GeometryBvr Class

The GeometryBvr class is a class of three-dimensional objects that includes surfaces, lights, sounds, their attributes, and/or combinations of these elements. Like other behaviors, the value of the elements of the geometry can change over time.

In general, every geometry behavior is spatially infinite and of infinite resolution. Conceptually, each of the infinitely many points in the geometry has associated with it an opacity value, a color, a normal (used for lighting computations), a texture coordinate, a detectability value, and a single-channel sound emanating from that point (generally, this is silence).

Surface geometry is either detectable or not. If a surface is detectable, the geometry fires a pick event whenever the cursor passes over a surface point. Neither lights nor sounds are detectable (or pickable).

Light geometries include ambient lights, directional lights, point lights, and spotlights. Light geometries can be attributed with both color and distance attenuation.

A texture in a geometry is an image, the points of which are mapped to the surface of the three-dimensional object represented by the geometry. If there is no surface in the geometry, the texture is ignored.

A geometry can also be a sound. The sound is audible when the geometry is within the appropriate range of a microphone behavior.

The bounding box query is used to construct and compose media, and different types of images and behaviors provide specific bounding boxes. This means, for example, that the bounding box of an image is not defined as the smallest axis-aligned, enclosing region of the nontransparent parts of an image. Instead, bounding boxes are defined on a per-operation basis. The emptyGeometry object, for example, has its own definition of a bounding box, defined below.

For more information about behaviors, see the Behavior class.

For relevant methods and fields from the Statics class, see the following topics.

GeometryBvr Methods

boundingBox Creates a bounding box behavior that defines the axis-aligned bounding box enclosing all nontransparent portions of the geometry behavior.

diffuseColor Specifies the diffuse color of the new geometry behavior. The diffuse color is the diffuse (or matte) reflective color of the surface.

lightAttenuation Creates a new geometry behavior in which any light sources have the given attenuation.

lightColor Creates a new geometry behavior in which all embedded lights have the specified color.

opacity Sets the opacity value for all surfaces to the given number behavior.

render(camera) Creates an image behavior that is a two-dimensional projection of this geometry behavior.

render(mic) Creates a sound behavior that represents the sound associated with this geometry behavior as detected by the given microphone.

textureImage Creates a new geometry behavior by mapping the given image, as defined by the given image behavior, to the surfaces of the original geometry.

transform Creates a new geometry behavior that is the result of applying the given three-dimensional transformation to the original geometry behavior.

undetectable Creates a new undetectable geometry behavior from the original geometry.

newUninitBvr Enables you to refer to an GeometryBvr behavior before that behavior has been defined.

boundingBox

GeometryBvr Class

Creates a bounding box behavior that defines the axis-aligned bounding box enclosing all nontransparent portions of the geometry behavior.

Syntax

public Bbox3Bvr boundingBox( );

Return Value

Returns the Bbox3Bvr object.

diffuseColor

GeometryBvr Class

Specifies the diffuse color of the new geometry behavior. The diffuse color is the diffuse (or matte) reflective color of the surface.

Syntax

public GeometryBvr diffuseColor( ColorBvr col );

Parameters

col
ColorBvr object.

Return Value

Returns the GeometryBvr object.

Remarks

By default, the diffuse color is white. The bounding box is the bounding box of the underlying geometry.
This attribute overrides previous values.

lightAttenuation

GeometryBvr Class

Creates a new geometry behavior in which any light sources have the given attenuation. The new attenuation is set to 1 / (const + linear ´ d + quadratic ´ d²) where d is the distance from the light to the object.

Syntax

public GeometryBvr lightAttenuation(
NumberBvr const, NumberBvr linear, NumberBvr quadratic );

Parameters

const, linear, and quadratic
NumberBvr objects specifying the attenuation of a light source. These parameters can also be of type double.

Return Value

Returns the GeometryBvr object.

Remarks

By default, the attenuation coefficients are (1, 0, 0), which means no light attenuation. The bounding box is the bounding box of the underlying geometry.
An attenuation of (1, 1, 0) gives a linear attenuation that is useful for light falloff in a room. An attenuation of (1, 0, 1) gives a quadratic attenuation that simulates lights that are in the open, such as street lamps and headlights. This attribute overrides previous values.

lightColor

GeometryBvr Class

Creates a new geometry behavior in which all embedded lights have the specified color.

Syntax

public GeometryBvr lightColor( ColorBvr col );

Parameters

col
ColorBvr object.

Return Value

Returns the GeometryBvr object.

