prepare for Metal render backend

ugh Apple. how about you don't deprecate OpenGL instead?

CMakeLists.txt

@@ -65,6 +65,11 @@ if (WIN32)
 else()
   set(WITH_RENDER_DX11_DEFAULT OFF)
 endif()
+if (APPLE)
+  set(WITH_RENDER_METAL_DEFAULT ON)
+else()
+  set(WITH_RENDER_METAL_DEFAULT OFF)
+endif()
 
 if (ANDROID)
   set(USE_GLES_DEFAULT ON)
@@ -81,6 +86,7 @@ option(WITH_JACK "Whether to build with JACK support. Auto-detects if JACK is av
 option(WITH_RENDER_SDL "Whether to build with the SDL_Renderer render backend." ${WITH_RENDER_SDL_DEFAULT})
 option(WITH_RENDER_OPENGL "Whether to build with the OpenGL render backend." ${WITH_RENDER_OPENGL_DEFAULT})
 option(WITH_RENDER_DX11 "Whether to build with the DirectX 11 render backend." ${WITH_RENDER_DX11_DEFAULT})
+option(WITH_RENDER_METAL "Whether to build with the Metal render backend." ${WITH_RENDER_METAL_DEFAULT})
 option(USE_GLES "Use OpenGL ES for the OpenGL render backend." ${USE_GLES_DEFAULT})
 option(SYSTEM_FFTW "Use a system-installed version of FFTW instead of the vendored one" OFF)
 option(SYSTEM_FMT "Use a system-installed version of fmt instead of the vendored one" OFF)
@@ -308,7 +314,7 @@ else()
 endif()
 
 if (BUILD_GUI)
-  if (NOT WITH_RENDER_SDL AND NOT WITH_RENDER_OPENGL AND NOT WITH_RENDER_DX11)
+  if (NOT WITH_RENDER_SDL AND NOT WITH_RENDER_OPENGL AND NOT WITH_RENDER_DX11 AND NOT WITH_RENDER_METAL)
     message(FATAL_ERROR "No render backends selected!")
   endif()
 endif()
@@ -753,6 +759,19 @@ if (WITH_RENDER_DX11)
   endif()
 endif()
 
+if (WITH_RENDER_METAL)
+  if (APPLE)
+    list(APPEND GUI_SOURCES src/gui/render/renderMetal.cpp)
+    list(APPEND GUI_SOURCES extern/imgui_patched/backends/imgui_impl_metal.cpp)
+    list(APPEND DEPENDENCIES_DEFINES HAVE_RENDER_METAL)
+    # TODO: what is being used?
+    #list(APPEND DEPENDENCIES_LIBRARIES d3d11)
+    message(STATUS "UI render backend: Metal")
+  else()
+    message(FATAL_ERROR "Metal render backend only for Apple operating systems!")
+  endif()
+endif()
+
 if (NOT WIN32 AND NOT APPLE)
   CHECK_INCLUDE_FILE(sys/io.h SYS_IO_FOUND)
   CHECK_INCLUDE_FILE(linux/input.h LINUX_INPUT_FOUND)

src/gui/gui.h

@@ -72,7 +72,8 @@
 enum FurnaceGUIRenderBackend {
   GUI_BACKEND_SDL=0,
   GUI_BACKEND_GL,
-  GUI_BACKEND_DX11
+  GUI_BACKEND_DX11,
+  GUI_BACKEND_METAL
 };
 
 #ifdef HAVE_RENDER_SDL
@@ -83,10 +84,15 @@ enum FurnaceGUIRenderBackend {
 #define GUI_BACKEND_DEFAULT GUI_BACKEND_DX11
 #define GUI_BACKEND_DEFAULT_NAME "DirectX 11"
 #else
+#ifdef HAVE_RENDER_METAL
+#define GUI_BACKEND_DEFAULT GUI_BACKEND_METAL
+#define GUI_BACKEND_DEFAULT_NAME "Metal"
+#else
 #define GUI_BACKEND_DEFAULT GUI_BACKEND_GL
 #define GUI_BACKEND_DEFAULT_NAME "OpenGL"
 #endif
 #endif
+#endif
 
 // TODO:
 // - add colors for FM envelope and waveform

src/gui/render.cpp

@@ -28,6 +28,9 @@
 #ifdef HAVE_RENDER_DX11
 #include "render/renderDX11.h"
 #endif
+#ifdef HAVE_RENDER_METAL
+#include "render/renderMetal.h"
+#endif
 
