Comments

imgui_draw.cpp

@@ -1995,10 +1995,10 @@ void ImFont::RenderText(float size, ImVec2 pos, ImU32 col, const ImVec4& clip_re
         {
             char_width = glyph->XAdvance * scale;
 
-            // Clipping on Y is more likely
+            // Arbitrarily assume that both space and tabs are empty glyphs as an optimization
             if (c != ' ' && c != '\t')
             {
-                // We don't do a second finer clipping test on the Y axis (TODO: do some measurement see if it is worth it, probably not)
+                // We don't do a second finer clipping test on the Y axis as we've already skipped anything before clip_rect.y and exit once we pass clip_rect.w
                 float y1 = (float)(y + glyph->Y0 * scale);
                 float y2 = (float)(y + glyph->Y1 * scale);
 
@@ -2042,8 +2042,8 @@ void ImFont::RenderText(float size, ImVec2 pos, ImU32 col, const ImVec4& clip_re
                         }
                     }
 
-                    // NB: we are not calling PrimRectUV() here because non-inlined causes too much overhead in a debug build.
-                    // inlined:
+                    // We are NOT calling PrimRectUV() here because non-inlined causes too much overhead in a debug build.
+                    // Inlined here:
                     {
                         idx_write[0] = (ImDrawIdx)(vtx_current_idx); idx_write[1] = (ImDrawIdx)(vtx_current_idx+1); idx_write[2] = (ImDrawIdx)(vtx_current_idx+2);
                         idx_write[3] = (ImDrawIdx)(vtx_current_idx); idx_write[4] = (ImDrawIdx)(vtx_current_idx+2); idx_write[5] = (ImDrawIdx)(vtx_current_idx+3);