Backends: OpenGL2/3, SDLRenderer2/3, DirectX9, Metal: moved Init/Shutdown code lower in the file.

Allows to point to local functions without forward declaring them.

backends/imgui_impl_dx9.cpp

@@ -325,46 +325,6 @@ static bool ImGui_ImplDX9_CheckFormatSupport(LPDIRECT3DDEVICE9 pDevice, D3DFORMA
     return support;
 }
 
-bool ImGui_ImplDX9_Init(IDirect3DDevice9* device)
-{
-    ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
-
-    // Setup backend capabilities flags
-    ImGui_ImplDX9_Data* bd = IM_NEW(ImGui_ImplDX9_Data)();
-    io.BackendRendererUserData = (void*)bd;
-    io.BackendRendererName = "imgui_impl_dx9";
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
-
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-    platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = 4096;
-
-    bd->pd3dDevice = device;
-    bd->pd3dDevice->AddRef();
-    bd->HasRgbaSupport = ImGui_ImplDX9_CheckFormatSupport(bd->pd3dDevice, D3DFMT_A8B8G8R8);
-
-    return true;
-}
-
-void ImGui_ImplDX9_Shutdown()
-{
-    ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
-    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
-    ImGuiIO& io = ImGui::GetIO();
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-
-    ImGui_ImplDX9_InvalidateDeviceObjects();
-    if (bd->pd3dDevice) { bd->pd3dDevice->Release(); }
-
-    io.BackendRendererName = nullptr;
-    io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
-    platform_io.ClearRendererHandlers();
-    IM_DELETE(bd);
-}
-
 // Convert RGBA32 to BGRA32 (because RGBA32 is not well supported by DX9 devices)
 static void ImGui_ImplDX9_CopyTextureRegion(bool tex_use_colors, const ImU32* src, int src_pitch, ImU32* dst, int dst_pitch, int w, int h)
 {
@@ -477,6 +437,47 @@ void ImGui_ImplDX9_NewFrame()
     IM_UNUSED(bd);
 }
 
+
+bool ImGui_ImplDX9_Init(IDirect3DDevice9* device)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IMGUI_CHECKVERSION();
+    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+
+    // Setup backend capabilities flags
+    ImGui_ImplDX9_Data* bd = IM_NEW(ImGui_ImplDX9_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_dx9";
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = 4096;
+
+    bd->pd3dDevice = device;
+    bd->pd3dDevice->AddRef();
+    bd->HasRgbaSupport = ImGui_ImplDX9_CheckFormatSupport(bd->pd3dDevice, D3DFMT_A8B8G8R8);
+
+    return true;
+}
+
+void ImGui_ImplDX9_Shutdown()
+{
+    ImGui_ImplDX9_Data* bd = ImGui_ImplDX9_GetBackendData();
+    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+
+    ImGui_ImplDX9_InvalidateDeviceObjects();
+    if (bd->pd3dDevice) { bd->pd3dDevice->Release(); }
+
+    io.BackendRendererName = nullptr;
+    io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
+    platform_io.ClearRendererHandlers();
+    IM_DELETE(bd);
+}
+
 //-----------------------------------------------------------------------------
 
 #endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_metal.mm

@@ -130,41 +130,6 @@ bool ImGui_ImplMetal_CreateDeviceObjects(MTL::Device* device)
 
