#include <stdio.h>
#include <cxcore.h>
#include <cv.h>
#include <highgui.h>
#pragma comment(lib,"cv.lib")
#pragma comment(lib,"cxcore.lib")
#pragma comment(lib,"highgui.lib")

void bitConvert(void *out, int outBit, void *in, int inHeight, int inWidth, int inChannel, int inBit);

int main(){
   IplImage *in, *out;
   int i,j;
   
   in = cvLoadImage("./image640.bmp", 0);
   out = cvCreateImage(cvSize(in->width, in->height), 16, in->nChannels);
   bitConvert((void*)out->imageData, out->depth, (void*)in->imageData, in->height, in->width, in->nChannels, in->depth);

   cvNamedWindow("in", 1);
   cvShowImage("in", in);
   cvNamedWindow("out", 1);
   cvShowImage("out", out);
   cvWaitKey(-1);

   cvDestroyWindow("in");
   cvDestroyWindow("out");

   cvReleaseImage( &in );
   cvReleaseImage( &out );

   return 0;
}


void bitConvert(void *out, int outBit, void *in, int inHeight, int inWidth, int inChannel, int inBit){
    int i, j;
    unsigned short tmp;

    double coefficient;
    unsigned short max;
    unsigned char *tmpAd8;
    unsigned short *tmpAd16;

    // 係数
    coefficient = pow(2.0, (outBit - inBit));

    // 最大値
    max = (unsigned short)(pow(2.0, outBit) - 1);

    for(i = 0; i < inHeight; ++i){
        for(j = 0; j < inWidth; ++j){
            switch(inBit){
            case 8:
                tmp = (unsigned short)(*((unsigned char *)in + i * inWidth + j) * coefficient);
                break;
            case 10:
            case 12:
            case 16:
                tmp = (unsigned short)(*((unsigned short *)in + i * inWidth + j) * coefficient);
                break;
            }

            // max超えることはないが、念のため
            if(tmp > max){
                tmp = max;
            }

            switch(outBit){
            case 8:
                *((unsigned char *)out + i * inWidth + j) = tmp;
                break;
            case 10:
            case 12:
            case 16:
                *((unsigned short *)out + i * inWidth + j) = tmp;
                break;
            }
        }
    }
}