s3d_angle_to_cam(3) [debian man page]

S3D_ANGLE_TO_CAM(3)						    s3d Manual						       S3D_ANGLE_TO_CAM(3)

NAME

       s3d_angle_to_cam - calculate angle between vector and cam

SYNOPSIS

       #include <s3d.h>

       float s3d_angle_to_cam(const float obj_pos[], const float cam_pos[], float *angle_rad);

DESCRIPTION

       Given obj_pos and cam_pos in the format float[3], angle_rad about which angle the object should be rotated around the y-axis so that it
       faces the camera. This might become handy if you have some text floating in space and want it to face the camera.
       http://en.wikipedia.org/wiki/Vector_(spatial)

AUTHOR

       Simon Wunderlich
	   Author of s3d

s3d															       S3D_ANGLE_TO_CAM(3)

persp_project(3alleg4)						  Allegro manual					    persp_project(3alleg4)

NAME

       persp_project, persp_project_f - Projects a 3d point into 2d screen space. Allegro game programming library.

SYNOPSIS

       #include <allegro.h>

       void persp_project(fixed x, fixed y, fixed z, fixed *xout, fixed *yout);

       void persp_project_f(float x, float y, float z, float *xout, float *yout);

DESCRIPTION

       Projects  the 3d point (x, y, z) into 2d screen space, storing the result in (*xout, *yout) and using the scaling parameters previously set
       by calling set_projection_viewport(). This function projects from the normalized viewing pyramid, which has a camera at the origin and fac-
       ing  along the positive z axis. The x axis runs left/right, y runs up/down, and z increases with depth into the screen. The camera has a 90
       degree field of view, ie. points on the planes x=z and -x=z will map onto the left and right edges of the screen, and the  planes  y=z  and
       -y=z  map  to  the  top	and  bottom of the screen. If you want a different field of view or camera location, you should transform all your
       objects with an appropriate viewing matrix, eg. to get the effect of panning the camera 10 degrees to the left, rotate all your objects	10
       degrees to the right.

SEE ALSO

       set_projection_viewport(3alleg4), get_camera_matrix(3alleg4), ex3d(3alleg4), exstars(3alleg4)

Allegro 							   version 4.4.2					    persp_project(3alleg4)