Added SDL3+SDL_GPU3 example.

Getting-Started.md

@@ -12,6 +12,7 @@ _(had to turn off wiki editing, see [Home](Home) for details. you may post meani
 - [Example: If you are using GLFW + Metal (on Apple devices)](#example-if-you-are-using-glfw--metal-on-apple-devices)
 - [Example: If you are using SDL2/SDL3 + OpenGL/WebGL](#example-if-you-are-using-sdl2sdl3--openglwebgl)
 - [Example: If you are using SDL2/SDL3 + Vulkan](#example-if-you-are-using-sdl2sdl3--vulkan)
+- [Example: If you are using SDL3 + SDL_GPU](#example-if-you-are-using-sdl3--sdl_gpu)
 - [Using another combination of backends?](#using-another-combination-of-backends)
 - [Additional code to enable Docking](#additional-code-to-enable-docking)
 - [Additional code to enable Multi-viewports](#additional-code-to-enable-multi-viewports)
@@ -457,6 +458,84 @@ ImGui::DestroyContext();
 ```
 That should be all!
 
+## Example: If you are using SDL3 + SDL_GPU
+
+Full standalone example [example_sdl3_sdlgpu3/main.cpp](https://github.com/ocornut/imgui/blob/master/examples/example_sdl3_sdlgpu3/main.cpp)
+
+Add to Includes:
+```cpp
+#include "imgui.h"
+#include "imgui_impl_sdl3.h"
+#include "imgui_impl_sdlgpu3.h"
+```
+Add to Initialization:
+```cpp
+// Setup Dear ImGui context
+IMGUI_CHECKVERSION();
+ImGui::CreateContext();
+ImGuiIO& io = ImGui::GetIO();
+io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
+io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
+io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;         // IF using Docking Branch
+
+// Setup Platform/Renderer backends
+ImGui_ImplSDL3_InitForSDLGPU(window);
+ImGui_ImplSDLGPU3_InitInfo init_info = {};
+init_info.Device = gpu_device;
+init_info.ColorTargetFormat = SDL_GetGPUSwapchainTextureFormat(gpu_device, window);
+init_info.MSAASamples = SDL_GPU_SAMPLECOUNT_1;                      // Only used in multi-viewports mode.
+init_info.SwapchainComposition = SDL_GPU_SWAPCHAINCOMPOSITION_SDR;  // Only used in multi-viewports mode.
+init_info.PresentMode = SDL_GPU_PRESENTMODE_VSYNC;
+ImGui_ImplSDLGPU3_Init(&init_info);
+```
+Add to start of main loop:
+```cpp
+// (Where your code calls SDL_PollEvent())
+ImGui_ImplSDL3_ProcessEvent(&event); // Forward your event to backend
+```
+```cpp
+// (After event loop)
+// Start the Dear ImGui frame
+ImGui_ImplSDLGPU3_NewFrame();
+ImGui_ImplSDL3_NewFrame();
+ImGui::NewFrame();
+ImGui::ShowDemoWindow(); // Show demo window! :)
+```
+Add to end of main loop:
+```cpp
+// Rendering
+// (Your code clears your framebuffer, renders your other stuff etc.)
+ImGui::Render();
+
+SDL_GPUCommandBuffer* command_buffer = SDL_AcquireGPUCommandBuffer(gpu_device); // Acquire a GPU command buffer
+SDL_WaitAndAcquireGPUSwapchainTexture(command_buffer, window, &swapchain_texture, nullptr, nullptr); // Acquire a swapchain texture
+
+ImGui_ImplSDLGPU3_PrepareDrawData(draw_data, command_buffer);
+
+// Setup and start a render pass
+SDL_GPUColorTargetInfo target_info = {};
+target_info.texture = swapchain_texture;
+target_info.clear_color = SDL_FColor { clear_color.x, clear_color.y, clear_color.z, clear_color.w };
+target_info.load_op = SDL_GPU_LOADOP_CLEAR;
+target_info.store_op = SDL_GPU_STOREOP_STORE;
+target_info.mip_level = 0;
+target_info.layer_or_depth_plane = 0;
+target_info.cycle = false;
+SDL_GPURenderPass* render_pass = SDL_BeginGPURenderPass(command_buffer, &target_info, 1, nullptr);
+
+// Render ImGui
+ImGui_ImplSDLGPU3_RenderDrawData(draw_data, command_buffer, render_pass);
+
+SDL_EndGPURenderPass(render_pass);
+```
+Add to Shutdown:
+```cpp
+ImGui_ImplSDL3_Shutdown();
+ImGui_ImplSDLGPU3_Shutdown();
+ImGui::DestroyContext();
+```
+That should be all!
+
 ## Using another combination of backends?
 
 The various examples above should reflect integration with a majority of backends, so you can follow the same logic.