How can I make a screensaver in C++ that fades an image in and out at random places on the screen with a specified time delay on the fade out?
Multimonitor support would be awesome.
If you have a working code or know where I can get it, it would be great. Otherwise point me in the right direction. I'm looking for a method that has a smooth and not laggy og flickery fade. The screensaver is for Windows XP.
I dont know C++, but I do know AS3, Javascript, and PHP. So I was hoping to relate some of that knowledge to C++.
What should I use to compile it?
First off if you're starting out in C++, don't start with a windows specific compiler like visual c++. Grab a nice cross-platform IDE that comes with a compiler like eclipse or code::blocks. Like any project, you are going to want to split it up into smaller tasks you can complete in stages. Sounds like you have a couple of hurdles.
Lack of C++ Knowledge (we were all here once)
Lack of knowledge about images (very common affliction)
Lack of experience (we'll work on this)
DO NOT let others discourage you. You CAN do this, and probably faster than you think possible. DO read a book or two about C++, you can get by for one project without knowing much but you WILL get frustrated often. Let's break up your project into a set of small goals. As you complete each goal your confidence in C++ will rise.
Image blending
Windows Screen Saver w/ multi-monitor support
Screen Canvas (directx, opengl, bitmaps?)
Timers
First, let's look at the problem of image blending. I assume that you'll want to "fade" the image in question into whatever windows background you have active. If you're going to have a solid-color background, you can just do it by changing the alpha transparency of the image in question between canvas refreshes. Essentially you'll want to average the color values of each pixel in the two images based on your refresh timer. In more direct terms to find the red, green, and blue pixel elements for any resultant pixel (P3)
N = timer ticks per interval (seconds/milliseconds/etc)
T = ticks that have occurred this interval
P1r = red pixel element from image 1
P2r = red pixel element from image 2
P3r = resultant red pixel element for blended image
P1g = green pixel element from image 1
P2g = green pixel element from image 2
P3g = resultant green pixel element for blended image
P1b = blue pixel element from image 1
P2b = blue pixel element from image 2
P3b = resultant blue pixel element for blended image
P3r = ((T/N * P1r) + ((N-T)/N * P2r))/2
P3g = ((T/N * P1g) + ((N-T)/N * P2g))/2
P3b = ((T/N * P1b) + ((N-T)/N * P2b))/2
Now let's look at the problem of windows screen savers and multi-monitor support. These are really two separate problems. Windows screensavers are really only regular .exe compiled files with a certain callback function. You can find many tutorials on setting up your screensaver functions on the net. Multi-monitor support will actually be a concern when you set up your Screen Canvas, which we'll discuss next.
When I refer to the Screen Canvas, I am referring to the area upon which your program will output visual data. All image rendering apps or tutorials will basically refer to this same concept. If you find this particularly interesting, please consider a graduate program or learning course in Computer Vision. Trust me you will not regret it. Anyway, considering the basic nature of your app I would reccommend against using openGL or DirectX, just because each have their own layer of app-specific knowledge you'll need to acquire before they are useful. On the other hand if you want built-in 3d niceties like double buffering and gpu offloading, I'd go with openGL (more platform agnostic). Lots of fun image libraries come as gimmes as well.
As for multi monitor support, this is a tricky but not complicated issue. You're basically just going to set your canvas bounds (screen boundary) to match the geometry of your multiple monitors. Shouldn't be an issue with multiple monitors of the same resolution, may get tricky with mismatched monitor resolutions (might have canvas areas not displayed on screen etc. There are well known algorithms and workarounds for these issues, but perhaps this is beyond the scope of this question.
Finally as to the timers required, this should be the easiest part. Windows and Linux handle time in their own strange ways (WHY doesn't MS implement STRPTIME), so If you are interested in portability I'd use a 3rd party library. Otherwise just use the windows settimer() basic functionality and have your image rendered in the callback function.
