scene - Create and manipulate 3D scenes widgets

scene pathName ?options?

Command-Line Name: -borderwidth

Database Name: borderWidth

Database Class: BorderWidth

Command-Line Name: -highlightthickness

Database Name: highlightThickness

Database Class: HighlightThickness

Command-Line Name: -background

Database Name: background

Database Class: Background

Command-Line Name: -height

Database Name: height

Database Class: Height

Specifies a desired window height that the scene widget should request from its geometry manager. The value may be specified in any of the forms acceptable to Tk_GetPixels(). Defaults to 320 pixels.

Command-Line Name: -width

Database Name: width

Database Class: Width

Specifies a desired window width that the scene widget should request from its geometry manager. The value may be specified in any of the forms acceptable to Tk_GetPixels(). Defaults to 320 pixels.

Command-Line Name: -ident

Database Name: ident

Database Class: Ident

Specifies a string value that may be used has a flag to identifiate this window. Default to the empty string.

Command-Line Name: -double

Database Name: double

Database Class: Double

Specifies a boolean value that indicates whether or not the user is asking for a double buffered window. Defaults to true.

Command-Line Name: -rgba

Database Name: rgba

Database Class: Rgba

Specifies a boolean value that indicates whether or not context is created in RGBA mode. Dafaults to true.

Command-Line Name: -depth

Database Name: depth

Database Class: Depth

Specifies a boolean value that indicates whether or not context is created with depth buffer. Defaults to true.

Command-Line Name: -orthographic

Database Name: orthographic

Database Class: Orthographic

Specifies a boolean value that indicates whether or not context used orthographic projection. Defaults to false.

Command-Line Name: -accum

Database Name: accum

Database Class: Accum

Command-Line Name: -alpha

Database Name: alpha

Database Class: Alpha

Specifies a boolean value that indicates whether or not context supports alpha. Defaults to false.

Command-Line Name: -stencil

Database Name: stencil

Database Class: Stencil

Specifies a boolean value that indicates whether or not context supports stencil. Defaults to false.

Command-Line Name: -stencilsize

Database Name: stencilsize

Database Class: StencilSize

Specifies an integer value that indicates size of stencil channel, if stencil is enabled. Defaults to 1.

Command-Line Name: -redsize

Database Name: redsize

Database Class: RedSize

Specifies an integer value that indicates size of red channel. Defaults to 1.

Command-Line Name: -greensize

Database Name: greensize

Database Class: GreenSize

Specifies an integer value that indicates size of green channel. Defaults to 1.

Command-Line Name: -bluesize

Database Name: bluesize

Database Class: BlueSize

Specifies an integer value that indicates size of blue channel. Defaults to 1.

Command-Line Name: -alphasize

Database Name: alphasize

Database Class: AlphaSize

Specifies an integer value that indicates size of alpha channel. Defaults to 1.

Command-Line Name: -accumredsize

Database Name: accumredsize

Database Class: AccumRedSize

Specifies an integer value that indicates size of red accumulation channel. Defaults to 1.

Command-Line Name: -accumgreensize

Database Name: accumgreensize

Database Class: AccumGreenSize

Specifies an integer value that indicates size of green accumulation channel. Defaults to 1.

Command-Line Name: -accumbluesize

Database Name: accumbluesize

Database Class: AccumBlueSize

Specifies an integer value that indicates size of blue accumulation channel. Defaults to 1.

Command-Line Name: -accumalphasize

Database Name: accumalphasize

Database Class: AccumAlphaSize

Specifies an integer value that indicates size of alpha accumulation channel. Defaults to 1.

Command-Line Name: -depthsize

Database Name: depthsize

Database Class: DepthSize

Specifies an integer value that indicates size of depth buffer. Defaults to 1.

Command-Line Name: -redraw

Database Name: redraw

Database Class: Redraw

Name of Tcl callback function to evaluate to render scene. If no callback specified, defaults to rendering all compiled lists declared for this widget.

Those options are use to configure viewport:

Command-Line Name: -left

Database Name: left

Database Class: Left

Specifies a double value that indicates left coordinate of intersection of visible region with plane at depth 1.0. Default to -1.0.

Command-Line Name: -right

Database Name: right

Database Class: Right

Specifies a double value that indicates right coordinate of intersection of visible region with plane at depth 1.0. Default to 1.0.

Command-Line Name: -bottom

Database Name: bottom

Database Class: Bottom

Specifies a double value that indicates bottom coordinate of intersection of visible region with plane at depth 1.0. Default to -1.0.

Command-Line Name: -top

Database Name: top

Database Class: Top

Specifies a double value that indicates top coordinate of intersection of visible region with plane at depth 1.0. Default to 1.0.

Command-Line Name: -near

Database Name: near

Database Class: Near

Specifies a double value that indicates distance of near face of the visible cube. Any object placed before this plane will be clipped. Default to 0.01.

