Cleanup: Remove no-op node preview function calls

This patch removes no-op node editor preview code (`PR_NODE_RENDER`)
and most calls to `BKE_node_preview_init_tree`. The only remaining call is
in the compositor.

 - Shader nodes previews don't seem to do anything.
 - In-node previews for the texture node system doesn't work either.

This is a first step to refactoring to remove `preview_xsize`,
`preview_ysize`, and `prvr` from nodes in DNA, aligned with
the general goal of removing runtime/derived data from data
structs.

Differential Revision: https://developer.blender.org/D13578

1 files changed, 1 insertions, 3 deletions

diff --git a/source/blender/editors/include/ED_render.h b/source/blender/editors/include/ED_render.h
index 50d7bfc3960..f60d62ed384 100644
--- a/source/blender/editors/include/ED_render.h
+++ b/source/blender/editors/include/ED_render.h
@@ -77,14 +77,12 @@ struct Scene *ED_render_job_get_current_scene(const struct bContext *C);
  * pr_method:
  * - PR_BUTS_RENDER: preview is rendered for buttons window
  * - PR_ICON_RENDER: preview is rendered for icons. hopefully fast enough for at least 32x32
- * - PR_NODE_RENDER: preview is rendered for node editor
  * - PR_ICON_DEFERRED: No render, we just ensure deferred icon data gets generated.
  */
 typedef enum ePreviewRenderMethod {
   PR_BUTS_RENDER = 0,
   PR_ICON_RENDER = 1,
-  PR_NODE_RENDER = 2,
-  PR_ICON_DEFERRED = 3,
+  PR_ICON_DEFERRED = 2,
 } ePreviewRenderMethod;
 
 void ED_preview_ensure_dbase(void);