SilverScreenAPI

SS_VIEW

Structure

This data type is used to store viewing information about a window

struct SS_VIEW

{

SS_XYZ camera;

SS_XYZ center;

double horz_angle;

double vert_angle;

double angle_of_vision;

double view_rotation;

double height;

double width;

int projection;

int view_type;

int left_pixel;

int right_pixel;

int top_pixel;

int bottom_pixel;

SS_XYZ view_direction;

MATRIX camera_matrix;

SS_XYZ view_plane_normal;

double window_xmin;

double window_xmax;

double window_ymin;

double window_ymax;

};

Members

Member

Description

camera

Center of projection

center

View reference point

horz_angle

Horizontal viewing angle

vert_angle

Vertical viewing angle

angle_of_vision

The angle of view in degrees.

view_rotation

The rotation angle applied along the direction of viewing (in degrees).

vert_angle

Vertical viewing angle

height

The world-space height of the viewport.

width

The world-space width of the viewport.

projections

A value whose meaning is as follows:

Constant	Meaning
VIEW_PARALLEL	The viewport uses a parallel projection (no foreshortening)
VIEW_PERSPECTIVE	The viewport uses a perspective projection (with foreshortening)

view_type

A value whose meaning is as follows:

Constant	Meaning
VIEW_OBLIQUE	The view projects using an oblique projection.
VIEW_NATURAL	The view uses a natural projection
VIEW_X_AXIAL	The view projects such that all lines parallel to the x-axis are horizontal
VIEW_Y_AXIAL	The view projects such that all lines parallel to the y-axis are vertical
VIEW_Z_AXIAL	The view projects such that all lines parallel to the z-axis are horizontal

left_pixel

The left-most pixel of the view in display coordinates

right_pixel

The right-most pixel of the view in display coordinates

bottom_pixel

The bottom-most pixel of the view in display coordinates

top_pixel

The top-most pixel of the view in display coordinates

view_direction

A vector that points in the direction of the camera

camera_matrix

The transformation matrix which brings you from world space to camera space. This does not include the "perspective transformation".

view_plane_normal

A vector that along with center defines a plane in world space upon which the viewing window is defined

window_xmin

Minimum x-coordinate value of the window boundary in camera space

window_xmax

Maximum x-coordinate value of the window boundary in camera space

window_ymin

Minimum y-coordinate value of the window boundary in camera space

window_ymax

Maximum y-coordinate value of the window boundary in camera space

Remarks

An oblique projection displays one of the principle faces of the drawing parallel to the viewing plane. Two of the world space axes are parallel to the viewing plane. The third axis is projected at an oblique (not parallel or perpendicular) angle to the viewing plane.

If the projection is parallel, then 'center' and 'angle_of_view' are not defined.