Geometry Nodes: String to Curves Node

This commit adds a node that generates a text paragraph as curve
instances. The inputs on the node control the overall shape of the
paragraph, and other nodes can be used to move the individual instances
afterwards. To output more than one line, the "Special Characters" node
can be used.

The node outputs instances instead of real geometry so that it doesn't
have to duplicate work for every character afterwards. This is much
more efficient, because all of the curve evaluation and nodes like fill
curve don't have to repeat the same calculation for every instance of
the same character.

In the future, the instances component will support attributes, and the
node can output attribute fields like "Word Index" and "Line Index".

Differential Revision: https://developer.blender.org/D11522

4 files changed, 21 insertions, 10 deletions

diff --git a/source/blender/blenkernel/BKE_font.h b/source/blender/blenkernel/BKE_font.h
index 522d3843bb2..827ae1b6a0f 100644
--- a/source/blender/blenkernel/BKE_font.h
+++ b/source/blender/blenkernel/BKE_font.h
@@ -85,6 +85,15 @@ bool BKE_vfont_to_curve_ex(struct Object *ob,
                            struct CharTrans **r_chartransdata);
 bool BKE_vfont_to_curve_nubase(struct Object *ob, int mode, struct ListBase *r_nubase);
 bool BKE_vfont_to_curve(struct Object *ob, int mode);
+void BKE_vfont_build_char(struct Curve *cu,
+                          struct ListBase *nubase,
+                          unsigned int character,
+                          struct CharInfo *info,
+                          float ofsx,
+                          float ofsy,
+                          float rot,
+                          int charidx,
+                          const float fsize);
 
 int BKE_vfont_select_get(struct Object *ob, int *r_start, int *r_end);
 void BKE_vfont_select_clamp(struct Object *ob);
diff --git a/source/blender/blenkernel/BKE_node.h b/source/blender/blenkernel/BKE_node.h
index bd969400f17..90285d9fc7c 100644
--- a/source/blender/blenkernel/BKE_node.h
+++ b/source/blender/blenkernel/BKE_node.h
@@ -1501,6 +1501,7 @@ int ntreeTexExecTree(struct bNodeTree *ntree,
 #define GEO_NODE_CURVE_PARAMETER 1088
 #define GEO_NODE_CURVE_FILLET 1089
 #define GEO_NODE_DISTRIBUTE_POINTS_ON_FACES 1090
+#define GEO_NODE_STRING_TO_CURVES 1091
 
 /** \} */
 
diff --git a/source/blender/blenkernel/intern/font.c b/source/blender/blenkernel/intern/font.c
index aa13f86523a..1053b727cbc 100644
--- a/source/blender/blenkernel/intern/font.c
+++ b/source/blender/blenkernel/intern/font.c
@@ -490,15 +490,15 @@ static void build_underline(Curve *cu,
   mul_v2_fl(bp[3].vec, font_size);
 }
 
-static void buildchar(Curve *cu,
-                      ListBase *nubase,
-                      unsigned int character,
-                      CharInfo *info,
-                      float ofsx,
-                      float ofsy,
-                      float rot,
-                      int charidx,
-                      const float fsize)
+void BKE_vfont_build_char(Curve *cu,
+                          ListBase *nubase,
+                          unsigned int character,
+                          CharInfo *info,
+                          float ofsx,
+                          float ofsy,
+                          float rot,
+                          int charidx,
+                          const float fsize)
 {
   VFontData *vfd = vfont_get_data(which_vfont(cu, info));
   if (!vfd) {
@@ -1525,7 +1525,7 @@ static bool vfont_to_curve(Object *ob,
       }
       /* We do not want to see any character for \n or \r */
       if (cha != '\n') {
-        buildchar(cu, r_nubase, cha, info, ct->xof, ct->yof, ct->rot, i, font_size);
+        BKE_vfont_build_char(cu, r_nubase, cha, info, ct->xof, ct->yof, ct->rot, i, font_size);
       }
 
       if ((info->flag & CU_CHINFO_UNDERLINE) && (cha != '\n')) {
diff --git a/source/blender/blenkernel/intern/node.cc b/source/blender/blenkernel/intern/node.cc
index 891d6c05a19..bf7c47e9cf0 100644
--- a/source/blender/blenkernel/intern/node.cc
+++ b/source/blender/blenkernel/intern/node.cc
@@ -5799,6 +5799,7 @@ static void registerGeometryNodes()
   register_node_type_geo_material_selection();
   register_node_type_geo_separate_components();
   register_node_type_geo_set_position();
+  register_node_type_geo_string_to_curves();
   register_node_type_geo_subdivision_surface();
   register_node_type_geo_switch();
   register_node_type_geo_transform();