prepare for software renderer

do not use or your Furnace will need a replacement

src/gui/gui.h

@@ -74,7 +74,8 @@ enum FurnaceGUIRenderBackend {
   GUI_BACKEND_GL2,
   GUI_BACKEND_GL1,
   GUI_BACKEND_DX11,
-  GUI_BACKEND_DX9
+  GUI_BACKEND_DX9,
+  GUI_BACKEND_SOFTWARE
 };
 
 #ifdef HAVE_RENDER_DX11
@@ -99,7 +100,8 @@ enum FurnaceGUIRenderBackend {
 #define GUI_BACKEND_DEFAULT GUI_BACKEND_SDL
 #define GUI_BACKEND_DEFAULT_NAME "SDL"
 #else
-#error how did you manage to do that?
+#define GUI_BACKEND_DEFAULT GUI_BACKEND_SOFTWARE
+#define GUI_BACKEDN_DEFAULT_NAME "Software"
 #endif
 #endif
 #endif

src/gui/render.cpp

@@ -31,6 +31,7 @@
 #ifdef HAVE_RENDER_DX11
 #include "render/renderDX11.h"
 #endif
+#include "render/renderSoftware.h"
 
 bool FurnaceGUI::initRender() {
   if (rend!=NULL) return false;
@@ -49,6 +50,8 @@ bool FurnaceGUI::initRender() {
     renderBackend=GUI_BACKEND_DX9;
   } else if (settings.renderBackend=="SDL") {
     renderBackend=GUI_BACKEND_SDL;
+  } else if (settings.renderBackend=="Software") {
+    renderBackend=GUI_BACKEND_SOFTWARE;
   } else {
     renderBackend=GUI_BACKEND_DEFAULT;
   }
@@ -99,6 +102,10 @@ bool FurnaceGUI::initRender() {
       rend=new FurnaceGUIRenderSDL;
       break;
 #endif
+    case GUI_BACKEND_SOFTWARE:
+      logI("render backend: Software");
+      rend=new FurnaceGUIRenderSoftware;
+      break;
     default:
       logE("invalid render backend!");
       return false;

