Cleanup: Remove scene frame macros (`CFRA` et al.)

Removes the following macros for scene/render frame values:
- `CFRA`
- `SUBFRA`
- `SFRA`
- `EFRA`

These macros don't add much, other than saving a few characters when typing.
It's not immediately clear what they refer to, they just hide what they
actually access. Just be explicit and clear about that.
Plus these macros gave read and write access to the variables, so eyesores like
this would be done (eyesore because it looks like assigning to a constant):
```
CFRA = some_frame_nbr;
```

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D15311

1 files changed, 8 insertions, 7 deletions

diff --git a/source/blender/editors/render/render_opengl.cc b/source/blender/editors/render/render_opengl.cc
index d907a52543c..7bd9812a178 100644
--- a/source/blender/editors/render/render_opengl.cc
+++ b/source/blender/editors/render/render_opengl.cc
@@ -494,7 +494,8 @@ static void screen_opengl_render_apply(const bContext *C, OGLRender *oglrender)
     for (view_id = 0; view_id < oglrender->views_len; view_id++) {
       context.view_id = view_id;
       context.gpu_offscreen = oglrender->ofs;
-      oglrender->seq_data.ibufs_arr[view_id] = SEQ_render_give_ibuf(&context, CFRA, chanshown);
+      oglrender->seq_data.ibufs_arr[view_id] = SEQ_render_give_ibuf(
+          &context, scene->r.cfra, chanshown);
     }
   }
 
@@ -1136,12 +1137,12 @@ static bool screen_opengl_render_anim_step(bContext *C, wmOperator *op)
   RenderResult *rr;
 
   /* go to next frame */
-  if (CFRA < oglrender->nfra) {
-    CFRA++;
+  if (scene->r.cfra < oglrender->nfra) {
+    scene->r.cfra++;
   }
-  while (CFRA < oglrender->nfra) {
+  while (scene->r.cfra < oglrender->nfra) {
     BKE_scene_graph_update_for_newframe(depsgraph);
-    CFRA++;
+    scene->r.cfra++;
   }
 
   is_movie = BKE_imtype_is_movie(scene->r.im_format.imtype);
@@ -1184,7 +1185,7 @@ static bool screen_opengl_render_anim_step(bContext *C, wmOperator *op)
   }
 
   if (oglrender->render_frames == nullptr ||
-      BLI_BITMAP_TEST_BOOL(oglrender->render_frames, CFRA - PSFRA)) {
+      BLI_BITMAP_TEST_BOOL(oglrender->render_frames, scene->r.cfra - PSFRA)) {
     /* render into offscreen buffer */
     screen_opengl_render_apply(C, oglrender);
   }
@@ -1204,7 +1205,7 @@ finally: /* Step the frame and bail early if needed */
   oglrender->nfra += scene->r.frame_step;
 
   /* stop at the end or on error */
-  if (CFRA >= PEFRA || !ok) {
+  if (scene->r.cfra >= PEFRA || !ok) {
     screen_opengl_render_end(C, static_cast<OGLRender *>(op->customdata));
     return false;
   }