I am looking for a cross-platform solution for saving and viewing 3D scenes (visualizations of engineering simulation models and results) but there (still) doesn't seem to be much out there.
I looked into this almost 10 years ago and settled on VRML then (and started the project that eventually turned in OpenVRML). Unfortunately, VRML/X3D has not become anywhere near ubiquitous in the past decade.
Ideally a solution would offer a C++ library that could be plugged in to a 3D rendering pipeline at some level to capture the 3D scene to a file; and a freely redistributable viewer that allowed view manipulation, part hiding, annotation, dimensioning, etc. At least linux, mac, and windows should be supported.
3D PDFs would seem to meet most of the viewer requirements, but the Adobe sdk is apparently only available on Windows.
Any suggestions ?
The closest thing that I'm aware of is Collada.
Many 3D engines can read it, and most 3D design tools can read and write it.
I believe the Ogre engine has pretty good support.
If you are using OpenGL, GLIntercept will save all OpenGL calls (with the data they were called with) to a XML file. It's only half the solution, though, but it shouldn't be hard to parse it and recreate the scene yourself.
Take a look at Ogre3d.org. Its just an engine, you must program with it. But OGRE is probably the better (free/open) platform to develop 3D right now.
Related
I started working at this company that uses an 2D OpenGL implementation to show our system's data (which runs on Windows.) The whole system was built with C++ (using C++Builder 2007). Thing is, all the text they print there are pixelized when you zoom in, which I think happens because the text is a bitmap:
From what I know they use the same font files as Windows does. I asked around here on why this happens and the answer I got is that the guy who implemented it (which doesn't work at the company anymore) said fonts on OpenGL are hard and this was the best he could do or something like it.
My question is: is there any simple and effective way to make the text also a vector (the same way those lines in the picture are?) So when I zoom the camera, which happens a lot, they don't pixelize. I have little knowledge of OpenGL and if you have some guide and/or tutorial related to this to point me towards the right direction I'd be very thankful. Basically any material would be great.
Most of OpenGL text rendering libraries come to this: creating bitmaps for the fonts. This means you are going to have problems with scaling and aliasing unless you do some hacks.
One of the popular hacks is Valve's approach: Chris Green. 2007. "Improved Alpha-Tested Magnification for Vector Textures and Special Effects.". You use signed distance field algo to generate your fonts bitmap which then helps you to smooth the text outlines on scale during rendering. Wikidot has the C++ implementation for Distance field generation.
If you stick to NVidia specific hardware, you can try the NVidia Path extension which allows you to render graphics directly on GPU. Remember, it is a NVidia only thing.
But in general, signed distance field based approach is the smoothest and easiest to implement.
BTW, freetype-gl uses Valve's approach and also the modern pipeline.
You can try freetype-gl its a library for font rendering in OpenGL.
The issue with using fonts in OpenGL is that they are handled inconsistently across platforms, and that they have minimal support. If you're willing to go with a helper library for OpenGL (SDL comes to mind), then this behaviour will likely be wrapped, meaning that you merely need to provide a suitable font file for them to use.
You may try out FTOGL4 , the fonts for OpenGL4
I'm quite new to the whole field of GIS, and I'm about to make a small program that essentially overlays GPS tracks on a map together with some other annotations. I primarily need to allow scanned (thus raster) maps (although it would be nice to support proper map formats and something like OpenStreetmap in the long run).
My first exploratory program uses Qt's graphics view framework and overlays the GPS points by simply projecting them onto the tangent plane to the WGS84 ellipsoid at a calibration point. This gives half-decent accuracy, and actually looks good. But then I started wondering. To get the accuracy I need (i.e. remove the "half" in "half-decent"), I have to correct for the map projection. While the math is not a problem in itself, supporting many map projection feels like needless work. Even though a few projections would probably be enough, I started thinking about just using something like the PROJ.4 library to do my projections. But then, why not take it all the way? Perhaps I might aswell use a full-blown map library such as Mapnik (edit: Quantum GIS also looks very nice), which will probably pay off when I start to want even more fancy annotations or some other symptom of featuritis.
So, finally, to the question: What would you do? Would you use a full-blown map library? If so, which one? Again, it's important that it supports using (and zooming in and out with) raster maps and has pretty overlay features. Or would you just keep it simple, and go with Qt's own graphics view framework together with something like PROJ.4 to handle the map projections? I appreciate any feedback!
Some technicalities: I'm writing in C++ with a Qt-based GUI, so I'd prefer something that plays relatively nicely with those. Also, the library must be free software (as in FOSS), and at least decently cross-platform (GNU/Linux, Windows and Mac, at least).
Edit: OK, it seems I didn't do quite enough research before asking this question. Both Quantum GIS and Mapnik seem very well suited for my purpose. The former especially so since it's based on Qt.
