TouchDesigner specific functions in Geometry Shader

[n23]

Hi,

I’m working on a geometry shader for converting models into voxels. Basically it should convert each triangle into a little cube (12 triangles).

In geometry shader I have current world coords (passed from vertex shader), so I can build 12 triangles in the proper place, but then TDWorldToProj() function is missing for easy conversion to final gl_Position.

On the wiki there’s no information about any TD functions available for geometry shaders derivative.ca/wiki099/index … _Functions

Why functions like TDWorldToProj() are not available in geometry shaders?

[n23]

I was able to do the projection using a tip from the wiki:

// For example you’d transform the vertex in SOP space into camera space with this line of code
// vec4 camSpaceVert = uTDMats[TDCameraIndex()].worldCam * vec4(P, 1.0);

Using .worldCamProj instead of .worldCam does the job:

vec4 camSpaceVert = uTDMats[TDCameraIndex()].worldCamProj * vec4(P, 1.0);

So I’ve solved my issue, but still it would be good to know why there’s no helper functions in geometry shaders. Performance reasons?