Snap System: Invert the test order of the elements to snap (useful for ruler)

When the function that tests snap on multiple elements starts from the face and ends at the vertex, the transition between elements becomes much smoother.

1 files changed, 50 insertions, 35 deletions

diff --git a/source/blender/editors/transform/transform_snap_object.c b/source/blender/editors/transform/transform_snap_object.c
index d1bcec39611..5e4aea63bb6 100644
--- a/source/blender/editors/transform/transform_snap_object.c
+++ b/source/blender/editors/transform/transform_snap_object.c
@@ -387,7 +387,7 @@ typedef struct Nearest2dPrecalc {
 	float ray_direction_local[3];
 	float ray_inv_dir[3];
 
-	float depth_range[2];
+	float ray_min_dist;
 	float pmat[4][4]; /* perspective matrix multiplied by object matrix */
 	float win_half[2];
 
@@ -401,12 +401,12 @@ typedef struct Nearest2dPrecalc {
 static void dist_squared_to_projected_aabb_precalc(
         struct Nearest2dPrecalc *neasrest_precalc,
         float lpmat[4][4], const float win_half[2],
-        const float depth_range[2], const float mval[2],
+        const float ray_min_dist, const float mval[2],
         const float ray_origin_local[3], const float ray_direction_local[3])
 {
 	copy_m4_m4(neasrest_precalc->pmat, lpmat);
 	copy_v2_v2(neasrest_precalc->win_half, win_half);
-	copy_v2_v2(neasrest_precalc->depth_range, depth_range);
+	neasrest_precalc->ray_min_dist = ray_min_dist;
 
 	copy_v3_v3(neasrest_precalc->ray_origin_local, ray_origin_local);
 	copy_v3_v3(neasrest_precalc->ray_direction_local, ray_direction_local);
@@ -513,11 +513,11 @@ static float dist_squared_to_projected_aabb(
 #define IGNORE_BEHIND_RAY
 #ifdef IGNORE_BEHIND_RAY
 		/* `if rtmax < depth_min`, the hit is behind us */
-		if (rtmax < data->depth_range[0]) {
+		if (rtmax < data->ray_min_dist) {
 			/* Test if the entire AABB is behind us */
 			float depth = depth_get(
 			        local_bvmax, data->ray_origin_local, data->ray_direction_local);
-			if (depth < (data->depth_range[0])) {
+			if (depth < (data->ray_min_dist)) {
 				return FLT_MAX;
 			}
 		}
@@ -528,11 +528,11 @@ static float dist_squared_to_projected_aabb(
 	}
 #ifdef IGNORE_BEHIND_RAY
 	/* `if rtmin < depth_min`, the hit is behing us */
-	else if (rtmin < data->depth_range[0]) {
+	else if (rtmin < data->ray_min_dist) {
 		/* Test if the entire AABB is behind us */
 		float depth = depth_get(
 		        local_bvmax, data->ray_origin_local, data->ray_direction_local);
-		if (depth < (data->depth_range[0])) {
+		if (depth < (data->ray_min_dist)) {
 			return FLT_MAX;
 		}
 	}
@@ -606,13 +606,13 @@ static float dist_squared_to_projected_aabb(
 
 static float dist_squared_to_projected_aabb_simple(
         float lpmat[4][4], const float win_half[2],
-        const float depth_range[2], const float mval[2],
+        const float ray_min_dist, const float mval[2],
         const float ray_origin_local[3], const float ray_direction_local[3],
         const float bbmin[3], const float bbmax[3])
 {
 	struct Nearest2dPrecalc data;
 	dist_squared_to_projected_aabb_precalc(
-	        &data, lpmat, win_half, depth_range,
+	        &data, lpmat, win_half, ray_min_dist,
 	        mval, ray_origin_local, ray_direction_local);
 
 	bool dummy[3] = {true, true, true};
@@ -646,6 +646,7 @@ typedef struct Nearest2dUserData {
 
 	bool r_axis_closest[3];
 
+	float depth_range[2];
 	void *userdata;
 	int index;
 	float co[3];
@@ -674,7 +675,7 @@ static bool cb_walk_leaf_snap_vert(const BVHTreeAxisRange *bounds, int index, vo
 	};
 
 	if (test_projected_vert_dist(
-	        neasrest_precalc->depth_range,
+	        data->depth_range,
 	        neasrest_precalc->mval, co,
 	        neasrest_precalc->pmat,
 	        neasrest_precalc->win_half,
@@ -697,7 +698,7 @@ static bool cb_walk_leaf_snap_edge(const BVHTreeAxisRange *UNUSED(bounds), int i
 	get_edge_verts(data->userdata, index, v_pair);
 
 	if (test_projected_edge_dist(
-	        neasrest_precalc->depth_range,
+	        data->depth_range,
 	        neasrest_precalc->mval,
 	        neasrest_precalc->pmat,
 	        neasrest_precalc->win_half,
@@ -1114,11 +1115,10 @@ static bool snapDerivedMesh(
 
