I need to write a method that check polygon mesh quality. In particular I need to detect T-junctions. Do you know where to start?
Thanks.
Related
I am using a MPU6050 IMU to map the path of a device (with starting point as origin). For this I need to convert the accelerometer and gyroscope readings into (Cartesian)co-ordinates. I think I need to continuously sample the accelerometer readings and go on adding (integrating) the sample to the previous point for each axes respectively. At startup the previous point will be (0,0,0).
I know this on paper. But I dont think it will be that simple. How will I know when the device is moving backwards, ie towards the origin?
The MPU6050 provides accleration and gyro reading in all axes. I used this to fetch the values. But I dont know how to continue. So what I need is an "Inertial Navigation system" which takes acceleration and angular velocity vectors as well as the current position as input and returns the new position. I know this will have errors, but I am not concerned about that for now.
If someone can guide me in this that would be great. Any hints or pointers will be appreciated.
Kiran G
Kiran,
To answer that question it would be good to know what kind of Gyro are you using or willing to use. It is very different depending if the output is an analog signal (voltage or current loop) or if that is any kind of (normally serial) bus.
Please note that most likely you will have also to filter the signal based on the expected dynamics of the environment.
I've been studying 3D graphics on my own for a while now and I want to get a greater understanding of just how everything works. What I would like to do is to create a simple game without using DirectX or OpenGL. I understand most of the math I believe, but the problem I am running up against is I do not know how to get control of the pixels being displayed in a window.
How do I specify what color I want each pixel in my window to be?
I understand I will probably run into issues with buffers and image shearing and probably terrible efficiency problems, but I want to create my own program so that I could see from the very lowest level, of the high level language, how the rendering process works. I really have no idea where to start though. I've figured out how to output BMPs, but I would like to have a running program spitting out 20+ frames per second. How do I accomplish this?
You could pick a environment that allows you to fill an array with values for pixels and display it as a bitmap. This way you come closest to poking RGB values in video memory. WPF, Silverlight, HTML5/Javascript can do this. If you do not make it full screen these technologies should suffice for now.
In WPF and Silverlight, use the WriteableBitmap.
In HTML5, use the canvas
Then it is up to you to implement the logic to draw lines, circles, bezier curves, 3D projections.
This is a lot of fun and you will learn a lot.
I'm reading between the lines that you're more interested in having full control over the rendering process from a low level, rather than having a specific interest in how to achieve that on one specific platform.
If that's the case then you will probably get a good bang for your buck looking at a library like SDL which provides you with a frame buffer that you can render to directly but abstracts away a lot of the platform specifics issues. It has been around for quite a while and there are some good tutorials to give you an idea of whether it's the kind of thing you're looking for - see this tutorial and the subsequent one in the same series, which should be enough to get you up and running.
You say you want to create some kind of a rendering engine, meaning desinging you own Pipeline and matrice classes. Which you are to use to transform 3D coordinates to 2D points.
When you have got the 2D points you've been looking for. You can use say for instance on windows, you can select a brush and draw you triangle values while coloring them at the same time.
I do not know why you would need Bitmaps, but if you want to practice say Texturing you can also do that yourself although off course on a weak computer this might take your frames per second significantly.
If you aim is to understand how rendering works on the lowest level. This is with no doubt a good practice.
Jt Schwinschwiga
provided GPS will not work precisely in closed environment like rooms etc,I m interested to know whether Accelerometer can be used to find the position of object relative to certain point? If not then what other technology iphone4 provides to cater it?
Thanks
The accelerometer cannot reliably provide location information, even with the aid of the gyroscope. GPS is the best you are likely to get.
OTOH, work-arounds abound in the augmented-reality space. Consider the ARDefender game.
I'm looking for a library to detect when ball hit in a audio of a tennis match.
I read this topic but I think there is a suite library for this job.
please guide me
tanx
I doubt that there is a library for this specific task. You can probably implement something from scratch though, using a sliding FFT to generate a power spectrum and some kind of simple template matching in the frequency domain.
I'd like to implement an old film effect on pictures. Does anyone know a library or even the rare maths involved? I'd like it to cope with red shift for over-exposition and the rest. Even if you don't know the maths or a library, a pointer to any technical doc will be appreciated.
Clarification: I need to write these routines for a project of my own. I'd like to know what kind of processing has to be done and how. Doesn't matter the environment and system, I just need some hint on how process RGB data
You mention Magic Bullet from Red Giant Software in your comments. There's an impressive amount of image processing know-how behind the development of Magic Bullet. You'd probably have an easier time implementing a host interface for After Effects or Final Cut Pro plug-ins and using Magic Bullet.
If you want to see some source code in action, examine the open source projects that do image processing like GIMP, CinePaint, FreeFrame, etc.
You could try with as3 bitmapdata noise function http://livedocs.adobe.com/flash/9.0/ActionScriptLangRefV3/flash/display/BitmapData.html#noise%28%29
If you can find a plugin for Paint.Net, I'm sure you could just use that dll in your program. Is this the sort of thing you're looking for?
Rare maths?
Create several different transparent PNGs with scratch and dust marks on it. Take a pic, adjust the hue, saturation and brightness (algorithms for this aren't that complex) to fade out the pic, then overlay one to many of the scratchy PNGs. The more scratch/dust PNGs you have, the more random the effect you can create.
Not much math here IMHO.