Backends: OpenGL2, OpenGL3, SDLRenderer3: replaced erroneous IM_ASSERT(tex->TexID == 0) calls. (#9295, #9293)

Amend/fix 0db5919 which revealed this.

backends/imgui_impl_opengl2.cpp

@@ -274,7 +274,7 @@ void ImGui_ImplOpenGL2_UpdateTexture(ImTextureData* tex)
     {
         // Create and upload new texture to graphics system
         //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
-        IM_ASSERT(tex->TexID == 0 && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->TexID == ImTextureID_Invalid && tex->BackendUserData == nullptr);
         IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
         const void* pixels = tex->GetPixels();
         GLuint gl_texture_id = 0;

backends/imgui_impl_opengl3.cpp

@@ -744,7 +744,7 @@ void ImGui_ImplOpenGL3_UpdateTexture(ImTextureData* tex)
     {
         // Create and upload new texture to graphics system
         //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
-        IM_ASSERT(tex->TexID == 0 && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->TexID == ImTextureID_Invalid && tex->BackendUserData == nullptr);
         IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
         const void* pixels = tex->GetPixels();
         GLuint gl_texture_id = 0;

backends/imgui_impl_sdlrenderer3.cpp

@@ -254,7 +254,7 @@ void ImGui_ImplSDLRenderer3_UpdateTexture(ImTextureData* tex)
     {
         // Create and upload new texture to graphics system
         //IMGUI_DEBUG_LOG("UpdateTexture #%03d: WantCreate %dx%d\n", tex->UniqueID, tex->Width, tex->Height);
-        IM_ASSERT(tex->TexID == 0 && tex->BackendUserData == nullptr);
+        IM_ASSERT(tex->TexID == ImTextureID_Invalid && tex->BackendUserData == nullptr);
         IM_ASSERT(tex->Format == ImTextureFormat_RGBA32);
 
         // Create texture

docs/CHANGELOG.txt

@@ -47,6 +47,10 @@ Breaking Changes:
      indices or memory offsets inside ImTextureID, where 0 might be a valid value.
    - If this is causing problem with e.g your custom ImTextureID definition, you can
      add '#define ImTextureID_Invalid 0' to your imconfig.h + PLEASE report this to GitHub.
+   - If you have hardcoded e.g. 'if (tex_id == 0)' checks they should be updated.
+     e.g. OpenGL2, OpenGL3 and SDLRenderer3 backends incorrectly had 'IM_ASSERT(tex->TexID == 0)'
+     lines which were replaced with 'IM_ASSERT(tex->TexID == ImTextureID_Invalid)'.
+     If you have copied or forked backends consider fixing locally. (#9295)
  - Separator(): fixed a legacy quirk where Separator() was submitting a zero-height
    item for layout purpose, even though it draws a 1-pixel separator.
    The fix could affect code e.g. computing height from multiple widgets in order to

imgui.cpp

@@ -398,6 +398,7 @@ IMPLEMENTING SUPPORT for ImGuiBackendFlags_RendererHasTextures:
  - 2026/03/12 (1.92.7) - Changed default ImTextureID_Invalid to -1 instead of 0 if not #define-d. (#9293, #8745, #8465, #7090)
                          It seems like a better default since it will work with backends storing indices or memory offsets inside ImTextureID, where 0 might be a valid value.
                          If this is causing problem with e.g. your custom ImTextureID definition, you can add '#define ImTextureID_Invalid 0' to your imconfig.h + PLEASE report this to GitHub.
+                         If you have hard-coded e.g. 'if (tex_id == 0)' checks they should be updated. e.g. OpenGL2, OpenGL3 and SDLRenderer3 backends incorrectly had 'IM_ASSERT(tex->TexID == 0)' lines which were replaced with 'IM_ASSERT(tex->TexID == ImTextureID_Invalid)'. (#9295)
  - 2026/02/26 (1.92.7) - Separator: fixed a legacy quirk where Separator() was submitting a zero-height item for layout purpose, even though it draws a 1-pixel separator.
                          The fix could affect code e.g. computing height from multiple widgets in order to allocate vertical space for a footer or multi-line status bar. (#2657, #9263)
                          The "Console" example had such a bug: