Backends: Null: added imgui_impl_null platform/renderer backend.

backends/imgui_impl_null.cpp

@@ -0,0 +1,97 @@
+// dear imgui: Null Platform+Renderer Backends
+// This is designed if you need to use a blind Dear Imgui context with no input and no output.
+
+// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
+// Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
+// Learn about Dear ImGui:
+// - FAQ                  https://dearimgui.com/faq
+// - Getting Started      https://dearimgui.com/getting-started
+// - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
+// - Introduction, links and more at the top of imgui.cpp
+
+// CHANGELOG
+// (minor and older changes stripped away, please see git history for details)
+//  2025-11-17: Initial version.
+
+#include "imgui.h"
+#ifndef IMGUI_DISABLE
+#include "imgui_impl_null.h"
+
+bool ImGui_ImplNull_Init()
+{
+    ImGui_ImplNullPlatform_Init();
+    ImGui_ImplNullRender_Init();
+    return true;
+}
+
+void ImGui_ImplNull_Shutdown()
+{
+    ImGui_ImplNullRender_Shutdown();
+    ImGui_ImplNullPlatform_Shutdown();
+}
+
+void ImGui_ImplNull_NewFrame()
+{
+    ImGui_ImplNullPlatform_NewFrame();
+    ImGui_ImplNullRender_NewFrame();
+}
+
+bool ImGui_ImplNullPlatform_Init()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;
+    return true;
+}
+
+void ImGui_ImplNullPlatform_Shutdown()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    io.BackendFlags &= ~ImGuiBackendFlags_HasMouseCursors;
+}
+
+void ImGui_ImplNullPlatform_NewFrame()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    io.DisplaySize = ImVec2(1920, 1080);
+    io.DeltaTime = 1.0f / 60.0f;
+}
+
+bool ImGui_ImplNullRender_Init()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags |= ImGuiBackendFlags_RendererHasTextures;
+    return true;
+}
+
+void ImGui_ImplNullRender_Shutdown()
+{
+    ImGuiIO& io = ImGui::GetIO();
+    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasVtxOffset;
+    io.BackendFlags &= ~ImGuiBackendFlags_RendererHasTextures;
+}
+
+void ImGui_ImplNullRender_NewFrame()
+{
+}
+
+void ImGui_ImplNullRender_UpdateTexture(ImTextureData* tex)
+{
+    if (tex->Status == ImTextureStatus_WantCreate || tex->Status == ImTextureStatus_WantDestroy)
+        tex->SetStatus(ImTextureStatus_OK);
+    if (tex->Status == ImTextureStatus_WantDestroy)
+    {
+        tex->SetTexID(ImTextureID_Invalid);
+        tex->SetStatus(ImTextureStatus_Destroyed);
+    }
+}
+
+void ImGui_ImplNullRender_RenderDrawData(ImDrawData* draw_data)
+{
+    if (draw_data->Textures != nullptr)
+        for (ImTextureData* tex : *draw_data->Textures)
+            if (tex->Status != ImTextureStatus_OK)
+                ImGui_ImplNullRender_UpdateTexture(tex);
+}
+
+#endif // #ifndef IMGUI_DISABLE

backends/imgui_impl_null.h

@@ -0,0 +1,34 @@
+// dear imgui: Null Platform+Renderer Backends
+// This is designed if you need to use a blind Dear Imgui context with no input and no output.
+
+// You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
+// Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
+// Learn about Dear ImGui:
+// - FAQ                  https://dearimgui.com/faq
+// - Getting Started      https://dearimgui.com/getting-started
+// - Documentation        https://dearimgui.com/docs (same as your local docs/ folder).
+// - Introduction, links and more at the top of imgui.cpp
+
+#pragma once
+#include "imgui.h"      // IMGUI_IMPL_API
+#ifndef IMGUI_DISABLE
+
+// Follow "Getting Started" link and check examples/ folder to learn about using backends!
+
+// Null = NullPlatform + NullRender
+IMGUI_IMPL_API bool     ImGui_ImplNull_Init();
+IMGUI_IMPL_API void     ImGui_ImplNull_Shutdown();
+IMGUI_IMPL_API void     ImGui_ImplNull_NewFrame();
+
+// Null platform only (single screen, fixed timestep, no inputs)
+IMGUI_IMPL_API bool     ImGui_ImplNullPlatform_Init();
+IMGUI_IMPL_API void     ImGui_ImplNullPlatform_Shutdown();
+IMGUI_IMPL_API void     ImGui_ImplNullPlatform_NewFrame();
+
+// Null renderer only (no output)
+IMGUI_IMPL_API bool     ImGui_ImplNullRender_Init();
+IMGUI_IMPL_API void     ImGui_ImplNullRender_Shutdown();
+IMGUI_IMPL_API void     ImGui_ImplNullRender_NewFrame();
+IMGUI_IMPL_API void     ImGui_ImplNullRender_RenderDrawData(ImDrawData* draw_data);
+
+#endif // #ifndef IMGUI_DISABLE