Advanced Topic: Hey if you're still reading there are a number of interesting algorithmic improvements you can make to this program. For instance, with your timer going off a set quanta each second, you could cache the first few blended images and save some processing time (our eyes are not terribly good at noticing differentiating between changing color gradients). If you are using openGL, you could cache sets of blended images as display lists (gotta use all that graphics card memory for something right?). Fun stuff, good luck!
"I dont know C++, but I do know AS3, Javascript, and PHP. So I was hoping to relate some of that knowledge to C++."
Oh boy, I suppose you're going to be surprised. To learn C++:
Buy at least one or two very good books (see here). Do not buy books that aren't very good. They'll teach you habits that you would have to unlearn later in order to make further progress.
Expect having to do plenty of hands-on code writing with a lot of reading in between. In the first few weeks, the compiler will spit legions of incomprehensible error messages at you, your code will keep crashing, and seasoned C++ programmers looking at your code will throw up their hands in disgust. And it's always your fault.
Plan a lot of time to learn. And I mean a real lot. No matter how much time you devote, it will take at least a couple of months until you upgrade from "dummy" to "novice".
Imagine having to hammer at it for a couple of years in order to become a real professional, constantly reading books and articles, devoting plenty of time to newsgroups and discussion forums, learning from others, banging your head against every wall surrounding your desk.
Be prepared to learn something you haven't known before at least once every week even after a decade of programming in C++ for a living.
Just for a moment, imagine I might not overstate this.
Edit for clarification: I have up-voted both Hunter Davis' and Elemental's answers, because they're very good, pretty much to the point, and in general the encouragement is supported by me despite my rant up there. In fact, I do not doubt that many are able to hack something together in C/C++ when given a skeleton example even if actually they don't know much of C++. Go ahead and try, there's a good chance you'll come up with a screen saver within reasonable time. But. Being able to "hack something together in C/C++" is far from "having learned C++". (And I mean very far.)
C++ is an incredible complex, mean, and stubborn beast. I also consider it almost breathtakingly beautiful, but in that it probably mirrors the view from a very high mountain: It's pretty hard to get to the point where you're able to appreciate the beauty.
C++ is a complex language and all that sbi indicates is probably true (certainly after 10 years of commercial C++ programming there is still some to learn) BUT I think that if you are confident in another language it should only take a couple of days to:
a) Install one of the compilers mentioned here (I would suggest VC as a quick in to windows programming)
b) Find some sample code of a screen saver that does something simple using the windows GDI (there is some code within the MS documentation on screen savers)
c) Modify this code to do what you want.
In terms of your limited requirement I think you will find that the window GDI++ libraries have sufficient power to do the alpha fades you require smoothly.
I'd look at microsoft c++ express. It's free and pretty capable. You may need to hack it, or get an older version, to produce unmanaged executables.
There are a lot of tutorials available for the rest
Related
I am trying to build a multimedia editor. It includes audio and relatively simple 2D graphics. I am using C++. I would like as much of it to be cross platform as possible.
I wrote audio interface classes for android and windows using a common API so I have that under control for now but I need a 2D graphics package and possibly a cross platform GUI as well.
The big challenge is in trying to render the time line. It needs to generate many rows of waveforms and intersperse them with characters and other shapes some of which may include blends and transparencies. Or rather I should say the big challenge has been animating the time line as often I will need to update it in real time. I have this working nicely using a lot of cashing and shifting around of the pixels of off-screen bitmaps. If I have 50 lines on the screen and the screen is 1000 pixels wide that translates to over 50,000 line draw operations per frame. Actually I use multi segment lines that end up drawing 3 times as many segments. To generate each line of the audio waveform it needs to look at a few hundred samples of audio and compute the max and min values or maybe do an FFT to create a line of different colored pixels if I want to offer this to the user some day. Various forms of cashing let me do this with reasonable latency.
The animation side of things will include everything from moving poly lines and polygons around in 2D to importing images and playing back moving multiple images (video) at different arbitrary frame rates. I don’t think 3D is very useful for now anyway.