 #pragma mark - Dear ImGui Metal Backend API
 
-bool ImGui_ImplMetal_Init(id<MTLDevice> device)
-{
-    ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
-
-    ImGui_ImplMetal_Data* bd = IM_NEW(ImGui_ImplMetal_Data)();
-    io.BackendRendererUserData = (void*)bd;
-    io.BackendRendererName = "imgui_impl_metal";
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
-
-    bd->SharedMetalContext = [[MetalContext alloc] init];
-    bd->SharedMetalContext.device = device;
-
-    return true;
-}
-
-void ImGui_ImplMetal_Shutdown()
-{
-    ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
-    IM_UNUSED(bd);
-    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
-    ImGuiIO& io = ImGui::GetIO();
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-
-    ImGui_ImplMetal_DestroyDeviceObjects();
-    ImGui_ImplMetal_DestroyBackendData();
-
-    io.BackendRendererName = nullptr;
-    io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
-    platform_io.ClearRendererHandlers();
-}
-
 void ImGui_ImplMetal_NewFrame(MTLRenderPassDescriptor* renderPassDescriptor)
 {
     ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
@@ -431,6 +396,41 @@ void ImGui_ImplMetal_DestroyDeviceObjects()
     [bd->SharedMetalContext.renderPipelineStateCache removeAllObjects];
 }
 
+bool ImGui_ImplMetal_Init(id<MTLDevice> device)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IMGUI_CHECKVERSION();
+    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+
+    ImGui_ImplMetal_Data* bd = IM_NEW(ImGui_ImplMetal_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_metal";
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+
+    bd->SharedMetalContext = [[MetalContext alloc] init];
+    bd->SharedMetalContext.device = device;
+
+    return true;
+}
+
+void ImGui_ImplMetal_Shutdown()
+{
+    ImGui_ImplMetal_Data* bd = ImGui_ImplMetal_GetBackendData();
+    IM_UNUSED(bd);
+    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+
+    ImGui_ImplMetal_DestroyDeviceObjects();
+    ImGui_ImplMetal_DestroyBackendData();
+
+    io.BackendRendererName = nullptr;
+    io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
+    platform_io.ClearRendererHandlers();
+}
+
 #pragma mark - MetalBuffer implementation
 
 @implementation MetalBuffer

backends/imgui_impl_opengl2.cpp

@@ -97,37 +97,6 @@ static ImGui_ImplOpenGL2_Data* ImGui_ImplOpenGL2_GetBackendData()
 }
 
 // Functions
-bool    ImGui_ImplOpenGL2_Init()
-{
-    ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
-
-    // Setup backend capabilities flags
-    ImGui_ImplOpenGL2_Data* bd = IM_NEW(ImGui_ImplOpenGL2_Data)();
-    io.BackendRendererUserData = (void*)bd;
-    io.BackendRendererName = "imgui_impl_opengl2";
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;       // We can honor ImGuiPlatformIO::Textures[] requests during render.
-
-    return true;
-}
-
-void    ImGui_ImplOpenGL2_Shutdown()
-{
-    ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData();
-    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
-    ImGuiIO& io = ImGui::GetIO();
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-
-    ImGui_ImplOpenGL2_DestroyDeviceObjects();
-
-    io.BackendRendererName = nullptr;
-    io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasTextures);
-    platform_io.ClearRendererHandlers();
-    IM_DELETE(bd);
-}
-
 void    ImGui_ImplOpenGL2_NewFrame()
 {
     ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData();
@@ -344,6 +313,37 @@ void    ImGui_ImplOpenGL2_DestroyDeviceObjects()
         }
 }
 
+bool    ImGui_ImplOpenGL2_Init()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IMGUI_CHECKVERSION();
+    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+
+    // Setup backend capabilities flags
+    ImGui_ImplOpenGL2_Data* bd = IM_NEW(ImGui_ImplOpenGL2_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_opengl2";
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;       // We can honor ImGuiPlatformIO::Textures[] requests during render.
+
+    return true;
+}
+
+void    ImGui_ImplOpenGL2_Shutdown()
+{
+    ImGui_ImplOpenGL2_Data* bd = ImGui_ImplOpenGL2_GetBackendData();
+    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+
+    ImGui_ImplOpenGL2_DestroyDeviceObjects();
+
+    io.BackendRendererName = nullptr;
+    io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasTextures);
+    platform_io.ClearRendererHandlers();
+    IM_DELETE(bd);
+}
+
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)

