• Free and open source
• Fast DWT shader using GPU
• Modifiable filter kernel and boundary extension scheme
• Completely integrated in JPEG2000 codec, JasPer
• Also as standalone C++ Class, with example usage. Easy integration into your own applications.
• Can be used to handle geometric, image, or any other data in 2D grid structure.

Version : 1.0 (Released on 18 July 2006)

System Requirement

Hardware: Pentium III or above, 128MB RAM, installed with graphics boards including nVidia GeForce FX, Quadro FX or above (large video RAM preferred)
OS: Windows 2000/XP, with OpenGL 1.4

Installation Instructions (source code)

1. Download the zip file and extract to a directory, e.g. c:\jasper
2. Start demo.dsw project file with Visual C++
3. Compile and run the executable demo.exe

C++ Class API:

// DWT transform, suitable for tasks that only do forward or inverse DWT once
// detail information about the parameters please see comment inside the cpp file
bool dwtallinone(extmode mode, int imagewidth, int imageheight, float* imagebuffer, int level, bool isforward, bool initGL, bool initGLEW);
bool dwtallinone(extmode mode, int imagewidth, int imageheight, float* imagebuffer, int beg_level, int end_level, bool isforward, bool initGL, bool initGLEW);

// initialize and feed in the buffer, both forward and inverse dwt are available for call after return
bool initialize(extmode mode, int imagewidth, int imageheight, float* imagebuffer, bool initGL, bool initGLEW);

//render input image data to texture
bool createImgTex( float *imgbuffer);

// the forward and inverse dwt function
bool forwarddwt(int level);
bool inversedwt(int level);

// retrieve the transformed buffer back
void getbuffer(float *myfloatbuffer);

There are 2 major ways to use this class.

1. For those who need to do either forward or inverse DWT only once. You only need to call the function dwtallinone() that handles everything and performs flexible levels of transform on your data. (Please note that levels start from 0, i.e. level 0 transform gives you 4 subbands, and level 1 will further process on the LL subband of level 0)
   
   e.g. do 2 levels of forward DWT to the imgbuffer
   
   imgbuffer=(float*)malloc(imgwidth*imgheight*3*sizeof(float));
   
   CDwtObj * mydwtobj = new CDwtObj;
   mydwtobj->dwtallinone(symper,imgwidth,imgheight,imgbuffer,2,true,true,true);
   delete mydwtobj;
   
   
   
2. For those who need to get more control of the tranform process and do some processing to the data in the wavelet domain. Please use initialize(), forwarddwt(), inversedwt(), createImgTex() and getbuffer().
   
   e.g. data processing in the wavelet domain
   
   imgbuffer=(float*)malloc(imgwidth*imgheight*3*sizeof(float));
   CDwtObj *mydwtobj=new CDwtObj;
   ......
   
   mydwtobj->initialize(symper,imgwidth,imgheight,imgbuffer,false,true);
   mydwtobj->forwarddwt(0);
   mydwtobj->forwarddwt(1);
   mydwtobj->getbuffer(imgbuffer);
   
   // do my processing to imgbuffer in the wavelet domain
   ......
   
   // reinput the updated buffer
   mydwtobj->createImgTex(imgbuffer);
   
   // inverse transform back
   mydwtobj->inverse_dwt(1);
   mydwtobj->inverse_dwt(0);
   mydwtobj->getbuffer(imgbuffer);
   
   delete mydwtobj;