Add OSX + Metal Backend (#10)

Author: jrachele

build.zig

@@ -8,6 +8,7 @@ pub const Backend = enum {
     win32_dx12,
     glfw,
     sdl2_opengl3,
+    osx_metal,
 };
 
 pub fn build(b: *std.Build) void {
@@ -79,6 +80,12 @@ pub fn build(b: *std.Build) void {
         if (options.use_32bit_draw_idx) "-DIMGUI_USE_32BIT_DRAW_INDEX" else "",
     };
 
+    const objcflags = &.{
+        "-Wno-deprecated",
+        "-Wno-pedantic",
+        "-Wno-availability",
+    };
+
     const imgui = if (options.shared) blk: {
         const lib = b.addSharedLibrary(.{
             .name = "imgui",
@@ -351,6 +358,19 @@ pub fn build(b: *std.Build) void {
                 .flags = &(cflags.* ++ .{"-DIMGUI_IMPL_OPENGL_LOADER_CUSTOM"}),
             });
         },
+        .osx_metal => {
+            imgui.linkFramework("Foundation");
+            imgui.linkFramework("Metal");
+            imgui.linkFramework("Cocoa");
+            imgui.linkFramework("QuartzCore");
+            imgui.addCSourceFiles(.{
+                .files = &.{
+                    "libs/imgui/backends/imgui_impl_osx.mm",
+                    "libs/imgui/backends/imgui_impl_metal.mm",
+                },
+                .flags = objcflags,
+            });
+        },
         .no_backend => {},
     }
 

libs/imgui/backends/imgui_impl_metal.h

@@ -0,0 +1,78 @@
+// dear imgui: Renderer Backend for Metal
+// This needs to be used along with a Platform Backend (e.g. OSX)
+
+// Implemented features:
+//  [X] Renderer: User texture binding. Use 'MTLTexture' as ImTextureID. Read the FAQ about ImTextureID!
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
+
+// 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
+
+#include "imgui.h"      // IMGUI_IMPL_API
+#ifndef IMGUI_DISABLE
+
+//-----------------------------------------------------------------------------
+// ObjC API
+//-----------------------------------------------------------------------------
+
+#ifdef __OBJC__
+
+extern "C" {
+@class MTLRenderPassDescriptor;
+@protocol MTLDevice, MTLCommandBuffer, MTLRenderCommandEncoder;
+
+// Follow "Getting Started" link and check examples/ folder to learn about using backends!
+IMGUI_IMPL_API bool ImGui_ImplMetal_Init(id<MTLDevice> device);
+IMGUI_IMPL_API void ImGui_ImplMetal_Shutdown();
+IMGUI_IMPL_API void ImGui_ImplMetal_NewFrame(MTLRenderPassDescriptor* renderPassDescriptor);
+IMGUI_IMPL_API void ImGui_ImplMetal_RenderDrawData(ImDrawData* drawData,
+                                                   id<MTLCommandBuffer> commandBuffer,
+                                                   id<MTLRenderCommandEncoder> commandEncoder);
+}
+
+// Called by Init/NewFrame/Shutdown
+IMGUI_IMPL_API bool ImGui_ImplMetal_CreateFontsTexture(id<MTLDevice> device);
+IMGUI_IMPL_API void ImGui_ImplMetal_DestroyFontsTexture();
+IMGUI_IMPL_API bool ImGui_ImplMetal_CreateDeviceObjects(id<MTLDevice> device);
+IMGUI_IMPL_API void ImGui_ImplMetal_DestroyDeviceObjects();
+
+#endif
+
+//-----------------------------------------------------------------------------
+// C++ API
+//-----------------------------------------------------------------------------
+
+// Enable Metal C++ binding support with '#define IMGUI_IMPL_METAL_CPP' in your imconfig.h file
+// More info about using Metal from C++: https://developer.apple.com/metal/cpp/
+
+#ifdef IMGUI_IMPL_METAL_CPP
+#include <Metal/Metal.hpp>
+#ifndef __OBJC__
+
+extern "C" {
+// Follow "Getting Started" link and check examples/ folder to learn about using backends!
+IMGUI_IMPL_API bool ImGui_ImplMetal_Init(MTL::Device* device);
+IMGUI_IMPL_API void ImGui_ImplMetal_Shutdown();
+IMGUI_IMPL_API void ImGui_ImplMetal_NewFrame(MTL::RenderPassDescriptor* renderPassDescriptor);
+IMGUI_IMPL_API void ImGui_ImplMetal_RenderDrawData(ImDrawData* draw_data,
+                                                   MTL::CommandBuffer* commandBuffer,
+                                                   MTL::RenderCommandEncoder* commandEncoder);
+}
+
+// Called by Init/NewFrame/Shutdown
+IMGUI_IMPL_API bool ImGui_ImplMetal_CreateFontsTexture(MTL::Device* device);
+IMGUI_IMPL_API void ImGui_ImplMetal_DestroyFontsTexture();
+IMGUI_IMPL_API bool ImGui_ImplMetal_CreateDeviceObjects(MTL::Device* device);
+IMGUI_IMPL_API void ImGui_ImplMetal_DestroyDeviceObjects();
+
+#endif
+#endif
+
+//-----------------------------------------------------------------------------
+
+#endif // #ifndef IMGUI_DISABLE