Having spent a bunch of time recently doing 2D work that involves pixel manipulation of bitmaps and blending/compositing, I've run up against the limits of my own understanding with respect to colorspaces, non-RGB color worlds, etc.
I'd like to go back to basics and learn how all this stuff actually works, so that I'm not shooting in the dark next time I need to think about how to set up a blend function, and I know how to play with color palettes, etc.
Any pointers for good places to start on the path? Online references good, actual books that are clearly written are better. (Not looking for something that's just piles of equations, but can follow mathy stuff if it's not too terse.)
Thanks!
I liked these tutorials:
http://www.student.kuleuven.be/~m0216922/CG/index.html
Related
As the title says, I'd like to program a 3d game (probably a BattleZone clone), but without the use of an API like OpenGL, DirectX, and the like. At the heart of the matter, I'd just like to learn how to draw basic 3d shapes to the screen and manipulate them. Don't care if it looks like crap. I've used OpenGL to achieve similar ends before, but really didn't learn about these topics.
The problem is, I have no idea where to start. I downloaded the Doom source code, but it's a bit over my head. Although I've programmed a bit, graphical matters are very much out of my depth.
I'd be very grateful if anyone could offer links or code (in any language) that would help me along in my purpose.
Sounds like an exciting project. I did something similar in the late 90's. Before OpenGL and DirectX became popular, there were a ton of great books on the subject.
Fundamentally you will have to learn how to
Represent 3D geometry
Transform that geometry (translate and rotate)
Project that geometry onto a 2D screen.
Each of those major topics has many sub-topics (for example, complex objects can be constructed from a number of polygons. You may want to limit polygons to being constructed of triangles only, or support other polygons. You may want to load common model formats e.g. .obj files so that you can create models with off the shelf tools).
The topics are way too broad for a detailed answer here. Whole books are written on the subject, including
Black Art of 3D Game Programming (Book, amazingly still available)
For a good introduction to the general topics, have a look at:
http://en.wikipedia.org/wiki/3D_projection
http://en.wikipedia.org/wiki/Orthographic_projection
http://en.wikipedia.org/wiki/Transformation_matrix#Perspective_projection
Doom, which you already looked at, used a special optimization called heightfield rendering and does not allow for rendering of arbitrary 3D shapes (e.g., you will not find a bridge in Doom that you can walk under).
I have the second edition of Computer Graphics: Principles and Practice in C and it uses SRGP (Simple Raster Graphics Programming) and SIGGRAPH which is a wrap-around SRGP, if you look up articles and papers on graphics research you'll see that both these libraries are used a lot, and they are way more direct and low level than the APIs you mentioned. I'm having a hard time locating them, so if you do, please give a link. Note that the third edition is in WPF, so I cannot guarantee much as to it's usefulness, and I don't know if the second edition is still in print, but I have found numerous references to the book, and it's got it's own page in Wikipedia.
Another solution would be the Win32 API which again does not provide much in terms of rendering, but it is trivial to draw dots and lines onto a window. I have written a few tutorials on it, but I didn't cover drawing pixels and lines, so they'll only be useful if you have trouble with the basics of setting up a window. Note that it is not intended for real-time rendering, so it may get slow.
Finally you can look at X11 programming, the foundation of most modern operating systems with a GUI. I haven't found the libraries for Windows, but again I didn't invest too much time on it. I know it is available for CIGWIN and for Linux in general though, and I believe it would be very interesting to look at the core of graphics since you're already looking under the hood of 3D graphics.
I've been studying 3D graphics on my own for a while now and I want to get a greater understanding of just how everything works. What I would like to do is to create a simple game without using DirectX or OpenGL. I understand most of the math I believe, but the problem I am running up against is I do not know how to get control of the pixels being displayed in a window.
How do I specify what color I want each pixel in my window to be?
I understand I will probably run into issues with buffers and image shearing and probably terrible efficiency problems, but I want to create my own program so that I could see from the very lowest level, of the high level language, how the rendering process works. I really have no idea where to start though. I've figured out how to output BMPs, but I would like to have a running program spitting out 20+ frames per second. How do I accomplish this?
You could pick a environment that allows you to fill an array with values for pixels and display it as a bitmap. This way you come closest to poking RGB values in video memory. WPF, Silverlight, HTML5/Javascript can do this. If you do not make it full screen these technologies should suffice for now.
In WPF and Silverlight, use the WriteableBitmap.
In HTML5, use the canvas
Then it is up to you to implement the logic to draw lines, circles, bezier curves, 3D projections.
This is a lot of fun and you will learn a lot.
I'm reading between the lines that you're more interested in having full control over the rendering process from a low level, rather than having a specific interest in how to achieve that on one specific platform.
If that's the case then you will probably get a good bang for your buck looking at a library like SDL which provides you with a frame buffer that you can render to directly but abstracts away a lot of the platform specifics issues. It has been around for quite a while and there are some good tutorials to give you an idea of whether it's the kind of thing you're looking for - see this tutorial and the subsequent one in the same series, which should be enough to get you up and running.
You say you want to create some kind of a rendering engine, meaning desinging you own Pipeline and matrice classes. Which you are to use to transform 3D coordinates to 2D points.
When you have got the 2D points you've been looking for. You can use say for instance on windows, you can select a brush and draw you triangle values while coloring them at the same time.
