28
votes
Accepted
What is Tessellation in computer graphics
Tesselation is a technique that allows you to generate primitives (triangles, lines, points and such) on the graphics-card. Specifically, it lets you repeatedly subdivide the current geometry into a ...
- 1,810
11
votes
Accepted
Why does checkerboard pattern on a computer screen appear with a yellowish tint?
Because your monitor is not properly calibrated.
On my screen at home the top and bottom parts have the same hue. At my office though, the top part tends to looks a bit yellow compared to the bottom ...
- 4,380
8
votes
How does a computer upscale 1024x768 resolution to 1920x1080?
In essence a image is a group of point samples (read A pixel is not a little square3). When you transform or scale the image you need to resample it. So what you do, theoretically, is take the point ...
- 8,397
7
votes
Accepted
How does the Painter's Algorithm handle transparency?
The common way to render transparent polygons in a rasterizer is by use of Alpha Blending, which basically combines the colour of the supposedly transparent pixel with the colour of the background at ...
- 1,674
6
votes
What is Tessellation in computer graphics
It activate 3 stages in the pipeline.
The first is the tessellation control shader (hull shader in D3D) which looks at a set of vertices and then outputs how it should be divided up in separate ...
- 5,920
5
votes
How does a computer upscale 1024x768 resolution to 1920x1080?
There are numerous upscaling and downscaling algorithms available to scale images from any resolution to any other arbitrary resolution. Each algorithm typically involves a trade-off between ...
- 151
4
votes
Get screen size and then resize image accordingly
The OS does not, in many or most cases, know the physical screen size! Often the only thing you can glean is the make and model, sometimes not even that. So if you do not want to have a database then ...
- 8,397
4
votes
vertical or horizontal line test
It is not generally useful to try to optimise small parts of a program before you have profiled the program to see where the most benefit can be gained by optimisation. Make sure everything is correct ...
4
votes
Difference in pixels between different monitors' sizes
The answer to both your questions is the same: the physical size of the monitor makes no difference at all. If your screen is 1920x1080 pixels, and you display a 960x540 image without any scaling, the ...
- 6,700
3
votes
How does the Painter's Algorithm handle transparency?
I would like to add that Painters' algorithm can be run from front to back with transparency provided your blending operations are associative. I would recommend reading Jim Blinn's "Compositing, Part ...
- 4,181
3
votes
Algorithm for thinning a thick line
the canny algorithm is a great start.
it takes a sobel input like so.
Computes its gradient. Then depending on the gradient orientation it compares all neighbouring pixels aligned with it. If its a ...
- 31
3
votes
Accepted
Why do some videos look smoother and others don't on the same monitor
As you have now mentionned that your computer can actually keep up (at 150 fps no less), I suspect you have a case of temporal aliasing.
The problem is that 150 is not a multiple of 60. Let's say we ...
- 1,585
3
votes
Accepted
library / tool for implementing algorithms
If you're completely new to graphics programming I would start with Processing. It's based on Java and JOGL but comes with a whole bunch of drawing commands built in, and its own basic IDE. It's very ...
- 2,372
3
votes
Accepted
Thick Line segment
The main part of it is simply Pythagoras's Theorem. The square root gives the length of the central line segment (which is the hypotenuse of a triangle formed by the change in x and change in y). The ...
- 6,700
3
votes
Accepted
human visual: relation of Distance and DPI
According to a review by Legge & Bigelow the arc or degrees of visual angle ($\alpha$) is,
$$
\alpha = 57.3 \times S/D,
$$
where S is height of object and D is distance to object. [1] $S/D$ is ...
- 8,397
2
votes
What is this technique called and how can I reproduce it algorithmically?
I've done something similar. The way I did it was by using a height map image to change the positions of vertices in a grid in a vertex shader. I generated a 2D grid of vertices that were evenly ...
- 3,401
2
votes
Calculate set of rectangles covering pixel diffs?
I would say it’s a weighted set covering problem.
In specific, the cost for a set of points is the number of extra pixels in the bounding rectangle of this set.
If the number of diff points is small,...
- 46
2
votes
Get screen size and then resize image accordingly
Back in the days, MSDN defined a couple of values which in most cases are useless (total crap):
https://msdn.microsoft.com/en-us/library/windows/desktop/dd144877%28v=vs.85%29.aspx
...
- 211
2
votes
Which technique is fast to generate real-time reflections?
Usually modern game engines use Screen Space Reflections which is some kind of screen space raymarching.
Basically, a simple way to achieve this is to shoot rays from the G-buffer. This means you use ...
- 176
2
votes
Bresenham's Algorithm not drawing horizontal lines
e = (float)(delta_x / delta_y) - 1.0;
e += (float)delta_x / delta_y;
Either of these lines will cause a divide-by-zero error when ...
- 6,700
2
votes
Purpose and workflow of wireframe models
Regarding wireframes as an edge list.
Wireframe models are used in engineering and CAD they provide several benefits. The Wikipedia page you linked has some benefits, this AutoCAD page has some more. ...
- 3,030
2
votes
Accepted
Purpose and workflow of wireframe models
Why are wireframes used?
Games don't really use wireframes much, but they might be useful for HUD items etc.
Asset creators, designers and engineers use wireframes to see whats inside objects. TO ...
- 8,397
1
vote
Why does a game at 1080p look better on a 1080p display than 1440p display of the same size
I just went through this with a new 4k monitor under Windows 10 (but have repeated it many times with many different monitors):
The On Screen Display (OSD) of the monitor should have an info page that ...
- 3,030
1
vote
wall clock using bresenhams circle drawing algo
The usual method is to just draw over the circle with your lines. The clock is behind the minute hand and the minute hand is behind the hour hand so the drawing order would be. Draw the clock face, ...
- 3,030
1
vote
Why do some videos look smoother and others don't on the same monitor
Humans don't really see anything beyond 20-25 fps. Even less is often sufficient; animation at 12 frames a second work quite well too. So when you watch TV, the fps of your image is 25-30, and yet ...
- 8,397
1
vote
How can I draw a filled circle on a grid with the less rectangle as possible?
To get a proper circle, you can use a transformation matrix to transform your cell coordinates into equally spaced cartesian coordinates. In the case of your 50 x 100 pixel cells, your transformation ...
- 3,401
1
vote
Convert RGB image to YUV420 using a hlsl shader
The problem here is that you're not storing the YUV values of a pixel at the same place in the result image. What you seem to be doing is first storing the full size Y image and after that the quarter-...
- 1,674
1
vote
Confused about graphic art and what software is used to create the environment of it?
This would be considered isometric. Isometric graphics were originally used to give a 3D look, when computers could not handle actual 3D graphics.
The creation of this image, however, is different ...
- 1,595
1
vote
Accepted
How to raytrace triangular faces when camera is not at origin?
Wow I'm stupid, the whole problem was I thought it was 1/t and it is actually 1-t in parametric form. Hope this helps someone ...
Only top scored, non community-wiki answers of a minimum length are eligible