At the moment I am using a crazy mix of GDI and GDI plus on windows and running it all in a win32 “thing”. This is not great as I cannot invert regions in off screen bitmaps and I cannot draw individual pixels quickly enough to for instance show a spectrogram in real time. I think they were written in the 90s so there must be something newer I can use and get better performance and cross platform capabilities. I have been pulling out my remaining hair to figure out what to use.
I found another library on android that will let me set pixels and the performance actually seems a lot better but it does not support writing text. So I am hoping there is something else I could use for that. On Android the plan is to generate the bitmap and then blit it into an interface build with a Native Android GUI. These solutions do not seem great though a vast majority of the rest of the code can be ported without issue just being standard C++ and these horrors being cleanly wrapped.
I have seen a few potential candidates: openGL and Vulkan, seem to do 2D graphics as well as 3D but perhaps they are much more complex then what I need.
For the GUI I looked at QT but gave up on it (it seems to need half of my hard drive and has an incomprehensible licensing model). I recently started looking at IMGUI. They say it redraws on every frame. I don’t know how that will play with my existing rendering system and if it would drain a phones battery. A while ago I was able to get visual studio to create a cross platform App that would run on android but for some reason ditched that perhaps I should revisit it.
For the time line I need to draw a waveform. This could be done by drawing a lot of lines (50-150 k/frame) they can just be vertical ones for the most part, they do not need to be of fractional pixel width they need not be anti-aliased, and can have their end points specified with just integers. I also need to add some other lines polygons and text that does need to be anti-aliased. I may need to set a lot of pixels directly. Blends and transparencies would be nice but not essential. I also need to copy square chunks of bit map around. I also need sprites for things like the cursor. I am currently doing this by copying fragments of the bit map on and off screen. It would also be very nice to be able to select square regions of off screen bitmaps to invert for doing selections. And I need to assemble this off screen in a 2 or 3 buffer configuration so I can reuse chunks of one bitmap to make the next one and present it to the user in a real time animation. (all of this works with my GDI / GDI + wrapper though I have to work around the inversion problem)
For the animation part I need to draw similar graphics primitives, though it would also be nice to draw characters at arbitrary angles and scaling. As for Video if I can extract the images I guess I could blit them to the screen as needed. Maybe I would need yet another package to composite them into the other parts of the frame. Farther it would be nice to be able to write the animation out in a higher quality format in non real time to make a video file of some kind. It would be nice if I did not have to wrap yet another framework to make this happen though I can deal with this if I need to.
For the GUI it does not have to be all that fancy. Ideally I would like to have 2 or 3 floating and dockable windows on the PC and a few screens on a phone. I will have to make slightly different UIs for both but the time line bitmap and the media window bitmaps should be reusable for the most part. I just need standard widgets for the most part though.
My needs are somewhere in-between that of a game and that of a regular boring old forms app except for the need to animate the waveform.
Does anyone have any suggestions and perhaps know these systems well enough to know if they have a good chance to do what I need?
I fear I would have to spend weeks learning each one just to see if they give me the capabilities I need.
Is IMGUI likely to eat the phones battery just to make the cursor blink?
Any tips would be most welcome.
Background
I work on the game Bitfighter. We're still compatible with OpenGL 1.1 and compile for OSX, Windows, and Linux.
We use vector graphics for everything, including text rendering and manipulation. We use a slightly-modified variation of 'FontStrokeRoman' from GLUT, which is just a bunch of static lines. We like this as it seems to perform very well, easy to rotate/scale/manipulate. We also allow for in-game chat so text is drawn on the fly.
Problem
We want to use more/different fonts.
We've found several other fonts we like, but they are all TTF-type fonts that are built as polygons (with curves, etc.) instead of strokes or spines. This brings up a few problems:
We'd have to use textures (which we've avoided so far in the game)
They're not easily resizable/rotatable/etc.
Performance is significantly less (theoretically?)
We've experimented with converting the TTF fonts to polygon point arrays and then triangulating the fill. This however has been difficult to render nicely - pixel hinting/anti-aliasing seems difficult to do in this case.