 bool FurnaceGUI::initRender() {
   if (rend!=NULL) return false;
@@ -36,6 +39,8 @@ bool FurnaceGUI::initRender() {
     renderBackend=GUI_BACKEND_GL;
   } else if (settings.renderBackend=="DirectX 11") {
     renderBackend=GUI_BACKEND_DX11;
+  } else if (settings.renderBackend=="Metal") {
+    renderBackend=GUI_BACKEND_METAL;
   } else if (settings.renderBackend=="SDL") {
     renderBackend=GUI_BACKEND_SDL;
   } else {
@@ -55,6 +60,12 @@ bool FurnaceGUI::initRender() {
       rend=new FurnaceGUIRenderDX11;
       break;
 #endif
+#ifdef HAVE_RENDER_METAL
+    case GUI_BACKEND_METAL:
+      logI("render backend: Metal");
+      rend=new FurnaceGUIRenderMetal;
+      break;
+#endif
 #ifdef HAVE_RENDER_SDL
     case GUI_BACKEND_SDL:
       logI("render backend: SDL_Renderer");

src/gui/render/renderMetal.h

@@ -0,0 +1,49 @@
+/**
+ * Furnace Tracker - multi-system chiptune tracker
+ * Copyright (C) 2021-2023 tildearrow and contributors
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "../gui.h"
+
+class FurnaceGUIRenderSDL: public FurnaceGUIRender {
+  SDL_Renderer* sdlRend;
+  public:
+    ImTextureID getTextureID(FurnaceGUITexture* which);
+    bool lockTexture(FurnaceGUITexture* which, void** data, int* pitch);
+    bool unlockTexture(FurnaceGUITexture* which);
+    bool updateTexture(FurnaceGUITexture* which, void* data, int pitch);
+    FurnaceGUITexture* createTexture(bool dynamic, int width, int height);
+    bool destroyTexture(FurnaceGUITexture* which);
+    void setTextureBlendMode(FurnaceGUITexture* which, FurnaceGUIBlendMode mode);
+    void setBlendMode(FurnaceGUIBlendMode mode);
+    void clear(ImVec4 color);
+    bool newFrame();
+    void createFontsTexture();
+    void destroyFontsTexture();
+    void renderGUI();
+    void wipe(float alpha);
+    void present();
+    bool getOutputSize(int& w, int& h);
+    int getWindowFlags();
+    void preInit();
+    bool init(SDL_Window* win);
+    void initGUI(SDL_Window* win);
+    void quitGUI();
+    bool quit();
+    FurnaceGUIRenderSDL():
+      sdlRend(NULL) {}
+};

