Updated ImGui.

3rdparty/ocornut-imgui/imgui.cpp

@@ -635,7 +635,6 @@ static inline bool      IsWindowContentHoverable(ImGuiWindow* window);
 static void             ClearSetNextWindowData();
 static void             CheckStacksSize(ImGuiWindow* window, bool write);
 static void             Scrollbar(ImGuiWindow* window, bool horizontal);
-static bool             CloseWindowButton(bool* p_opened);
 
 static void             AddDrawListToRenderList(ImVector<ImDrawList*>& out_render_list, ImDrawList* draw_list);
 static void             AddWindowToRenderList(ImVector<ImDrawList*>& out_render_list, ImGuiWindow* window);
@@ -2342,9 +2341,13 @@ static void AddDrawListToRenderList(ImVector<ImDrawList*>& out_render_list, ImDr
             return;
     }
 
+    // Draw list sanity check. Detect mismatch between PrimReserve() calls and incrementing _VtxCurrentIdx, _VtxWritePtr etc.
+    IM_ASSERT(draw_list->_VtxWritePtr == draw_list->VtxBuffer.Data + draw_list->VtxBuffer.Size);
+    IM_ASSERT(draw_list->_IdxWritePtr == draw_list->IdxBuffer.Data + draw_list->IdxBuffer.Size);
+    IM_ASSERT((int)draw_list->_VtxCurrentIdx == draw_list->VtxBuffer.Size);                   
+
     // Check that draw_list doesn't use more vertices than indexable (default ImDrawIdx = 2 bytes = 64K vertices)
     // If this assert triggers because you are drawing lots of stuff manually, A) workaround by calling BeginChild()/EndChild() to put your draw commands in multiple draw lists, B) #define ImDrawIdx to a 'unsigned int' in imconfig.h and render accordingly.
-    IM_ASSERT((int)draw_list->_VtxCurrentIdx == draw_list->VtxBuffer.Size);                   // Sanity check. Bug or mismatch between PrimReserve() calls and incrementing _VtxCurrentIdx, _VtxWritePtr etc.
     IM_ASSERT((int64_t)draw_list->_VtxCurrentIdx <= ((int64_t)1L << (sizeof(ImDrawIdx)*8)));  // Too many vertices in same ImDrawList. See comment above.
     
     out_render_list.push_back(draw_list);
@@ -2371,13 +2374,14 @@ void ImGui::PushClipRect(const ImVec2& clip_rect_min, const ImVec2& clip_rect_ma
     ImGuiWindow* window = GetCurrentWindow();
 
     ImRect cr(clip_rect_min, clip_rect_max);
-    if (intersect_with_existing_clip_rect)
-    {
-        // Clip our argument with the current clip rect
+    if (intersect_with_existing_clip_rect)      // Clip our argument with the current clip rect
         cr.Clip(window->ClipRect);
-    }
     cr.Max.x = ImMax(cr.Min.x, cr.Max.x);
     cr.Max.y = ImMax(cr.Min.y, cr.Max.y);
+    cr.Min.x = (float)(int)(cr.Min.x + 0.5f);   // Round (expecting to round down). Ensure that e.g. (int)(max.x-min.x) in user code produce correct result.
+    cr.Min.y = (float)(int)(cr.Min.y + 0.5f);
+    cr.Max.x = (float)(int)(cr.Max.x + 0.5f);
+    cr.Max.y = (float)(int)(cr.Max.y + 0.5f);
 
     IM_ASSERT(cr.Min.x <= cr.Max.x && cr.Min.y <= cr.Max.y);
     window->ClipRect = cr;
@@ -3375,7 +3379,7 @@ bool ImGui::BeginChild(const char* str_id, const ImVec2& size_arg, bool border,
     ImGuiWindowFlags flags = ImGuiWindowFlags_NoTitleBar|ImGuiWindowFlags_NoResize|ImGuiWindowFlags_NoSavedSettings|ImGuiWindowFlags_ChildWindow;
 
