I have a UI (used Qt creator) that I am working on that creates opengl models at runtime, such that when I click a button it draws a cube or any other model.
Can anyone please show me an example of how the c++ container class std::vector can be used for this in Qt ?
Why do you want to use std::vector in Qt. Are they pure C++ objects. Look into QList, QVector and variants (they also offer STL like iterators).
I can think of no reason why you cannot use std::vector in a Qt project.
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before I used Qt and customized my own Widget which is inherits from QGLWidget
i used OpenGl in standard projects and free glut.
by doing this, I used glutBitmapChracter but now in Qt there is no need to manage windows because I created customize widget with gui.
so how can I draw text on the widget?
if I want to include the free glut and use glutBitmapCharacter I nedd also to init the glut and im getting confused?
is there any other way or do I have to use external library?
You are using a QGLWidget and want to draw 2D text on top of the 3D scene?
glutBitmapCharacter should still work in a QGLWidget, just like other GL library code. I do not think you need to call glutInit to use the GLUT character drawing functions.
Or you could use the Qt 2D text drawing methods (QPainter) to draw text on top of your QGLWidget. A Qt book or online documentation will explain how to do this. (I have the books on Qt programming by Blanchette and Summerfield, and can recommend them.)
Hope this helps.
I am working on OpenGL to create a GUI .I want to create some tabs which will help me to display different things in different windows. How is this possible using OpenGL? I read in some articles that we can use QT for that. Since I have already developed some of the GUI part in OpenGL using GLUT library ,is it possible to use the same code in QT? If so brief me how to make settings for OpenGL libraries in QT creator.
In my GUI I am trying to create a Car which is following a track.
I think you might be mixing some things up: OpenGL is a API with which you can instruct drivers to draw visual primitives, like lines, boxes, 3D triangles, pictures from buffer onto a render plane.
GLUT is a library that gives you a minimal environment around that, ie. it handles creating a window etc.
Neither of them are high-level UI description tools. Qt is really most likely what you want, as it will not only give you things like tab widgets etc, but also a feature-rich framework to do things like defining what should happen when you click a button, close a window etc.
There's a lot of examples of OpenGL usage within Qt widgets. In fact, a lot of visualization frontends use Qt and OpenGL. Qt has extensive documentation on how to generate OpenGL contextes and draw inside Qt applications.
I have been looking far and wide to find out how, if it’s possible, you can fill a particular area in a QML screen with an OpenGL context and do custom OpenGL only in that context. I’ve seen plenty of demos where the QML components like buttons, etc lay on top or below a screen-wide OpenGL context (as is typically required by games), but I’d like to be able to situate several distinct OpenGL contexts within QML and have the QML file define how large they are, where they are positioned, etc.
Now, since Qt 5 is all OpenGL under the hood, it makes me wonder if using a Canvas element with custom drawing via javascript could result in similar rendering performance as custom OpenGL? This would be a meaningful alternative but it’s not clear to me how the javascript drawing is handled via runtime compared to custom OpenGL drawing.
What is it that you want to draw? QQuickPaintedItem may be the simplest way to go about it. When you're using QOpenGLFramebufferObject as the target, the painter will use OpenGL to paint the texture. It might be easier than writing your own OpenGL code if all you're doing is 2D.
I'm currently trying to get Qt working with my existing program.
I'm using SFML for creating my OpenGL rendering context and creating the window. The things I tried out so far however always create a separate window by Qt instead of just rendering into the existing context.
Is there any way I can force Qt to render to an already existing OpenGL context?
I've not looked into the specifics, but this has been done for openage.
I think looking at the documentation for QQuickRenderControl might be a good place to start.
Qt wants full control over the windows and the event loop, so this will not work (unless you put a lot of effort into it). Your best bet is using a QGLWidget and emulate the event management of SFML with that, so that your application effectively runs on Qt. It is very well possible to render Qt widgets into a OpenGL window (Qt has a OpenGL widget backend) but this must be still managed by Qt itself.
I know QML is fine for making interfaces in Qt but, how about the layouts of these interfaces?
I want to make an application looking like similar to, for example, spotify. But I want layouts to be "movable" and completely customizable by the user. Is it difficult to make that through QML? Should I better use the usual Qt layout stuff (gridlayout, graphicwidgets, graphic items...) ?
Layout of QML elements works by using anchors attached to other QML elements. You can change anchors at runtime by using Javascript. Building a flexible GUI with QML is possible but challenging because the documentation is sparse in some areas, and debugging is difficult.
Qt Quick Layouts were added in Qt 5.1. They work similarly to layouts in standard widget-based Qt and are usable in Qt Creator.