Remarks

By default, a light source is white. The bounding box is the bounding box of the underlying geometry.
This attribute overrides previous values.

opacity

GeometryBvr Class

Sets the opacity value for all surfaces to the given number behavior. Opacity values can range from 0.0 to 1.0.

Syntax

public GeometryBvr opacity( NumberBvr opac );

Parameters

opac
NumberBvr object representing the opacity value. The geometry is fully opaque if the value is 1, and fully transparent if the value is 0. This parameter can also be of type double.

Return Value

Returns the GeometryBvr object.

Remarks

If the opac parameter has a value outside the 0.0 to 1.0 range, the integer part of the value is discarded and only the fractional part is used. By default, the opacity is 1.
This attribute composes values. The resulting opacity is the new value times the old value.

render(camera)

GeometryBvr Class

Creates an image behavior that is a two-dimensional projection of this geometry behavior. The camera parameter defines how the geometry is projected into two dimensions.

Syntax

public ImageBvr render( CameraBvr camera );

Parameters

camera
CameraBvr object.

Return Value

Returns the ImageBvr object.

Remarks

The resulting image is infinite in extent. The bounding box of a rendered geometry is the axis-aligned extent of the projection of the three-dimensional bounding box onto the image plane.

render(mic)

GeometryBvr Class

Creates a sound behavior that represents the sound associated with this geometry behavior as detected by the given microphone.

Syntax

public SoundBvr render( MicrophoneBvr mic );

Parameters

mic
MicrophoneBvr object.

Return Value

Returns the SoundBvr object.

textureImage

GeometryBvr Class

Creates a new geometry behavior by mapping the given image, as defined by the given image behavior, to the surfaces of the original geometry.

This method replaces the earlier texture method. Texture continues to work for backward compatibility, but you should use textureImage, which defines the texture axes more accurately. Note that textureImage can be used only with versions of Microsoft® DirectAnimation® 6.xx.xxx.xxx or later.

Syntax

public GeometryBvr textureImage( ImageBvr image );

Parameters

image
ImageBvr object.

Return Value

Returns the GeometryBvr object.

Remarks

If the geometry has no surfaces, the texture is ignored. If the original geometry already has a texture, the new texture completely overlays the original. Texture maps have no effect when applied to a geometry that lacks texture coordinates. By default, a geometry has no texture. The bounding box is the bounding box of the underlying geometry.
This attribute overrides previous values.

transform

GeometryBvr Class

Creates a new geometry behavior that is the result of applying the given three-dimensional transformation to the original geometry behavior.

Syntax

public GeometryBvr transform( Transform3Bvr xf );

Parameters

xf
Transform3Bvr object.

Return Value

Returns the GeometryBvr object.

Remarks

The transformation applies to all points in the geometry, including those associated with the positions and orientations of light sources, textures, and sounds. The bounding box of a transformed geometry is the axis-aligned box enclosing the box that is the result of applying the transformation to the underlying geometry.
This attribute composes values.

Example

The following example rotates a red cube around the y-axis by PI/3 radians:

//Get the cube (assume there is light)
GeometryBvr c0 = import("cube.x");
//Color it red
GeometryBvr c1 = c0.diffuseColor(red);
//Rotate it
GeometryBvr c2 = c1.transform(
rotate(yVector3, toBvr(Math.PI/3)));

undetectable

GeometryBvr Class

Creates a new undetectable geometry behavior from the original geometry. An undetectable geometry means that, while the geometry is still as visible or as audible as before, any attempts to pick it are ignored.

Syntax

public GeometryBvr undetectable( );

Return Value

Returns the GeometryBvr object.

Remarks

The undetectable method is useful for specifying which objects are detectable and which are not. For example, suppose a semitransparent green sphere is used to simulate a glow around an object. Because this sphere encloses the object, the object itself would be unpickable. Instead, the pick information would always be for the sphere. Tagging the sphere as unpickable allows the object itself to be picked. This attribute overrides previous values.

newUninitBvr

GeometryBvr Class

Enables you to refer to an GeometryBvr behavior before that behavior has been defined. With this method you can create the behavior and use it in the definition of other behaviors, but not actually define its contents until some later point. (This is accomplished with the init method, which is available on all behaviors.) The system generates a run-time error if you initialize a non-uninitialized behavior, initialize an uninitialized behavior that has already been initialized, or run an initialized behavior that has not yet been initialized.

Syntax

public static GeometryBvr newUninitBvr( );

Return Value

Returns the GeometryBvr object.