Slicer3:Python:ScriptedActor - Revision history

Pieper: /* Answer */

2014-10-28T17:19:16Z

Answer

Pieper: /* Considerations */

2009-05-07T18:48:48Z

Considerations

Pieper: /* Considerations */

2009-05-07T18:46:26Z

Considerations

Pieper: /* Answer */

2009-05-07T18:25:50Z

Answer

Pieper: /* Answer */

2009-05-07T18:23:49Z

Answer

Pieper: New page: After a conversation with Gordon Kindlmann, I (Steve Pieper) decided to try an experiment... == Question == Can python be used to tie non-VTK-aware OpenGL C++ code into VTK? == Answer =...

2009-05-07T18:15:01Z

New page: After a conversation with Gordon Kindlmann, I (Steve Pieper) decided to try an experiment... == Question == Can python be used to tie non-VTK-aware OpenGL C++ code into VTK? == Answer =...

New page

After a conversation with Gordon Kindlmann, I (Steve Pieper) decided to try an experiment...

== Question ==

Can python be used to tie non-VTK-aware OpenGL C++ code into VTK?

== Answer ==

I [http://viewvc.slicer.org/viewcvs.cgi?rev=9422&view=rev checked in some code] to make this possible. The C++ class, vtkOpenGLScriptedActor, allows you to specify a script that should be executed inside the VTK render process. This calls out to python, where arbitrary code can be run (something like a callback).

The example script shows how to draw some simple OpenGL shapes in the same window with a VTK managed sphere. The example relies on having [http://pyopengl.sourceforge.net/ PyOpenGL] installed in Slicer's python.

The result is shown in the image to the right.

[[Image:VtkOpenGLScriptedActor.png|thumb|300px|right]]

← Older revision		Revision as of 18:48, 7 May 2009
Line 41:		Line 41:
	* The python code can invoke arbitrary C or C++ code through various mechanisms. If this code isn't VTK-aware, then the python code may be able to provide the needed compatibility glue.		* The python code can invoke arbitrary C or C++ code through various mechanisms. If this code isn't VTK-aware, then the python code may be able to provide the needed compatibility glue.
	* Additional experiments and research will be needed to determine how much OpenGL state needs to be explicitly saved and restored in order to ensure that VTK assumptions are met. Mike Halle points out that OpenGL state saving/restoring can be expensive, so care should be taken.		* Additional experiments and research will be needed to determine how much OpenGL state needs to be explicitly saved and restored in order to ensure that VTK assumptions are met. Mike Halle points out that OpenGL state saving/restoring can be expensive, so care should be taken.
		+	* The python code can be passed references to VTK objects (like vtkImageData or vtkPolyData) from which the data arrays can be made available as numpy arrays to feed into custom rendering code. Similarly, a vtkProperty can be used to store rendering parameters.

← Older revision		Revision as of 18:46, 7 May 2009
Line 40:		Line 40:
	* OpenGL is moving to Vertex Buffer Objects and these are interoperable with numpy arrays, so large amounts of data can be manipulated with single calls.		* OpenGL is moving to Vertex Buffer Objects and these are interoperable with numpy arrays, so large amounts of data can be manipulated with single calls.
	* The python code can invoke arbitrary C or C++ code through various mechanisms. If this code isn't VTK-aware, then the python code may be able to provide the needed compatibility glue.		* The python code can invoke arbitrary C or C++ code through various mechanisms. If this code isn't VTK-aware, then the python code may be able to provide the needed compatibility glue.
		+	* Additional experiments and research will be needed to determine how much OpenGL state needs to be explicitly saved and restored in order to ensure that VTK assumptions are met. Mike Halle points out that OpenGL state saving/restoring can be expensive, so care should be taken.

← Older revision		Revision as of 18:25, 7 May 2009
Line 13:		Line 13:

	The result is shown in the image to the right.		The result is shown in the image to the right.
		+
		+	The excerpt of code below shows how the actor is instanced and used.
		+
		+	<pre>
		+	sactor = s.vtkOpenGLScriptedActor()
		+	sactor.SetMapper(mapper) # not really used, but needed so actor is called
		+	sactor.SetScript('Render()')
		+	ren1.AddActor(sactor)
		+
		+	def Render():
		+	glDisable( GL_CULL_FACE )
		+	## Moves the drawing origin 1.5 units to the left
		+	glTranslatef(-1.5,0.0,0.0)
		+	## Starts the geometry generation mode
		+	glBegin(GL_TRIANGLES)
		+	glVertex3f( 0.0, 1.0, 0.0)
		+	glVertex3f(-1.0, -1.0, 0.0)
		+	glVertex3f( 1.0, -1.0, 0.0)
		+	glEnd()
		+	</pre>

	== Considerations ==		== Considerations ==

@@ Line 8: / Line 8: @@
 [[Image:VtkOpenGLScriptedActor.png|thumb|300px|right]]
-I [http://viewvc.slicer.org/viewcvs.cgi?rev=9422&view=rev checked in some code] to make this possible.  The C++ class, vtkOpenGLScriptedActor, allows you to specify a script that should be executed inside the VTK render process.  This calls out to python, where arbitrary code can be run (something like a callback).
+I [http://viewvc.slicer.org/viewvc.cgi/Slicer3?view=revision&revision=9422 checked in some code] to make this possible.  The C++ class, vtkOpenGLScriptedActor, allows you to specify a script that should be executed inside the VTK render process.  This calls out to python, where arbitrary code can be run (something like a callback).
 The example script shows how to draw some simple OpenGL shapes in the same window with a VTK managed sphere.  The example relies on having [http://pyopengl.sourceforge.net/ PyOpenGL] installed in Slicer's python.

@@ Line 6: / Line 6: @@
 == Answer ==
 I [http://viewvc.slicer.org/viewcvs.cgi?rev=9422&view=rev checked in some code] to make this possible.  The C++ class, vtkOpenGLScriptedActor, allows you to specify a script that should be executed inside the VTK render process.  This calls out to python, where arbitrary code can be run (something like a callback).
@@ Line 13: / Line 14: @@
 The result is shown in the image to the right.
-[[Image:VtkOpenGLScriptedActor.png|thumb|300px|right]]
+== Considerations ==