WIP. Crude dynamic font texture update.

backends/imgui_impl_dx9.cpp

@@ -37,9 +37,7 @@
 static LPDIRECT3DDEVICE9        g_pd3dDevice = NULL;
 static LPDIRECT3DVERTEXBUFFER9  g_pVB = NULL;
 static LPDIRECT3DINDEXBUFFER9   g_pIB = NULL;
-static LPDIRECT3DTEXTURE9       g_FontTexture = NULL;
-static int                      g_FontTextureWidth = 0;
-static int                      g_FontTextureHeight = 0;
+static ImVector<LPDIRECT3DTEXTURE9> g_FontTextures;
 static int                      g_VertexBufferSize = 5000, g_IndexBufferSize = 10000;
 
 struct CUSTOMVERTEX
@@ -56,6 +54,8 @@ struct CUSTOMVERTEX
 #define IMGUI_COL_TO_DX9_ARGB(_COL)     (((_COL) & 0xFF00FF00) | (((_COL) & 0xFF0000) >> 16) | (((_COL) & 0xFF) << 16))
 #endif
 
+static LPDIRECT3DTEXTURE9 ImGui_ImplDX9_UpdateTexture(const ImTextureData& texture_data);
+
 static void ImGui_ImplDX9_SetupRenderState(ImDrawData* draw_data)
 {
     // Setup viewport
@@ -259,19 +259,17 @@ void ImGui_ImplDX9_Shutdown()
     if (g_pd3dDevice) { g_pd3dDevice->Release(); g_pd3dDevice = NULL; }
 }
 
-static bool ImGui_ImplDX9_UpdateFontsTexture()
+static LPDIRECT3DTEXTURE9 ImGui_ImplDX9_UpdateTexture(const ImTextureData& texture_data)
 {
-    ImGuiIO& io = ImGui::GetIO();
-
-    // Build texture atlas
-    unsigned char* pixels;
-    int width, height, bytes_per_pixel;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height, &bytes_per_pixel);
-    io.Fonts->MarkClean();
+    LPDIRECT3DTEXTURE9 texture         = (LPDIRECT3DTEXTURE9)texture_data.GetTexID();
+    unsigned char*     pixels          = (unsigned char*)texture_data.TexPixels;
+    int                width           = texture_data.TexWidth;
+    int                height          = texture_data.TexHeight;
+    int                bytes_per_pixel = 4;
 
     // Convert RGBA32 to BGRA32 (because RGBA32 is not well supported by DX9 devices)
 #ifndef IMGUI_USE_BGRA_PACKED_COLOR
-    if (io.Fonts->TexData.TexFormat == ImTextureFormat_RGBA32)
+    if (texture_data.TexFormat == ImTextureFormat_RGBA32)
     {
         ImU32* dst_start = (ImU32*)ImGui::MemAlloc(width * height * bytes_per_pixel);
         for (ImU32* src = (ImU32*)pixels, *dst = dst_start, *dst_end = dst_start + width * height; dst < dst_end; src++, dst++)
@@ -280,33 +278,31 @@ static bool ImGui_ImplDX9_UpdateFontsTexture()
     }
 #endif
 
+    D3DSURFACE_DESC surface_desc = {};
+    if (texture)
+        texture->GetLevelDesc(0, &surface_desc);
+
     // Upload texture to graphics system
-    if ((!g_FontTexture) || (g_FontTextureWidth != width) || (g_FontTextureHeight != height))
+    if ((!texture) || (surface_desc.Width != width) || (surface_desc.Height != height))
     {
-        // (Re-)create texture
-        if (g_FontTexture)
-            g_FontTexture->Release();
-        io.Fonts->SetTexID(NULL);
-        g_FontTexture = NULL;
-        if (g_pd3dDevice->CreateTexture(width, height, 1, D3DUSAGE_DYNAMIC, D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT, &g_FontTexture, NULL) < 0)
+        // Create texture
+        texture = NULL;
+        if (g_pd3dDevice->CreateTexture(width, height, 1, D3DUSAGE_DYNAMIC, D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT, &texture, NULL) < 0)
             return false;
 
         // Store size
-        g_FontTextureWidth = width;
-        g_FontTextureHeight = height;
+        surface_desc.Width  = width;
+        surface_desc.Height = height;
     }
 
