Watch a demo from my application

Check this out.

Odd Magic Square NxN C++ code

The blogger interface is stupid it keeps formatting my input so I am attaching the whole cpp file. Get the C++ Code. Ofcourse rename the file remove the .zip extension

Magic Squares Algorithm & C++ implementation

Hi all,
This time around its something a bit tricky generating an odd magic square. Details are given everywhere. The wiki entry is sufficient, check it out http://en.wikipedia.org/wiki/Magic_square.

I base on the same logic which is commonly followed the one up one right stepping strategy. Here is the pseudocode,

 
//n is the dimension of magic square for a 3*3 square n=3; 

int magic[n][n]={0};

curRow=0, curCol=1;

oldRow=0, oldCol=0;

count =0;

for(i=1;i<=n;i++) 

{    

   for(j=1;j<=n;j++)      

   {       

      //See if we are into an empty cell       

      if( magic[curRow][curCol]==0 )       

      {           

          magic[curRow][curCol] = ++count;       

      }     

      else 

      {        
  
         //Move down from the previous row but keep the same column           

         magic[(oldRow+1)%n][oldCol] = ++count;           

         curRow = (oldRow+1)%n;           

         curCol = oldCol;       

      }        

      //Store the last row and column index        

      oldRow=curRow;       

      oldCol=curCol;        

      

      //Move one up and one right       

      curRow=(curRow-1)%n;       

      curCol=(curCol+1)%n;              

     

      //Wrap around the size       

      if(curRow<0) 

         curRow =n-1;

   }

}

Some recent stuff

Getting a list of files of a specific extension in a specified folder in Win32 API for c/c++

Often in a Win32/C/C++ application, we need a function to go through a specific folder and snatch all files matching a specified extension. While there is support for doing so in C# but there is no convenient function to do it in Win32/C/C++. Here I am sharing the function I use quite often in my day to day applications. It might help others also.

 

void GetFileList (std::vector& list, std::string dir, std::string extension)
{
 WIN32_FIND_DATA findData;
 HANDLE fileHandle;
 int flag = 1;
 std::string search ("*.");
 if (dir.length() == 0) dir = ".";
 dir += "/";
 //search = dir + search + extension;
 std::string temp = dir;
 temp.append(search);
 temp.append(extension);
 search = temp;
 // SetCurrentDirectory(dir.c_str());
 fileHandle = FindFirstFile(search.c_str(), &findData);
 
 if (fileHandle == INVALID_HANDLE_VALUE) return;
 while (flag)
 {
  list.push_back(findData.cFileName);
  flag = FindNextFile(fileHandle, &findData);
 }
 FindClose(fileHandle);
}

Here's something intersting

Check this out.

Light makes a very big difference.

Don't believe me take at a look at the snapshots yourself. I have added gradient based lighting on the 2D object based texture slice volume rendering.

Transfer function loaded into 2D object based texture slicing

Today, I added the transfer functions. First I made a simple class to wrap a transfer function. This class has a very easy interface. To add color point curve, simply call TransferFunction::AddPoint(int intensity, float opacity). Then I added it to my object based 2D texture slicer. See the snapshots for details.

View aligned 3D Texture Slicing

Today I did the View aligned 3D Texture Slicing. The only thing different here is that we have to get the intersection test between a plane parallel to the viewing plane and intersect it to the unit cube placed at origin.

I will add transfer functions to this and the object aligned version later.

Object aligned slice based volume rendering

I just finished 2D texture slices based volume rendering today. Here are the snapshots of the application. Its damn fast. I will be adding some transfer function editing facility into it tomorrow.

A cool idea though will now work on transfer functions and then view aligned slicing of 3D texture.

Implementation details:

I used glut and OpenGL for this b/c I think its much more fast to develop applications in OpenGL and glut. First I determine the current view direction vector which is simply obtained using the following code

   GLfloat matView[16];
   glGetFloatv(GL_MODELVIEW_MATRIX, matView);
   GLfloat viewDir[3]={ -matView[2], -matView[6], -matView[10]};

Next a 3d texture is loaded from the CT/MRI scans and then using this code, object space quad slices are generated. Here I am only giving the code for the PosZ axis. A slight modification is needed for the other axes.

void DrawSliceZPos()
{
   float zPos = 0.5;
   float zAmt = -1.0f/zSlices;

   glBindTexture(GL_TEXTURE_3D,textureID);
   glBegin(GL_QUADS);

   //offset the slice so its in the middle
   zPos += zAmt/2.0f;
   for(int i=zSlices-1;i>=0;i--)
   {
      float tex = (((float)i)/zSlices);
      glTexCoord3f(0,0,tex); glVertex3f(-0.5, -0.5, zPos);
      glTexCoord3f(0,1,tex); glVertex3f(-0.5,  0.5, zPos);
      glTexCoord3f(1,1,tex); glVertex3f( 0.5,  0.5, zPos);
      glTexCoord3f(1,0,tex); glVertex3f( 0.5, -0.5, zPos);
      zPos += zAmt;
   }
   glEnd();
}

The appropriate slices are drawn based on the maximum abs value of the current view direction as

switch(GetMaxDim(viewDir))
{
   case 0:
      if(viewDir[maxDim] > 0.0f)
         DrawSlicePosX();
      else
         DrawSliceNegX();
   break;
   ...
   case n: ... and so on
}

Thats it and finally the result is blended to produce the rendering as shown above.

A simple 3d mesh viewer using C++, JUCE and OpenGL

This is the current project I am working on. Its made completely in C++ using JUCE and OpenGL.
I had a lot of fun making this.

A simple 3d wave CG shader

I have been doing GPU programming for a while and during my learning I made this small demo showing a 3D wave using OpenGL and GLSL. The idea is pretty simple though.

Just for fun.