Register a post-render-hook in fsbrain >= 0.5.0

fsbrain_register_post_render_hook.R

library(fsbrain)

# We use thickness on fsaverage as demo data
sjd = fsaverage.path();
sj = "fsaverage";

# Visualize once with standard settings:
vis.subject.morph.native(sjd, sj, "thickness");

# Register a post-render callback function that can do whatever you want:
post_render_hook = function(x){ rgl::light3d(diffuse="#333333"); message(sprintf("Adding more light to view '%s'.\n", x)); }
options('fsbrain.callback_hook_after_render' = post_render_hook);

# Visualize again. After rendering of each tile/rgl scene, the post_render_hook gets called.
# The scene is now brighter:
vis.subject.morph.native(sjd, sj, "thickness");

# You can reset to defaults if you do not want the hook anymore:
options('fsbrain.callback_hook_after_render' = NULL);