Add flag for software rendering.

This flag is currently unused.

PiperOrigin-RevId: 885453938
Change-Id: Ia2112410ff12c7b18ad154f18887d4d795bafa3d

src/experimental/filament/render_context_filament.h

@@ -41,6 +41,9 @@ struct mjrFilamentConfig {
 
   // The backend graphics API to use.
   int graphics_api;
+
+  // Use software rendering even if the platform supports hardware rendering.
+  bool force_software_rendering;
 };
 
 void mjrf_defaultFilamentConfig(mjrFilamentConfig* config);

src/experimental/platform/graphics_mode.cc

@@ -28,14 +28,16 @@ bool IsFilament(GraphicsMode gfx_mode) {
   return gfx_mode == GraphicsMode::FilamentOpenGl ||
          gfx_mode == GraphicsMode::FilamentVulkan ||
          gfx_mode == GraphicsMode::FilamentWebGl ||
-         gfx_mode == GraphicsMode::FilamentOpenGlHeadless;
+         gfx_mode == GraphicsMode::FilamentOpenGlHeadless ||
+         gfx_mode == GraphicsMode::FilamentOpenGlSoftware;
 }
 
 bool IsOpenGl(GraphicsMode gfx_mode) {
   return gfx_mode == GraphicsMode::ClassicOpenGl ||
          gfx_mode == GraphicsMode::ClassicOpenGlHeadless ||
          gfx_mode == GraphicsMode::FilamentOpenGl ||
-         gfx_mode == GraphicsMode::FilamentOpenGlHeadless;
+         gfx_mode == GraphicsMode::FilamentOpenGlHeadless ||
+         gfx_mode == GraphicsMode::FilamentOpenGlSoftware;
 }
 
 bool IsVulkan(GraphicsMode gfx_mode) {
@@ -48,7 +50,12 @@ bool IsWebGl(GraphicsMode gfx_mode) {
 
 bool IsHeadless(GraphicsMode gfx_mode) {
   return gfx_mode == GraphicsMode::ClassicOpenGlHeadless ||
-         gfx_mode == GraphicsMode::FilamentOpenGlHeadless;
+         gfx_mode == GraphicsMode::FilamentOpenGlHeadless ||
+         gfx_mode == GraphicsMode::FilamentOpenGlSoftware;
+}
+
+bool IsSoftware(GraphicsMode gfx_mode) {
+  return gfx_mode == GraphicsMode::FilamentOpenGlSoftware;
 }
 
 GraphicsMode GraphicsModeFromString(std::string_view str,
@@ -65,6 +72,8 @@ GraphicsMode GraphicsModeFromString(std::string_view str,
     return GraphicsMode::FilamentWebGl;
   } else if (str == "opengl_headless") {
     return GraphicsMode::FilamentOpenGlHeadless;
+  } else if (str == "opengl_software") {
+    return GraphicsMode::FilamentOpenGlSoftware;
   } else if (str.empty()) {
     return default_mode;
   } else {

src/experimental/platform/graphics_mode.h

@@ -38,6 +38,9 @@ enum class GraphicsMode {
 
   // Similar to FilamentOpenGl, but assumes "headless" rendering.
   FilamentOpenGlHeadless,
+
+  // Similar to FilamentOpenGl, but forces software rendering.
+  FilamentOpenGlSoftware,
 };
 
 bool IsClassic(GraphicsMode gfx_mode);
@@ -46,6 +49,7 @@ bool IsOpenGl(GraphicsMode gfx_mode);
 bool IsVulkan(GraphicsMode gfx_mode);
 bool IsWebGl(GraphicsMode gfx_mode);
 bool IsHeadless(GraphicsMode gfx_mode);
+bool IsSoftware(GraphicsMode gfx_mode);
 
 GraphicsMode GraphicsModeFromString(std::string_view str,
                                     GraphicsMode default_mode);

src/experimental/platform/renderer.cc

@@ -88,6 +88,7 @@ void Renderer::Init(const mjModel* model) {
       mjrFilamentConfig render_config;
       mjrf_defaultFilamentConfig(&render_config);
       render_config.native_window = native_window_;
+      render_config.force_software_rendering = IsSoftware(gfx_);
       render_config.graphics_api =
           IsOpenGl(gfx_) || IsWebGl(gfx_) ? mjGFX_OPENGL : mjGFX_VULKAN;
       mjrf_makeFilamentContext(model, &render_context_, &render_config);

src/experimental/studio/app.cc

@@ -1761,6 +1761,7 @@ void App::MainMenuGui() {
       ImGui::Separator();
 
 
+      #ifdef __linux__
       if (ImGui::BeginMenu("Graphics Mode (Experimental)")) {
         std::optional<platform::GraphicsMode> mode;
         if (ImGui::MenuItem(
@@ -1783,6 +1784,11 @@ void App::MainMenuGui() {
                 gfx_mode_ == platform::GraphicsMode::FilamentOpenGlHeadless)) {
           mode = platform::GraphicsMode::FilamentOpenGlHeadless;
         }
+        if (ImGui::MenuItem(
+                "Filament OpenGL Software", nullptr,
+                gfx_mode_ == platform::GraphicsMode::FilamentOpenGlSoftware)) {
+          mode = platform::GraphicsMode::FilamentOpenGlSoftware;
+        }
         if (ImGui::MenuItem(
                 "Filament Vulkan", nullptr,
                 gfx_mode_ == platform::GraphicsMode::FilamentVulkan)) {
@@ -1802,6 +1808,7 @@ void App::MainMenuGui() {
         }
         ImGui::EndMenu();
       }
+      #endif  // __linux__
 
       ImGui::EndMenu();
     }