1get_camera_matrix(3)            Allegro manual            get_camera_matrix(3)
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NAME

6       get_camera_matrix  - Constructs a camera matrix for perspective projec‐
7       tion. Allegro game programming library.
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SYNOPSIS

10       #include <allegro.h>
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13       void get_camera_matrix(MATRIX  *m,  fixed  x,  y,  z,  xfront,  yfront,
14       zfront, fixed xup, yup, zup, fov, aspect);
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DESCRIPTION

17       Constructs  a  camera matrix for translating world-space objects into a
18       normalised view space, ready for the perspective projection. The x,  y,
19       and  z  parameters  specify  the  camera  position, xfront, yfront, and
20       zfront are the 'in front' vector specifying which  way  the  camera  is
21       facing  (this  can  be  any length: normalisation is not required), and
22       xup, yup, and zup are the 'up' direction vector.
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24       The fov parameter specifies the field of view (ie. width of the  camera
25       focus) in binary, 256 degrees to the circle format. For typical projec‐
26       tions, a field of view in the region 32-48 will  work  well.  64  (90°)
27       applies no extra scaling - so something which is one unit away from the
28       viewer will be directly scaled to the viewport. A bigger FOV moves  you
29       closer to the viewing plane, so more objects will appear. A smaller FOV
30       moves you away from the viewing plane, which means you  see  a  smaller
31       part of the world.
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33       Finally,  the  aspect  ratio  is  used to scale the Y dimensions of the
34       image relative to the X axis, so you can use it to adjust  the  propor‐
35       tions  of  the  output  image (set it to 1 for no scaling - but keep in
36       mind that the projection also performs scaling according to  the  view‐
37       port  size).  Typically, you will pass (float)w/(float)h, where w and h
38       are the parameters you passed to set_projection_viewport.
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40       Note that versions prior to 4.1.0 multiplied this aspect ratio by 4/3.
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SEE ALSO

44       apply_matrix(3),    get_align_matrix(3),    set_projection_viewport(3),
45       persp_project(3)
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49Allegro                          version 4.2.2            get_camera_matrix(3)
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