We've even experimented with skeletonize-ing the polygon fonts using libraries like 'campskeleton', so we can output a vector-stroke font (with not much success that looks good).
What should we do?
I know this question is somewhat general. We want to keep performance and text manipulation abilities but be able to use better fonts. I am open to any suggestion in any direction.
Some solutions could be answers to the following:
How do we properly anti-alias polygon-based text and still keep performance?
Do textures really perform worse than static point arrays? Maybe I have a faulty assumption
Can textured fonts be resized/rotated in a fast manner?
Something entirely different?
After some convincing (thanks Serge) and trying out several of the suggestions here (including FTGL that uses freetype), we have settled on:
Font-Stash which uses stb_truetype
This seemed perfect for our game. Rendering performance was comparable to the vector-based stroke font we used - textured quads really are not that slow, once generated, and the caching from Font-Stash helps immensely. Also, the use of stb_truetype allowed us to not require another dependency in the game across all platforms.
For what its worth, this solution was roughly an order of magnitude faster than using FTGL for true-type fonts, probably because of the caching.
Thanks for the suggestions and pointers.
Update
The Font-Stash link above was a fork of the original here. The original has since been updated, has added some of the features that the fork, and can allow different rendering back-ends.
I'm no OpenGL expert, or graphical expert in general.
And, really, Raptor, I -hate- to be the guy that says this, because I know how you feel right now.
I really hate to say it, but honestly, I'd just give TTF fonts a shot, using their textures and polygons as they were intended. I doubt that such a usage would truly be detrimental towards your performance these days. It would likely be more valuable to save time to use them as is, rather than spending time to experiment around for some clever solution that more fits your desires.
I doubt that text drawing using polygons/textures would be detrimental, whatsoever, to you performance. This especially applies for today's computers. How many years back, technologically, do you intend on supporting with your application? Or perhaps you wish to run it on the Raspberry PI as well? Or other mobile platforms that do not have high graphical capabilities? Support of any of these could, perhaps, invalidate my claims.
But, like I said, I really hate to be the guy that suggests you to trudge forward as is. Because, I've been there, asking for performance advice (sometimes over even tinier things) and just groaning when someone says 'forget about it, the compiler will handle it' or 'computers are so advanced you shouldn't worry about it'. I honestly hope that someone else comes in with experience, and a good answer for you. However, if not, I just want let you know: I cannot foresee the possibility that using TTF, as it was intended, would be detrimental whatsoever to your gameplay performance.
Did you try outline glyph decomposition using freetype FT_Outline_Decompose ?
Freetype is the tool of choice for font rendering and glyph outlines extraction. Hinting is supported and rendering modes allows you to specify that you want antialiazing, hinting, monochrome targets etc.
Freetype also has a built in glyph/bitmaps cache mechanism which may be useful.
Note : OGFLT seems to bridge the gap between freetype and opengl although I never has the chance to use it
I've always been inspired by dynamic, futuristic-like user interfaces. The best I can describe is a graphic interface such as in the latest Iron Man movies.
Although I wouldn't build a full blown application, I would like to make little snipplets of animations that I plan to make interactive. And maybe put them together someday to make something bigger. Admittedly, I will use for audio manipulation in the future but anyway, that's not the point since it's the animations/graphics I'm unsure of.
I know it's possible to make those kind of animations in Adobe After Effects. I'm just having a hard time thinking of the processes (artistically and programmability) to proceed.
While researching on this on my own I have acquired basic experience with OGRE 3D and Blender. I've imported and compiled meshes on OGRE, have been able to do basic things like move the meshes around which is about it.
I'm beginning to think I may be approaching this the wrong way and there are better tools or if 3D is overkill for those kind of animations when 2D would suffice and maybe provide a smoother experience.
I'm having trouble understanding the process and am wondering two things:
1.)The main thing I'm having trouble understanding is how to get still graphics to make animations? Do the meshes keep the timeline from a program like Blender then a graphics engine like OGRE reads the timeline and plays them?
