Package Jitter

jit.gl.volume

Create a volume visualization

Description

Creates a transparent volume from a volumetric density field. This process is GL accelerated by using graphics hardware.

Discussion

Internally, jit.gl.volume creates a 3d jit.gl.texture object and applies it to multiple view-aligned slices of geometry. The resulting slices are then blended together using the standard ob3d blend modes. The density and intensity attributes subsequently control which features are visibile. By enabling the cubes attribute, slices will be rendered in both horizontal and vertical direction, which may result in a visualization which that is comparatively better or worse depending on the volume dataset being used.
The jit.gl.volume object requires one argument: the name of a drawing context. A named drawing context is a named instance of a jit.window, jit.pwindow, or jit.matrix object that has an instance of the jit.gl.render object associated with it. Additionally it can reference the name of a jit.gl.node sub-context. This value may also be set via the OB3D drawto attribute. If no argument is present, the object is implicitly added to the first valid drawing context or sub-context found in the current patch or by searching up the patcher hierarchy.

Attributes

bounds[int]

Flag which enables or disables the rendering of the bounding box surrounding the volume (default = 0).

density[float]

The density threshold for constructing the surface. (default = 0.5)

intensity[float]

The intensity scale factor for multiplying against volume density values. (default = 0.5)

slices[int]

Sets he number of slices used as proxies for rendering the volume data.

OB3D Attributes

anim[symbol]

The name of a jit.anim.node object that handles all spatial transforms for this instance (default = UID). The default value references an internal object, but can be overridden by setting to the name of an existing external jit.anim.node instance. This allows for more advanced control of the spatial transform.

anchor[3 floats]

The anchor position in local space (default = 0. 0. 0.). Allows for offsetting the local 3D origin around which transforms are applied.

animmode[symbol]

Determines which space the anim_move and anim_turn messages will affect the position and orientation of this object (default = parent).
local = Rotate relative to local axis
parent = Rotate relative to parent axis
world = Rotate relative to world axis

automatic[int]

Automatic rendering flag (default = 1) When the flag is set, rendering occurs when the associated jit.gl.render object receives a bang message

aux_color[4 floats]

The auxiliary color in the form red green blue alpha (default = 0. 0. 0. 0.) The list elements should be in the range 0.-1.

axes[int]

x/y/z axis rendering off/on (default = 0)

blend[symbol]

The named blending mode. The possible values are:
add = blend_mode 1 1
multiply = blend_mode 2 1
screen = blend_mode 4 1
exclusion = blend_mode 4 5
colorblend = blend_mode 3 4
alphablend = blend_mode 6 7
coloradd = blend_mode 3 1
alphaadd = blend_mode 6 1

blend_enable[int]

Blending flag (default = 0) When the flag is set, blending is enabled for all rendered objects.

blend_mode[2 ints]

The source and destination planes associated with the blend mode (default = 6 7) Blend modes are specified in the form src_blend_mode dst_blend_mode. The supported modes are:
0 = zero
1 = one
2 = destination color
3 = source color
4 = one minus destination color
5 = one minus source color
6 = source alpha
7 = one minus source alpha
8 = destination alpha
9 = one minus destination alpha
10 = source alpha saturate

depth_clear[int]

Depth buffer clear flag (default = 0) When the flag is set, the depth buffer is cleared before rendering the object.

depth_enable[int]

Depth buffering flag (default = 1) When the flag is set, depth buffering is enabled.

depth_write[int]

Depth write flag (default = 1). When the flag is set, writing to the depth buffer is enabled. This will have no effect if depth_enable is turned off.

drawto[symbol]

The named drawing context in which to draw (default = none) A named drawing context is a named instance of a jit.window, jit.pwindow, or jit.matrix object that has an instance of the jit.gl.render object associated with it.

enable[int]

Enable flag (default = 1) When the flag is set, drawing is enabled.

filterclass[symbol]

The name of this object's pick filter class (default = default). This controls the visibility of objects to the jit.gl.handle and jit.gl.picker objects. In order to select this object, the filterclass value must be in the picking object's filters list.

layer[int]

Object layer number (default = 0) When in automatic mode, the layer number determines the rendering order (low to high). Objects in the same layer have no guarantee which will be rendered first.

name[symbol]

The instance name (default = UID)

position[3 floats]

The 3D origin in the form x y z (default = 0. 0. 0.)

quat[4 floats]

The current rotation as a quaternion(default = 0. 0. 0. 1.). A quaternion is a mathematical construct that is a four dimensional vector, and can be visualized as a rotation around an arbitrary axis. Quaternions are a useful representation of an orientation in 3D space.

rotate[4 floats]

The angle of rotation and the xyz vector about which the rotation is performed in the form rotation-angle x y z (default = 0. 0. 0. 1.)

rotatexyz[3 floats]

Sets the current rotation to the concatenation of rotations about the positive x, y, and z axes, also known as Euler angles (default = 0. 0. 0.). The default order is yzx and can be changed with the jit.gl.render rotate_order attribute. Angles are expressed in degrees.

scale[3 floats]

The 3D scaling factor in the form x y z (default = 1. 1. 1.)

