Allow Linux build without X11 dependency

CMakeLists.txt

@@ -174,6 +174,9 @@ else()
         set_cpp_flag("-march=x86-64")
         set_cpp_flag("-mtune=generic")
     endif()
+    if(LINUX)
+        set_cpp_flag("-DUSE_X11=1")
+    endif()
 
     # Use -g3 to have even more debug info
     set_cpp_flag("-g -g3" DEBUG)

src/Main/BUILD.gn

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import("//ui/ozone/ozone.gni")
+import("//build/config/ui.gni")
 import("../swiftshader.gni")
 
 # Need a separate config to ensure the warnings are added to the end.
@@ -50,10 +50,12 @@ swiftshader_source_set("swiftshader_main") {
   if (use_ozone && !is_win) {
     sources += [ "FrameBufferOzone.cpp" ]
   } else if (is_linux) {
-    sources += [
-      "FrameBufferX11.cpp",
-      "libX11.cpp",
-    ]
+    if (use_x11) {
+      sources += [
+        "FrameBufferX11.cpp",
+        "libX11.cpp",
+      ]
+    }
   } else if (is_mac) {
     sources += [ "FrameBufferOSX.mm" ]
   } else if (is_win) {

src/OpenGL/libEGL/BUILD.gn

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import("//build/config/ui.gni")
 import("../../swiftshader.gni")
 
 # Need a separate config to ensure the warnings are added to the end.
@@ -70,7 +71,9 @@ swiftshader_shared_library("swiftshader_libEGL") {
   } else if (is_win) {
     ldflags = [ "/DEF:" + rebase_path("libGLESv2.def", root_build_dir) ]
   } else if (is_linux) {
-    sources += [ "../../Main/libX11.cpp" ]
+    if (use_x11) {
+      sources += [ "../../Main/libX11.cpp" ]
+    }
     ldflags =
         [ "-Wl,--version-script=" + rebase_path("libEGL.lds", root_build_dir) ]
   }

src/OpenGL/libEGL/Display.cpp

@@ -30,7 +30,7 @@
 #include <sys/ioctl.h>
 #include <linux/fb.h>
 #include <fcntl.h>
-#elif defined(__linux__)
+#elif defined(USE_X11)
 #include "Main/libX11.hpp"
 #elif defined(__APPLE__)
 #include "OSXUtils.hpp"
@@ -66,7 +66,7 @@ Display *Display::get(EGLDisplay dpy)
 
 	static void *nativeDisplay = nullptr;
 
-	#if defined(__linux__) && !defined(__ANDROID__)
+	#if defined(USE_X11)
 		// Even if the application provides a native display handle, we open (and close) our own connection
 		if(!nativeDisplay && dpy != HEADLESS_DISPLAY && libX11 && libX11->XOpenDisplay)
 		{
@@ -89,7 +89,7 @@ Display::~Display()
 {
 	terminate();
 
-	#if defined(__linux__) && !defined(__ANDROID__)
+	#if defined(USE_X11)
 		if(nativeDisplay && libX11->XCloseDisplay)
 		{
 			libX11->XCloseDisplay((::Display*)nativeDisplay);
@@ -677,7 +677,7 @@ bool Display::isValidWindow(EGLNativeWindowType window)
 			return false;
 		}
 		return true;
-	#elif defined(__linux__)
+	#elif defined(USE_X11)
 		if(nativeDisplay)
 		{
 			XWindowAttributes windowAttributes;
@@ -686,6 +686,8 @@ bool Display::isValidWindow(EGLNativeWindowType window)
 			return status != 0;
 		}
 		return false;
+	#elif defined(__linux__)
+		return false;  // Non X11 linux is headless only
 	#elif defined(__APPLE__)
 		return sw::OSX::IsValidWindow(window);
 	#elif defined(__Fuchsia__)
@@ -843,7 +845,7 @@ sw::Format Display::getDisplayFormat() const
 
 		// No framebuffer device found, or we're in user space
 		return sw::FORMAT_X8B8G8R8;
-	#elif defined(__linux__)
+	#elif defined(USE_X11)
 		if(nativeDisplay)
 		{
 			Screen *screen = libX11->XDefaultScreenOfDisplay((::Display*)nativeDisplay);
@@ -861,6 +863,8 @@ sw::Format Display::getDisplayFormat() const
 		{
 			return sw::FORMAT_X8R8G8B8;
 		}
+	#elif defined(__linux__)  // Non X11 linux is headless only
+		return sw::FORMAT_A8B8G8R8;
 	#elif defined(__APPLE__)
 		return sw::FORMAT_A8B8G8R8;
 	#elif defined(__Fuchsia__)

src/OpenGL/libEGL/Surface.cpp

@@ -26,7 +26,7 @@
 #include "common/debug.h"
 #include "Main/FrameBuffer.hpp"
 