     const ImVec2 content_avail = ImGui::GetContentRegionAvail();
-    ImVec2 size = ImRound(size_arg);
+    ImVec2 size = ImFloor(size_arg);
     if (size.x <= 0.0f)
     {
         if (size.x == 0.0f)
@@ -4084,7 +4088,12 @@ bool ImGui::Begin(const char* name, bool* p_opened, const ImVec2& size_on_first_
         if (!(flags & ImGuiWindowFlags_NoTitleBar))
         {
             if (p_opened != NULL)
-                CloseWindowButton(p_opened);
+            {
+                const float pad = 2.0f;
+                const float rad = (window->TitleBarHeight() - pad*2.0f) * 0.5f;
+                if (CloseButton(window->GetID("#CLOSE"), window->Rect().GetTR() + ImVec2(-pad - rad, pad + rad), rad))
+                    *p_opened = false;
+            }
 
             const ImVec2 text_size = CalcTextSize(name, NULL, true);
             if (!(flags & ImGuiWindowFlags_NoCollapse))
@@ -4121,9 +4130,9 @@ bool ImGui::Begin(const char* name, bool* p_opened, const ImVec2& size_on_first_
     const ImRect title_bar_rect = window->TitleBarRect();
     const float border_size = window->BorderSize;
     ImRect clip_rect;
-    clip_rect.Min.x = title_bar_rect.Min.x + 0.5f + ImMax(border_size, window->WindowPadding.x*0.5f);
-    clip_rect.Min.y = title_bar_rect.Max.y + window->MenuBarHeight() + 0.5f + border_size;
-    clip_rect.Max.x = window->Pos.x + window->Size.x - window->ScrollbarSizes.x - ImMax(border_size, window->WindowPadding.x*0.5f);
+    clip_rect.Min.x = title_bar_rect.Min.x + ImMax(border_size, (float)(int)(window->WindowPadding.x*0.5f));
+    clip_rect.Min.y = title_bar_rect.Max.y + window->MenuBarHeight() + border_size;
+    clip_rect.Max.x = window->Pos.x + window->Size.x - window->ScrollbarSizes.x - ImMax(border_size, (float)(int)(window->WindowPadding.x*0.5f));
     clip_rect.Max.y = window->Pos.y + window->Size.y - border_size - window->ScrollbarSizes.y;
     PushClipRect(clip_rect.Min, clip_rect.Max, true);
 
@@ -5392,13 +5401,11 @@ bool ImGui::InvisibleButton(const char* str_id, const ImVec2& size_arg)
 }
 
 // Upper-right button to close a window.
-static bool CloseWindowButton(bool* p_opened)
+bool ImGui::CloseButton(ImGuiID id, const ImVec2& pos, float radius)
 {
     ImGuiWindow* window = ImGui::GetCurrentWindow();
 
-    const ImGuiID id = window->GetID("#CLOSE");
-    const float size = window->TitleBarHeight() - 4.0f;
-    const ImRect bb(window->Rect().GetTR() + ImVec2(-2.0f-size,2.0f), window->Rect().GetTR() + ImVec2(-2.0f,2.0f+size));
+    const ImRect bb(pos - ImVec2(radius,radius), pos + ImVec2(radius,radius));
 
     bool hovered, held;
     bool pressed = ImGui::ButtonBehavior(bb, id, &hovered, &held);
@@ -5406,18 +5413,15 @@ static bool CloseWindowButton(bool* p_opened)
     // Render
     const ImU32 col = ImGui::GetColorU32((held && hovered) ? ImGuiCol_CloseButtonActive : hovered ? ImGuiCol_CloseButtonHovered : ImGuiCol_CloseButton);
     const ImVec2 center = bb.GetCenter();
-    window->DrawList->AddCircleFilled(center, ImMax(2.0f,size*0.5f), col, 16);
+    window->DrawList->AddCircleFilled(center, ImMax(2.0f, radius), col, 12);
 
-    const float cross_extent = (size * 0.5f * 0.7071f) - 1.0f;
+    const float cross_extent = (radius * 0.7071f) - 1.0f;
     if (hovered)
     {
         window->DrawList->AddLine(center + ImVec2(+cross_extent,+cross_extent), center + ImVec2(-cross_extent,-cross_extent), ImGui::GetColorU32(ImGuiCol_Text));
         window->DrawList->AddLine(center + ImVec2(+cross_extent,-cross_extent), center + ImVec2(-cross_extent,+cross_extent), ImGui::GetColorU32(ImGuiCol_Text));
     }
 
-    if (p_opened != NULL && pressed)
-        *p_opened = false;
-
     return pressed;
 }
 