I do not know why you would need Bitmaps, but if you want to practice say Texturing you can also do that yourself although off course on a weak computer this might take your frames per second significantly.
If you aim is to understand how rendering works on the lowest level. This is with no doubt a good practice.
Jt Schwinschwiga
I would like to do an interesting project for a computer graphics course. I know that there is a lot of literature out there (i.e. SIGGRAPH conference papers). I have a very large range of interest with regard to computer graphics (i.e. image processing, 3D modeling, rendering, animation). However, I've only taken computer vision/graphics for 2 semesters and thus don't have too much background experience, except for the class projects that I had to do.
I've been looking through SIGGRAPH papers trying to see if there is anything that will be of interest to me but the literature is extremely vast. I was wondering if anyone has any topic suggestions, anything interesting that you ran across that you could recommend. I would prefer to do something fun yet slightly challenging (not really interested in making a shooter game).
If this question does not belong here, I apologize and please let me know where I should move it.
Thanks!
Image Drawing animator. (the name is kind of misleading, but I didn't care much about it)
Anyway, the software does the following:
Takes an image say a JPEG or BMP as input.
Extract the lines from the image. (I used Matlab and Laplace transformations)
Convert the static lines to Vector paths.
Simulate drawing the image using the extracted paths.
In summary, you should give an image, for example a city scape, the program extract all lines and start drawing the buildings, streets and sunset lines, then finally add the colors one by one, until the full image is done.
Real time hand(s) detector.
You'll have plenty of interesting and fun applications with this.
I'd like to implement an old film effect on pictures. Does anyone know a library or even the rare maths involved? I'd like it to cope with red shift for over-exposition and the rest. Even if you don't know the maths or a library, a pointer to any technical doc will be appreciated.
Clarification: I need to write these routines for a project of my own. I'd like to know what kind of processing has to be done and how. Doesn't matter the environment and system, I just need some hint on how process RGB data
You mention Magic Bullet from Red Giant Software in your comments. There's an impressive amount of image processing know-how behind the development of Magic Bullet. You'd probably have an easier time implementing a host interface for After Effects or Final Cut Pro plug-ins and using Magic Bullet.
If you want to see some source code in action, examine the open source projects that do image processing like GIMP, CinePaint, FreeFrame, etc.
You could try with as3 bitmapdata noise function http://livedocs.adobe.com/flash/9.0/ActionScriptLangRefV3/flash/display/BitmapData.html#noise%28%29
If you can find a plugin for Paint.Net, I'm sure you could just use that dll in your program. Is this the sort of thing you're looking for?
Rare maths?
Create several different transparent PNGs with scratch and dust marks on it. Take a pic, adjust the hue, saturation and brightness (algorithms for this aren't that complex) to fade out the pic, then overlay one to many of the scratchy PNGs. The more scratch/dust PNGs you have, the more random the effect you can create.
Not much math here IMHO.
Hey guys, I would like to develop a light/laser show editor and simulator, and for this of course I am going to learn some graphics programming. I am thinking about using C# and XNA.
I was just wondering what aspects of graphics programming I should research or focus on given the project I am working on. I am new to graphics programming so I don't know much about it, but for example I imagine something that I might look into would (possibly?) be volumetric lighting.
For example, what would be a practical way to go about rendering a 'laser' of varied width/color? I read somewhere to just draw a cylinder and apply a shader to it, I would like to confirm that this is the way.
Given that this seems like a big project, I was thinking about starting off by creating light sources and giving them properties so that I can easily manipulate them. I have (mis)read that only a certain amount of lights can be rendered at any given time, I believe eight. Does this only apply to ambient lights? Given this possible limitation, and the fact that most of the lights I will use will be directional, such as head-lights or lasers, what would be a different way to render these? Is that what volumetric lighting would be?
I'd just like to get some things clear before I dive into it. Since I'm new to this I probably didn't make the best use of words, so if something doesn't make sense please let me know. Thanks and sorry for my ignorance.
The answer to this depends on the level of sophistication that you need in your display simulation. Computer graphics is ultimately a simulation of the transport of light; that simulation can be as sophisticated as calculating the fraction of laser light deflected by particles in the atmosphere to the viewer's eyepoint, or as simple as drawing a line. Try out the cylinder effect and see if it works for your project. If you need something more sophisticated, look into shader programming (using Nvidia Cg, for example), and volumetric shading as you mentioned; also post-processing glow effects may be useful. For OpenGL, I believe there is a limit of 8? light sources in a scene, but you could conceivably work around this limit by doing your own shading logic.
Well if it's just for light show simulations I'd imagine your going to need a lot of custom lighting effects - so regardless if you decide to use XNA or straight DirectX your best bet would be to start by learning shader languages and how to program various lighting effects using them. Once you can reproduce the type of laser lighting you want, then you can experiment with the polygons you want to use to represent the lasers. (I've used the cylinder method in some of my work for personal purposes, but I'm not sure how well straight cylinders will fit your purpose).
Although its faster, I think its best not to use vanilla hardware lighting because of its limitations. Pixel shaders can help with you task. Also you may want to chose OpenGL because of portability and its clarity in rendering methods. I worked on Direct3D for several years before switching to OpenGL. OpenGL functions and states are easier to learn and rendering methods (like multi-pass rendering) is a lot clear. If you like to code on C# (which I dont recommend for these tasks), you can use CsGL library to access OpenGL functions.