src/gui/render/renderMetal.mm

@@ -0,0 +1,171 @@
+/**
+ * Furnace Tracker - multi-system chiptune tracker
+ * Copyright (C) 2021-2023 tildearrow and contributors
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+// TODO: everything
+
+#include "renderMetal.h"
+#include "backends/imgui_impl_metal.h"
+#include <Metal/Metal.h>
+#include <QuartzCore/QuartzCore.h>
+
+class FurnaceMetalTexture: public FurnaceGUITexture {
+  public:
+  MTLTexture* tex;
+  FurnaceMetalTexture():
+    tex(NULL) {}
+};
+
+ImTextureID FurnaceGUIRenderMetal::getTextureID(FurnaceGUITexture* which) {
+  FurnaceSDLTexture* t=(FurnaceSDLTexture*)which;
+  return t->tex;
+}
+
+bool FurnaceGUIRenderMetal::lockTexture(FurnaceGUITexture* which, void** data, int* pitch) {
+  FurnaceSDLTexture* t=(FurnaceSDLTexture*)which;
+  return SDL_LockTexture(t->tex,NULL,data,pitch)==0;
+}
+
+bool FurnaceGUIRenderMetal::unlockTexture(FurnaceGUITexture* which) {
+  FurnaceSDLTexture* t=(FurnaceSDLTexture*)which;
+  SDL_UnlockTexture(t->tex);
+  return true;
+}
+
+bool FurnaceGUIRenderMetal::updateTexture(FurnaceGUITexture* which, void* data, int pitch) {
+  FurnaceSDLTexture* t=(FurnaceSDLTexture*)which;
+  return SDL_UpdateTexture(t->tex,NULL,data,pitch)==0;
+}
+
+FurnaceGUITexture* FurnaceGUIRenderMetal::createTexture(bool dynamic, int width, int height) {
+  SDL_Texture* t=SDL_CreateTexture(sdlRend,SDL_PIXELFORMAT_ABGR8888,dynamic?SDL_TEXTUREACCESS_STREAMING:SDL_TEXTUREACCESS_STATIC,width,height);
+
+  if (t==NULL) return NULL;
+  FurnaceSDLTexture* ret=new FurnaceSDLTexture;
+  ret->tex=t;
+  return ret;
+}
+
+bool FurnaceGUIRenderMetal::destroyTexture(FurnaceGUITexture* which) {
+  FurnaceSDLTexture* t=(FurnaceSDLTexture*)which;
+
+  SDL_DestroyTexture(t->tex);
+  delete t;
+  return true;
+}
+
+void FurnaceGUIRenderMetal::setTextureBlendMode(FurnaceGUITexture* which, FurnaceGUIBlendMode mode) {
+  FurnaceSDLTexture* t=(FurnaceSDLTexture*)which;
+  switch (mode) {
+    case GUI_BLEND_MODE_NONE:
+      SDL_SetTextureBlendMode(t->tex,SDL_BLENDMODE_NONE);
+      break;
+    case GUI_BLEND_MODE_BLEND:
+      SDL_SetTextureBlendMode(t->tex,SDL_BLENDMODE_BLEND);
+      break;
+    case GUI_BLEND_MODE_ADD:
+      SDL_SetTextureBlendMode(t->tex,SDL_BLENDMODE_ADD);
+      break;
+    case GUI_BLEND_MODE_MULTIPLY:
+      SDL_SetTextureBlendMode(t->tex,SDL_BLENDMODE_MOD);
+      break;
+  }
+}
+
+void FurnaceGUIRenderMetal::setBlendMode(FurnaceGUIBlendMode mode) {
+  switch (mode) {
+    case GUI_BLEND_MODE_NONE:
+      SDL_SetRenderDrawBlendMode(sdlRend,SDL_BLENDMODE_NONE);
+      break;
+    case GUI_BLEND_MODE_BLEND:
+      SDL_SetRenderDrawBlendMode(sdlRend,SDL_BLENDMODE_BLEND);
+      break;
+    case GUI_BLEND_MODE_ADD:
+      SDL_SetRenderDrawBlendMode(sdlRend,SDL_BLENDMODE_ADD);
+      break;
+    case GUI_BLEND_MODE_MULTIPLY:
+      SDL_SetRenderDrawBlendMode(sdlRend,SDL_BLENDMODE_MOD);
+      break;
+  }
+}
+
+void FurnaceGUIRenderMetal::clear(ImVec4 color) {
+  SDL_SetRenderDrawColor(sdlRend,color.x*255,color.y*255,color.z*255,color.w*255);
+  SDL_RenderClear(sdlRend);
+}
+
+bool FurnaceGUIRenderMetal::newFrame() {
+  return ImGui_ImplSDLRenderer2_NewFrame();
+}
+
+void FurnaceGUIRenderMetal::createFontsTexture() {
+  ImGui_ImplSDLRenderer2_CreateFontsTexture();
+}
+
+void FurnaceGUIRenderMetal::destroyFontsTexture() {
+  ImGui_ImplSDLRenderer2_DestroyFontsTexture();
+}
+
+void FurnaceGUIRenderMetal::renderGUI() {
+  ImGui_ImplSDLRenderer2_RenderDrawData(ImGui::GetDrawData());
+}
+
+void FurnaceGUIRenderMetal::wipe(float alpha) {
+  SDL_SetRenderDrawBlendMode(sdlRend,SDL_BLENDMODE_BLEND);
+  SDL_SetRenderDrawColor(sdlRend,0,0,0,255*alpha);
+  SDL_RenderFillRect(sdlRend,NULL);
+}
+
+void FurnaceGUIRenderMetal::present() {
+  SDL_RenderPresent(sdlRend);
+}
+
+bool FurnaceGUIRenderMetal::getOutputSize(int& w, int& h) {
+  return SDL_GetRendererOutputSize(sdlRend,&w,&h)==0;
+}
+
+int FurnaceGUIRenderMetal::getWindowFlags() {
+  return 0;
+}
+
+void FurnaceGUIRenderMetal::preInit() {
+  SDL_SetHint(SDL_HINT_RENDER_DRIVER,"metal");
+}
+
+bool FurnaceGUIRenderMetal::init(SDL_Window* win) {
+  SDL_SetHint(SDL_HINT_RENDER_DRIVER,"metal");
+
+  sdlRend=SDL_CreateRenderer(win,-1,SDL_RENDERER_ACCELERATED|SDL_RENDERER_PRESENTVSYNC|SDL_RENDERER_TARGETTEXTURE);
+  return (sdlRend!=NULL);
+}
+
+void FurnaceGUIRenderMetal::initGUI(SDL_Window* win) {
+  ImGui_ImplSDL2_InitForSDLRenderer(win,sdlRend);
+  ImGui_ImplSDLRenderer2_Init(sdlRend);
+}
+
+void FurnaceGUIRenderMetal::quitGUI() {
+  ImGui_ImplSDLRenderer2_Shutdown();
+}
+
+bool FurnaceGUIRenderMetal::quit() {
+  if (sdlRend==NULL) return false;
+  SDL_DestroyRenderer(sdlRend);
+  sdlRend=NULL;
+  return true;
+}

src/gui/settings.cpp

@@ -1316,6 +1316,11 @@ void FurnaceGUI::drawSettings() {
               settings.renderBackend="DirectX 11";
             }
 #endif
+#ifdef HAVE_RENDER_METAL
+            if (ImGui::Selectable("Metal",curRenderBackend=="Metal")) {
+              settings.renderBackend="Metal";
+            }
+#endif
 #ifdef HAVE_RENDER_GL
             if (ImGui::Selectable("OpenGL",curRenderBackend=="OpenGL")) {
               settings.renderBackend="OpenGL";