backends/imgui_impl_opengl3.cpp

@@ -312,139 +312,6 @@ static void ImGui_ImplOpenGL3_ShutdownLoader()
 }
 
 // Functions
-bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
-{
-    ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
-
-    // Initialize loader
-    if (!ImGui_ImplOpenGL3_InitLoader())
-        return false;
-
-    // Setup backend capabilities flags
-    ImGui_ImplOpenGL3_Data* bd = IM_NEW(ImGui_ImplOpenGL3_Data)();
-    io.BackendRendererUserData = (void*)bd;
-    io.BackendRendererName = "imgui_impl_opengl3";
-
-    // Query for GL version (e.g. 320 for GL 3.2)
-    const char* gl_version_str = (const char*)glGetString(GL_VERSION);
-#if defined(IMGUI_IMPL_OPENGL_ES2)
-    // GLES 2
-    bd->GlVersion = 200;
-    bd->GlProfileIsES2 = true;
-    IM_UNUSED(gl_version_str);
-#else
-    // Desktop or GLES 3
-    GLint major = 0;
-    GLint minor = 0;
-    glGetIntegerv(GL_MAJOR_VERSION, &major);
-    glGetIntegerv(GL_MINOR_VERSION, &minor);
-    if (major == 0 && minor == 0)
-        sscanf(gl_version_str, "%d.%d", &major, &minor); // Query GL_VERSION in desktop GL 2.x, the string will start with "<major>.<minor>"
-    bd->GlVersion = (GLuint)(major * 100 + minor * 10);
-    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &bd->MaxTextureSize);
-
-#if defined(IMGUI_IMPL_OPENGL_ES3)
-    bd->GlProfileIsES3 = true;
-#else
-    if (strncmp(gl_version_str, "OpenGL ES 3", 11) == 0)
-        bd->GlProfileIsES3 = true;
-#endif
-
-#if defined(GL_CONTEXT_PROFILE_MASK)
-    if (!bd->GlProfileIsES3 && bd->GlVersion >= 320)
-        glGetIntegerv(GL_CONTEXT_PROFILE_MASK, &bd->GlProfileMask);
-    bd->GlProfileIsCompat = (bd->GlProfileMask & GL_CONTEXT_COMPATIBILITY_PROFILE_BIT) != 0;
-#endif
-
-    bd->UseBufferSubData = false;
-    /*
-    // Query vendor to enable glBufferSubData kludge
-#ifdef _WIN32
-    if (const char* vendor = (const char*)glGetString(GL_VENDOR))
-        if (strncmp(vendor, "Intel", 5) == 0)
-            bd->UseBufferSubData = true;
-#endif
-    */
-#endif
-
-#ifdef IMGUI_IMPL_OPENGL_DEBUG
-    printf("GlVersion = %d, \"%s\"\nGlProfileIsCompat = %d\nGlProfileMask = 0x%X\nGlProfileIsES2/IsEs3 = %d/%d\nGL_VENDOR = '%s'\nGL_RENDERER = '%s'\n", bd->GlVersion, gl_version_str, bd->GlProfileIsCompat, bd->GlProfileMask, bd->GlProfileIsES2, bd->GlProfileIsES3, (const char*)glGetString(GL_VENDOR), (const char*)glGetString(GL_RENDERER)); // [DEBUG]
-#endif
-
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_VTX_OFFSET
-    if (bd->GlVersion >= 320)
-        io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
-#endif
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;       // We can honor ImGuiPlatformIO::Textures[] requests during render.
