Fix T101991: "Absolute Grid Snap" not working

Error introduced in rB1edebb794b76.

In that commit it was kind of forgotten that the snap to grid is also
used in 3D views.

Also a refactoring and cleanup was applied to simplify the code.

source/blender/editors/transform/transform.c

@@ -1721,13 +1721,17 @@ void saveTransform(bContext *C, TransInfo *t, wmOperator *op)
   }
 }
 
-static void initSnapSpatial(TransInfo *t, float r_snap[2], float r_snap_y[2])
+static void initSnapSpatial(TransInfo *t, float r_snap[3], float *r_snap_precision)
 {
+  /* Default values. */
+  r_snap[0] = r_snap[1] = 1.0f;
+  r_snap[1] = 0.0f;
+  *r_snap_precision = 0.1f;
+
   if (t->spacetype == SPACE_VIEW3D) {
     if (t->region->regiondata) {
       View3D *v3d = t->area->spacedata.first;
-      r_snap[0] = ED_view3d_grid_view_scale(t->scene, v3d, t->region, NULL) * 1.0f;
-      r_snap[1] = r_snap[0] * 0.1f;
+      r_snap[0] = r_snap[1] = r_snap[2] = ED_view3d_grid_view_scale(t->scene, v3d, t->region, NULL);
     }
   }
   else if (t->spacetype == SPACE_IMAGE) {
@@ -1741,24 +1745,16 @@ static void initSnapSpatial(TransInfo *t, float r_snap[2], float r_snap_y[2])
     ED_space_image_grid_steps(sima, grid_steps_x, grid_steps_y, grid_size);
     /* Snapping value based on what type of grid is used (adaptive-subdividing or custom-grid). */
     r_snap[0] = ED_space_image_increment_snap_value(grid_size, grid_steps_x, zoom_factor);
-    r_snap[1] = r_snap[0] / 2.0f;
-    r_snap_y[0] = ED_space_image_increment_snap_value(grid_size, grid_steps_y, zoom_factor);
-    r_snap_y[1] = r_snap_y[0] / 2.0f;
+    r_snap[1] = ED_space_image_increment_snap_value(grid_size, grid_steps_y, zoom_factor);
+    *r_snap_precision = 0.5f;
   }
   else if (t->spacetype == SPACE_CLIP) {
-    r_snap[0] = 0.125f;
-    r_snap[1] = 0.0625f;
+    r_snap[0] = r_snap[1] = 0.125f;
+    *r_snap_precision = 0.5f;
   }
   else if (t->spacetype == SPACE_NODE) {
     r_snap[0] = r_snap[1] = ED_node_grid_size();
   }
-  else if (t->spacetype == SPACE_GRAPH) {
-    r_snap[0] = 1.0;
-    r_snap[1] = 0.1f;
-  }
-  else {
-    r_snap[0] = r_snap[1] = 1.0f;
-  }
 }
 
 bool initTransform(bContext *C, TransInfo *t, wmOperator *op, const wmEvent *event, int mode)
@@ -1898,7 +1894,7 @@ bool initTransform(bContext *C, TransInfo *t, wmOperator *op, const wmEvent *eve
 
   initSnapping(t, op); /* Initialize snapping data AFTER mode flags */
 
-  initSnapSpatial(t, t->snap_spatial_x, t->snap_spatial_y);
+  initSnapSpatial(t, t->snap_spatial, &t->snap_spatial_precision);
 
   /* EVIL! posemode code can switch translation to rotate when 1 bone is selected.
    * will be removed (ton) */

source/blender/editors/transform/transform.h

@@ -555,9 +555,12 @@ typedef struct TransInfo {
   /** Snapping Gears. */
   float snap[2];
   /** Spatial snapping gears(even when rotating, scaling... etc). */
-  float snap_spatial_x[2];
-  /** Spatial snapping in the Y coordinate, for non-uniform grid in UV Editor. */
-  float snap_spatial_y[2];
+  float snap_spatial[3];
+  /**
+   * Precision factor that is multiplied to snap_spatial when precision
+   * modifier is enabled for snap to grid or incremental snap.
+   */
+  float snap_spatial_precision;
   /** Mouse side of the current frame, 'L', 'R' or 'B' */
   char frame_side;
 

source/blender/editors/transform/transform_mode_translate.c

@@ -590,7 +590,8 @@ void initTranslation(TransInfo *t)
   t->num.flag = 0;
   t->num.idx_max = t->idx_max;
 