Most importantly:
2.)Do I even need graphics (meshes)? Most of the interface are thin-border boxes, text and shapes of transparent LED-like colors that can move around dynamically to make that futuristic effect.
Please share your opinions, suggestions and anything you think might help me accomplish to develop those kinds of sexy eye candy! Thanks.
When you look at awesome futuristic UIs in movies, they are usually made of
basic primitives
desaturated colors, and/or one color tone
transparency
a cool font or two
high-tech text, graphs or similar
simple animations to make things look "alive", blinking lights/text and similar
a touch interface, of course
Maybe you can't do a lot about the touch interface, but the rest is really not hard graphics wise, it's a matter of carefully crafted artwork and combining simple elements in a cool way.
Also I would look into Adobe Photoshop and fancy texturing rather than Blender and fancy modelling, as you are looking for a fancy 2D UI, and detailed 3D models will not be that important. Playing around in photoshop (well, or GIMP if you want a free alternative) can help you develop your art skills, and help you get that high-tech, sci-fi look on a 2D surface.
You know, I would go as far as to suggest making some sci-fi wallpapers in the style you are after before trying to solve this problem in code. I think you will find that photo manipulation skills and an eye for art will help you here. And for gods sake, look at those movies (Iron Man, Minority Report etc.) that have those UIs you are aiming at, and analyze what exactly they are. Decompose them like I did in the list above.
As for the "which tools should I use?", I say the answer to that is fairly simple:
OpenGL
Photoshop (or GIMP if you are a starving student etc.)
A compiler & toolchain
A code editor/IDE
A cup
I see this is tagged C++, which is an excellent choice of programming language if I may say so.
Ogre is a full blown 3D engine, which is fine, but not exactly targeted at what you want to use it for. You might find that you struggle to get what you want done (disclaimer: I have not tried this in Ogre, and it might work well for this. Then again, when did you last see Ogre used in an audio manipulation program?). My advice is to learn good, simple OpenGL. That would give you complete power over your UI, not get in your way or limit you in any way. It is also cross platform, well documented, and used by tons of developers all over the world (also for audio manipulation applications). I can't see how you could possibly go wrong with it. The fun part is that it probably won't take you long to get advanced enough in it to start developing some pretty nice UIs. As I mentioned, it's more of an art problem than a coding problem.
The cup is for the coffee, by the way. :)
The easiest and most efficient way is to keep track of all your graphics data (meshes, animations, effects) in "media files" and load & play them in runtime. Though you'll be able to easily change your game without changing the code.
For example, you have a Diablo-like game and you wanna turn it to the future-style. You just need to rewrite some player and AI scripts and modify meshes/effects/sounds/animations. But if you've done those via code - it will be a new game from scratch.
I would suggest Ogre, but you already used that, so by my opinion, you are on the right track.
Look up 'billboards' in Ogre documentation, re: LED and 2D stuff.
So the title says it. I couldn't find any info on how actualy build effects into 3D game. I'll maybe stick to some engine later, but for understanding of this whole thing I would need to try it on my own for this time. I found a few about particle systems which may be the right way but any other connection between DirectX and particle systems on google gave results as 3DSmax and etc.
So I would be thankful if you would point me on some tutorials for this, or explaining it...
Last possibilitie would be pointing me on some simple engine focused on this thing (I don't really want to fight through tons of code and understanding how this engine works, I just need to see how they implement this FX stuff).
Thanks
PS: the other possibilitie would be if you know about good book discusing this. It can be more complex but apart from tutorial, books are usually wrote more basicly so this would be also nice way to go
First of all: particle effects are just one kind of effects, it's better you specify the word particle engine :p.
Secondly: search int he articles of Gamedev, it's really the best resource if you want things like this. You can find lots of articles and even better, tons of links, and useful information on the discussion boards. Two articles I can link to is the NeHe lesson about particles in OpenGL, it's not directx but NeHe tutorials for OpenGL are very good. I also found one for directx8 and VB (so a little bit older).
Keep in mind though that a particle engine is often a huge performance hit if you can't optimize it yourself, so try to look at open source game engines (e.g. OGRE) on how they implement it or even better, specific particle engines.