@@ -7801,10 +7805,11 @@ bool ImGui::InputTextEx(const char* label, char* buf, int buf_size, const ImVec2
         draw_window->DrawList->AddText(g.Font, g.FontSize, render_pos - render_scroll, GetColorU32(ImGuiCol_Text), buf, buf+edit_state.CurLenA, 0.0f, is_multiline ? NULL : &clip_rect);
 
         // Draw blinking cursor
-        ImVec2 cursor_screen_pos = render_pos + cursor_offset - render_scroll;
         bool cursor_is_visible = (g.InputTextState.CursorAnim <= 0.0f) || fmodf(g.InputTextState.CursorAnim, 1.20f) <= 0.80f;
-        if (cursor_is_visible)
-            draw_window->DrawList->AddLine(cursor_screen_pos + ImVec2(0.0f,-g.FontSize+0.5f), cursor_screen_pos + ImVec2(0.0f,-1.5f), GetColorU32(ImGuiCol_Text));
+        ImVec2 cursor_screen_pos = render_pos + cursor_offset - render_scroll;
+        ImRect cursor_screen_rect(cursor_screen_pos.x, cursor_screen_pos.y-g.FontSize+0.5f, cursor_screen_pos.x, cursor_screen_pos.y-1.5f);
+        if (cursor_is_visible && cursor_screen_rect.Overlaps(clip_rect))
+            draw_window->DrawList->AddLine(cursor_screen_rect.Min, cursor_screen_rect.Max, GetColorU32(ImGuiCol_Text));
 
         // Notify OS of text input position for advanced IME (-1 x offset so that Windows IME can cover our cursor. Bit of an extra nicety.)
         if (is_editable)
@@ -8430,7 +8435,7 @@ bool ImGui::BeginMenuBar()
     ImGui::BeginGroup(); // Save position
     ImGui::PushID("##menubar");
     ImRect rect = window->MenuBarRect();
-    PushClipRect(ImVec2(rect.Min.x+0.5f, rect.Min.y-0.5f+window->BorderSize), ImVec2(rect.Max.x+0.5f, rect.Max.y-0.5f), false);
+    PushClipRect(ImVec2(rect.Min.x, rect.Min.y + window->BorderSize), ImVec2(rect.Max.x, rect.Max.y), false);
     window->DC.CursorPos = ImVec2(rect.Min.x + window->DC.MenuBarOffsetX, rect.Min.y);// + g.Style.FramePadding.y);
     window->DC.LayoutType = ImGuiLayoutType_Horizontal;
     window->DC.MenuBarAppending = true;
@@ -9350,8 +9355,8 @@ void ImGui::ShowMetricsWindow(bool* opened)
                         ImDrawIdx* idx_buffer = (draw_list->IdxBuffer.Size > 0) ? draw_list->IdxBuffer.Data : NULL;
                         for (int i = elem_offset; i < elem_offset + (int)pcmd->ElemCount; i++)
                             vtxs_rect.Add(draw_list->VtxBuffer[idx_buffer ? idx_buffer[i] : i].pos);
-                        clip_rect.Round(); overlay_draw_list->AddRect(clip_rect.Min, clip_rect.Max, ImColor(255,255,0));
-                        vtxs_rect.Round(); overlay_draw_list->AddRect(vtxs_rect.Min, vtxs_rect.Max, ImColor(255,0,255));
+                        clip_rect.Floor(); overlay_draw_list->AddRect(clip_rect.Min, clip_rect.Max, ImColor(255,255,0));
+                        vtxs_rect.Floor(); overlay_draw_list->AddRect(vtxs_rect.Min, vtxs_rect.Max, ImColor(255,0,255));
                     }
                     if (!draw_opened)
                         continue;

