votes
1 answer
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why does black text have orange and blue pixels

Why is it that when you zoom in to some black text you find that it is made up of orange, slightly black and blue pixels like the picture below.
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21 votes
2 answers
3k views

What is Illustrator's vector rasterization process?

I am currently trying to understand a few things about vector graphics rasterization and the different ways it is implemented in various application types. I tested and compared a few programs and ...
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16 votes
2 answers
1k views

Subpixel Rendering for a Ray Tracer

In font rendering, it is common to use subpixel rendering. The basic idea here is to break the pixel into its RGB components and then compute a value for each separately. Since each component is ...
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12 votes
2 answers
7k views

Fast antialiased line drawing

Bresenham's line algorithm is a way of drawing straight lines using only fast integer operations (addition, subtraction, and multiplication by 2). However, it generates aliased lines. Is there a ...
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12 votes
2 answers
2k views

Sub-pixel antialiasing rules

I recently had an issue with sub-pixel anti-aliasing of text, which produces very harsh colours and made me wonder how it is meant to be done properly: I've drawn some cases of a black tile ...
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10 votes
1 answer
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How do I accurately compute coverage of overlapping analytical curves?

Antialiasing of 2D shapes boils down to computing the fraction of a pixel that is covered by the shape. For simple non-overlapping shapes, this is not too difficult: clip the shape against the pixel ...
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