DefaultCamera2D and DefaultCamera3D

Synopsis

define a Graphics Display Kit camera

GDcamera_notify_templ

group+OPort  GDcamera_notify_templ
{
int  update;
enum type {choices = {"3D", "2D"}; };
enum mode { choices = {"Manual", "Automatic"}; };
enum  auto_norm { choices = {"None", "Data Change", "Object Attach",
"Data and Object"}; };
float norm_scale;
enum extents { choices = {"Compute", "Window"}; };
enum  mapping { choices = {"World", "Pixel"}; };
int image_pass;
int pickable;
int nobjs;
GDobject_templ+IPort2 *objects[]; // Objects to render
float  xmin; // Viewport specification
float  ymin;
float  xmax;
float  ymax;
float  from[3]; // Camera orientation
float  up[3];
float  at[3];
float  scale;
GDxform_templ+IPort2 &xform;
int  perspec; // Camera projection
int  hither;
float  front
float  back;
float  fov;
float  wsize;
int  depth_cue; // Depth cue information
float  depth_front;
float  depth_back;
float  depth_scale;
float jitter_scale;
int+write dep;
method+notify_val upd_func = "GDcamera_update";
method+notify_deinst del_func = "GDcamera_delete";
};

GDcamera_templ

GDcamera_notify_templ+OPort GDcamera_templ;

GDcamera

GDcamera_templ  GDcamera
<NEiconName="camera"> {
nobjs => array_size(objects);
ptr+nonotify+nosave  local_ptr;
};

DefaultCamera

GDcamera  DefaultCamera
{
mode = GD_CAMERA_AUTO_UPDATE;
pickable = 1;
auto_norm = GD_CAMERA_AUTO_NORM_NONE;
norm_scale = GD_DEFAULT_NORM_SCALE;
extents = GD_CAMERA_COMPUTE_EXTENT;
mapping = GD_CAMERA_MAP_WORLD;
xmin = 0.0;
ymin = 0.0;
xmax = 1.0;
ymax = 1.0;
from = {0.0, 0.0, 12.0};
up = {0.0, 1.0, 0.0};
at = {0.0, 0.0, 0.0};
scale = 1.0;
perspec = 0;
hither = 0;
front = GD_DEFAULT_FRONT_PAR;
back = GD_DEFAULT_BACK;
fov = GD_DEFAULT_VIEW_ANGLE
wsize = GD_DEFAULT_WSIZE;
depth_cue = 0;
depth_front = GD_DEFAULT_DEPTH_FRONT;
depth_back = GD_DEFAULT_DEPTH_BACK;
depth_scale = GD_DEFAULT_DEFAULT_SCALE;
jitter_scale = 1.0;
};

DefaultCamera2D

DefaultCamera  DefaultCamera2D
{
type = GD_CAMERA_2D;
image_pass = 1;
};

DefaultCamera3D

DefaultCamera  DefaultCamera3D
{
type = GD_CAMERA_3D;
image_pass = 0;
};

Description

These templates define a Graphics Display Kit camera. GDcamera_notify_templ defines the elements that cause the camera's methods to execute. GDcamera is used to define a camera without default values. DefaultCamera2D define a 2D camera with default values; in other words, Graphics Display Kit objects connected to DefaultCamera2D are rendered in 2D. DefaultCamera3D defines a 3D camera with default values; in other words, Graphics Display Kit objects connected to DefaultCamera3D are rendered in 3D.

Input Ports

objects

One or more objects to be rendered. This input port is an array of connections to objects matching type GDobject_templ.

xform

A transformation that represents the camera's orientation. xform is a connection to an object that matches type GDxform_templ. The subelements from, at, up and scale are used to calculate the transformation.

Parameters

update

When the mode parameter (see below) is set to 0, determines whether the view is updated: 0 means no; 1 means yes.

type

This parameter controls the camera's type:

mode

This parameter controls the camera's update mode:

auto_norm

This parameter controls if and when the objects in the camera are normalized to fit in the view.

norm_scale

This parameter applies a scale to normalization. By default, norm_scale is set to 0.8, indicating that when normalization takes place, any objects will be scaled to fill 80% of the camera.

extents

This parameter controls how the extents of the objects connected to the camera are computed when doing normalization:

mapping

This parameter controls the mapping of the camera:

image_pass

This parameter controls if there is a separate pass to render the images in 2D cameras. A value of 1 means all images are rendered in a separate pass prior to all other objects in the 2D camera. A value of 0 means that images are rendered in the same pass as all other objects. When a separate image pass is enabled, images are rendered "behind" the other objects in the camera. Otherwise, all objects in the camera are rendered in the order that they were attached to the camera.

pickable

This parameter controls if the camera is pickable: 0 means the camera is not pickable; 1 means the camera is pickable. When the camera is not pickable, all the objects in that camera are also unpickable. Use this subelement if objects in the view, such as annotation or legends, should not be transformed.

nobjs

The number of Graphics Display Kit objects connected to the camera. nobjs is updated automatically when the size of the array changes.

xmin
ymin
xmax
ymax

The camera's viewport; that is, the region it occupies in the view. For the purposes of specifying a viewport, point (0,0) is the top-left corner of the view and point (1,1) is the bottom-right corner. The viewport specification is not currently supported by the camera.

from

The X, Y, and Z position in world coordinates of the camera.

up

An X, Y, and Z direction vector indicating the vertical axis of the camera.

at

The X, Y, and Z position in world coordinates at which the camera is pointed.

scale

The scale term that is applied to the camera.

perspec

The camera type: 0 means parallel; 1 means perspective.

hither

Whether front and back clipping is in effect: 0 means no; 1 means yes.

front

The distance in world coordinates from the camera's origin (from) to the front clip plane. The distance is measured along the front-at line.

The valid values of front depends on the type of camera. If the camera's type is parallel, then front can be any value, positive or negative. If the camera's type is perspective, then front can be any positive value.

back

The distance in world coordinates from the camera's origin (from) to the back clip plane. The distance is measured along the front-at line.

back must be greater than front for both parallel and perspective cameras.

fov

For perspective cameras only, the angle in degrees formed by the edges of the field of view volume. fov must be a value between 0 and 180.

wsize

For parallel cameras only, a scale factor in world coordinates that determines the range of viewing.

depth_cue

Whether depth cueing is in effect: 0 means no; 1 means yes.

depth_front

The distance in world coordinates from the camera's origin (from) to where depth cueing begins. The distance is measured along the front-at line.

depth_back

The distance in world coordinates from the camera's origin (from) to where the maximum depth scale is applied. The distance is measured along the front-at line.

depth_scale

The maximum depth scale.

Specify a value between 0 and 1. For example, 0.1 means that a factor of 0.1 is applied to locations at and further than depth_back.

jitter_scale

This parameter is used to scale the jitter offset that can be applied to any of the objects in the camera. Jitter offset is used to move objects either positively or negatively in the camera in order to resolve the ambiguity in rendering objects at the same depth. Jitter_scale is useful for adjusting the amount of the jitter offset in order to reduce artifacts that may be introduced in cases where the objects are very thin geometries. Note that when an object is locked, its coordinates are not transformed, thus they are not jittered.

Example

Libraries.Graphics_Display.Views.View2D
Libraries.Graphics_Display.Views.View3D

File

v/gd.v