Accidentally sent incomplete message :(
lets assume your eye coord is osg::Vec4 eyeCoord:
eyeCoord = eyeCoord * osgProjectionMatrix;//get it from camera
if (eyeCoord.w() < 0 )
//vertex behind camera
else
{
eyeCoord /= eyeCoord.w();
eyeCoord.x() *= 0.5;
eyeCoord.y() *= 0.5;
eyeCoord.x() += 0.5;
eyeCoord.y() += 0.5;
eyeCoord.x() *= width;
eyeCoord.y() *= height;
}
now your eyeCoord.xy contains screen coords in pixels
Cheers,
Sergey
28.05.2012, 14:00, "Sergey Polischuk" <[email protected]>:
> Hi, Shuiying
>
> lets assume your eye coord is osg::Vec4 eyeCoord:
>
> eyeCoord = eyeCoord * osgProjectionMatrix;
> if (eyeCoord.w() < 0 )
> //vertex behind camera
> else
> {
> eyeCoord /= eyeCoord.w()
>
> }
>
> 26.05.2012, 19:58, "wang shuiying" <[email protected]>:
>
>> Hallo,
>>
>> I simulate a real camera with OSG camera node and for debugging I have
>> some problem with the pixel location. I would like to know whether the
>> following statement is correct or false:
>>
>> if coordinate of vertex in eye coordinate is (xe,ye,ze), and we assume
>> that xe>0,ye<0,ze<0, namely, the verice should appear next to bottom
>> right corner of the image. (Origin of the image is top left, x forwards
>> to right, y forwards to bottom)
>>
>> Then can its corresponding pixel location(px, py) on the image
>> calculated like following? (x resolution of image is xRes, y
>> Resoluation is yRes, yaw angle of camera is ViewYaw, pitch angle of
>> camera is ViewPitch, near plane is 1 )
>>
>> px=xe/abs(ze)* (xRes/2/tan(ViewYaw/2)) +xRes/2
>>
>> py=abs(ye)/abs(ze)* (yRes/2/tan(ViewPitch/2)) +yRes/2
>>
>> I get coordinate of vertex in eye coordinate by a product of vertex
>> global coordinate and camera->getViewmatrix(), and then calculate the
>> corresponding pixel location following the above formulas. But the
>> location is not correct compared to what appears on the image. the error
>> is about 50 pixels in the x coordinate.
>>
>> Can anybody give me some tips on that?
>>
>> Thank you very much in advance!
>>
>> Best regards
>>
>> Shuiying
>>
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>
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