-
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-    platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = (int)bd->MaxTextureSize;
-
-    // Store GLSL version string so we can refer to it later in case we recreate shaders.
-    // Note: GLSL version is NOT the same as GL version. Leave this to nullptr if unsure.
-    if (glsl_version == nullptr)
-    {
-#if defined(IMGUI_IMPL_OPENGL_ES2)
-        glsl_version = "#version 100";
-#elif defined(IMGUI_IMPL_OPENGL_ES3)
-        glsl_version = "#version 300 es";
-#elif defined(__APPLE__)
-        glsl_version = "#version 150";
-#else
-        glsl_version = "#version 130";
-#endif
-    }
-    IM_ASSERT((int)strlen(glsl_version) + 2 < IM_COUNTOF(bd->GlslVersionString));
-    strcpy(bd->GlslVersionString, glsl_version);
-    strcat(bd->GlslVersionString, "\n");
-
-    // Make an arbitrary GL call (we don't actually need the result)
-    // IF YOU GET A CRASH HERE: it probably means the OpenGL function loader didn't do its job. Let us know!
-    GLint current_texture;
-    glGetIntegerv(GL_TEXTURE_BINDING_2D, &current_texture);
-
-    // Detect extensions we support
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_POLYGON_MODE
-    bd->HasPolygonMode = (!bd->GlProfileIsES2 && !bd->GlProfileIsES3);
-#endif
-#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
-    bd->HasBindSampler = (bd->GlVersion >= 330 || bd->GlProfileIsES3);
-#endif
-    bd->HasClipOrigin = (bd->GlVersion >= 450);
-#ifdef IMGUI_IMPL_OPENGL_HAS_EXTENSIONS
-    GLint num_extensions = 0;
-    glGetIntegerv(GL_NUM_EXTENSIONS, &num_extensions);
-    for (GLint i = 0; i < num_extensions; i++)
-    {
-        const char* extension = (const char*)glGetStringi(GL_EXTENSIONS, i);
-        if (extension != nullptr && strcmp(extension, "GL_ARB_clip_control") == 0)
-            bd->HasClipOrigin = true;
-    }
-#endif
-
-    return true;
-}
-
-void    ImGui_ImplOpenGL3_Shutdown()
-{
-    ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
-    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
-    ImGuiIO& io = ImGui::GetIO();
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-
-    ImGui_ImplOpenGL3_DestroyDeviceObjects();
-
-    io.BackendRendererName = nullptr;
-    io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
-    platform_io.ClearRendererHandlers();
-    IM_DELETE(bd);
-
-    ImGui_ImplOpenGL3_ShutdownLoader();
-}
-
 void    ImGui_ImplOpenGL3_NewFrame()
 {
     ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
@@ -1055,6 +922,139 @@ void    ImGui_ImplOpenGL3_DestroyDeviceObjects()
             ImGui_ImplOpenGL3_DestroyTexture(tex);
 }
 
