Sets a source string that will be inserted before the hook point in the generated shader for the pipeline that this snippet is attached to.
Please see the documentation of each hook point in Pipeline for a description of how this string should be used.
This function should only be called before the snippet is attached to its first pipeline. After that the snippet should be considered immutable.
| this |
A Snippet |
| pre |
The new source string for the pre section of this snippet. |