Command-Line Name: -far

Database Name: far

Database Class: Far

Specifies a double value that indicates distance of far face of the visible cube. Any object placed behind this plane will be clipped. Default to 10.0.

The scene command creates a new window (given by the pathName argument) and makes it into a 3D scene renderer widget. Additional options, described above, may be specified on the command line or in the option database to configure aspects of the scene such as its colors and 3-D relief. The scene command returns its pathName argument. At the time this command is invoked, there must not exist a window named pathName, but pathName's parent must exist.

Scene widgets implement a state machine, based on the OpenGL API.

The scene command creates a new Tcl command whose name is pathName. This command may be used to invoke various operations on the widget. It has the following general form:

pathName option ?arg arg ...?

Option and the args determine the exact behavior of the command. The following widget commands are possible for scene widgets: cget, configure, version, extensions, begin, end, lbegin, lend, ldelete, lcall, vertex, normal, color, material, texture, texmode, fog, translate, scale, rotate, enable, and disable. cameramove, camerarotate, navigate, render, and dump,

pathName cget

Returns the current value of the configuration option given by option. Option may have any of the values accepted by the scene command.

pathName configure

Query or modify the configuration options of the widget. If no option is specified, returns a list describing all of the available options for pathName (see Tk_ConfigureInfo for information on the format of this list). If option is specified with no value, then the command returns a list describing the one named option (this list will be identical to the corresponding sublist of the value returned if no option is specified). If one or more option-value pairs are specified, then the command modifies the given widget option(s) to have the given value(s); in this case the command returns an empty string. Option may have any of the values accepted by the scene command.

pathName version

Returns version of OpenGL engine

pathName extensions

Returns list of extensions supported by OpenGL engine

pathName begin mode

This commands starts declaration of object. mode must be one of points,lines,line_loop,line_strip, triangles,triangle_strip,triangle_fan, quads,quad_strip or polygon.

pathName end

Terminates current object

pathName lbegin

Starts a new compiled list. Returns the list Id.

pathName lend

Termintes current list.

pathName ldelete ?listid listid ...?

Delete compiled lists.

pathName lcall ?listid listid ...?

Call compiled lists.

pathName vertex

Add new vertex to object currently defined.

pathName normal

Defines normal for next vertices in object currently defined.

pathName color colorvalue

Defines color for next vertices in object currently defined.

pathName material ?options ...?

Defines material for next vertices in object currently defined. Valid options are -side, -diffuse, -specular, -emission, -shininess, -texture and -texcoords.

pathName light ?lightid? ?options ...?

Defines properties for light lightid, with id an integer in the range 0 ... 7. Valid options are:

• -position vector: set light position
• -direction vector: set spot direction
• -ambient color: set ambient color for light
• -diffuse color: set diffuse color for light
• -specular color: set specular color for light
• -exponent double: set exponent for light attenuation. Default to 0.0
• -cutoff double: set cutoff for light, in degres. Defaut to 180
• -constant double: set constant coefficient for light attenuation. Default to 1.0
• -linear double: set linear coefficient for light attenuation. Default to 0.0
• -quadratic double: set quadratic coefficient for light attenuation. Default to 0.0

.

pathName texture photoName

Defines a scene texture from Tk photo. Photo content is converted into texture immediatly, so photo handle is no more used, and can be released. Returns a texture Id to be used as -texture argument in material sub-command.

pathName texmode

Defines the texture mode for future material. Valid values are decal, replace, modulate or blend.

pathName fog

pathName translate

Translates scene. This transformation can be compiled into list.

pathName scale

Scales scene. This transformation can be compiled into list.

pathName rotate angle

Rotate scene. This transformation can be compiled into list.

pathName enable ?flag flag ...?

pathName disable ?flag flag ...?

Enable or disable features for scene. Valid values for flags are:

• offset
• fog
• lighting
• light0
• light1
• light2
• light3
• light4
• light5
• light6
• light7
• cull_face
• normalize
• dither
• depth_test
• alpha_test
• color_material
• blend
• texture_2d

pathName navigate

This commands registers bindings to navigate into scene. This is a simple helper.

pathName cameramove

Moves camera location

pathName camerarotate

pathName render

pathName dump ?photoname?

Takes snapshot of scene content and save it into a Tk Photo handle. If photoname is ommited, a photo name is automatically attributed to result. Name of photo handle is returned.

In the current implementation, new scenes are not given any default behavior. You'll have to execute explicit Tcl commands to give the scene its behavior.

Even if no code comes from it, the developpment of this 3D scene widget has been inspired by the Togl widget from Brian Paul (the author of the so great Mesa library). The Togl widget was however not yet ported to Win32 platform when this project was initiated, whereas it was our first need. Furthermore, the Togl widget requires C programming, whereas we had the need for a pure portable scripting approach. We have the hope that, whereas Togl is particulary suitable in offering to OpenGL developpers an easy way to build a GUI for their application, our scene widget might help the Tcl/Tk communauty in easily  providing some 3D functionnalities in their applications.