jit.gl.asyncread
Read back from an OpenGL framebuffer
Description
Uses Pixel Buffer Objects (PBOs) to perform asynchronous reads of the OpenGL context at high framerates. The performance gain comes from using two pixel buffer objects in tandem to amortize the cost of the read operation over time without blocking other rendering commands from executing as is typically the case when naive methods are used.
Discussion
This 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.
Arguments
None.
Attributes
matrixoutput[int]
Output a copy of the frame buffer (OpenGL render context). The output matrix dimensions adapt to the size of the window.
mode[symbol]
Sets the reading mode (default = interleaved).
Possible values:
'interleaved'
(
Reads an entire frame into each internal buffer, switching buffers every other frame. In interleaved mode, the readback is delayed for one frame.
)
'split'
(
Reads a single frame in two passes and the output is concurrent.
)
out_name[symbol]
read-only
Returns the name of the internal frame buffer (OpenGL render context).
texture[symbol]
Sets the name of the texture to readback. If not set, the readback is performed on the the drawto context.
OB3D Attributes
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
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.
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)
shader[symbol]
The name of the shader to be applied (default = none)
Common Box Attributes
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'
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]
You can override the default appearance of a user interface object by assigning a JavaScript file with code for painting the object. The file must be in the search path.
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
jit_gl_texture
Binds the texture specified by texture-name to this object. Equivalent to setting the texture attribute to texture-name .
- texture-name
[symbol]
get_shader
Open an editor window containing the object's current JXS shader.
See Also
| Name | Description |
|---|---|
| jit.gl.node | Create hierarchical rendering groups |
| jit.gl.pix | Generates pixel processing shaders from a gen patcher |
| jit.gl.slab | Process texture data |
| jit.gl.videoplane | Display video in OpenGL |
| jit.world | The Jitter world context |