Merge branch 'master' into xr-controller-supportxr-controller-support

2 files changed, 69 insertions, 7 deletions

diff --git a/source/blender/editors/space_image/image_draw.c b/source/blender/editors/space_image/image_draw.c
index d2af26aa1d7..fc04ec1fe02 100644
--- a/source/blender/editors/space_image/image_draw.c
+++ b/source/blender/editors/space_image/image_draw.c
@@ -34,6 +34,7 @@
 #include "DNA_scene_types.h"
 #include "DNA_screen_types.h"
 #include "DNA_space_types.h"
+#include "DNA_view2d_types.h"
 
 #include "PIL_time.h"
 
@@ -576,3 +577,62 @@ void draw_image_cache(const bContext *C, ARegion *region)
     ED_mask_draw_frames(mask, region, cfra, sfra, efra);
   }
 }
+
+float ED_space_image_zoom_level(const View2D *v2d, const int grid_dimension)
+{
+  /* UV-space length per pixel */
+  float xzoom = (v2d->cur.xmax - v2d->cur.xmin) / ((float)(v2d->mask.xmax - v2d->mask.xmin));
+  float yzoom = (v2d->cur.ymax - v2d->cur.ymin) / ((float)(v2d->mask.ymax - v2d->mask.ymin));
+
+  /* Zoom_factor for UV/Image editor is calculated based on:
+   * - Default grid size on startup, which is 256x256 pixels
+   * - How blend factor for grid lines is set up in the fragment shader `grid_frag.glsl`. */
+  float zoom_factor;
+  zoom_factor = (xzoom + yzoom) / 2.0f; /* Average for accuracy.  */
+  zoom_factor *= 256.0f / (powf(grid_dimension, 2));
+  return zoom_factor;
+}
+
+void ED_space_image_grid_steps(SpaceImage *sima,
+                               float grid_steps[SI_GRID_STEPS_LEN],
+                               const int grid_dimension)
+{
+  if (sima->flag & SI_CUSTOM_GRID) {
+    for (int step = 0; step < SI_GRID_STEPS_LEN; step++) {
+      grid_steps[step] = powf(1, step) * (1.0f / ((float)sima->custom_grid_subdiv));
+    }
+  }
+  else {
+    for (int step = 0; step < SI_GRID_STEPS_LEN; step++) {
+      grid_steps[step] = powf(grid_dimension, step) *
+                         (1.0f / (powf(grid_dimension, SI_GRID_STEPS_LEN)));
+    }
+  }
+}
+
+/**
+ * Calculate the increment snapping value for UV/image editor based on the zoom factor
+ * The code in here (except the offset part) is used in `grid_frag.glsl` (see `grid_res`) for
+ * drawing the grid overlay for the UV/Image editor.
+ */
+float ED_space_image_increment_snap_value(const int grid_dimesnions,
+                                          const float grid_steps[SI_GRID_STEPS_LEN],
+                                          const float zoom_factor)
+{
+  /* Small offset on each grid_steps[] so that snapping value doesn't change until grid lines are
+   * significantly visible.
+   * `Offset = 3/4 * (grid_steps[i] - (grid_steps[i] / grid_dimesnsions))`
+   *
+   * Refer `grid_frag.glsl` to find out when grid lines actually start appearing */
+
+  for (int step = 0; step < SI_GRID_STEPS_LEN; step++) {
+    float offset = (3.0f / 4.0f) * (grid_steps[step] - (grid_steps[step] / grid_dimesnions));
+
+    if ((grid_steps[step] - offset) > zoom_factor) {
+      return grid_steps[step];
+    }
+  }
+
+  /* Fallback */
+  return grid_steps[0];
+}
diff --git a/source/blender/editors/space_image/space_image.c b/source/blender/editors/space_image/space_image.c
index de8e4684d45..f14a8266cdd 100644
--- a/source/blender/editors/space_image/space_image.c
+++ b/source/blender/editors/space_image/space_image.c
@@ -126,13 +126,7 @@ static SpaceLink *image_create(const ScrArea *UNUSED(area), const Scene *UNUSED(
   simage->tile_grid_shape[0] = 1;
   simage->tile_grid_shape[1] = 1;
 
-  /* tool header */
-  region = MEM_callocN(sizeof(ARegion), "tool header for image");
-
-  BLI_addtail(&simage->regionbase, region);
-  region->regiontype = RGN_TYPE_TOOL_HEADER;
-  region->alignment = (U.uiflag & USER_HEADER_BOTTOM) ? RGN_ALIGN_BOTTOM : RGN_ALIGN_TOP;
-  region->flag = RGN_FLAG_HIDDEN | RGN_FLAG_HIDDEN_BY_USER;
+  simage->custom_grid_subdiv = 10;
 
   /* header */
   region = MEM_callocN(sizeof(ARegion), "header for image");
@@ -141,6 +135,14 @@ static SpaceLink *image_create(const ScrArea *UNUSED(area), const Scene *UNUSED(
   region->regiontype = RGN_TYPE_HEADER;
   region->alignment = (U.uiflag & USER_HEADER_BOTTOM) ? RGN_ALIGN_BOTTOM : RGN_ALIGN_TOP;
 
+  /* tool header */
+  region = MEM_callocN(sizeof(ARegion), "tool header for image");
+
+  BLI_addtail(&simage->regionbase, region);
+  region->regiontype = RGN_TYPE_TOOL_HEADER;
+  region->alignment = (U.uiflag & USER_HEADER_BOTTOM) ? RGN_ALIGN_BOTTOM : RGN_ALIGN_TOP;
+  region->flag = RGN_FLAG_HIDDEN | RGN_FLAG_HIDDEN_BY_USER;
+
   /* buttons/list view */
   region = MEM_callocN(sizeof(ARegion), "buttons for image");