+bool    ImGui_ImplOpenGL3_Init(const char* glsl_version)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IMGUI_CHECKVERSION();
+    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+
+    // Initialize loader
+    if (!ImGui_ImplOpenGL3_InitLoader())
+        return false;
+
+    // Setup backend capabilities flags
+    ImGui_ImplOpenGL3_Data* bd = IM_NEW(ImGui_ImplOpenGL3_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_opengl3";
+
+    // Query for GL version (e.g. 320 for GL 3.2)
+    const char* gl_version_str = (const char*)glGetString(GL_VERSION);
+#if defined(IMGUI_IMPL_OPENGL_ES2)
+    // GLES 2
+    bd->GlVersion = 200;
+    bd->GlProfileIsES2 = true;
+    IM_UNUSED(gl_version_str);
+#else
+    // Desktop or GLES 3
+    GLint major = 0;
+    GLint minor = 0;
+    glGetIntegerv(GL_MAJOR_VERSION, &major);
+    glGetIntegerv(GL_MINOR_VERSION, &minor);
+    if (major == 0 && minor == 0)
+        sscanf(gl_version_str, "%d.%d", &major, &minor); // Query GL_VERSION in desktop GL 2.x, the string will start with "<major>.<minor>"
+    bd->GlVersion = (GLuint)(major * 100 + minor * 10);
+    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &bd->MaxTextureSize);
+
+#if defined(IMGUI_IMPL_OPENGL_ES3)
+    bd->GlProfileIsES3 = true;
+#else
+    if (strncmp(gl_version_str, "OpenGL ES 3", 11) == 0)
+        bd->GlProfileIsES3 = true;
+#endif
+
+#if defined(GL_CONTEXT_PROFILE_MASK)
+    if (!bd->GlProfileIsES3 && bd->GlVersion >= 320)
+        glGetIntegerv(GL_CONTEXT_PROFILE_MASK, &bd->GlProfileMask);
+    bd->GlProfileIsCompat = (bd->GlProfileMask & GL_CONTEXT_COMPATIBILITY_PROFILE_BIT) != 0;
+#endif
+
+    bd->UseBufferSubData = false;
+    /*
+    // Query vendor to enable glBufferSubData kludge
+#ifdef _WIN32
+    if (const char* vendor = (const char*)glGetString(GL_VENDOR))
+        if (strncmp(vendor, "Intel", 5) == 0)
+            bd->UseBufferSubData = true;
+#endif
+    */
+#endif
+
+#ifdef IMGUI_IMPL_OPENGL_DEBUG
+    printf("GlVersion = %d, \"%s\"\nGlProfileIsCompat = %d\nGlProfileMask = 0x%X\nGlProfileIsES2/IsEs3 = %d/%d\nGL_VENDOR = '%s'\nGL_RENDERER = '%s'\n", bd->GlVersion, gl_version_str, bd->GlProfileIsCompat, bd->GlProfileMask, bd->GlProfileIsES2, bd->GlProfileIsES3, (const char*)glGetString(GL_VENDOR), (const char*)glGetString(GL_RENDERER)); // [DEBUG]
+#endif
+
+#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_VTX_OFFSET
+    if (bd->GlVersion >= 320)
+        io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+#endif
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;       // We can honor ImGuiPlatformIO::Textures[] requests during render.
+
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Renderer_TextureMaxWidth = platform_io.Renderer_TextureMaxHeight = (int)bd->MaxTextureSize;
+
+    // Store GLSL version string so we can refer to it later in case we recreate shaders.
+    // Note: GLSL version is NOT the same as GL version. Leave this to nullptr if unsure.
+    if (glsl_version == nullptr)
+    {
+#if defined(IMGUI_IMPL_OPENGL_ES2)
+        glsl_version = "#version 100";
+#elif defined(IMGUI_IMPL_OPENGL_ES3)
+        glsl_version = "#version 300 es";
+#elif defined(__APPLE__)
+        glsl_version = "#version 150";
+#else
+        glsl_version = "#version 130";
+#endif
+    }
+    IM_ASSERT((int)strlen(glsl_version) + 2 < IM_COUNTOF(bd->GlslVersionString));
+    strcpy(bd->GlslVersionString, glsl_version);
+    strcat(bd->GlslVersionString, "\n");
+
+    // Make an arbitrary GL call (we don't actually need the result)
+    // IF YOU GET A CRASH HERE: it probably means the OpenGL function loader didn't do its job. Let us know!
+    GLint current_texture;
+    glGetIntegerv(GL_TEXTURE_BINDING_2D, &current_texture);
+
+    // Detect extensions we support
+#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_POLYGON_MODE
+    bd->HasPolygonMode = (!bd->GlProfileIsES2 && !bd->GlProfileIsES3);
+#endif
+#ifdef IMGUI_IMPL_OPENGL_MAY_HAVE_BIND_SAMPLER
+    bd->HasBindSampler = (bd->GlVersion >= 330 || bd->GlProfileIsES3);
+#endif
+    bd->HasClipOrigin = (bd->GlVersion >= 450);
+#ifdef IMGUI_IMPL_OPENGL_HAS_EXTENSIONS
+    GLint num_extensions = 0;
+    glGetIntegerv(GL_NUM_EXTENSIONS, &num_extensions);
+    for (GLint i = 0; i < num_extensions; i++)
+    {
+        const char* extension = (const char*)glGetStringi(GL_EXTENSIONS, i);
+        if (extension != nullptr && strcmp(extension, "GL_ARB_clip_control") == 0)
+            bd->HasClipOrigin = true;
+    }
+#endif
+
+    return true;
+}
+
+void    ImGui_ImplOpenGL3_Shutdown()
+{
+    ImGui_ImplOpenGL3_Data* bd = ImGui_ImplOpenGL3_GetBackendData();
+    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+
+    ImGui_ImplOpenGL3_DestroyDeviceObjects();
+
+    io.BackendRendererName = nullptr;
+    io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
+    platform_io.ClearRendererHandlers();
+    IM_DELETE(bd);
+
+    ImGui_ImplOpenGL3_ShutdownLoader();
+}
+
 //-----------------------------------------------------------------------------
 
