Judging from the source code and andres' comments in the past, the upcoming Processing 2.0 only supports vertex and fragment shaders since it follows the OpenGL ES 2.0 specifications to ensure it will run on both desktop and mobile platforms. The current version of GLGraphics already supports geometry shaders (but only runs on Processing <2.0). Perhaps a future version of GLGraphics that is compatible with Processing 2.0 will support geometry and maybe even tessellator shaders.

Hi,

The getTessellation method returns null in the core PShape class and isn't overridden in the extended PShapeSVG and PShapeOBJ classes, however it is overridden in the PShapeOpenGL class. There is a lot of tesselation-related code in this class, but I believe it's mainly for drawing accurate geometry, lines in particular, as efficiently as possible. Not so much related to the tesselation shader as discussed above.

Hi, support for geometry shaders is not planned for Processing 2.x. As Amnon pointed out, the shader API follows the GLES 2.0 spec, which doesn't include geometry shaders. However, you can get the underlying JOGL objects and access all the GL functions for profiles 3.0+, which you can use to create and run shader programs with a geometry stage. The section "PGL interface" in this post might help.