 		float lpmat[4][4];
 		float ray_org_local[3];
-		float depth_range_local[2];
+		float ray_min_dist;
 		if (ELEM(snapdata->snap_to, SCE_SNAP_MODE_VERTEX, SCE_SNAP_MODE_EDGE)) {
 			mul_m4_m4m4(lpmat, snapdata->pmat, obmat);
-			depth_range_local[0] = snapdata->depth_range[0] * local_scale;
-			depth_range_local[1] = local_depth + depth_range_local[0];
+			ray_min_dist = snapdata->depth_range[0] * local_scale;
 		}
 
 		copy_v3_v3(ray_org_local, snapdata->ray_origin);
@@ -1137,7 +1137,7 @@ static bool snapDerivedMesh(
 				/* In vertex and edges you need to get the pixel distance from ray to BoundBox, see T46816. */
 				if (ELEM(snapdata->snap_to, SCE_SNAP_MODE_VERTEX, SCE_SNAP_MODE_EDGE)) {
 					float dist_px_sq = dist_squared_to_projected_aabb_simple(
-					        lpmat, snapdata->win_half, snapdata->depth_range, snapdata->mval,
+					        lpmat, snapdata->win_half, ray_min_dist, snapdata->mval,
 					        ray_org_local, ray_normal_local, bb->vec[0], bb->vec[6]);
 					if (dist_px_sq > SQUARE(*dist_px))
 					{
@@ -1320,12 +1320,13 @@ static bool snapDerivedMesh(
 			    .is_persp = snapdata->view_proj == VIEW_PROJ_PERSP,
 			    .dist_px_sq = SQUARE(*dist_px),
 			    .r_axis_closest = {1.0f, 1.0f, 1.0f},
+			    .depth_range = {snapdata->depth_range[0],  *ray_depth + snapdata->depth_range[0]},
 			    .userdata = &treedata_type,
 			    .index = -1};
 
 			dist_squared_to_projected_aabb_precalc(
 			        &neasrest2d.data_precalc, lpmat, snapdata->win_half,
-			        depth_range_local, snapdata->mval, ray_org_local, ray_normal_local);
+			        ray_min_dist, snapdata->mval, ray_org_local, ray_normal_local);
 
 			BVHTree_WalkLeafCallback cb_walk_leaf =
 			        (snapdata->snap_to == SCE_SNAP_MODE_VERTEX) ?
@@ -1611,16 +1612,16 @@ static bool snapEditMesh(
 			    .is_persp = snapdata->view_proj == VIEW_PROJ_PERSP,
 			    .dist_px_sq = SQUARE(*dist_px),
 			    .r_axis_closest = {1.0f, 1.0f, 1.0f},
+			    .depth_range = {snapdata->depth_range[0], *ray_depth + snapdata->depth_range[0]},
 			    .userdata = &treedata_type,
 			    .index = -1};
 
-			float lpmat[4][4], depth_range_local[2];
+			float lpmat[4][4];
 			mul_m4_m4m4(lpmat, snapdata->pmat, obmat);
-			depth_range_local[0] = snapdata->depth_range[0] * local_scale;
-			depth_range_local[1] = local_depth + depth_range_local[0];
 			dist_squared_to_projected_aabb_precalc(
 			        &neasrest2d.data_precalc, lpmat, snapdata->win_half,
-			        snapdata->depth_range, snapdata->mval, ray_org_local, ray_normal_local);
+			        (snapdata->depth_range[0] * local_scale), snapdata->mval,
+			        ray_org_local, ray_normal_local);
 
 			BVHTree_WalkLeafCallback cb_walk_leaf =
 			        (snapdata->snap_to == SCE_SNAP_MODE_VERTEX) ?
@@ -2076,23 +2077,37 @@ static bool transform_snap_context_project_view3d_mixed_impl(
 	BLI_assert(snap_to_flag != 0);
 	BLI_assert((snap_to_flag & ~(1 | 2 | 4)) == 0);
 
-	for (int i = 0; i < 3; i++) {
-		if ((snap_to_flag & (1 << i)) && (is_hit == false || use_depth)) {
-
-			if (ED_transform_snap_object_project_view3d(
-			        sctx,
-			        elem_type[i], params,
-			        mval, dist_px, &ray_depth,
-			        r_co, r_no))
-			{
-				is_hit = true;
-				if (use_depth == false) {
-					ray_depth = BVH_RAYCAST_DIST_MAX;
-				}
-				else {
+	if (use_depth) {
+		const float dist_px_orig = *dist_px;
+		for (int i = 2; i >= 0; i--) {
+			if (snap_to_flag & (1 << i)) {
+				if (i == 0)
+					*dist_px = dist_px_orig;
+				if (ED_transform_snap_object_project_view3d(
+				        sctx,
+				        elem_type[i], params,
+				        mval, dist_px, &ray_depth,
+				        r_co, r_no))
+				{
 					/* 0.01 is a random but small value to prioritizing
 					 * the first elements of the loop */
-					ray_depth -= 0.01f;
+					ray_depth += 0.01f;
+					is_hit = true;
+				}
+			}
+		}
+	}
+	else {
+		for (int i = 0; i < 3; i++) {
+			if (snap_to_flag & (1 << i)) {
+				if (ED_transform_snap_object_project_view3d(
+					sctx,
+					elem_type[i], params,
+					mval, dist_px, &ray_depth,
+					r_co, r_no))
+				{
+					is_hit = true;
+					break;
 				}
 			}
 		}