Im trying to do a screen-flashing application that flashes the screen depending on the audio(like an audio visualizer, but instead of a visualization like bars or something like that, just flash the screen).
I already made the music player and know how to make the widget get full screen and change color(which will flash), but I dont know how to detect the (I think it's audio-card)buffer is full, because when it is full I would change the color of the widget, and this would be really super fast, so the screen flashes super quickly.
Any ideas on how to detect if the buffer is full, or any other approach I might pursue to achieve my goal?
Thanks beforehand.
Have you checked the SoundMixer Class computeSpectrum method? It doesn't give you a buffer info rather it returns info about the sound being played that you can use in order to represent the sound graphically.
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I want to make a game (something like theses) in C++ (Visual C++). Now a graphic game needs to refresh its picture quite often.
I can print around 20 blank lines. This method is unefficient and quite "laggy". What I need is something fast and efficient and that cause no memory problem because the game will process a lot of data (like mouvements, scores, coins...).
I've also tried to use system('cls'). This is quite bad because can "kinda" gives the player an epileptic attack!
Is there a better solution??
Thanks.
The command line has no image output. The only way you can fake it on the command line is the way you have described it.
The way to make a game efficient is to create a window yourself and then draw with DirectX or OpenGL something into that window. Then you can clear it and redraw it. This might not satisfy you at the moment, as it sounds more like a quick project. But in the long run, you will not be happy to "draw" on the command line if you search for efficiency.
I am working on drawing in the sliceViewers, which contains a RenderWindow. But if I enlarge or diminish the window, or change the layout of my module, the drawings become not fit. In other words, the drawing is misplaced when the sliceViewer size is changed.
And what I want is to monitor the size of the sliceViewer in realtime. Once it is changed in any scenrios, I rerender the drawing with the saved data.
I have searched something like observer of vtk or QtObject::connect(), but don't know whether they are really useful or not. Can they help or there is other method?
Thanks in advanced.
What I need to do is create a program that overlays the whole screen and every 30 seconds the screen needs to flash black once.
the program just needs to be on top of everything, doesn't have to work over the top of games, but wouldn't say no if it did!
But i've got no idea where to start. Ideally the solution would be cross-platform for both windows and osx.
Does anybody have any ideas about where I should start or could whip up a quick demo?
OpenGL (you tagged it as such) will not help you with this.
Create a program, that overlays the whole screen,
The canonical way to do this is by creating a decorationless, borderless top level window with some stay-on-top property being set.
and every 30 seconds the screen needs to flash black once.
How do you define "flash back once"? You mean you want the display become visible for one single vertical retrace period or a given amount of time? Being the electronics tinkerer I am, honestly, I'd do this using a handfull of transistors, resistors and capacitors, blanking the analog VGA signal.
Anyway, if you want to do this using software, this is going to be hard work. If you'd do this using the aforementioned stay-on-top window, when you "flash" it away, all the programs with visible output would receive redraw events, which to process would take some time. In the best case scenario the system uses a compositing window manager which can practically immediately show the desktop. Without a compositor its going to be impossible to "flash" the screen.
Ideally the solution would be cross-platform for both windows and osx
A task like this can not be solved cross plattform. There's too much OS dependent work to do for this.
I presume this is for some kind of nerological or psychological experiment. I think doing this using some VGA intercepting circurity would be actually the easier, quicker to implement solution. I can help you with that. But I think there's another StackExchange better suited for this. Unfortunately digital display interfaces (DVI, HDMI and Display Port) use a complex line code scheme, which can not be blanked as easily as VGA, so you must have a computer capable of analog (=VGA) output and a display with a VGA input.
I need to implement a simple sound editor with a specific signal processing function.
I want to display the sound information vertically as a large picture - 1024 x [large height].
So I'm looking for Qt's best way to implement low-cpu-consuming vertical scrolling similar to web-browsers scrolling.
You need to create a custom widget by overriding it's paintEvent().
Have a look at this self-explanatory example on how to create a following widget.
A normal QScrollArea will give you what you want 99% of the time. But you're wanting to create a bitmap of potentially massive size, and you want to store it in RAM - you will quickly run out of space.
You are probably going to need a need a system where you save the image to file, and use the scroll area's bounds to intelligently load it's contents from the file (and a certain size around it to make it smooth) - Qt does not provide this. This is hardly groundbreaking stuff, so a web search for "scrolling very large images" or something similar should give a smart result.
If your intention is to plot STFT data, then you can easily adopt one of the widgets in the QWT library:
http://qwt.sourceforge.net/
Anyway, take a look at it, it is a great source of inspiration and the code is available...
I am working on a game which would take touch gestures as inputs. Now, i would like to display the path/gesture as the user draws it. Can someone please tell me how to do this in cocos2d?
I tried to override the draw method and used ccDrawPoint(). But the point just keeps following the touch. I guess this is because the previous drawing is getting overwritten.
Can you tell me where i am going wrong here or suggest a better way to implement this?
i found a solution with CCRenderTexture sample test in cocos2d. Though i could not find enough documentation on it, but the sample code is enough for a start.