Docs, Backends: OpenGL3, Vulkan: added comments about custom sampler. (#9378)

backends/imgui_impl_opengl3.cpp

@@ -25,6 +25,7 @@
 // (minor and older changes stripped away, please see git history for details)
 //  2026-06-23: OpenGL: GLSL version detection assume GLSL 410 when GL context is 4.1. Fixes an issue running on macOS with Wine. (#9427, #6577)
 //  2026-04-23: OpenGL: Added support for standard draw callbacks (in platform_io): DrawCallback_ResetRenderState, DrawCallback_SetSamplerLinear, DrawCallback_SetSamplerNearest. (#9378)
+//                      (Breaking): this change prioritize using glBindSampler() when available, which would override glTexParameter() settings you may have set on custom textures.
 //  2026-03-12: OpenGL: Fixed invalid assert in ImGui_ImplOpenGL3_UpdateTexture() if ImTextureID_Invalid is defined to be != 0, which became the default since 2026-03-12. (#9295)
 //  2025-12-11: OpenGL: Fixed embedded loader multiple init/shutdown cycles broken on some platforms. (#8792, #9112)
 //  2025-09-18: Call platform_io.ClearRendererHandlers() on shutdown.
@@ -549,7 +550,7 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
                 GL_CALL(glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->GetTexID()));
 
                 // Emulate sampler change (even though it is technically part of texture data)
-                // As a sort of hack/workaround, we only start writing using glTextParameter() if sampler is ever changed explicitly.
+                // As a sort of hack/workaround, we only start writing using glTexParameter() if sampler is ever changed explicitly.
                 if (!bd->HasBindSampler && bd->UseTexParameterToSetSampler)
                 {
                     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, bd->NextSampler);

backends/imgui_impl_vulkan.cpp

@@ -537,8 +537,17 @@ static void ImGui_ImplVulkan_SetupRenderState(ImDrawData* draw_data, VkPipeline
 
 // Draw callbacks
 static void ImGui_ImplVulkan_DrawCallback_ResetRenderState(const ImDrawList*, const ImDrawCmd*)     {} // Intentionally empty. Used as an identifier for rendering loop to call its code. Simpler to implement this way.
-static void ImGui_ImplVulkan_DrawCallback_SetSamplerLinear(const ImDrawList*, const ImDrawCmd*)     { ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData(); vkCmdBindDescriptorSets(bd->RenderState->CommandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, bd->PipelineLayout, 1, 1, &bd->SamplerLinearDS, 0, nullptr); }
+static void ImGui_ImplVulkan_DrawCallback_SetSamplerLinear(const ImDrawList*, const ImDrawCmd*)     { ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData(); vkCmdBindDescriptorSets(bd->RenderState->CommandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, bd->RenderState->PipelineLayout, 1, 1, &bd->SamplerLinearDS, 0, nullptr); }
-static void ImGui_ImplVulkan_DrawCallback_SetSamplerNearest(const ImDrawList*, const ImDrawCmd*)    { ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData(); vkCmdBindDescriptorSets(bd->RenderState->CommandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, bd->PipelineLayout, 1, 1, &bd->SamplerNearestDS, 0, nullptr); }
+static void ImGui_ImplVulkan_DrawCallback_SetSamplerNearest(const ImDrawList*, const ImDrawCmd*)    { ImGui_ImplVulkan_Data* bd = ImGui_ImplVulkan_GetBackendData(); vkCmdBindDescriptorSets(bd->RenderState->CommandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, bd->RenderState->PipelineLayout, 1, 1, &bd->SamplerNearestDS, 0, nullptr); }
+
+// If you want to use your own sampler, you can create your own callback, access ImGui_ImplVulkan_RenderState for command-buffer and pipeline layout, e.g.
+/*
+void ImGui_ImplVulkan_DrawCallback_SetSamplerCustom(const ImDrawList*, const ImDrawCmd* cmd)
+{
+    ImGui_ImplVulkan_RenderState* render_state = (ImGui_ImplVulkan_RenderState*)ImGui::GetPlatformIO().Renderer_RenderState;
+    vkCmdBindDescriptorSets(render_state->CommandBuffer, VK_PIPELINE_BIND_POINT_GRAPHICS, render_state->PipelineLayout, 1, 1, (VkDescriptorSet*)cmd->UserCallbackData, 0, nullptr);
+}
+*/
 
 // Render function
 void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer command_buffer, VkPipeline pipeline)

backends/imgui_impl_vulkan.h

@@ -167,6 +167,7 @@ IMGUI_IMPL_API bool             ImGui_ImplVulkan_LoadFunctions(uint32_t api_vers
 
 // [BETA] Selected render state data shared with callbacks.
 // This is temporarily stored in GetPlatformIO().Renderer_RenderState during the ImGui_ImplVulkan_RenderDrawData() call.
+//      ImGui_ImplVulkan_RenderState* render_state = (ImGui_ImplVulkan_RenderState*)ImGui::GetPlatformIO().Renderer_RenderState;
 // (Please open an issue if you feel you need access to more data)
 struct ImGui_ImplVulkan_RenderState
 {

docs/CHANGELOG.txt

@@ -142,6 +142,8 @@ Breaking Changes:
   - DirectX10, DirectX11, SDLGPU3, Vulkan: removed samplers from `ImGui_ImplXXXX_RenderState`.
     Prefer to use backend-agnostic DrawCallback_SetSamplerLinear which works everywhere! (#9378)
     If there is a legit need/request for them or any render state we can always add them back.
+  - OpenGL3: the new sampler support system prioritize using glBindSampler() when available,
+    which would override glTexParameter() settings you may have set on custom textures. (#9378)
 
 Other Changes: