Add support for the SDL3+GPU API backend.

build.zig

@@ -10,6 +10,7 @@ pub const Backend = enum {
     glfw,
     sdl2_opengl3,
     osx_metal,
+    sdl3_gpu,
 };
 
 pub fn build(b: *std.Build) void {
@@ -385,6 +386,18 @@ pub fn build(b: *std.Build) void {
                 .flags = objcflags,
             });
         },
+        .sdl3_gpu => {
+            if (b.lazyDependency("zsdl", .{})) |zsdl| {
+                imgui.addIncludePath(zsdl.path("libs/sdl3/include"));
+            }
+            imgui.addCSourceFiles(.{
+                .files = &.{
+                    "libs/imgui/backends/imgui_impl_sdl3.cpp",
+                    "libs/imgui/backends/imgui_impl_sdlgpu3.cpp",
+                },
+                .flags = cflags,
+            });
+        },
         .no_backend => {},
     }
 

build.zig.zon

@@ -26,8 +26,8 @@
             .lazy = true,
         },
         .zsdl = .{
-            .url = "https://github.com/zig-gamedev/zsdl/archive/360a5033010c71445ba42d1de3973abd50c6b128.tar.gz",
-            .hash = "1220b661c47496008c7b2717c06b7bc1f79b1cfc430c885222d5d49c91d3fc57cbde",
+            .url = "https://github.com/zig-gamedev/zsdl/archive/d03b4d4e7cb7a74e01d9dad30d0f1692286f58f8.tar.gz",
+            .hash = "12205dcdb071febd9d3412a65e6235b832205cc49c1e20c88a71f62ada4e27dfb878",
             .lazy = true,
         },
         .freetype = .{

libs/imgui/backends/imgui_impl_sdl3.h

@@ -0,0 +1,55 @@
+// dear imgui: Platform Backend for SDL3
+// This needs to be used along with a Renderer (e.g. SDL_GPU, DirectX11, OpenGL3, Vulkan..)
+// (Info: SDL3 is a cross-platform general purpose library for handling windows, inputs, graphics context creation, etc.)
+
+// Implemented features:
+//  [X] Platform: Clipboard support.
+//  [X] Platform: Mouse support. Can discriminate Mouse/TouchScreen.
+//  [X] Platform: Keyboard support. Since 1.87 we are using the io.AddKeyEvent() function. Pass ImGuiKey values to all key functions e.g. ImGui::IsKeyPressed(ImGuiKey_Space). [Legacy SDL_SCANCODE_* values are obsolete since 1.87 and not supported since 1.91.5]
+//  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
+//  [X] Platform: Mouse cursor shape and visibility (ImGuiBackendFlags_HasMouseCursors). Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
+//  [x] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable' -> the OS animation effect when window gets created/destroyed is problematic. SDL2 backend doesn't have issue.
+// Missing features or Issues:
+//  [ ] Platform: Multi-viewport: Minimized windows seems to break mouse wheel events (at least under Windows).
+//  [x] Platform: IME support. Position somehow broken in SDL3 + app needs to call 'SDL_SetHint(SDL_HINT_IME_SHOW_UI, "1");' before SDL_CreateWindow()!.
+
+// 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
+
+struct SDL_Window;
+struct SDL_Renderer;
+struct SDL_Gamepad;
+typedef union SDL_Event SDL_Event;
+
+// FIX (zig-gamedev):
+extern "C" {
+
+// Follow "Getting Started" link and check examples/ folder to learn about using backends!
+IMGUI_IMPL_API bool     ImGui_ImplSDL3_InitForOpenGL(SDL_Window* window, void* sdl_gl_context);
+IMGUI_IMPL_API bool     ImGui_ImplSDL3_InitForVulkan(SDL_Window* window);
+IMGUI_IMPL_API bool     ImGui_ImplSDL3_InitForD3D(SDL_Window* window);
+IMGUI_IMPL_API bool     ImGui_ImplSDL3_InitForMetal(SDL_Window* window);
+IMGUI_IMPL_API bool     ImGui_ImplSDL3_InitForSDLRenderer(SDL_Window* window, SDL_Renderer* renderer);
+IMGUI_IMPL_API bool     ImGui_ImplSDL3_InitForSDLGPU(SDL_Window* window);
+IMGUI_IMPL_API bool     ImGui_ImplSDL3_InitForOther(SDL_Window* window);
+IMGUI_IMPL_API void     ImGui_ImplSDL3_Shutdown();
+IMGUI_IMPL_API void     ImGui_ImplSDL3_NewFrame();
+IMGUI_IMPL_API bool     ImGui_ImplSDL3_ProcessEvent(const SDL_Event* event);
+
+}
+
+// Gamepad selection automatically starts in AutoFirst mode, picking first available SDL_Gamepad. You may override this.
+// When using manual mode, caller is responsible for opening/closing gamepad.
+enum ImGui_ImplSDL3_GamepadMode { ImGui_ImplSDL3_GamepadMode_AutoFirst, ImGui_ImplSDL3_GamepadMode_AutoAll, ImGui_ImplSDL3_GamepadMode_Manual };
+IMGUI_IMPL_API void     ImGui_ImplSDL3_SetGamepadMode(ImGui_ImplSDL3_GamepadMode mode, SDL_Gamepad** manual_gamepads_array = nullptr, int manual_gamepads_count = -1);
+
+#endif // #ifndef IMGUI_DISABLE