dx-doc 1:4.4.4-7 / usr / share / doc / dx / help / dxall1311

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#!N 
#!N  #!Rdxnca DXNewCamera #!N #!N Function #!N 
#!N Creates a new Camera. #!N #!N Syntax #!N  #!F-adobe-times-bold-r-normal--18*   #include 
<dx/dx.h> Camera DXNewCamera() #!EF #!N #!N Functional Details #!N #!N Creates 
a new Camera. A camera defines the position and orientation of 
the viewer, the volume of interest of the object being viewed, 
and the size of the image to contain the resulting view. 
#!N #!N A summary of how to interpret a camera follows. 
#!N #!N The position and orientation of the view are defined 
by where the viewer is standing,  #!F-adobe-times-bold-r-normal--18*   from #!EF , where 
the viewer is looking,  #!F-adobe-times-bold-r-normal--18*   to #!EF , and the tilt 
of the viewer's head,  #!F-adobe-times-bold-r-normal--18*   up #!EF . #!N #!N The 
volume of interest of the object being viewed depends on the 
type of camera. An orthographic camera defines a box that is 
centered on the  #!F-adobe-times-bold-r-normal--18*   to #!EF point and has an infinite 
 #!F-adobe-times-bold-r-normal--18*   z #!EF axis lying along the  #!F-adobe-times-bold-r-normal--18*   to #!EF - 
 #!F-adobe-times-bold-r-normal--18*   from #!EF vector. The  #!F-adobe-times-bold-r-normal--18*   y #!EF axis is perpendicular 
to the  #!F-adobe-times-bold-r-normal--18*   to #!EF -  #!F-adobe-times-bold-r-normal--18*   from #!EF vector in 
the direction of the  #!F-adobe-times-bold-r-normal--18*   up #!EF vector. The x- and 
y-dimensions of the box are given by the  #!F-adobe-times-bold-r-normal--18*   width #!EF 
and  #!F-adobe-times-bold-r-normal--18*   aspect #!EF parameters of the camera, where  #!F-adobe-times-bold-r-normal--18*   aspect 
#!EF is defined as the ratio of the height to width. 
#!N #!N In orthographic projection, objects do not appear smaller as 
they get more distant, and in fact, distance between the object 
and the viewer has no effect on the appearance of the 
object. The distance between the  #!F-adobe-times-bold-r-normal--18*   to #!EF and  #!F-adobe-times-bold-r-normal--18*   from 
#!EF points is irrelevant; only the direction is important. #!N #!N 
The volume of interest defined by a perspective camera is a 
pyramid with an apex at the  #!F-adobe-times-bold-r-normal--18*   from #!EF position, and 
a base at the  #!F-adobe-times-bold-r-normal--18*   to #!EF point perpendicular to the 
 #!F-adobe-times-bold-r-normal--18*   to #!EF -  #!F-adobe-times-bold-r-normal--18*   from #!EF vector. The width of 
the base is defined by the angle formed by the sides 
of the pyramid at the apex and the distance between the 
 #!F-adobe-times-bold-r-normal--18*   to #!EF and  #!F-adobe-times-bold-r-normal--18*   from #!EF points. The angle formed 
by the sides of the pyramid is also known as the 
"field of view" and is the  #!F-adobe-times-bold-r-normal--18*   fov #!EF parameter. #!N 
#!N The  #!F-adobe-times-bold-r-normal--18*   fov #!EF is defined as twice the tangent 
of half the angle (e.g., for a 90-degree sweep, the fov 
is 2 * tan(45 degrees), or 2.0). The  #!F-adobe-times-bold-r-normal--18*   fov #!EF 
can also be thought as the ratio of the width of 
the base to the distance to the viewer (e.g., for a 
20-meter wide area from a distance of 10 meters , set 
the  #!F-adobe-times-bold-r-normal--18*   fov #!EF to 20/10, or 2.0). The base height 
is defined by the resulting width times the  #!F-adobe-times-bold-r-normal--18*   aspect #!EF 
. #!N #!N With a perspective camera, objects appear smaller with 
increasing distance. When the perspective pyramid is projected onto the image, 
the sides of the pyramid are made parallel, with a cross-section 
equal to the base dimensions. This has the effect of widening 
(in x and y) the objects in front of the pyramid 
base and compressing (in x and y) the objects behind the 
pyramid base. #!N #!N The Camera created can be deleted with 
DXDelete. See  #!Lmemng,dxall1023 h Memory Management  #!EL  . #!N #!N The horizontal size of the 
image containing the resulting view is defined as the  #!F-adobe-times-bold-r-normal--18*   resolution 
#!EF in pixels, and the vertical size is determined by the 
 #!F-adobe-times-bold-r-normal--18*   resolution #!EF *  #!F-adobe-times-bold-r-normal--18*   aspect #!EF . The same aspect 
ratio is used for both the size of the image and 
the volume of interest to prevent the object from being stretched 
in one of the dimensions. The background color of the image 
is also a parameter to the camera. #!N #!N By default, 
the camera is orthographic, looking from the positive z axis toward 
the origin; x and y each range from  #!F-adobe-times-medium-i-normal--18*   -1 #!EF 
to  #!F-adobe-times-medium-i-normal--18*   +1 #!EF . The image is 640 by 480 
pixels, with the origin at the center of the image. #!N 
#!N Return Value #!N #!N Returns the Camera or returns  #!F-adobe-times-bold-r-normal--18*   
NULL #!EF and sets an error code. #!N #!N See Also 
#!N #!N  #!F-adobe-times-bold-r-normal--18*    #!Ldxgcmp,dxall1225 h DXGetCameraMatrix, DXGetCameraRotation, DXGetCameraMatrixWithFuzz  #!EL  ,  #!Ldxrndr,dxall1357 h DXRender  #!EL  ,  #!Ldxsbc,dxall1368 h DXSetBackgroundColor, DXGetBackgroundColor  #!EL  ,  #!Ldxsoc,dxall1384 h DXSetOrthographic, DXGetOrthographic  #!EL  , 
 #!Ldxspe,dxall1388 h DXSetPerspective, DXGetPerspective  #!EL  ,  #!Ldxsrn,dxall1389 h DXSetResolution, DXGetCameraResolution  #!EL  ,  #!Ldxsvw,dxall1393 h DXSetView, DXGetView  #!EL  #!EF #!N #!N  #!Lcamsec,dxall1138 h Camera Class  #!EL  . #!N 
#!N #!N  #!F-adobe-times-medium-i-normal--18*   Next Topic #!EF #!N #!N  #!Ldxncd,dxall1312 h DXNewClipped  #!EL  #!N  #!F-adobe-times-medium-i-normal--18*   
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