 #if defined(__GNUC__)

backends/imgui_impl_sdlrenderer2.cpp

@@ -24,6 +24,7 @@
 // - Introduction, links and more at the top of imgui.cpp
 
 // CHANGELOG
+// (minor and older changes stripped away, please see git history for details)
 //  2026-03-12: Fixed invalid assert in ImGui_ImplSDLRenderer2_UpdateTexture() if ImTextureID_Invalid is defined to be != 0, which became the default since 2026-03-12. (#9295)
 //  2025-09-18: Call platform_io.ClearRendererHandlers() on shutdown.
 //  2025-06-11: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. Removed ImGui_ImplSDLRenderer2_CreateFontsTexture() and ImGui_ImplSDLRenderer2_DestroyFontsTexture().
@@ -72,41 +73,6 @@ static ImGui_ImplSDLRenderer2_Data* ImGui_ImplSDLRenderer2_GetBackendData()
 }
 
 // Functions
-bool ImGui_ImplSDLRenderer2_Init(SDL_Renderer* renderer)
-{
-    ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
-    IM_ASSERT(renderer != nullptr && "SDL_Renderer not initialized!");
-
-    // Setup backend capabilities flags
-    ImGui_ImplSDLRenderer2_Data* bd = IM_NEW(ImGui_ImplSDLRenderer2_Data)();
-    io.BackendRendererUserData = (void*)bd;
-    io.BackendRendererName = "imgui_impl_sdlrenderer2";
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
-
-    bd->Renderer = renderer;
-
-    return true;
-}
-
-void ImGui_ImplSDLRenderer2_Shutdown()
-{
-    ImGui_ImplSDLRenderer2_Data* bd = ImGui_ImplSDLRenderer2_GetBackendData();
-    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
-    ImGuiIO& io = ImGui::GetIO();
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-
-    ImGui_ImplSDLRenderer2_DestroyDeviceObjects();
-
-    io.BackendRendererName = nullptr;
-    io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
-    platform_io.ClearRendererHandlers();
-    IM_DELETE(bd);
-}
-
 static void ImGui_ImplSDLRenderer2_SetupRenderState(SDL_Renderer* renderer)
 {
     // Clear out any viewports and cliprect set by the user
@@ -293,6 +259,41 @@ void ImGui_ImplSDLRenderer2_DestroyDeviceObjects()
         }
 }
 
+bool ImGui_ImplSDLRenderer2_Init(SDL_Renderer* renderer)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IMGUI_CHECKVERSION();
+    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+    IM_ASSERT(renderer != nullptr && "SDL_Renderer not initialized!");
+
+    // Setup backend capabilities flags
+    ImGui_ImplSDLRenderer2_Data* bd = IM_NEW(ImGui_ImplSDLRenderer2_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_sdlrenderer2";
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+
+    bd->Renderer = renderer;
+
+    return true;
+}
+
+void ImGui_ImplSDLRenderer2_Shutdown()
+{
+    ImGui_ImplSDLRenderer2_Data* bd = ImGui_ImplSDLRenderer2_GetBackendData();
+    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+
+    ImGui_ImplSDLRenderer2_DestroyDeviceObjects();
+
+    io.BackendRendererName = nullptr;
+    io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
+    platform_io.ClearRendererHandlers();
+    IM_DELETE(bd);
+}
+
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)

