Fix T93360: 'Iteractive Light Track' do not work over empty background

Bug introduced in {rBaa0ac0035a0d}.

The invalid depth fallback was changed to `FLT_MAX` in order to match the
annotation and gpencil operations.

This broke the `Interactive Light Track` operator which invalidates the
operation if the depth value is `1.0f`.

The chosen solution was to change the value tested in the annotation and
gpencil operations.

7 files changed, 33 insertions, 20 deletions

diff --git a/source/blender/editors/gpencil/annotate_paint.c b/source/blender/editors/gpencil/annotate_paint.c
index bf53241a947..47af2cff0ce 100644
--- a/source/blender/editors/gpencil/annotate_paint.c
+++ b/source/blender/editors/gpencil/annotate_paint.c
@@ -78,6 +78,8 @@
 /* ******************************************* */
 /* 'Globals' and Defines */
 
+#define DEPTH_INVALID 1.0f
+
 /* values for tGPsdata->status */
 typedef enum eGPencil_PaintStatus {
   GP_STATUS_IDLING = 0, /* stroke isn't in progress yet */
@@ -324,6 +326,9 @@ static void annotation_stroke_convertcoords(tGPsdata *p,
                                             float *depth)
 {
   bGPdata *gpd = p->gpd;
+  if (depth && (*depth == DEPTH_INVALID)) {
+    depth = NULL;
+  }
 
   /* in 3d-space - pt->x/y/z are 3 side-by-side floats */
   if (gpd->runtime.sbuffer_sflag & GP_STROKE_3DSPACE) {
@@ -1003,14 +1008,14 @@ static void annotation_stroke_newfrombuffer(tGPsdata *p)
           int last_valid = 0;
 
           for (i = 0; i < gpd->runtime.sbuffer_used; i++) {
-            if (depth_arr[i] != FLT_MAX) {
+            if (depth_arr[i] != DEPTH_INVALID) {
               break;
             }
           }
           first_valid = i;
 
           for (i = gpd->runtime.sbuffer_used - 1; i >= 0; i--) {
-            if (depth_arr[i] != FLT_MAX) {
+            if (depth_arr[i] != DEPTH_INVALID) {
               break;
             }
           }
@@ -1018,14 +1023,14 @@ static void annotation_stroke_newfrombuffer(tGPsdata *p)
 
           /* invalidate non-endpoints, so only blend between first and last */
           for (i = first_valid + 1; i < last_valid; i++) {
-            depth_arr[i] = FLT_MAX;
+            depth_arr[i] = DEPTH_INVALID;
           }
 
           interp_depth = true;
         }
 
         if (interp_depth) {
-          interp_sparse_array(depth_arr, gpd->runtime.sbuffer_used, FLT_MAX);
+          interp_sparse_array(depth_arr, gpd->runtime.sbuffer_used, DEPTH_INVALID);
         }
       }
     }
diff --git a/source/blender/editors/gpencil/gpencil_fill.c b/source/blender/editors/gpencil/gpencil_fill.c
index 9860c75f290..90cf64b58d8 100644
--- a/source/blender/editors/gpencil/gpencil_fill.c
+++ b/source/blender/editors/gpencil/gpencil_fill.c
@@ -1415,7 +1415,7 @@ static void gpencil_get_depth_array(tGPDfill *tgpf)
     }
     else {
       if (interp_depth) {
-        interp_sparse_array(tgpf->depth_arr, totpoints, FLT_MAX);
+        interp_sparse_array(tgpf->depth_arr, totpoints, DEPTH_INVALID);
       }
     }
   }
diff --git a/source/blender/editors/gpencil/gpencil_intern.h b/source/blender/editors/gpencil/gpencil_intern.h
index 3f3fd4fff39..cfc1257204b 100644
--- a/source/blender/editors/gpencil/gpencil_intern.h
+++ b/source/blender/editors/gpencil/gpencil_intern.h
@@ -27,6 +27,8 @@
 
 #include "ED_numinput.h"
 
+#define DEPTH_INVALID 1.0f
+
 /* internal exports only */
 struct Material;
 struct bGPDspoint;
diff --git a/source/blender/editors/gpencil/gpencil_paint.c b/source/blender/editors/gpencil/gpencil_paint.c
index f0118988559..018334a851e 100644
--- a/source/blender/editors/gpencil/gpencil_paint.c
+++ b/source/blender/editors/gpencil/gpencil_paint.c
@@ -429,6 +429,9 @@ static void gpencil_stroke_convertcoords(tGPsdata *p,
                                          float *depth)
 {
   bGPdata *gpd = p->gpd;
+  if (depth && (*depth == DEPTH_INVALID)) {
+    depth = NULL;
+  }
 
   /* in 3d-space - pt->x/y/z are 3 side-by-side floats */
   if (gpd->runtime.sbuffer_sflag & GP_STROKE_3DSPACE) {
@@ -1126,7 +1129,7 @@ static void gpencil_stroke_newfrombuffer(tGPsdata *p)
 
