I am new to C++ and I would like to know what the limitations are in graphics for a console application. For example---Could I create something as compicated as some of the
very colorful screensavers that have all kinds of splashes of color?? Could I draw lines
of changing color based on input strings??? I would appreciate any advice someone could
give me.
Thanks Doug
If you want to do some serious animation you'll pribably want hardware accelerated graphics (DirectX, OpenGL). If you just want simple images and animations a GUI app would do. As far as the console it's not really intended for more than text output but it can draw lines and change colors if you really want too.
However none of the three are limitations of C++ ... C++ as a language does not care about graphics that would be an OS limitation primarily and you'll find most of your drawing code however you go about it will be somewhat OS or hardware dependent unless you use a cross platform library with GUI or graphics support like QT, wxWidgets, OpenGL, etc.
As others have said, a console application is for text, not graphics! I don't know of any way (or reason) to do graphics in a console.
To do the kinds of things you are interested in (except maybe Windows screensavers) using Visual C++, I would recommend starting off with the SDL library. The Lazy Foo Productions website has an excellent series of game programming tutorials, and the first lesson gives you a step-by-step guide to build an app that displays stuff on the screen. It even has screenshots showing how to configure Visual Studio 2010, which is pretty important if you're new to this kind of thing.
SDL is free, cross-platform, and will let you (within your program's window):
draw pixels, lines, and rectangles in any color
draw text
draw images
make animations (by changing/redrawing the screen many times per second)
obtain keyboard input (including when keys are released)
It will also let you do 3D graphics with OpenGL, but that's another story.
You could, if you're very desperate- but certainly not platform-independently. From memory, the Windows API is quite good about letting you do a lot of crazy shit to it's console. However, it's probably better advised to get a genuine graphical API for this purpose, such as GDI, DirectX or OpenGL.
C++ does not have any standard facilities for drawing graphics in a console application. Any features (like changing the font color) will depend on your OS. I doubt you will find functions that do much more than changing the text color though. (For example, on Windows you would use system("color xx") to change the foreground and background color.)
Basically, if you want graphics you're going to have to abandon the console application and look for a graphics API.
Could I create something as compicated as some of the very colorful screensavers that have all kinds of splashes of color??
If by "splash" you mean "chunk of text", then yes. Otherwise no.
Could I draw lines of changing color based on input strings???
No, consoles are textual media.
If you want to try to do things to the console you need to use the Windows Console Functions. Standard C++ does not have any way to change console color.
Related
My situation
I want to build a cross platform application, with a gui, that displays a 3d view of some simple cubes, that the user can interact with. Qt seemed like a good tool for the job and I think I have the gui part sufficiently down for the most part. For the 3d part OpenGl or the qt/3d implementation seemed like the right tool, but it does not work. When I try to run the examples from Qt, that use a 3d view, they are unstable, they crash, show a black window and on the offchance, that I find one, that does work there is aggressive flickering and my entire system becomes unresponsive when I only try to resize it. I don't know what is wrong, I don't think I can do a better job, than the official examples and I don't think, that trying to debug the examples is the way to go. (If someone has an idea how to fix this tell me, but I don't even have an error message)
My question:
Is there a simple framework, that would allow me to display simple 3d shapes and include that in a Qt application. I don't need shadows, or reflections or transparency or anything more fancy, than ambient light. Just some solid coloured boxes I can rotate and click on. I think it would even be fine, if it ran on CPU rather than GPU. It would be nice, if I could keep using C++, but if it only exists in another language, what gives. I don't really want to build a framework from scratch. How could I include such a foreign framework in Qt?
I am using ubuntu 20.04 with intel graphics, but as I said, I want the resulting application to work on as many platforms as possible.
I am working on an application that uses Qt3D with then OpenGL renderer. Deploying the app to a handful of users, I found some severe issues with Intel Integrated Graphics, ranging from crash to rendering bugs like flickering. This unfortunately doesn't comes from Qt or OpenGL itself but more from how Intel implements their OpenGL drivers.
The crash bug seems to impact older intel chips, very few references of that apart some random minecraft FAQ on reddit: https://www.reddit.com/r/Minecraft/comments/48ktct/19_faqs/
But what is claimed there seem to align with what my users are experiencing.
The flickering bug has only been reported recently and I unfortunately don't have the right hardware to replicate it yet...
I know it's like random, not sourced information but I thought that personnal experience might help.
I used osgQt many years ago. It looks active still. I know the military likes them.
https://github.com/openscenegraph/osgQt
I would like to have a tool to debug 2D planar meshes. I would like to be able to display them and debug to be able to debug certain things.
Is there a widget (for any toolkit on Linux - QT, GTK+Cairo, ...) which would display the images, scroll them and zoom it. Is there any widget which would handle it (without need to implement zooming, scrolling etc. by hand)?
Side requirements:
Needs to work on CentOS 6
I need it for C++. Unfortunately changing the build system in my situation is harder then it sounds.