-#if defined(__linux__) && !defined(__ANDROID__)
+#if defined(USE_X11)
 #include "Main/libX11.hpp"
 #elif defined(_WIN32)
 #include <tchar.h>
@@ -341,7 +341,7 @@ bool WindowSurface::checkForResize()
 	#elif defined(__ANDROID__)
 		int windowWidth;  window->query(window, NATIVE_WINDOW_WIDTH, &windowWidth);
 		int windowHeight; window->query(window, NATIVE_WINDOW_HEIGHT, &windowHeight);
-	#elif defined(__linux__)
+	#elif defined(USE_X11)
 		XWindowAttributes windowAttributes;
 		Status status = libX11->XGetWindowAttributes((::Display*)display->getNativeDisplay(), window, &windowAttributes);
 
@@ -352,6 +352,10 @@ bool WindowSurface::checkForResize()
 
 		int windowWidth = windowAttributes.width;
 		int windowHeight = windowAttributes.height;
+	#elif defined(__linux__)
+		// Non X11 linux is headless only
+		int windowWidth = 100;
+		int windowHeight = 100;
 	#elif defined(__APPLE__)
 		int windowWidth;
 		int windowHeight;

src/OpenGL/libEGL/libEGL.cpp

@@ -25,7 +25,7 @@
 
 #if defined(__ANDROID__)
 #include <system/window.h>
-#elif defined(__linux__)
+#elif defined(USE_X11)
 #include "Main/libX11.hpp"
 #endif
 
@@ -120,7 +120,9 @@ EGLDisplay GetDisplay(EGLNativeDisplayType display_id)
 	}
 
 	#if defined(__linux__) && !defined(__ANDROID__)
+		#if defined(USE_X11)
 		if(!libX11)
+		#endif  // Non X11 linux is headless only
 		{
 			return success(HEADLESS_DISPLAY);
 		}
@@ -178,6 +180,8 @@ const char *QueryString(EGLDisplay dpy, EGLint name)
 			"EGL_KHR_client_get_all_proc_addresses "
 #if defined(__linux__) && !defined(__ANDROID__)
 			"EGL_KHR_platform_gbm "
+#endif
+#if defined(USE_X11)
 			"EGL_KHR_platform_x11 "
 #endif
 			"EGL_EXT_client_extensions "
@@ -1002,7 +1006,7 @@ EGLBoolean WaitNative(EGLint engine)
 
 	if(context)
 	{
-		#if defined(__linux__) && !defined(__ANDROID__)
+		#if defined(USE_X11)
 			egl::Display *display = context->getDisplay();
 
 			if(!display)
@@ -1171,33 +1175,37 @@ EGLDisplay GetPlatformDisplayEXT(EGLenum platform, void *native_display, const E
 	#if defined(__linux__) && !defined(__ANDROID__)
 		switch(platform)
 		{
+		#if defined(USE_X11)
 		case EGL_PLATFORM_X11_EXT: break;
+		#endif
 		case EGL_PLATFORM_GBM_KHR: break;
 		default:
 			return error(EGL_BAD_PARAMETER, EGL_NO_DISPLAY);
 		}
 
-		if(platform == EGL_PLATFORM_X11_EXT)
+		if(platform == EGL_PLATFORM_GBM_KHR)
 		{
-			if(!libX11)
-			{
-				return error(EGL_BAD_ATTRIBUTE, EGL_NO_DISPLAY);
-			}
-
 			if(native_display != (void*)EGL_DEFAULT_DISPLAY || attrib_list != NULL)
 			{
 				return error(EGL_BAD_ATTRIBUTE, EGL_NO_DISPLAY);   // Unimplemented
 			}
+
+			return success(HEADLESS_DISPLAY);
 		}
-		else if(platform == EGL_PLATFORM_GBM_KHR)
+		#if defined(USE_X11)
+		else if(platform == EGL_PLATFORM_X11_EXT)
 		{
+			if(!libX11)
+			{
+				return error(EGL_BAD_ATTRIBUTE, EGL_NO_DISPLAY);
+			}
+
 			if(native_display != (void*)EGL_DEFAULT_DISPLAY || attrib_list != NULL)
 			{
 				return error(EGL_BAD_ATTRIBUTE, EGL_NO_DISPLAY);   // Unimplemented
 			}
-
-			return success(HEADLESS_DISPLAY);
 		}
+		#endif
 
 		return success(PRIMARY_DISPLAY);   // We only support the default display
 	#else