So I would be thankful if you would point me on some tutorials for this
You need to download microsoft DirectX SDK.
In addition to it, you should try NVidia SDK.
You may also try ATI SDK. Study them all.
In addition to them... there are couple of books on OpenGL: "Red Book", "Blue Book", Orange Book . "Computer graphics using OpenGL" by Francis Hill is also a very good one.
Get this info, and start reading.
how actualy build effects into 3D game
This question is too broad. There are lighting effects, particle systems, post-processing effects, physics (which are also effects), and even character animation is an effect. It is unclear what kind of effects you are talking about.
What do you think is better DirectX or OpenGL.
They are more or less equal. You can do same things in both of them. Try both and pick one you liked more. OpenGL is better for playing around and experimenting (because you can easily draw triangle without messing with hardware buffers), available on larger selection of platforms, plus GLSL is better than HLSL (because it doesn't "compile into assembly"). DirectX is geared towards performance from the beginning, available on XBox360, and 9th version was actually good. openGL is more "abstract" and DirectX is closer to hardware.
If you could use the factors as simplicity, area of usage, performance, number of examples and resources etc
If you want simplicity, you should forget about making game engine. You'll have to learn quite a lot of things if you want to deal with 3D.
Both DirectX and OpenGL are used for making 3d-related products.
You can get good performance with both DirectX and OpenGL, and get poor performance if you don't know what you're doing.
Both DirectX and OpenGL have insane amount of examples and books - just search for it. They weren't made yesterday, so enough information is already available.
You need to select goal, select platform, select your API, research available technologies, and start writing code. Wondering "which one is better" is a waste of time. 3D knowledge and algorithm are equally applicable to both APIs.
OpenGL is the best bet to learn I feel. Glut is available free of cost and has all the functions you need to implement a particle engine. Plus theres loads of sample code online. I like the way functions are . Easy to remember and use logically
The best books for learning D3D9.0c/D3D10 are by Frank Luna. Just put him in to amazon or google and you'll get results. He teaches how to build a fully-fledged game engine from scratch.
For those not familiar with Core Image, here's a good description of it:
http://developer.apple.com/macosx/coreimage.html
Is there something equivalent to Apple's CoreImage/CoreVideo for Windows? I looked around and found the DirectX/Direct3D stuff, which has all the underlying pieces, but there doesn't appear to be any high level API to work with, unless you're willing to use .NET AND use WPF, neither of which really interest me.
The basic idea would be create/load an image, attach any number of filters that can be chained together, forming a graph, and then render the image to an HDC, using the GPU to do most of the hard work. DirectX/Direct3D has these pieces, but you have to jump through a lot of hoops (or so it appears) to use it.
There are a variety of tools for working with shaders (such as RenderMonkey and FX-Composer), but no direct equivalent to CoreImage.
But stacking up fragment shaders on top of each other is not very hard, so if you don't mind learning OpenGL it would be quite doable to build a framework that applies shaders to an input image and draws the result to an HDC.
Adobe's new Pixel Blender is the closest technology out there. It is cross-platform -- it's part of the Flash 10 runtime, as well as the key pixel-oriented CS4 apps, namely After Effects and (soon) Photoshop. It's unclear, however, how much is currently exposed for embedding in other applications at this point. In the most extreme case it should be possible to embed by embedding a Flash view, but that is more overhead than would obviously be idea.
There is also at least one smaller-scale 3rd party offering: Conduit Pixel Engine. It is commercial, with no licensing price clearly listed, however.
I've now got a solution to this. I've implemented an ImageContext class, a special Image class, and a Filter class that allows similar functionality to Apple's CoreImage. All three use OpenGL (I gave up trying to get this to work on DirectX due to image quality issues, if someone knows DirectX well contact me, because I'd love to have a Dx version) to render an image(s) to a context and use the filters to apply their effects (as HLGL frag shaders). There's a brief write up here:
ImageKit
with a screen shot of an example filter and some sample source code.