The Qt Graphics View is certainly a useful tool, it gives you scrolling, zooming, rotating easily. You probably want to learn the basics of Qt before. (and Qt is in C++).
Here's an off the wall suggestion.
This would be fairly easy to implement in a web browser. Web browser engines already have the base functionality for resizing and scrolling over images. You may need a little JavaScript to bind it together, of course.
So why not use WebKit? There are bindings for many of the leading toolkits (e.g. QWebView for Qt), so you could take your pick of which one you're most comfortable with.
Yes, it's overkill. But it's code you don't have to write, and time is money.
I'm a Rails/web developer with little experience with C++, so I'm not totally sure what direction to head in: I'm looking to build a simple simulator that I can use to test an algorithm I'm building that converts standard images to radial coordinates, and all I really need to be able to do is to plot points (which will represent LEDs) on a blank window and continuously refresh them (the LEDs blink). I don't want to build a gui; command line is fine, as I'll be the only person using the tool.
I'm not sure whether this is even possible or not... I did some Java programming years ago and I remember being able to pretty easily open a window and render images in it. Is there a C++ equivalent?
Thanks in advance!
What you are describing is a perfect fit for a GUI application, rather than command line, as far as I understand.
But if you want something really simple, and not spend some time learning a GUI development framework (MFC, Qt, WxWidgets, etc), you should check the following resources:
character based basic console graphics
some more advanced console graphics with blinking, box drawing, etc.
using full GDI graphics on console
It's not that easy in C++, because there is no standard way in doing this. It's not part of the language. There are a lot of frameworks though, some lightweight and some bloating. It also depends your platform. Anyhow, I think I would use OpenGL and do that calculation thing in a shader. That way you don't have to recompile and rerun all the C++ code. You can even do it in way that updates the GPU shader whenever you save your shader file giving you immediate results.
I have been using a few cross-platform GUI libraries (such as FLTK, wxWidgets, GTK++), however I feel like none fulfil my needs as I would like to create something that looks the same regardless of the platform (I understand that there will be people against building GUI's that don't have a native look on the platforms but that's not the issue here).
To build my controls, I usually rely on basic shapes provided by the library and make my way up binding & coding everything together...
So I decided to give it a try and do some opengl for 2D GUI programming (as it would still be cross-platform. With that in mind, I couldn't help to notice that the applications that I have written using wxWidgets & FLTK usually have a average RAM consume of 1/2MB, whereas a very basic openGL window with a simple background ranges from 6 to 9 MB.
This brings me to the actual question for this thread,
I thought that all the rendering of the screen was made using either opengl/direct (under the covers).
Could someone please explain or link me some sort of article that could give me some insight of how these things actually work?
Thanks for reading!
These multiplatform toolkits usually support quite a lot of backends which does the drawing. Even though some of the toolkits support OpenGL as their backend, the default is usually the "native" backend.
Take a look eg. at Qt. On Windows it uses GDI for drawing for its native backend. On linux it uses XRender I think. Same on Symbian and Mac. Qt also has its own software rasterizer. And of course there is an OpenGL backend.
So why the application using some of these GUI toolkits can take less memory than a simple OpenGL application? If the toolkit use the "native" backend, everything is already loaded in memory, because it is very likely that all visible GUI uses the same drawing API. The native APIs can also use only one buffer representing a whole screen in which all applications can draw.
However when using OpenGL you have your own buffer which represents the application window. Not to mention that an OpenGL application usually has several framebuffers, like z-buffer, stencil buffer, back buffer, which are not essential for 2D drawing, but they take some space (even though its probably the space in graphics card memory). Finally, when using OpenGL, it is possible that the necessary libraries are not yet loaded.
Your question is exceedingly vague, but it seems like you're asking about why your GL app takes up more memory than a basic GUI window.
It's because it's an OpenGL application. This means it has to store all of the machinery needed to make OpenGL work. It means it needs a hefty-sized framebuffer: back buffer, z-buffer, etc. It needs a lot of boilerplate to function.
Really, I wouldn't worry about it. It's something every application does.
Hello I am new to c++ and am wondering where to go about looking to print directly to the screen? For example the HUD interface that appears on laptops when you change the volume. I'm not really looking for any fancy graphics, just, say, a variable or info from a file.
I've tried googling but havn't come up with anything yet. So...where should I begin looking?
Thanks!
Under windows there are a few ways to do it. You could use DirectDraw Overlays (If the system supports them). Or you could create a layered window (WS_EX_LAYERED) and make everything but the bit you want to display transparent.
Pure C++ has only one screen interface, in the library. That's text-oriented. To do graphics, you need another OS-specific interface. So, you'd be looking at the API documentation for your OS.
BTW, the overlay graphics when you change the volume on your laptop are really special, IIRC. They're generated by your laptop itself, using System Management Mode - not the OS itself, and certainly not a program.