3rdparty/ocornut-imgui/imgui.h

@@ -1185,9 +1185,9 @@ struct ImDrawList
     IMGUI_API void  PrimRect(const ImVec2& a, const ImVec2& b, ImU32 col);      // Axis aligned rectangle (composed of two triangles)
     IMGUI_API void  PrimRectUV(const ImVec2& a, const ImVec2& b, const ImVec2& uv_a, const ImVec2& uv_b, ImU32 col);
     IMGUI_API void  PrimQuadUV(const ImVec2& a, const ImVec2& b, const ImVec2& c, const ImVec2& d, const ImVec2& uv_a, const ImVec2& uv_b, const ImVec2& uv_c, const ImVec2& uv_d, ImU32 col);
-    inline    void  PrimVtx(const ImVec2& pos, const ImVec2& uv, ImU32 col)     { PrimWriteIdx((ImDrawIdx)_VtxCurrentIdx); PrimWriteVtx(pos, uv, col); }
     inline    void  PrimWriteVtx(const ImVec2& pos, const ImVec2& uv, ImU32 col){ _VtxWritePtr->pos = pos; _VtxWritePtr->uv = uv; _VtxWritePtr->col = col; _VtxWritePtr++; _VtxCurrentIdx++; }
     inline    void  PrimWriteIdx(ImDrawIdx idx)                                 { *_IdxWritePtr = idx; _IdxWritePtr++; }
+    inline    void  PrimVtx(const ImVec2& pos, const ImVec2& uv, ImU32 col)     { PrimWriteIdx((ImDrawIdx)_VtxCurrentIdx); PrimWriteVtx(pos, uv, col); }
     IMGUI_API void  UpdateClipRect();
     IMGUI_API void  UpdateTextureID();
 };
@@ -1289,15 +1289,6 @@ struct ImFontAtlas
 // ImFontAtlas automatically loads a default embedded font for you when you call GetTexDataAsAlpha8() or GetTexDataAsRGBA32().
 struct ImFont
 {
-    // Members: Settings
-    float                       FontSize;           // <user set>      // Height of characters, set during loading (don't change after loading)
-    float                       Scale;              // = 1.0f          // Base font scale, multiplied by the per-window font scale which you can adjust with SetFontScale()
-    ImVec2                      DisplayOffset;      // = (0.0f,1.0f)   // Offset font rendering by xx pixels
-    ImWchar                     FallbackChar;       // = '?'           // Replacement glyph if one isn't found. Only set via SetFallbackChar()
-    ImFontConfig*               ConfigData;         //                 // Pointer within ImFontAtlas->ConfigData
-    int                         ConfigDataCount;    //
-
-    // Members: Runtime data
     struct Glyph
     {
         ImWchar                 Codepoint;
@@ -1305,13 +1296,23 @@ struct ImFont
         float                   X0, Y0, X1, Y1;
         float                   U0, V0, U1, V1;     // Texture coordinates
     };
-    float                       Ascent, Descent;    // Ascent: distance from top to bottom of e.g. 'A' [0..FontSize]
-    ImFontAtlas*                ContainerAtlas;     // What we has been loaded into
-    ImVector<Glyph>             Glyphs;
+
+    // Members: Hot ~62/78 bytes
+    float                       FontSize;           // <user set>   // Height of characters, set during loading (don't change after loading)
+    float                       Scale;              // = 1.f        // Base font scale, multiplied by the per-window font scale which you can adjust with SetFontScale()
+    ImVec2                      DisplayOffset;      // = (0.f,1.f)  // Offset font rendering by xx pixels
+    ImVector<Glyph>             Glyphs;             //              // All glyphs.
+    ImVector<float>             IndexXAdvance;      //              // Sparse. Glyphs->XAdvance in a directly indexable way (more cache-friendly, for CalcTextSize functions which are often bottleneck in large UI).
+    ImVector<short>             IndexLookup;        //              // Sparse. Index glyphs by Unicode code-point.
     const Glyph*                FallbackGlyph;      // == FindGlyph(FontFallbackChar)
-    float                       FallbackXAdvance;   //
-    ImVector<float>             IndexXAdvance;      // Sparse. Glyphs->XAdvance directly indexable (more cache-friendly that reading from Glyphs, for CalcTextSize functions which are often bottleneck in large UI)
-    ImVector<int>               IndexLookup;        // Sparse. Index glyphs by Unicode code-point.
+    float                       FallbackXAdvance;   // == FallbackGlyph->XAdvance
+    ImWchar                     FallbackChar;       // = '?'        // Replacement glyph if one isn't found. Only set via SetFallbackChar()
+
+    // Members: Cold ~18/26 bytes
+    short                       ConfigDataCount;    // ~ 1          // Number of ImFontConfig involved in creating this font. Bigger than 1 when merging multiple font sources into one ImFont.
+    ImFontConfig*               ConfigData;         //              // Pointer within ContainerAtlas->ConfigData
+    ImFontAtlas*                ContainerAtlas;     //              // What we has been loaded into
+    float                       Ascent, Descent;    //              // Ascent: distance from top to bottom of e.g. 'A' [0..FontSize]
 