-  copy_v2_v2(t->snap, t->snap_spatial_x);
+  t->snap[0] = 1.0;
+  t->snap[1] = t->snap_spatial_precision;
 
   copy_v3_fl(t->num.val_inc, t->snap[0]);
   t->num.unit_sys = t->scene->unit.system;

source/blender/editors/transform/transform_snap.c

@@ -519,16 +519,14 @@ void applyGridAbsolute(TransInfo *t)
     return;
   }
 
-  float grid_size_x = (t->modifiers & MOD_PRECISION) ? t->snap_spatial_x[1] : t->snap_spatial_x[0];
-  float grid_size_y = (t->modifiers & MOD_PRECISION) ? t->snap_spatial_y[1] : t->snap_spatial_y[0];
-  float grid_size_z = grid_size_x;
-
-  if (grid_size_y == 0.0f) {
-    grid_size_y = grid_size_x; /* Just use `grid_size_x` when `grid_size_y` isn't set correctly. */
+  float grid_size[3];
+  copy_v3_v3(grid_size, t->snap_spatial);
+  if (t->modifiers & MOD_PRECISION) {
+    mul_v3_fl(grid_size, t->snap_spatial_precision);
   }
 
   /* Early exit on unusable grid size. */
-  if (grid_size_x == 0.0f || grid_size_y == 0.0f || grid_size_z == 0.0f) {
+  if (is_zero_v3(grid_size)) {
     return;
   }
 
@@ -554,9 +552,9 @@ void applyGridAbsolute(TransInfo *t)
         copy_v3_v3(iloc, td->ob->obmat[3]);
       }
 
-      loc[0] = roundf(iloc[0] / grid_size_x) * grid_size_x;
-      loc[1] = roundf(iloc[1] / grid_size_y) * grid_size_y;
-      loc[2] = roundf(iloc[2] / grid_size_z) * grid_size_z;
+      loc[0] = roundf(iloc[0] / grid_size[0]) * grid_size[0];
+      loc[1] = roundf(iloc[1] / grid_size[1]) * grid_size[1];
+      loc[2] = grid_size[2] ? roundf(iloc[2] / grid_size[2]) * grid_size[2] : iloc[2];
 
       sub_v3_v3v3(tvec, loc, iloc);
       mul_m3_v3(td->smtx, tvec);
@@ -1660,8 +1658,7 @@ bool snapNodesTransform(
 
 static void snap_grid_apply(TransInfo *t,
                             const int max_index,
-                            const float grid_dist_x,
-                            const float grid_dist_y,
+                            const float grid_dist[3],
                             const float loc[3],
                             float r_out[3])
 {
@@ -1680,7 +1677,7 @@ static void snap_grid_apply(TransInfo *t,
   }
 
   for (int i = 0; i <= max_index; i++) {
-    const float iter_fac = ((i == 1) ? grid_dist_y : grid_dist_x) * asp[i];
+    const float iter_fac = grid_dist[i] * asp[i];
     r_out[i] = iter_fac * roundf((in[i] + center_global[i]) / iter_fac) - center_global[i];
   }
 }
@@ -1705,15 +1702,18 @@ bool transform_snap_grid(TransInfo *t, float *val)
     return false;
   }
 
-  float grid_dist_x = (t->modifiers & MOD_PRECISION) ? t->snap_spatial_x[1] : t->snap_spatial_x[0];
-  float grid_dist_y = (t->modifiers & MOD_PRECISION) ? t->snap_spatial_y[1] : t->snap_spatial_y[0];
+  float grid_dist[3];
+  copy_v3_v3(grid_dist, t->snap_spatial);
+  if (t->modifiers & MOD_PRECISION) {
+    mul_v3_fl(grid_dist, t->snap_spatial_precision);
+  }
 
   /* Early bailing out if no need to snap */
-  if (grid_dist_x == 0.0f || grid_dist_y == 0.0f) {
+  if (is_zero_v3(grid_dist)) {
     return false;
   }
 
-  snap_grid_apply(t, t->idx_max, grid_dist_x, grid_dist_y, val, val);
+  snap_grid_apply(t, t->idx_max, grid_dist, val, val);
   t->tsnap.snapElem = SCE_SNAP_MODE_GRID;
   return true;
 }