get_camera_matrix(3alleg4)       Allegro manual       get_camera_matrix(3alleg4)

       get_camera_matrix - Constructs a camera matrix for perspective
       projection. Allegro game programming library.

       #include <allegro.h>

       void get_camera_matrix(MATRIX *m, fixed x, y, z, xfront, yfront, zfront,
       fixed xup, yup, zup, fov, aspect);

       Constructs a camera matrix for translating world-space objects into a
       normalised view space, ready for the perspective projection. The x, y,
       and z parameters specify the camera position, xfront, yfront, and zfront
       are the 'in front' vector specifying which way the camera is facing (this
       can be any length: normalisation is not required), and xup, yup, and zup
       are the 'up' direction vector.

       The fov parameter specifies the field of view (ie. width of the camera
       focus) in binary, 256 degrees to the circle format. For typical
       projections, a field of view in the region 32-48 will work well. 64 (90
       degrees) applies no extra scaling - so something which is one unit away
       from the viewer will be directly scaled to the viewport. A bigger FOV
       moves you closer to the viewing plane, so more objects will appear. A
       smaller FOV moves you away from the viewing plane, which means you see a
       smaller part of the world.

       Finally, the aspect ratio is used to scale the Y dimensions of the image
       relative to the X axis, so you can use it to adjust the proportions of
       the output image (set it to 1 for no scaling - but keep in mind that the
       projection also performs scaling according to the viewport size).
       Typically, you will pass (float)w/(float)h, where w and h are the
       parameters you passed to set_projection_viewport.

       Note that versions prior to 4.1.0 multiplied this aspect ratio by 4/3.

       apply_matrix(3alleg4), get_align_matrix(3alleg4),
       set_projection_viewport(3alleg4), persp_project(3alleg4)

Allegro                           version 4.4.3       get_camera_matrix(3alleg4)