     // Methods
     IMGUI_API ImFont();
@@ -1327,7 +1328,8 @@ struct ImFont
     // 'wrap_width' enable automatic word-wrapping across multiple lines to fit into given width. 0.0f to disable.
     IMGUI_API ImVec2            CalcTextSizeA(float size, float max_width, float wrap_width, const char* text_begin, const char* text_end = NULL, const char** remaining = NULL) const; // utf8
     IMGUI_API const char*       CalcWordWrapPositionA(float scale, const char* text, const char* text_end, float wrap_width) const;
-    IMGUI_API void              RenderText(float size, ImVec2 pos, ImU32 col, const ImVec4& clip_rect, const char* text_begin, const char* text_end, ImDrawList* draw_list, float wrap_width = 0.0f, bool cpu_fine_clip = false) const;
+    IMGUI_API void              RenderChar(ImDrawList* draw_list, float size, ImVec2 pos, ImU32 col, unsigned short c) const;
+    IMGUI_API void              RenderText(ImDrawList* draw_list, float size, ImVec2 pos, ImU32 col, const ImVec4& clip_rect, const char* text_begin, const char* text_end, float wrap_width = 0.0f, bool cpu_fine_clip = false) const;
 };
 
 //---- Include imgui_user.h at the end of imgui.h

3rdparty/ocornut-imgui/imgui_draw.cpp

@@ -920,14 +920,6 @@ void ImDrawList::AddText(const ImFont* font, float font_size, const ImVec2& pos,
 
     IM_ASSERT(font->ContainerAtlas->TexID == _TextureIdStack.back());  // Use high-level ImGui::PushFont() or low-level ImDrawList::PushTextureId() to change font.
 
-    // reserve vertices for worse case (over-reserving is useful and easily amortized)
-    const int char_count = (int)(text_end - text_begin);
-    const int vtx_count_max = char_count * 4;
-    const int idx_count_max = char_count * 6;
-    const int vtx_begin = VtxBuffer.Size;
-    const int idx_begin = IdxBuffer.Size;
-    PrimReserve(idx_count_max, vtx_count_max);
-
     ImVec4 clip_rect = _ClipRectStack.back();
     if (cpu_fine_clip_rect)
     {
@@ -936,18 +928,7 @@ void ImDrawList::AddText(const ImFont* font, float font_size, const ImVec2& pos,
         clip_rect.z = ImMin(clip_rect.z, cpu_fine_clip_rect->z);
         clip_rect.w = ImMin(clip_rect.w, cpu_fine_clip_rect->w);
     }
-    font->RenderText(font_size, pos, col, clip_rect, text_begin, text_end, this, wrap_width, cpu_fine_clip_rect != NULL);
-
-    // give back unused vertices
-    // FIXME-OPT: clean this up
-    VtxBuffer.resize((int)(_VtxWritePtr - VtxBuffer.Data));
-    IdxBuffer.resize((int)(_IdxWritePtr - IdxBuffer.Data));
-    int vtx_unused = vtx_count_max - (VtxBuffer.Size - vtx_begin);
-    int idx_unused = idx_count_max - (IdxBuffer.Size - idx_begin);
-    CmdBuffer.back().ElemCount -= idx_unused;
-    _VtxWritePtr -= vtx_unused;
-    _IdxWritePtr -= idx_unused;
-    _VtxCurrentIdx = (unsigned int)VtxBuffer.Size;
+    font->RenderText(this, font_size, pos, col, clip_rect, text_begin, text_end, wrap_width, cpu_fine_clip_rect != NULL);
 }
 
 void ImDrawList::AddText(const ImVec2& pos, ImU32 col, const char* text_begin, const char* text_end)
@@ -1696,6 +1677,7 @@ void ImFont::BuildLookupTable()
     for (int i = 0; i != Glyphs.Size; i++)
         max_codepoint = ImMax(max_codepoint, (int)Glyphs[i].Codepoint);
 
+    IM_ASSERT(Glyphs.Size < 32*1024);
     IndexXAdvance.clear();
     IndexXAdvance.resize(max_codepoint + 1);
     IndexLookup.clear();
@@ -1703,13 +1685,13 @@ void ImFont::BuildLookupTable()
     for (int i = 0; i < max_codepoint + 1; i++)
     {
         IndexXAdvance[i] = -1.0f;
-        IndexLookup[i] = -1;
+        IndexLookup[i] = (short)-1;
     }
     for (int i = 0; i < Glyphs.Size; i++)
     {
         int codepoint = (int)Glyphs[i].Codepoint;
         IndexXAdvance[codepoint] = Glyphs[i].XAdvance;
-        IndexLookup[codepoint] = i;
+        IndexLookup[codepoint] = (short)i;
     }
 
