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#!F-adobe-helvetica-medium-r-normal--18*
#!N
#!N #!Rdxspe
DXSetPerspective, DXGetPerspective #!N #!N Function #!N #!N Set or retrieve a
perspective view. #!N #!N Syntax #!N #!F-adobe-times-bold-r-normal--18* #include <dx/dx.h> Camera DXSetPerspective(Camera
c, double fov, double aspect) Camera DXGetPerspective(Camera c, float *fov, float
*aspect) #!EF #!N #!N Functional Details #!N #!N 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 #!F-adobe-times-bold-r-normal--18* DXSetPerspective #!EF defines
the volume of interest of a perspective camera #!F-adobe-times-bold-r-normal--18* c #!EF
. This is a pyramid with an apex at the #!F-adobe-times-bold-r-normal--18*
from #!EF position, and a base centered on #!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. This angle is also known as the "field of view"
and is specified by 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 #!F-adobe-times-bold-r-normal--18* fov
#!EF setting should be 2 * tan(45-degrees), or 2.0). The #!F-adobe-times-bold-r-normal--18*
fov #!EF can also be thought of as the ratio of
the width of the base to the distance from the viewer
(e.g., for a view of a 20-meter wide area from a
distance of 10 meters, the #!F-adobe-times-bold-r-normal--18* fov #!EF setting should be
20/10, or 2.0). The height is defined by width of the
base times the #!F-adobe-times-bold-r-normal--18* aspect #!EF . With a perspective camera,
objects appear smaller with increasing distance. #!N #!N #!F-adobe-times-bold-r-normal--18* DXGetPerspective #!EF
returns the #!F-adobe-times-bold-r-normal--18* fov #!EF and #!F-adobe-times-bold-r-normal--18* aspect #!EF parameters of
a perspective camera #!F-adobe-times-bold-r-normal--18* c #!EF . If #!F-adobe-times-bold-r-normal--18* fov #!EF
is not #!F-adobe-times-bold-r-normal--18* NULL #!EF , returns the camera fov in
#!F-adobe-times-bold-r-normal--18* *fov #!EF . If #!F-adobe-times-bold-r-normal--18* aspect #!EF is not #!F-adobe-times-bold-r-normal--18*
NULL #!EF , returns the camera aspect ratio in #!F-adobe-times-bold-r-normal--18* *aspect
#!EF . #!N #!N Return Value #!N #!N #!F-adobe-times-bold-r-normal--18* DXSetPerspective #!EF
returns the camera or returns #!F-adobe-times-bold-r-normal--18* NULL #!EF and sets an
error code. #!N #!N #!F-adobe-times-bold-r-normal--18* DXGetPerspective #!EF returns as follows: #!N
#!I0 #!N #!F-adobe-times-medium-r-normal--18* #!N #!N #!I30 #!N o #!F-adobe-times-bold-r-normal--18* If the
object is a perspective camera: #!EF returns the camera and the
camera parameters. #!N #!I30 #!N o #!F-adobe-times-bold-r-normal--18* If the object is
not a perspective camera: #!EF returns #!F-adobe-times-bold-r-normal--18* NULL #!EF without setting
an error code. #!N #!I30 #!N o #!F-adobe-times-bold-r-normal--18* If the object
is not a valid camera: #!EF returns #!F-adobe-times-bold-r-normal--18* NULL #!EF and
sets an error code. #!N #!I0 #!N #!EF #!N #!N #!N
See Also #!N #!N #!F-adobe-times-bold-r-normal--18* #!Ldxgcmp,dxall1225 h DXGetCameraMatrix, DXGetCameraRotation, DXGetCameraMatrixWithFuzz #!EL , #!Ldxnca,dxall1311 h DXNewCamera #!EL , #!Ldxrndr,dxall1357 h DXRender #!EL ,
#!Ldxsoc,dxall1384 h DXSetOrthographic, DXGetOrthographic #!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 #!Ldxsrn,dxall1389 h DXSetResolution, DXGetCameraResolution #!EL #!N #!F-adobe-times-medium-i-normal--18*
#!N
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