smooth_shading[int]

Smooth shading flag (default = 0) When the flag is set, smooth shading is used when rendering.

transform_reset[int]

Modelview and projection transform reset flag (default = 0) When the flag is set, the modelview and projection transforms are set to the identity transform before rendering the object. This is useful for sprite or billboard overlays, or automatic scaling to window size. The transform_reset flag modes are:
0 = do nothing (default)
1 = proportional orthographic glOrtho(-aspect, aspect, -1.0, 1.0, near_clip, far_clip);
2 = orthographic normalized glOrtho(-1.0, 1.0, -1.0, 1.0, near_clip, far_clip);
3 = proportional perspective with near clip = 0.001 gluPerspective(lens_angle, aspect, 0.001/*near_clip*/, far_clip);
4 = normalized perspective with near clip = 0.001 gluPerspective(lens_angle, 1.0, 0.001/*near_clip*/, far_clip);

viewalign[int]

View aligned transformation flag (default = 0)

Common Box Attributes

Below is a list of attributes shared by all objects. If you want to change one of these attributes for an object based on the object box, you need to place the word sendbox in front of the attribute name, or use the object's Inspector.

annotation[symbol]

Sets the text that will be displayed in the Clue window when the user moves the mouse over the object.

background[int]: 0

Adds or removes the object from the patcher's background layer. background 1 adds the object to the background layer, background 0 removes it. Objects in the background layer are shown behind all objects in the default foreground layer.

color[4 floats]

Sets the color for the object box outline.

fontface[int]

Sets the type style used by the object. The options are:

plain
bold
italic
bold italic Possible values:

0 = 'regular'
1 = 'bold'
2 = 'italic'
3 = 'bold italic'

fontname[symbol]

Sets the object's font.

fontsize[float]

Sets the object's font size (in points). Possible values:

'8'
'9'
'10'
'11'
'12'
'13'
'14'
'16'
'18'
'20'
'24'
'30'
'36'
'48'
'64'
'72'

hidden[int]: 0

Toggles whether an object is hidden when the patcher is locked.

hint[symbol]

Sets the text that will be displayed in as a pop-up hint when the user moves the mouse over the object in a locked patcher.

ignoreclick[int]: 0

Toggles whether an object ignores mouse clicks in a locked patcher.

jspainterfile[symbol]

JS Painter File

patching_rect[4 floats]: 0. 0. 100. 0.

Sets the position and size of the object in the patcher window.

position[2 floats]
write-only

Sets the object's x and y position in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its size unchanged.

presentation[int]: 0

Sets whether an object belongs to the patcher's presentation.

presentation_rect[4 floats]: 0. 0. 0. 0.

Sets the x and y position and width and height of the object in the patcher's presentation, leaving its patching position unchanged.

rect[4 floats]
write-only

Sets the x and y position and width and height of the object in both patching and presentation modes (if the object belongs to its patcher's presentation).

size[2 floats]
write-only

Sets the object's width and height in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its position unchanged.

textcolor[4 floats]

Sets the color for the object's text in RGBA format.

textjustification[int]

Sets the justification for the object's text. Possible values:

0 = 'left'
1 = 'center'
2 = 'right'

varname[symbol]

Sets the patcher's scripting name, which can be used to address the object by name in pattr, scripting messages to thispatcher, and the js object.

Messages

OB3D Messages

bang

Equivalent to the draw message.

draw

Draws the object in the named drawing destination. If the matrixoutput attribute is supported and set to 1, the geometry matrices are sent out the object's left outlet.

drawraw

Equivalent to draw with the inherit_all attribute set to 1.

drawimmediate

Equivalent to draw but ignoring any potential renderer setup

anim_move

Move the object along the axis provided, relative to the space indicated by animmode.

Arguments:
  • x [float]
  • y [float]
  • z [float]

anim_turn

Rotate the object along each axis by the amount provided, relative to the space indicated by animmode.

Arguments:
  • x [float]
  • y [float]
  • z [float]

anim_grow

Scale the object along each axis by the amount provided.

Arguments:
  • x [float]
  • y [float]
  • z [float]

anim_reset

Reset the local transformation attributes to their default values (position = 0 0 0, rotatexyz = 0 0 0, and scale = 1 1 1)

update_node

Update the node transformation attributes.

See Also

Name Description
jit.gl.graph Graph floats into 3D space
jit.gl.gridshape Generate simple geometric shapes as a grid
jit.gl.handle Use mouse movement to control position/rotation
jit.gl.isosurf Generate a GL based surface extraction
jit.gl.mesh Generate GL geometry from matrices
jit.gl.model Read and draw various 3D model formats
jit.gl.nurbs Generate NURBS surface
jit.gl.plato Generate platonic solids
jit.gl.render Render Jitter OpenGL objects
jit.gl.shader Manage a GL shader
jit.gl.sketch Use drawing commands with OpenGL
jit.gl.slab Process texture data
jit.gl.text2d Render bitmap text
jit.gl.text3d Render vector text
jit.gl.texture Create OpenGL textures
jit.gl.videoplane Display video in OpenGL