     // Create a glyph to handle TAB
@@ -1723,7 +1705,7 @@ void ImFont::BuildLookupTable()
         tab_glyph.Codepoint = '\t';
         tab_glyph.XAdvance *= 4;
         IndexXAdvance[(int)tab_glyph.Codepoint] = (float)tab_glyph.XAdvance;
-        IndexLookup[(int)tab_glyph.Codepoint] = (int)(Glyphs.Size-1);
+        IndexLookup[(int)tab_glyph.Codepoint] = (short)(Glyphs.Size-1);
     }
 
     FallbackGlyph = NULL;
@@ -1744,9 +1726,9 @@ const ImFont::Glyph* ImFont::FindGlyph(unsigned short c) const
 {
     if (c < IndexLookup.Size)
     {
-        const int i = IndexLookup[c];
+        const short i = IndexLookup[c];
         if (i != -1)
-            return &Glyphs[i];
+            return &Glyphs.Data[i];
     }
     return FallbackGlyph;
 }
@@ -1942,7 +1924,23 @@ ImVec2 ImFont::CalcTextSizeA(float size, float max_width, float wrap_width, cons
     return text_size;
 }
 
-void ImFont::RenderText(float size, ImVec2 pos, ImU32 col, const ImVec4& clip_rect, const char* text_begin, const char* text_end, ImDrawList* draw_list, float wrap_width, bool cpu_fine_clip) const
+void ImFont::RenderChar(ImDrawList* draw_list, float size, ImVec2 pos, ImU32 col, unsigned short c) const
+{
+    if (c == ' ' || c == '\t' || c == '\n' || c == '\r') // Match behavior of RenderText(), those 4 codepoints are hard-coded.
+        return;
+    if (const Glyph* glyph = FindGlyph(c))
+    {
+        float scale = (size >= 0.0f) ? (size / FontSize) : 1.0f;
+        pos.x = (float)(int)pos.x + DisplayOffset.x;
+        pos.y = (float)(int)pos.y + DisplayOffset.y;
+        ImVec2 pos_tl(pos.x + glyph->X0 * scale, pos.y + glyph->Y0 * scale);
+        ImVec2 pos_br(pos.x + glyph->X1 * scale, pos.y + glyph->Y1 * scale);
+        draw_list->PrimReserve(6, 4);
+        draw_list->PrimRectUV(pos_tl, pos_br, ImVec2(glyph->U0, glyph->V0), ImVec2(glyph->U1, glyph->V1), col);
+    }
+}
+
+void ImFont::RenderText(ImDrawList* draw_list, float size, ImVec2 pos, ImU32 col, const ImVec4& clip_rect, const char* text_begin, const char* text_end, float wrap_width, bool cpu_fine_clip) const
 {
     if (!text_end)
         text_end = text_begin + strlen(text_begin);
@@ -1960,14 +1958,22 @@ void ImFont::RenderText(float size, ImVec2 pos, ImU32 col, const ImVec4& clip_re
     const bool word_wrap_enabled = (wrap_width > 0.0f);
     const char* word_wrap_eol = NULL;
 
