Add support for OpenSans and font-awesome fonts.

PiperOrigin-RevId: 833666932
Change-Id: I5f0207c3331705b9078a1297b3e7b2a8d363ad60

src/experimental/studio/CMakeLists.txt

@@ -56,6 +56,9 @@ endif()
 
 include(third_party_deps/dear_imgui)
 include(third_party_deps/implot)
+include(third_party_deps/opensans)
+include(third_party_deps/font_awesome)
+
 target_link_libraries(${MUJOCO_STUDIO_TARGET_NAME}
     PRIVATE
         ${MUJOCO_STUDIO_RENDER_DEPS}
@@ -68,20 +71,36 @@ target_link_libraries(${MUJOCO_STUDIO_TARGET_NAME}
         mujoco::toolbox
 )
 
+file(MAKE_DIRECTORY ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/assets)
+
+add_custom_command(
+    TARGET ${MUJOCO_STUDIO_TARGET_NAME}
+    POST_BUILD
+    COMMAND ${CMAKE_COMMAND}
+        -E copy
+            ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/../_deps/opensans-src/fonts/ttf/OpenSans-Regular.ttf
+            ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/assets
+    COMMENT "Copying OpenSans-Regular.ttf assets to build directory"
+)
+add_custom_command(
+    TARGET ${MUJOCO_STUDIO_TARGET_NAME}
+    POST_BUILD
+    COMMAND ${CMAKE_COMMAND}
+        -E copy
+            ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/../_deps/font_awesome-src/fonts/fontawesome-webfont.ttf
+            ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/assets
+    COMMENT "Copying fontawesome-webfont.ttf to build directory"
+)
+
 # Filament backend requires additional files to be copied into an "assets" folder.
 if(MUJOCO_USE_FILAMENT)
-    if(WIN32)
-        # Copy to work around lack of symlink permissions on Windows.
-        set(COPY_COMMAND copy_directory)
-    else()
-        set(COPY_COMMAND create_symlink)
-    endif()
     add_custom_command(
         TARGET ${MUJOCO_STUDIO_TARGET_NAME}
         POST_BUILD
-        COMMAND ${CMAKE_COMMAND} -E ${COPY_COMMAND}
-            ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/../src/experimental/filament/assets
-            ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/assets
+        COMMAND ${CMAKE_COMMAND}
+            -E copy_directory
+                ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/../src/experimental/filament/assets
+                ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/assets
         COMMENT "Copying Filament assets to build directory"
     )
 endif()

src/experimental/toolbox/window.cc

@@ -45,6 +45,27 @@ static void InitImGui(SDL_Window* window, const LoadAssetFn& load_asset_fn) {
   ImGui::StyleColorsDark();
   ImGui_ImplSDL2_InitForOther(window);
 
+#ifndef __EMSCRIPTEN__
+  // TODO: Get font loading working for wasm.
+  ImFontConfig main_cfg;
+  main_cfg.OversampleH = 8;
+  main_cfg.OversampleV = 4;
+  main_cfg.GlyphExtraSpacing.x = 0.3f;
+
+  auto main_font = load_asset_fn("OpenSans-Regular.ttf");
+  io.Fonts->AddFontFromMemoryTTF(main_font.data(), main_font.size(), 18.f,
+                                 &main_cfg);
+
+  ImFontConfig icon_cfg;
+  icon_cfg.OversampleH = 3;
+  icon_cfg.OversampleV = 3;
+  icon_cfg.MergeMode = true;
+  icon_cfg.GlyphMinAdvanceX = 14.0f;
+  auto icon_font = load_asset_fn("fontawesome-webfont.ttf");
+  constexpr ImWchar icon_ranges[] = {0xf000, 0xf3ff, 0x000};
+  io.Fonts->AddFontFromMemoryTTF(icon_font.data(), icon_font.size(), 14.f,
+                                &icon_cfg, icon_ranges);
+#endif
   io.Fonts->Build();
 }