           /* find first valid contact point */
           for (i = 0; i < gpd->runtime.sbuffer_used; i++) {
-            if (depth_arr[i] != FLT_MAX) {
+            if (depth_arr[i] != DEPTH_INVALID) {
               break;
             }
           }
@@ -1138,7 +1141,7 @@ static void gpencil_stroke_newfrombuffer(tGPsdata *p)
           }
           else {
             for (i = gpd->runtime.sbuffer_used - 1; i >= 0; i--) {
-              if (depth_arr[i] != FLT_MAX) {
+              if (depth_arr[i] != DEPTH_INVALID) {
                 break;
               }
             }
@@ -1148,14 +1151,14 @@ static void gpencil_stroke_newfrombuffer(tGPsdata *p)
            * first and last contact in an imaginary line between them */
           for (i = 0; i < gpd->runtime.sbuffer_used; i++) {
             if (!ELEM(i, first_valid, last_valid)) {
-              depth_arr[i] = FLT_MAX;
+              depth_arr[i] = DEPTH_INVALID;
             }
           }
           interp_depth = true;
         }
 
         if (interp_depth) {
-          interp_sparse_array(depth_arr, gpd->runtime.sbuffer_used, FLT_MAX);
+          interp_sparse_array(depth_arr, gpd->runtime.sbuffer_used, DEPTH_INVALID);
         }
       }
     }
diff --git a/source/blender/editors/gpencil/gpencil_primitive.c b/source/blender/editors/gpencil/gpencil_primitive.c
index 7382aca9a87..8157e9d8fe7 100644
--- a/source/blender/editors/gpencil/gpencil_primitive.c
+++ b/source/blender/editors/gpencil/gpencil_primitive.c
@@ -841,7 +841,7 @@ static void gpencil_primitive_update_strokes(bContext *C, tGPDprimitive *tgpi)
           /* find first valid contact point */
           int i;
           for (i = 0; i < gps->totpoints; i++) {
-            if (depth_arr[i] != FLT_MAX) {
+            if (depth_arr[i] != DEPTH_INVALID) {
               break;
             }
           }
@@ -853,7 +853,7 @@ static void gpencil_primitive_update_strokes(bContext *C, tGPDprimitive *tgpi)
           }
           else {
             for (i = gps->totpoints - 1; i >= 0; i--) {
-              if (depth_arr[i] != FLT_MAX) {
+              if (depth_arr[i] != DEPTH_INVALID) {
                 break;
               }
             }
@@ -864,14 +864,14 @@ static void gpencil_primitive_update_strokes(bContext *C, tGPDprimitive *tgpi)
            * first and last contact in an imaginary line between them */
           for (i = 0; i < gps->totpoints; i++) {
             if (!ELEM(i, first_valid, last_valid)) {
-              depth_arr[i] = FLT_MAX;
+              depth_arr[i] = DEPTH_INVALID;
             }
           }
           interp_depth = true;
         }
 
         if (interp_depth) {
-          interp_sparse_array(depth_arr, gps->totpoints, FLT_MAX);
+          interp_sparse_array(depth_arr, gps->totpoints, DEPTH_INVALID);
         }
       }
     }
@@ -1041,7 +1041,7 @@ static void gpencil_primitive_update_strokes(bContext *C, tGPDprimitive *tgpi)
         gpd->runtime.sbuffer, &gpd->runtime.sbuffer_size, &gpd->runtime.sbuffer_used, false);
 
     /* add small offset to keep stroke over the surface */
-    if ((depth_arr) && (gpd->zdepth_offset > 0.0f)) {
+    if ((depth_arr) && (gpd->zdepth_offset > 0.0f) && (depth_arr[i] != DEPTH_INVALID)) {
       depth_arr[i] *= (1.0f - (gpd->zdepth_offset / 1000.0f));
     }
 
diff --git a/source/blender/editors/gpencil/gpencil_utils.c b/source/blender/editors/gpencil/gpencil_utils.c
index 86df452f49a..99cf2b52df7 100644
--- a/source/blender/editors/gpencil/gpencil_utils.c
+++ b/source/blender/editors/gpencil/gpencil_utils.c
@@ -991,6 +991,10 @@ void gpencil_stroke_convertcoords_tpoint(Scene *scene,
 {
   ToolSettings *ts = scene->toolsettings;
 
+  if (depth && (*depth == DEPTH_INVALID)) {
+    depth = NULL;
+  }
+
   int mval_i[2];
   round_v2i_v2fl(mval_i, &point2D->x);
 
diff --git a/source/blender/editors/space_view3d/view3d_utils.c b/source/blender/editors/space_view3d/view3d_utils.c
index d6a1cd930fc..f01955a6468 100644
--- a/source/blender/editors/space_view3d/view3d_utils.c
+++ b/source/blender/editors/space_view3d/view3d_utils.c
@@ -1127,7 +1127,7 @@ bool ED_view3d_depth_read_cached_seg(
 
   data.vd = vd;
   data.margin = margin;
-  data.depth = FLT_MAX;
+  data.depth = 1.0f;
 
   copy_v2_v2_int(p1, mval_sta);
   copy_v2_v2_int(p2, mval_end);
@@ -1136,7 +1136,7 @@ bool ED_view3d_depth_read_cached_seg(
 
   *depth = data.depth;
 
-  return (*depth != FLT_MAX);
+  return (*depth != 1.0f);
 }
 
 /** \} */
@@ -1647,6 +1647,9 @@ bool ED_view3d_depth_read_cached(const ViewDepths *vd,
                                  int margin,
                                  float *r_depth)
 {
+  BLI_assert(1.0 <= vd->depth_range[1]);
+  *r_depth = 1.0f;
+
   if (!vd || !vd->depths) {
     return false;
   }
@@ -1676,15 +1679,11 @@ bool ED_view3d_depth_read_cached(const ViewDepths *vd,
     depth = vd->depths[y * vd->w + x];
   }
 
-  BLI_assert(1.0 <= vd->depth_range[1]);
   if (depth != 1.0f) {
     *r_depth = depth;
     return true;
   }
 
-  /* Grease-pencil and annotations also need the returned depth value to be high
-   * so the caller can detect it's invalid. */
-  *r_depth = FLT_MAX;
   return false;
 }