gistfile1.txt

void findHomogrpahy( vector <ofVec2f> inPts, vector <ofVec2f> outPts, CvMat * homography){

    homography = cvCreateMat(3,3,CV_32FC1);
    
    CvPoint2D32f * srcPts = new CvPoint2D32f[ inPts.size() ];
    CvPoint2D32f * dstPts = new CvPoint2D32f[ outPts.size() ];
    
    for(int i = 0; i < inPts.size(); i++){
        srcPts[i].x = inPts[i].x;
        srcPts[i].y = inPts[i].y;
        //cout << i << " srcPts is " << srcPts[i].x << " " << srcPts[i].y << endl;
    }

    for(int i = 0; i < outPts.size(); i++){
        dstPts[i].x = outPts[i].x;
        dstPts[i].y = outPts[i].y;
        //cout << i << " dstPt is " << dstPts[i].x << " " << dstPts[i].y << endl;
    }

    CvMat cvsrc = cvMat(1, inPts.size(), CV_32FC2, srcPts);
    CvMat cvdst = cvMat(1, outPts.size(), CV_32FC2, dstPts);
    
    cvFindHomography(&cvsrc, &cvdst, homography, CV_RANSAC, 2);
    bCallib = true;

    delete [] srcPts;
    delete [] dstPts;
}

ofPoint transform(ofPoint in, CvMat * homography){
    if( bCallib == false ) return in;
    
    float xIn = in.x;
    float yIn = in.y;
    
    ofPoint out;

    float *data = homography->data.fl;
    
    float a = data[0];
    float b = data[1];
    float c = data[2];
    float d = data[3];
    
    float e = data[4];
    float f = data[5];
    float i = data[6];
    float j = data[7];
    
    //from Myler & Weeks - so fingers crossed!
    out.x = ((a*xIn + b*yIn + c) / (i*xIn + j*yIn + 1));
    out.y = ((d*xIn + e*yIn + f) / (i*xIn + j*yIn + 1));
    
    return out;
}