improve text input

src/font.cpp

@@ -83,7 +83,7 @@ std::vector<TextMesh::Token> TextMesh::tokenize(const std::string& s, const Font
         bool is_delim = std::find(delims.begin(), delims.end(), c) != delims.end();
         wrap |= is_delim; // set wrap to notify a delimiter has been reached
         // when a new non-delim char is detected, start a new token
-        if (wrap && !is_delim)
+        if (wrap && !is_delim && !tmp.empty())
         {
             parts.push_back(tmp);
             tmp.clear();
@@ -130,40 +130,61 @@ bool TextMesh::create()
     return true;
 }
 
-void TextMesh::update(kFont id, const char* text)
+void TextMesh::update(kFont id, const std::string& text)
 {
     font_id = id;
     auto& f = FontManager::get(id);
+    float spacing = f.bounds.w - f.bounds.y;
+    float avg_width = f.bounds.z - f.bounds.x;
+    cur_box = glm::vec4(0, 0, 5, spacing);
+
+    glm::vec2 bbmin(FLT_MAX);
+    glm::vec2 bbmax(-FLT_MAX);
+    if (text.empty())
+    {
+        bbmin = { 0, -spacing * 0.5f };
+        bbmax = { 1, +spacing * 0.5f };
+    }
+
     if (f.chars.size())
     {
         float x = 0;
         float y = 0;
         std::vector<glm::vec4> v;
         std::vector<GLushort> idx;
-        glm::vec2 bbmin(FLT_MAX);
-        glm::vec2 bbmax(-FLT_MAX);
 
         std::vector<Token> parts = max_width > 0 ? 
             tokenize(text, f) : 
             std::vector<Token>{ Token(text, 0.f) };
 
+        if (parts.empty())
+        {
+            bbmin = { 0, -spacing * 0.5f };
+            bbmax = { 1, +spacing * 0.5f };
+        }
+
         for (auto p : parts)
         {
-            if (max_width > 0 && x + p.w > max_width * f.scale)
+            if (max_width > 0 && (x + p.w) * f.scale > max_width)
             {
                 x = 0;
-                y += f.size * f.scale;
+                y += spacing;
             }
             for (char c : p.s)
             {
                 if (c == '\n')
                 {
                     x = 0;
-                    y += f.size * f.scale;
+                    y += spacing;
                     continue;
                 }
                 stbtt_aligned_quad q;
                 stbtt_GetBakedQuad((stbtt_bakedchar*)f.chars.data(), f.w, f.h, c - f.start_char, &x, &y, &q, true);
+                if (max_width > 0 && x * f.scale > max_width /*font scale factor*/)
+                {
+                    x = 0;
+                    y += spacing;
+                }
                 auto n = (int)v.size();
                 v.emplace_back(q.x0 / f.scale, q.y1 / f.scale, q.s0, q.t1);
                 v.emplace_back(q.x0 / f.scale, q.y0 / f.scale, q.s0, q.t0);
@@ -177,6 +198,7 @@ void TextMesh::update(kFont id, const char* text)
                 idx.push_back(n + 3);
                 bbmin = glm::min(bbmin, { q.x0 / f.scale, q.y0 / f.scale });
                 bbmax = glm::max(bbmax, { q.x1 / f.scale, q.y1 / f.scale });
+                cur_box = glm::vec4(x, y, 5, spacing);
             }
         }
         for (auto& vi : v)