-    // Store our identifier
-    io.Fonts->SetTexID((ImTextureID)g_FontTexture);
-
     {
         D3DLOCKED_RECT tex_locked_rect;
         RECT dirty_rect;
         dirty_rect.left = 0;
         dirty_rect.right = width;
         dirty_rect.top = 0;
         dirty_rect.bottom = height;
-        if (g_FontTexture->LockRect(0, &tex_locked_rect, &dirty_rect, 0) != D3D_OK)
+        if (texture->LockRect(0, &tex_locked_rect, &dirty_rect, 0) != D3D_OK)
             return false;
 
         if (tex_locked_rect.Pitch == (width * 4))
@@ -329,24 +325,23 @@ static bool ImGui_ImplDX9_UpdateFontsTexture()
                 read_ptr += src_stride;
             }
         }
-        g_FontTexture->UnlockRect(0);
+        texture->UnlockRect(0);
     }
 
     // Upload the dirty region
 #ifndef IMGUI_USE_BGRA_PACKED_COLOR
-    if (io.Fonts->TexData.TexFormat == ImTextureFormat_RGBA32)
+    if (texture_data.TexFormat == ImTextureFormat_RGBA32)
         ImGui::MemFree(pixels);
 #endif
 
-    return true;
+    return texture;
 }
 
 bool ImGui_ImplDX9_CreateDeviceObjects()
 {
     if (!g_pd3dDevice)
         return false;
-    if (!ImGui_ImplDX9_UpdateFontsTexture())
-        return false;
+
     return true;
 }
 
@@ -356,16 +351,75 @@ void ImGui_ImplDX9_InvalidateDeviceObjects()
         return;
     if (g_pVB) { g_pVB->Release(); g_pVB = NULL; }
     if (g_pIB) { g_pIB->Release(); g_pIB = NULL; }
-    if (g_FontTexture) { g_FontTexture->Release(); g_FontTexture = NULL; ImGui::GetIO().Fonts->SetTexID(NULL); } // We copied g_pFontTextureView to io.Fonts->TexID so let's clear that as well.
+
+    for (int i = 0; i < g_FontTextures.Size; ++i)
+        g_FontTextures[i]->Release();
+    g_FontTextures.resize(0);
 }
 
 void ImGui_ImplDX9_NewFrame()
 {
     ImGuiIO& io = ImGui::GetIO();
 
-    if (!g_FontTexture)
-        ImGui_ImplDX9_CreateDeviceObjects();
+    if (g_FontTextures.empty())
+    {
+        if (io.Fonts->TexData.TexPixels == NULL || io.Fonts->IsDirty())
+        {
+            if (io.Fonts->ConfigData.empty())
+                io.Fonts->AddFontDefault();
+            io.Fonts->Build();
+        }
+    }
+}
+
+static void ImGui_ImplDX9_DeleteTextures(ImVector<LPDIRECT3DTEXTURE9>& textures)
+{
+    if (textures.empty())
+        return;
+
+    for (int i = 0; i < textures.Size; ++i)
+        textures[i]->Release();
+}
+
+static void ImGui_ImplDX9_UpdateTextures(ImVector<LPDIRECT3DTEXTURE9>& textures, const ImVector<ImTextureData*>& textures_data)
+{
+    ImVector<LPDIRECT3DTEXTURE9> discarded = textures;
+
+    bool recreate_all = textures.empty();
+
+    for (int i = 0; i < textures_data.Size; ++i)
+    {
+        ImTextureData* texture_data = textures_data[i];
+
+        LPDIRECT3DTEXTURE9 current_texture = (LPDIRECT3DTEXTURE9)texture_data->GetTexID();
+        if (current_texture == NULL || recreate_all)
+        {
+            texture_data->EnsureFormat(ImTextureFormat_RGBA32);
+
+            LPDIRECT3DTEXTURE9 new_texture = ImGui_ImplDX9_UpdateTexture(*texture_data);
+            if (current_texture != NULL && new_texture != current_texture)
+                textures.find_erase_unsorted(current_texture);
+
+            if (new_texture != NULL && new_texture != current_texture)
+                textures.push_back(new_texture);
+
+            discarded.find_erase_unsorted(new_texture);
+
+            texture_data->SetTexID(new_texture);
+        }
+        else if (current_texture)
+            discarded.find_erase_unsorted(current_texture);
+    }
+
+    ImGui_ImplDX9_DeleteTextures(discarded);
+
+    for (int i = 0; i < discarded.Size; ++i)
+        textures.find_erase_unsorted(discarded[i]);
+}
+
+void ImGui_ImplDX9_UpdateTextures()
+{
+    ImTextureUpdateData texture_update_data = ImGui::GetTextureUpdateData();
 
-    if (io.Fonts->IsDirty())
-        ImGui_ImplDX9_UpdateFontsTexture(); // We ignore the return value because if it fails that almost certainly means the device is invalid, and the font will get reinitialised by ImGui_ImplDX9_CreateDeviceObjects() later
+    ImGui_ImplDX9_UpdateTextures(g_FontTextures, texture_update_data.Textures);
 }

backends/imgui_impl_dx9.h

@@ -17,6 +17,7 @@ struct IDirect3DDevice9;
 IMGUI_IMPL_API bool     ImGui_ImplDX9_Init(IDirect3DDevice9* device);
 IMGUI_IMPL_API void     ImGui_ImplDX9_Shutdown();
 IMGUI_IMPL_API void     ImGui_ImplDX9_NewFrame();
+IMGUI_IMPL_API void     ImGui_ImplDX9_UpdateTextures();
 IMGUI_IMPL_API void     ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data);
 