See GDAL www.gdal.org for a solid background library for raster formats and manipulation, and it incorporates PROJ.4 for transformations.
QGIS relies on GDAL for some data import, amongst other things.
I'm playing around with OpenGL and I'm finding myself writing code that I feel like I shouldn't have to write.
GLU and GLUT are nice but not really what I'm thinking of.
Code to load .obj models (vertex and normal vectors) from Blender and render them.
Code for collision detection.
Code for navigation/camera stuff.
Code for simple terrain generation.
But at the same time I feel like a full-blown game engine is more than I need.
Are there any good libraries built on top of OpenGL that I could take advantage of, perhaps to create relatively simple games? I don't necessarily need all of the items listed above. Those are just examples of what I'm thinking of.
Yes.
I can't be more specific as I don't write my own game engines but I do have a list of libraries online at this location, most of which sit below being a full engine.
Ogre
Irrlicht
openscenegraph (replaces performer)
Depending on how much you need, one of these toolkits / libraries might suit your purpose.
GLUT - OpenGL Utility Toolkit
Ogre3D - OGRE Object Oriented Graphics Library
Open Inventor - OpenGL toolkit for scene management created by SGI
Performer - OpenGL toolkit for real-time rendering created by SGI
I learnt my opengl stuff from GameTutorials and Gamedev. Unfortunately gametutorials are no longer a free selection of tutorial (there's some examples) but they were good. Coupled with SDL, you would have code to do everything you wanted - and you'd be able to understand what is going on under the covers, something I find is very useful later on (if, for example you wanted to write HTML5/WebGL code later).
A lot of the game engines aren't as well documented as I'd like (well, weren't a few years back when I was looking), but they might still do what you need. Sourceforge has many, including Ogre3d, Irrlicht, and CrystalSpace.
In general I agree with your sentiment. There is a school of thought that says that programming should consist of pluggable modules. Once youve written an OpenGL app, you should be able to grab a model loader, and/or a skeletal animation engine and plug them in.
The depressing thing is, most of the game engines on that list (that Ive looked at) are all or nothing propositions. They provide an entire framework and do not really take into account the more common real case scenario.
That said, all is not lost. A lot of those engines package up a number of other 'utility' libraries into their distribution. With a bit of patience it is possible to piece together the component libraries yourself: OpenAL for the sound, Freetype for font rendering, libpng, libjpeg etc for image codecs
I've been looking for a good cross-platform 2D drawing library that can be called from C++ and can be used to draw some fairly simple geometry; lines, rectangles, circles, and text (horizontal and vertical) for some charts, and save the output to PNG.
I think a commercial package would be preferable over open source because we would prefer not to have to worry about licensing issues (unless there's something with a BSD style license with no credit clause). I've looked at Cairo Graphics which seemed promising, but the text rendering looks like crap out of the box, and upgrading the text back-end brings us into murky license land.
I need it for Windows, Mac and Linux. Preferably something fairly lightweight and simple to integrate. I've thought about Qt but that's way too heavy for our application.
Any ideas on this would be awesome.
Try Anti-Grain Geometry. From the description:
Anti-Grain Geometry (AGG) is an Open Source, free of charge graphic library, written in industrially standard C++. The terms and conditions of use AGG are described on The License page. AGG doesn't depend on any graphic API or technology. Basically, you can think of AGG as of a rendering engine that produces pixel images in memory from some vectorial data. But of course, AGG can do much more than that. The ideas and the philosophy of AGG are:
Anti-Aliasing.
Subpixel Accuracy.
The highest possible quality.
High performance.
Platform independence and compatibility.
Flexibility and extensibility.
Lightweight design.
Reliability and stability (including numerical stability).
Another one: Skia. Used in Android and Chrome, under active development, HW acceleration.
Have a look at SFML. It's open source but the license is very permissive.
Drawing simple shapes
Displaying text
Antigrain does high quality primitive rendering and seems to be able to render true type fonts and has a commercial license available upon request.
http://www.antigrain.com/
Have you tried FLTK? It is lightweight, cross-platform, has support for 2D/3D graphics and comes with a good widget set (including a charting component). The API is simple and straight forward.
Use SDL
There is also libgd - simple one, but well-written.
Regarding Cairo Graphics, I can't believe it renders text that looks bad. If you are particularly concerned about text rendering, State of the Text Rendering from Jan 2010 gives quite good overview.
I use CImg: cross platform (self contained single header file), simple, concise.
PNG is not natively supported but can be handled if ImageMagick is installed (see supported formats).
See also this related question.
You might use Allegro 5 (since SDL and SFML are mentioned). This provides all of the platforms you require (and more) and can render shapes and save to PNG. Version 5 has a much improved API and hardware acceleration. With any of these low level cross platform libraries you'd have to find your own charting solution.
I put some notes on my blog about Allegro and using it on the Mac.
OpenGL?
I would go for AGG or Cairo.
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.