ssyybbyy

04-08-2014, 05:15 PM

1263

Hello every body, I have a plane and attached figure shows two positions of the plane, (a) no rotation and (b) with rotation where rotation axis is defined by ax + by + cz.

Now, the plane will rotate, but it will always look without rotation as shown in figure (a).

I think I need to play around with my glutReshape function which looks like follows:

void glutReshape(int width, int height)

{

width = glutGet(GLUT_WINDOW_WIDTH);

height = glutGet(GLUT_WINDOW_HEIGHT);

if (width && height)

{

glViewport(0, 0, width, height);

nearDist = 150.0 / tan((kFovY / 2.0) * kPI / 180.0);

farDist = nearDist + 100.0;

aspect = (double) width / height;

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

gluPerspective(kFovY, aspect, 0.1, farDist+20);

glMatrixMode(GL_MODELVIEW);

glLoadIdentity();

gluLookAt( 0.0, 0.0, (nearDist + 5.0), // camera/ eye

0.0, 0.0, 0.0, // center

0.0, 1.0, 0.0); // up vector

}

}

But I fail to correctly manipulate it. When rotation axis will move from (0, 0, 1) to (ax + by + bz), the eye/ camera will be changed from ( 0, 0, nearDist +5) to ( {(nearDist+5)*ax, (nearDist+ 5)*ay, (nearDist + 5)*az}. Is it right?

But what about the up vector? How will it change for this rotation? How can I calculate new up vector? Also what other parameters in my glutReshape function needs to be changed?

Please provide me some suggestion how I can fix this problem.

Thanks in advance.

Hello every body, I have a plane and attached figure shows two positions of the plane, (a) no rotation and (b) with rotation where rotation axis is defined by ax + by + cz.

Now, the plane will rotate, but it will always look without rotation as shown in figure (a).

I think I need to play around with my glutReshape function which looks like follows:

void glutReshape(int width, int height)

{

width = glutGet(GLUT_WINDOW_WIDTH);

height = glutGet(GLUT_WINDOW_HEIGHT);

if (width && height)

{

glViewport(0, 0, width, height);

nearDist = 150.0 / tan((kFovY / 2.0) * kPI / 180.0);

farDist = nearDist + 100.0;

aspect = (double) width / height;

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

gluPerspective(kFovY, aspect, 0.1, farDist+20);

glMatrixMode(GL_MODELVIEW);

glLoadIdentity();

gluLookAt( 0.0, 0.0, (nearDist + 5.0), // camera/ eye

0.0, 0.0, 0.0, // center

0.0, 1.0, 0.0); // up vector

}

}

But I fail to correctly manipulate it. When rotation axis will move from (0, 0, 1) to (ax + by + bz), the eye/ camera will be changed from ( 0, 0, nearDist +5) to ( {(nearDist+5)*ax, (nearDist+ 5)*ay, (nearDist + 5)*az}. Is it right?

But what about the up vector? How will it change for this rotation? How can I calculate new up vector? Also what other parameters in my glutReshape function needs to be changed?

Please provide me some suggestion how I can fix this problem.

Thanks in advance.