 // Use if you want to reset your rendering device without losing Dear ImGui state.

examples/example_win32_directx9/main.cpp

@@ -95,8 +95,6 @@ int main(int, char**)
         if (done)
             break;
 
-        ImGui::UpdateFontDemo();
-
         // Start the Dear ImGui frame
         ImGui_ImplDX9_NewFrame();
         ImGui_ImplWin32_NewFrame();
@@ -151,6 +149,7 @@ int main(int, char**)
         if (g_pd3dDevice->BeginScene() >= 0)
         {
             ImGui::Render();
+            ImGui_ImplDX9_UpdateTextures();
             ImGui_ImplDX9_RenderDrawData(ImGui::GetDrawData());
             g_pd3dDevice->EndScene();
         }

imgui.cpp

@@ -3442,6 +3442,12 @@ ImDrawData* ImGui::GetDrawData()
     return viewport->DrawDataP.Valid ? &viewport->DrawDataP : NULL;
 }
 
+ImTextureUpdateData ImGui::GetTextureUpdateData()
+{
+    ImGuiContext& g = *GImGui;
+    return g.IO.Fonts->GetTextureUpdateData();
+}
+
 double ImGui::GetTime()
 {
     return GImGui->Time;
@@ -3922,6 +3928,7 @@ void ImGui::NewFrame()
 
     // Setup current font and draw list shared data
     g.IO.Fonts->Locked = true;
+    g.IO.Fonts->ClearTransientTextures();
     SetCurrentFont(GetDefaultFont());
     IM_ASSERT(g.Font->IsLoaded());
     ImRect virtual_space(FLT_MAX, FLT_MAX, -FLT_MAX, -FLT_MAX);

imgui.h

@@ -147,6 +147,7 @@ struct ImGuiTextBuffer;             // Helper to hold and append into a text buf
 struct ImGuiTextFilter;             // Helper to parse and apply text filters (e.g. "aaaaa[,bbbbb][,ccccc]")
 struct ImGuiViewport;               // A Platform Window (always only one in 'master' branch), in the future may represent Platform Monitor
 struct ImTexture;
+struct ImTextureUpdateData;
 
 // Enums/Flags (declared as int for compatibility with old C++, to allow using as flags and to not pollute the top of this file)
 // - Tip: Use your programming IDE navigation facilities on the names in the _central column_ below to find the actual flags/enum lists!
@@ -274,6 +275,7 @@ namespace ImGui
     IMGUI_API void          EndFrame();                                 // ends the Dear ImGui frame. automatically called by Render(). If you don't need to render data (skipping rendering) you may call EndFrame() without Render()... but you'll have wasted CPU already! If you don't need to render, better to not create any windows and not call NewFrame() at all!
     IMGUI_API void          Render();                                   // ends the Dear ImGui frame, finalize the draw data. You can then get call GetDrawData().
     IMGUI_API ImDrawData*   GetDrawData();                              // valid after Render() and until the next call to NewFrame(). this is what you have to render.
+    IMGUI_API ImTextureUpdateData GetTextureUpdateData();
 
     // Demo, Debug, Information
     IMGUI_API void          ShowDemoWindow(bool* p_open = NULL);        // create Demo window. demonstrate most ImGui features. call this to learn about the library! try to make it always available in your application!
@@ -2623,6 +2625,7 @@ struct ImTextureData
 {
     IMGUI_API ImTextureData();
     IMGUI_API ~ImTextureData();
+    IMGUI_API void              Reset();
     IMGUI_API void              AllocatePixels(int width, int height, ImTextureFormat format, bool clear = true);
     IMGUI_API void              DiscardPixels();
     IMGUI_API void              EnsureFormat(ImTextureFormat format);
@@ -2637,6 +2640,11 @@ struct ImTextureData
     int                         TexHeight;
 };
 
