Vieinco

08-27-2010, 08:36 AM

Please help! =) I can't get the correct transformation in OpleGL.

I have point3D - P(X,Y,Z), and projection matrix M, which equal to K*(R|T) where

K - camera calibration matrix

http://i.imgur.com/alJOE.gif

(R|T) - point (object) coordinate system transformation (R - rotation matrix, T - translation vector)

As a result we have projected point as p = M*P

I know P,K,R,T, and I wont to calculate p in OpenGl terms.

In OpenCV terms it will be look as follows (little abstraction code):

CvMat* R = cvCreateMat(4,4, CV_32F, getRotationData());

CvMat* T = cvCreateMat(4,1, CV_32F, getTranslationData());

CvMat* K = cvCreateMat(4,4, CV_32F, getCameraCalibrationData());

// (R|T)

R->data.fl[3] = T->data.fl[0];

R->data.fl[7] = T->data.fl[1];

R->data.fl[11] = T->data.fl[2];

R->data.fl[15] = T->data.fl[3];

CvMat M = cvMat(4,4, CV_32F);

// M = R*(R|T)

cvMulMat(K, R, &M);

CvMat* P = cvCreateMat(4,1, CV_32F, getTestedPoint3D());

cvMar p = cvMat(4,1, CV_32F); // result transformation

// p = M*P

cvMulMat(&M, P, &p);

// project

float z = p.data.fl[2];

float x = p.data.fl[0] / z;

float y = p.data.fl[1] / z;

printf("Point projection [%f,%f]", x, y);

cvDrawPonit(img, cvPoint(x,y), CV_RGB(255,0,0)); /// <- !!!!

Sombody helps me to translate this logic to OpenGl! =(

How could I set GL_PROJECTION and what could i do in GL_MODELVIEW mode or some else? =(

I have point3D - P(X,Y,Z), and projection matrix M, which equal to K*(R|T) where

K - camera calibration matrix

http://i.imgur.com/alJOE.gif

(R|T) - point (object) coordinate system transformation (R - rotation matrix, T - translation vector)

As a result we have projected point as p = M*P

I know P,K,R,T, and I wont to calculate p in OpenGl terms.

In OpenCV terms it will be look as follows (little abstraction code):

CvMat* R = cvCreateMat(4,4, CV_32F, getRotationData());

CvMat* T = cvCreateMat(4,1, CV_32F, getTranslationData());

CvMat* K = cvCreateMat(4,4, CV_32F, getCameraCalibrationData());

// (R|T)

R->data.fl[3] = T->data.fl[0];

R->data.fl[7] = T->data.fl[1];

R->data.fl[11] = T->data.fl[2];

R->data.fl[15] = T->data.fl[3];

CvMat M = cvMat(4,4, CV_32F);

// M = R*(R|T)

cvMulMat(K, R, &M);

CvMat* P = cvCreateMat(4,1, CV_32F, getTestedPoint3D());

cvMar p = cvMat(4,1, CV_32F); // result transformation

// p = M*P

cvMulMat(&M, P, &p);

// project

float z = p.data.fl[2];

float x = p.data.fl[0] / z;

float y = p.data.fl[1] / z;

printf("Point projection [%f,%f]", x, y);

cvDrawPonit(img, cvPoint(x,y), CV_RGB(255,0,0)); /// <- !!!!

Sombody helps me to translate this logic to OpenGl! =(

How could I set GL_PROJECTION and what could i do in GL_MODELVIEW mode or some else? =(