-    ImDrawVert* vtx_write = draw_list->_VtxWritePtr;
-    ImDrawIdx* idx_write = draw_list->_IdxWritePtr;
-    unsigned int vtx_current_idx = draw_list->_VtxCurrentIdx;
-
+    // Skip non-visible lines
     const char* s = text_begin;
     if (!word_wrap_enabled && y + line_height < clip_rect.y)
         while (s < text_end && *s != '\n')  // Fast-forward to next line
             s++;
+
+    // Reserve vertices for remaining worse case (over-reserving is useful and easily amortized)
+    const int vtx_count_max = (int)(text_end - s) * 4;
+    const int idx_count_max = (int)(text_end - s) * 6;
+    const int idx_expected_size = draw_list->IdxBuffer.Size + idx_count_max;
+    draw_list->PrimReserve(idx_count_max, vtx_count_max);
+
+    ImDrawVert* vtx_write = draw_list->_VtxWritePtr;
+    ImDrawIdx* idx_write = draw_list->_IdxWritePtr;
+    unsigned int vtx_current_idx = draw_list->_VtxCurrentIdx;
+
     while (s < text_end)
     {
         if (word_wrap_enabled)
@@ -2036,11 +2042,10 @@ void ImFont::RenderText(float size, ImVec2 pos, ImU32 col, const ImVec4& clip_re
             if (c != ' ' && c != '\t')
             {
                 // 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);
-
-                float x1 = (float)(x + glyph->X0 * scale);
-                float x2 = (float)(x + glyph->X1 * scale);
+                float x1 = x + glyph->X0 * scale;
+                float x2 = x + glyph->X1 * scale;
+                float y1 = y + glyph->Y0 * scale;
+                float y2 = y + glyph->Y1 * scale;
                 if (x1 <= clip_rect.z && x2 >= clip_rect.x)
                 {
                     // Render a character
@@ -2099,9 +2104,13 @@ void ImFont::RenderText(float size, ImVec2 pos, ImU32 col, const ImVec4& clip_re
         x += char_width;
     }
 
+    // Give back unused vertices
+    draw_list->VtxBuffer.resize((int)(vtx_write - draw_list->VtxBuffer.Data));
+    draw_list->IdxBuffer.resize((int)(idx_write - draw_list->IdxBuffer.Data));
+    draw_list->CmdBuffer[draw_list->CmdBuffer.Size-1].ElemCount -= (idx_expected_size - draw_list->IdxBuffer.Size);
     draw_list->_VtxWritePtr = vtx_write;
-    draw_list->_VtxCurrentIdx = vtx_current_idx;
     draw_list->_IdxWritePtr = idx_write;
+    draw_list->_VtxCurrentIdx = (unsigned int)draw_list->VtxBuffer.Size;
 }
 
 //-----------------------------------------------------------------------------

3rdparty/ocornut-imgui/imgui_internal.h

@@ -135,7 +135,7 @@ static inline ImVec2 ImLerp(const ImVec2& a, const ImVec2& b, const ImVec2& t)
 static inline float  ImLengthSqr(const ImVec2& lhs)                             { return lhs.x*lhs.x + lhs.y*lhs.y; }
 static inline float  ImLengthSqr(const ImVec4& lhs)                             { return lhs.x*lhs.x + lhs.y*lhs.y + lhs.z*lhs.z + lhs.w*lhs.w; }
 static inline float  ImInvLength(const ImVec2& lhs, float fail_value)           { float d = lhs.x*lhs.x + lhs.y*lhs.y; if (d > 0.0f) return 1.0f / sqrtf(d); return fail_value; }
-static inline ImVec2 ImRound(ImVec2 v)                                          { return ImVec2((float)(int)v.x, (float)(int)v.y); }
+static inline ImVec2 ImFloor(ImVec2 v)                                          { return ImVec2((float)(int)v.x, (float)(int)v.y); }
 
 // We call C++ constructor on own allocated memory via the placement "new(ptr) Type()" syntax.
 // Defining a custom placement new() with a dummy parameter allows us to bypass including <new> which on some platforms complains when user has disabled exceptions.
@@ -231,7 +231,7 @@ struct IMGUI_API ImRect
     void        Expand(const ImVec2& amount)    { Min.x -= amount.x; Min.y -= amount.y; Max.x += amount.x; Max.y += amount.y; }
     void        Reduce(const ImVec2& amount)    { Min.x += amount.x; Min.y += amount.y; Max.x -= amount.x; Max.y -= amount.y; }
     void        Clip(const ImRect& clip)        { if (Min.x < clip.Min.x) Min.x = clip.Min.x; if (Min.y < clip.Min.y) Min.y = clip.Min.y; if (Max.x > clip.Max.x) Max.x = clip.Max.x; if (Max.y > clip.Max.y) Max.y = clip.Max.y; }
-    void        Round()                         { Min.x = (float)(int)Min.x; Min.y = (float)(int)Min.y; Max.x = (float)(int)Max.x; Max.y = (float)(int)Max.y; }
+    void        Floor()                         { Min.x = (float)(int)Min.x; Min.y = (float)(int)Min.y; Max.x = (float)(int)Max.x; Max.y = (float)(int)Max.y; }
     ImVec2      GetClosestPoint(ImVec2 p, bool on_edge) const
     {
         if (!on_edge && Contains(p))