+struct ImTextureUpdateData
+{
+    ImVector<ImTextureData*>    Textures;
+};
+
 struct ImFontAtlas
 {
     IMGUI_API ImFontAtlas();
@@ -2661,6 +2669,8 @@ struct ImFontAtlas
     IMGUI_API bool              IsDirty(); // Returns true if the font needs to be (re-)built. User code should call GetTexData*** and update either the whole texture or dirty region as required.
     IMGUI_API void              GetTexDataAsAlpha8(unsigned char** out_pixels, int* out_width, int* out_height, int* out_bytes_per_pixel = NULL);  // 1 byte per-pixel
     IMGUI_API void              GetTexDataAsRGBA32(unsigned char** out_pixels, int* out_width, int* out_height, int* out_bytes_per_pixel = NULL);  // 4 bytes-per-pixel
+    IMGUI_API void                BuildTextureUpdateData(ImTextureUpdateData* texture_update_data);
+    IMGUI_API ImTextureUpdateData GetTextureUpdateData();
     bool                        IsBuilt() const             { return Fonts.Size > 0 && (TexData.TexPixels != NULL); }
     void                        SetTexID(ImTextureID id)    { TexData.TexID = id; }
     ImTextureID                 GetTexID() const            { return TexData.TexID; }
@@ -2701,6 +2711,8 @@ struct ImFontAtlas
     IMGUI_API bool              GetMouseCursorTexData(ImGuiMouseCursor cursor, ImVec2* out_offset, ImVec2* out_size, ImVec2 out_uv_border[2], ImVec2 out_uv_fill[2]);
     IMGUI_API void              MarkDirty(); // Mark atlas texture as dirty
     IMGUI_API void              MarkClean(); // Mark the whole texture as clean. Should be called after uploading texture.
+    IMGUI_API void              PushTexPage();
+    IMGUI_API void              ClearTransientTextures();
 
     //-------------------------------------------
     // Members
@@ -2721,6 +2733,7 @@ struct ImFontAtlas
     ImVector<ImFontAtlasCustomRect> CustomRects;    // Rectangles for packing custom texture data into the atlas.
     ImVector<ImFontConfig>      ConfigData;         // Configuration data
     ImVec4                      TexUvLines[IM_DRAWLIST_TEX_LINES_WIDTH_MAX + 1];  // UVs for baked anti-aliased lines
+    ImVector<ImTextureData>     TexPages;
 
     // [Internal] Font builder
     const ImFontBuilderIO*      FontBuilderIO;      // Opaque interface to a font builder (default to stb_truetype, can be changed to use FreeType by defining IMGUI_ENABLE_FREETYPE).
@@ -2845,7 +2858,15 @@ inline ImTexture::ImTexture(ImTextureID texture_id)
 
 inline ImTextureID ImTexture::GetID() const
 {
-    return Type == ImTextureType_Atlas ? FontAtlas->TexData.TexID : TextureId;
+    if (Type == ImTextureType_Atlas)
+    {
+        if (FontAtlasPage < FontAtlas->TexPages.Size)
+            return FontAtlas->TexPages[FontAtlasPage].GetTexID();
+        else
+            return FontAtlas->TexData.GetTexID();
+    }
+    else
+        return TextureId;
 }
 
 //-----------------------------------------------------------------------------

imgui_demo.cpp

@@ -7690,6 +7690,8 @@ void ShowExampleAppDocuments(bool* p_open)
     ImGui::End();
 }
 
+#include "imgui_internal.h"
+
 static const char* font_path_prefix = "../../misc/fonts/";
 static const char* fonts[] =
 {
@@ -7716,6 +7718,8 @@ void ImGui::UpdateFontDemo()
         if (selected_font_size < 0)
             selected_font_size = font_size;
 
+        io.Fonts->Locked = false; // #thedmd: remove this
+        io.Fonts->PushTexPage();
         io.Fonts->Clear();
         if (selected_font_index == 0)
         {
@@ -7735,7 +7739,9 @@ void ImGui::UpdateFontDemo()
         selected_font_index = -1;
         selected_font_size = -1.0f;
 
-        //io.Fonts->Build();
+        io.Fonts->Build();
+        io.Fonts->Locked = true; // #thedmd: remove this
+        ImGui::SetCurrentFont(ImGui::GetDefaultFont());
     }
 }
 
@@ -7774,10 +7780,12 @@ void ImGui::ShowFontDemoWindow()
         {
             ImVec4 tint_col = ImVec4(1.0f, 1.0f, 1.0f, 1.0f);
             ImVec4 border_col = ImVec4(1.0f, 1.0f, 1.0f, 0.5f);
-            ImGui::Image(atlas->GetTexID(), ImVec2((float)atlas->TexData.TexWidth, (float)atlas->TexData.TexHeight), ImVec2(0, 0), ImVec2(1, 1), tint_col, border_col);
+            ImGui::Image(ImTexture(atlas), ImVec2((float)atlas->TexData.TexWidth, (float)atlas->TexData.TexHeight), ImVec2(0, 0), ImVec2(1, 1), tint_col, border_col);
             //ImGui::TreePop();
         }
 
+        UpdateFontDemo();
+
         ImGui::End();
     }
 }