src/gui/render/renderSoftware.cpp

@@ -0,0 +1,144 @@
+/**
+ * Furnace Tracker - multi-system chiptune tracker
+ * Copyright (C) 2021-2024 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 "renderSoftware.h"
+#include "imgui_sw.hpp"
+#include "../../ta-log.h"
+
+class FurnaceSoftwareTexture: public FurnaceGUITexture {
+  public:
+  SWTexture* tex;
+  FurnaceSoftwareTexture():
+    tex(NULL) {}
+};
+
+ImTextureID FurnaceGUIRenderSoftware::getTextureID(FurnaceGUITexture* which) {
+  FurnaceSoftwareTexture* t=(FurnaceSoftwareTexture*)which;
+  return t->tex;
+}
+
+bool FurnaceGUIRenderSoftware::lockTexture(FurnaceGUITexture* which, void** data, int* pitch) {
+  FurnaceSoftwareTexture* t=(FurnaceSoftwareTexture*)which;
+  if (!t->tex->managed) return false;
+  *data=t->tex->pixels;
+  *pitch=t->tex->width*(t->tex->isAlpha?1:4);
+  return true;
+}
+
+bool FurnaceGUIRenderSoftware::unlockTexture(FurnaceGUITexture* which) {
+  return true;
+}
+
+bool FurnaceGUIRenderSoftware::updateTexture(FurnaceGUITexture* which, void* data, int pitch) {
+  FurnaceSoftwareTexture* t=(FurnaceSoftwareTexture*)which;
+  if (!t->tex->managed) return false;
+  memcpy(t->tex->pixels,data,pitch*t->tex->height);
+  return true;
+}
+
+FurnaceGUITexture* FurnaceGUIRenderSoftware::createTexture(bool dynamic, int width, int height, bool interpolate) {
+  FurnaceSoftwareTexture* ret=new FurnaceSoftwareTexture;
+  ret->tex=new SWTexture(width,height);
+  return ret;
+}
+
+bool FurnaceGUIRenderSoftware::destroyTexture(FurnaceGUITexture* which) {
+  FurnaceSoftwareTexture* t=(FurnaceSoftwareTexture*)which;
+
+  delete t->tex;
+  delete t;
+  return true;
+}
+
+void FurnaceGUIRenderSoftware::setTextureBlendMode(FurnaceGUITexture* which, FurnaceGUIBlendMode mode) {
+  // TODO
+}
+
+void FurnaceGUIRenderSoftware::setBlendMode(FurnaceGUIBlendMode mode) {
+  // TODO
+}
+
+void FurnaceGUIRenderSoftware::clear(ImVec4 color) {
+  // TODO
+}
+
+bool FurnaceGUIRenderSoftware::newFrame() {
+  return ImGui_ImplSW_NewFrame();
+}
+
+bool FurnaceGUIRenderSoftware::canVSync() {
+  return false;
+}
+
+void FurnaceGUIRenderSoftware::createFontsTexture() {
+  ImGui_ImplSW_CreateFontsTexture();
+}
+
+void FurnaceGUIRenderSoftware::destroyFontsTexture() {
+  ImGui_ImplSW_DestroyFontsTexture();
+}
+
+void FurnaceGUIRenderSoftware::renderGUI() {
+  ImGui_ImplSW_RenderDrawData(ImGui::GetDrawData());
+}
+
+void FurnaceGUIRenderSoftware::wipe(float alpha) {
+  // TODO
+}
+
+void FurnaceGUIRenderSoftware::present() {
+  // TODO?
+}
+
+bool FurnaceGUIRenderSoftware::getOutputSize(int& w, int& h) {
+  SDL_Surface* surf=SDL_GetWindowSurface(sdlWin);
+  if (surf==NULL) return false;
+  w=surf->w;
+  h=surf->h;
+  return true;
+}
+
+int FurnaceGUIRenderSoftware::getWindowFlags() {
+  return 0;
+}
+
+void FurnaceGUIRenderSoftware::setSwapInterval(int swapInterval) {
+}
+
+void FurnaceGUIRenderSoftware::preInit() {
+}
+
+bool FurnaceGUIRenderSoftware::init(SDL_Window* win, int swapInterval) {
+  sdlWin=win;
+  return true;
+}
+
+void FurnaceGUIRenderSoftware::initGUI(SDL_Window* win) {
+  // hack
+  ImGui_ImplSDL2_InitForMetal(win);
+  ImGui_ImplSW_Init(win);
+}
+
+void FurnaceGUIRenderSoftware::quitGUI() {
+  ImGui_ImplSW_Shutdown();
+}
+
+bool FurnaceGUIRenderSoftware::quit() {
+  return true;
+}

src/gui/render/renderSoftware.h

@@ -0,0 +1,51 @@
+/**
+ * Furnace Tracker - multi-system chiptune tracker
+ * Copyright (C) 2021-2024 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 FurnaceGUIRenderSoftware: public FurnaceGUIRender {
+  SDL_Window* sdlWin;
+  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 interpolate=true);
+    bool destroyTexture(FurnaceGUITexture* which);
+    void setTextureBlendMode(FurnaceGUITexture* which, FurnaceGUIBlendMode mode);
+    void setBlendMode(FurnaceGUIBlendMode mode);
+    void clear(ImVec4 color);
+    bool newFrame();
+    bool canVSync();
+    void createFontsTexture();
+    void destroyFontsTexture();
+    void renderGUI();
+    void wipe(float alpha);
+    void present();
+    bool getOutputSize(int& w, int& h);
+    int getWindowFlags();
+    void setSwapInterval(int swapInterval);
+    void preInit();
+    bool init(SDL_Window* win, int swapInterval);
+    void initGUI(SDL_Window* win);
+    void quitGUI();
+    bool quit();
+    FurnaceGUIRenderSoftware():
+      sdlWin(NULL) {}
+};

src/gui/settings.cpp

@@ -428,6 +428,10 @@ void FurnaceGUI::drawSettings() {
             settingsChanged=true;
           }
 #endif
+          if (ImGui::Selectable("Software",curRenderBackend=="Software")) {
+            settings.renderBackend="Software";
+            settingsChanged=true;
+          }
           ImGui::EndCombo();
         }
         if (ImGui::IsItemHovered()) {