backends/imgui_impl_sdlrenderer3.cpp

@@ -24,6 +24,7 @@
 // - Introduction, links and more at the top of imgui.cpp
 
 // CHANGELOG
+// (minor and older changes stripped away, please see git history for details)
 //  2026-03-12: Fixed invalid assert in ImGui_ImplSDLRenderer3_UpdateTexture() if ImTextureID_Invalid is defined to be != 0, which became the default since 2026-03-12. (#9295)
 //  2025-09-18: Call platform_io.ClearRendererHandlers() on shutdown.
 //  2025-06-11: Added support for ImGuiBackendFlags_RendererHasTextures, for dynamic font atlas. Removed ImGui_ImplSDLRenderer3_CreateFontsTexture() and ImGui_ImplSDLRenderer3_DestroyFontsTexture().
@@ -70,41 +71,6 @@ static ImGui_ImplSDLRenderer3_Data* ImGui_ImplSDLRenderer3_GetBackendData()
 }
 
 // Functions
-bool ImGui_ImplSDLRenderer3_Init(SDL_Renderer* renderer)
-{
-    ImGuiIO& io = ImGui::GetIO();
-    IMGUI_CHECKVERSION();
-    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
-    IM_ASSERT(renderer != nullptr && "SDL_Renderer not initialized!");
-
-    // Setup backend capabilities flags
-    ImGui_ImplSDLRenderer3_Data* bd = IM_NEW(ImGui_ImplSDLRenderer3_Data)();
-    io.BackendRendererUserData = (void*)bd;
-    io.BackendRendererName = "imgui_impl_sdlrenderer3";
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
-    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
-
-    bd->Renderer = renderer;
-
-    return true;
-}
-
-void ImGui_ImplSDLRenderer3_Shutdown()
-{
-    ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
-    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
-    ImGuiIO& io = ImGui::GetIO();
-    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
-
-    ImGui_ImplSDLRenderer3_DestroyDeviceObjects();
-
-    io.BackendRendererName = nullptr;
-    io.BackendRendererUserData = nullptr;
-    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
-    platform_io.ClearRendererHandlers();
-    IM_DELETE(bd);
-}
-
 static void ImGui_ImplSDLRenderer3_SetupRenderState(SDL_Renderer* renderer)
 {
     // Clear out any viewports and cliprect set by the user
@@ -309,6 +275,41 @@ void ImGui_ImplSDLRenderer3_DestroyDeviceObjects()
         }
 }
 
+bool ImGui_ImplSDLRenderer3_Init(SDL_Renderer* renderer)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    IMGUI_CHECKVERSION();
+    IM_ASSERT(io.BackendRendererUserData == nullptr && "Already initialized a renderer backend!");
+    IM_ASSERT(renderer != nullptr && "SDL_Renderer not initialized!");
+
+    // Setup backend capabilities flags
+    ImGui_ImplSDLRenderer3_Data* bd = IM_NEW(ImGui_ImplSDLRenderer3_Data)();
+    io.BackendRendererUserData = (void*)bd;
+    io.BackendRendererName = "imgui_impl_sdlrenderer3";
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;  // We can honor the ImDrawCmd::VtxOffset field, allowing for large meshes.
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;   // We can honor ImGuiPlatformIO::Textures[] requests during render.
+
+    bd->Renderer = renderer;
+
+    return true;
+}
+
+void ImGui_ImplSDLRenderer3_Shutdown()
+{
+    ImGui_ImplSDLRenderer3_Data* bd = ImGui_ImplSDLRenderer3_GetBackendData();
+    IM_ASSERT(bd != nullptr && "No renderer backend to shutdown, or already shutdown?");
+    ImGuiIO& io = ImGui::GetIO();
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+
+    ImGui_ImplSDLRenderer3_DestroyDeviceObjects();
+
+    io.BackendRendererName = nullptr;
+    io.BackendRendererUserData = nullptr;
+    io.BackendFlags &= ~(ImGuiBackendFlags_RendererHasVtxOffset | ImGuiBackendFlags_RendererHasTextures);
+    platform_io.ClearRendererHandlers();
+    IM_DELETE(bd);
+}
+
 //-----------------------------------------------------------------------------
 
 #if defined(__clang__)