Transform: reduce overhead when checking if snapping is active

No functional changes.

The code previously contained redundant and complex checks for
different snapping scenarios, which involved combinations of multiple
snapping flags and modes on each mouse interaction. This resulted in
unnecessary code duplication and overhead.

To address this issue, the code has been simplified and micro-optimized
by moving these checks to the initialization of the snapping parameters.

This results in a more streamlined and efficient codebase.

source/blender/editors/transform/transform.c

@@ -1069,17 +1069,24 @@ int transformEvent(TransInfo *t, const wmEvent *event)
         break;
 
       case TFM_MODAL_SNAP_INV_ON:
-        t->modifiers |= MOD_SNAP_INVERT;
-        t->redraw |= TREDRAW_HARD;
+        if (!(t->modifiers & MOD_SNAP_INVERT)) {
+          t->modifiers |= MOD_SNAP_INVERT;
+          transform_snap_flag_from_modifiers_set(t);
+          t->redraw |= TREDRAW_HARD;
+        }
         handled = true;
         break;
       case TFM_MODAL_SNAP_INV_OFF:
-        t->modifiers &= ~MOD_SNAP_INVERT;
-        t->redraw |= TREDRAW_HARD;
-        handled = true;
+        if (t->modifiers & MOD_SNAP_INVERT) {
+          t->modifiers &= ~MOD_SNAP_INVERT;
+          transform_snap_flag_from_modifiers_set(t);
+          t->redraw |= TREDRAW_HARD;
+          handled = true;
+        }
         break;
       case TFM_MODAL_SNAP_TOGGLE:
         t->modifiers ^= MOD_SNAP;
+        transform_snap_flag_from_modifiers_set(t);
         t->redraw |= TREDRAW_HARD;
         handled = true;
         break;

source/blender/editors/transform/transform_snap.cc

@@ -51,8 +51,6 @@
 #include "transform_convert.h"
 #include "transform_snap.h"
 
-static bool doForceIncrementSnap(const TransInfo *t);
-
 /* use half of flt-max so we can scale up without an exception */
 
 /* -------------------------------------------------------------------- */
@@ -120,10 +118,17 @@ bool validSnap(const TransInfo *t)
              (SNAP_MULTI_POINTS | SNAP_SOURCE_FOUND);
 }
 
+void transform_snap_flag_from_modifiers_set(TransInfo *t)
+{
+  SET_FLAG_FROM_TEST(t->tsnap.flag,
+                     (((t->modifiers & (MOD_SNAP | MOD_SNAP_INVERT)) == MOD_SNAP) ||
+                      ((t->modifiers & (MOD_SNAP | MOD_SNAP_INVERT)) == MOD_SNAP_INVERT)),
+                     SCE_SNAP);
+}
+
 bool transform_snap_is_active(const TransInfo *t)
 {
-  return ((t->modifiers & (MOD_SNAP | MOD_SNAP_INVERT)) == MOD_SNAP) ||
-         ((t->modifiers & (MOD_SNAP | MOD_SNAP_INVERT)) == MOD_SNAP_INVERT);
+  return (t->tsnap.flag & SCE_SNAP) != 0;
 }
 
 bool transformModeUseSnap(const TransInfo *t)
@@ -151,6 +156,11 @@ static bool doForceIncrementSnap(const TransInfo *t)
     return false;
   }
 
+  if (ELEM(t->spacetype, SPACE_ACTION, SPACE_NLA)) {
+    /* No incremental snapping. */
+    return false;
+  }
+
   return !transformModeUseSnap(t);
 }
 
@@ -456,15 +466,7 @@ bool transform_snap_project_individual_is_active(const TransInfo *t)
     return false;
   }
 
-  if (t->flag & T_NO_PROJECT) {
-    return false;
-  }
-
-  if (!((t->tsnap.flag & SCE_SNAP_PROJECT) || (t->tsnap.mode & SCE_SNAP_MODE_FACE_NEAREST))) {
-    return false;
-  }
-
-  if (doForceIncrementSnap(t)) {
+  if (!(t->tsnap.flag & SCE_SNAP_PROJECT)) {
     return false;
   }
 
@@ -516,10 +518,6 @@ static bool transform_snap_mixed_is_active(const TransInfo *t)
     return false;
   }
 
-  if (doForceIncrementSnap(t)) {
-    return false;
-  }
-
   return true;
 }
 
@@ -733,7 +731,12 @@ static eSnapTargetOP snap_target_select_from_spacetype(TransInfo *t)
 
 static void initSnappingMode(TransInfo *t)
 {
-  if ((t->spacetype != SPACE_VIEW3D) || !(t->tsnap.mode & SCE_SNAP_MODE_FACE_RAYCAST)) {
+  if (doForceIncrementSnap(t)) {
+    t->tsnap.mode = SCE_SNAP_MODE_INCREMENT;
+  }
+
+  if ((t->spacetype != SPACE_VIEW3D) || !(t->tsnap.mode & SCE_SNAP_MODE_FACE_RAYCAST) ||
+      (t->tsnap.mode & SCE_SNAP_MODE_FACE_NEAREST) || (t->flag & T_NO_PROJECT)) {
     /* Force project off when not supported. */
     t->tsnap.flag &= ~SCE_SNAP_PROJECT;
   }
@@ -1602,7 +1605,7 @@ static void snap_increment_apply(const TransInfo *t,
                                  const float increment_dist,
                                  float *r_val)
 {
-  BLI_assert((t->tsnap.mode & SCE_SNAP_MODE_INCREMENT) || doForceIncrementSnap(t));
+  BLI_assert(t->tsnap.mode & SCE_SNAP_MODE_INCREMENT);
   BLI_assert(max_index <= 2);
 
   /* Early bailing out if no need to snap */
@@ -1636,7 +1639,7 @@ bool transform_snap_increment_ex(const TransInfo *t, bool use_local_space, float
     return false;
   }
 
-  if (!(t->tsnap.mode & SCE_SNAP_MODE_INCREMENT) && !doForceIncrementSnap(t)) {
+  if (!(t->tsnap.mode & SCE_SNAP_MODE_INCREMENT)) {
     return false;
   }
 
@@ -1669,8 +1672,7 @@ bool transform_snap_increment(const TransInfo *t, float *r_val)
 float transform_snap_increment_get(const TransInfo *t)
 {
   if (transform_snap_is_active(t) &&
-      (!transformModeUseSnap(t) ||
-       (t->tsnap.mode & (SCE_SNAP_MODE_INCREMENT | SCE_SNAP_MODE_GRID)))) {
+      (t->tsnap.mode & (SCE_SNAP_MODE_INCREMENT | SCE_SNAP_MODE_GRID))) {
     return (t->modifiers & MOD_PRECISION) ? t->snap[1] : t->snap[0];
   }
 

source/blender/editors/transform/transform_snap.h

@@ -43,6 +43,7 @@ bool transform_snap_increment_ex(const TransInfo *t, bool use_local_space, float
 bool transform_snap_increment(const TransInfo *t, float *val);
 float transform_snap_increment_get(const TransInfo *t);
 
+void transform_snap_flag_from_modifiers_set(TransInfo *t);
 bool transform_snap_is_active(const TransInfo *t);
 
 bool validSnap(const TransInfo *t);