Draw geometric shapes in c++ without using opengl - c++

I'm looking for a simple library that can create and draw some geometric shapes without using openGL or directX and also have documentation.

just gdi would be enough i guess
https://learn.microsoft.com/en-gb/windows/win32/api/wingdi/nf-wingdi-ellipse?redirectedfrom=MSDN

You could use any GUI library, like Gtk, Qt, Motif, etc. ...
If you are on Linux, you could draw on screen directly with X11.

There's a lot of 2D graphics library, but under the hood most of them use OpenGL, so technically you still use OpenGL but not directly (which is probably what you meant).
Some of them:
SFML
SDL
Skia
Cairo
As frederic mentioned you can also use some GUI libraries, since most of them have something like Canvas (the name can vary) which allows to draw shapes very easily.

Related

Most efficient way to draw rectangle to screen

Essentially I want a border-less, black window which I can set the location and size of./
I then want to draw a filled white polygon given four points.
I say efficient, as I am currently using OpenCV to draw which I believe is every inefficient. I want to be able to change the points and have it redraw with new points at least 30fps.
My target platform is Windows with C++.
Does anyone know the quickest way to achieve this, maybe with a small library?
I would recommend you use openGl eg via the GLUT library.
The easiest way to do this will be to use DirectX. You can create, resize, and reposition the window with the Windows API and render into it with DirectX. DX has a much more accessible API than OpenGL, because OGL is full of implicit globals and weak typing, and the support libraries like GLUT are terrible C hackery as well, whereas DX is easy to whip up RAII with a couple of custom deleters and is object-orientated.
You can also use, if on Vista or later, Direct2D, which is more designed for simple 2D rendering.

Can I draw geometric primitives with OpenGL using anything other than GLUT?

I know GLUT's quadrics, I used it in a few programs when I was in school. Now I'm working on a real world application and I find myself in need of drawing some geometric primitives (cubes, spheres, cylinders), but now I also know that GLUT is a no longer supported and it's last update was in like 2005. So I'm wondering if there's anything other than GLUT's quadrics to draw such geometric shapes. I'm asking if there's anything made before I go ahead and start making my own from vertices arrays.
Yes, you can! You can use the native API of the OS to create a window with OpenGL capabilities.
The advantage of GLUT is that is makes this task easier and is a cross-platform solution.
There are other cross-platform libraries that are more complex to work with but provide the same functionality, like Qt.
NeHe has a huge amount of examples that use several different technologies to accomplish what you are looking for. Check the bottom of the page.
Here is a demo for Windows that creates a window and draws a simple OpenGL triangle inside it. This demo removes all the window frame to give the impression that a triangle is floating on the screen. And here is a similar demo for Linux.
GLUT is just some conveniece framework that came to life way after OpenGL. The problem is not, that GLUT is unmaintained. The problem is, that GLUT was not and never will be meant for serious applications.
Then there's also GLU providing some primitives, but just as GLUT it's merely a companion library. You don't need either.
The way OpenGL works is, that you deliver it arrays of vertex attributes (position, color, normal, texture coordinates, etc.) and tell to draw a set of primitives (points, lines, triangles) from those attributes from a second array of indices referencing into the vertex attribute arrays.
There used to be the immediate mode in versions prior to OpenGL-3 core, but that got depreceated – good riddance. It's only use was for populating display lists which used to have a slight performance advantage if one was using indirect GLX. With VBOs (server (=GPU) side vertex attribute storage) that's no longer an issue.
While GLUT has not been maintained, FreeGLUT has. There are still several alternatives though.
GLFW is a cross-platform windowing system which is easy to get up and running, and also provides the programmer with control of the main application loop.
SFML has support for many languages and also integration capabilities with other windowing schemes, in addition to being cross-platform.
Finally, Qt is another, popular, cross-platform windowing framework.
Now I'm working on a real world application and I find myself in need of drawing some geometric primitives (cubes, spheres, cylinders),
Actually, I don't remember anything except glut that would provide generic primitives. This might have something to do with the fact that those generic primitives are very easy to implement from scratch.
You can use other libraries (libsdl, for example, or Qt) to initialize OpenGL, though.
Most likely if you find generic library for loading meshes (or anything that provides "Mesh" object), then it will have primtives.
is a no longer supported and it's last update was in like 2005
Contrary to popular belief, code doesn't rot and it doesn't get worse with time. No matter how many years ago it was written, if it still works, you can use it.
Also there is FreeGLUT project. Last update: 2012.

Fast C++ Graphics (as in programming time)

I've played around with GLUT, but I've also read about SDL and one or two other graphics libraries. All I want to do at this point is 2D work. For what I'm doing right now, pixel by pixel plotting is all I need (say, plot(x,y,color) or something of the sort), but in the future I would appreciate the use of sprites. I've given point plotting a go with GLUT but it's rather non-intuitive coming from a B.A.S.I.C. background.
I work on both Ubuntu and Windows, so solutions for both systems are welcome.
SDL is probably a good choice; another option to look at would be Qt (just subclass a QWidget and override its paintEvent() method and do your pixel plotting inside that). Qt can also provide windowing/infrastructure support for OpenGL graphics if that's your preference.

Blitting zoomed images using SDL

Is there any way to Blit a zoomed (in) version of a certain image/sprite using SDL? (Besides manually saving a zoomed version of the image..)
Thanks :-)
Not with the SDL API itself.
I think there exist libraries (for SDL) who support zooming (so called resizing).
EDIT: http://www.ferzkopp.net/joomla/content/view/19/14/
Generally speaking, SDL isn't suitable for graphics that require real-time rotations and zooming. For that, you'd need an library based around an accelerated API such as DirectX or OpenGL. I understand that SFML meets this requirement.

Drawing strings in OpenGL

What's the quickest, easiest way to draw text in standard OGL ??
Text is surprisingly involved in OpenGl
Take a look at this example from NeHe
OpenGL does not support drawing text. You need to use some library to render text to bitmap and then you can use OpenGL to render the bitmap. Freetype2 and Pango are good cross-platform low level solutions. Game programming libraries such as ClanLib and GUI libraries such as Qt may also have their own ways for rendering text.
It depends on the framework you are working on like the one above me said. for example, SDL is multi-platform and one can draw text using a special lib inside SDL:
http://gameprogrammingtutorials.blogspot.com/2010/02/sdl-tutorial-series-part-6-displaying.html
If you're using glut look at the following functions:
glutStrokeString,
glutBitmapString
in glut documentation..
Use textures. Each character is a textured quad, and texture coordinates enclose the specific characters.
Then, you can affine using display lists, generating raster representing string at runtime, outlining, blending...
You can use a platform specific OpenGL API (i.e. wglUseFontOutlines), but I think it will be deprecated since OpenGL 3.2.
OpenGL does not support text rendering directly. You have a variety of options:
Some OS bindings, such as WGL and
AGL, do have limited font support
(mostly they render system fonts
into bitmaps for use in Open GL).
The GLUT toolkit (and similar
toolkits) also has some font support
(bitmap and stroke).
You can use a
library such as FreeType (mostly a
font renderer, you still may wish to
use something like Pango for text
layout).
You can use simple textured
quads (this is effectively what
Quake 1 did).
Depends on what framework you are using. One common method is to render text to an offscreen buffer and use that as a texture.