android build support

Author: Shivansps

CMakeLists.txt

@@ -47,6 +47,15 @@ endif()
 
 PROJECT(FS2_Open LANGUAGES ${FSO_LANGUAGES})
 
+if (ANDROID)
+    message(STATUS "Building for Android (NDK)")
+    add_definitions(-DPLATFORM_ANDROID)
+	set(FSO_BUILD_INCLUDED_LIBS ON FORCE)
+	set(USING_PREBUILT_LIBS ON FORCE)
+	set(SDL2_USE_PRECOMPILED ON FORCE)
+	set(OPENAL_USE_PRECOMPILED ON FORCE)
+endif()
+
 # Check if the external modules exists
 IF(NOT IS_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/cmake/external/rpavlik-cmake-modules/launcher-templates")
 	message(FATAL_ERROR "External submodules could not be found. Please make sure you have updated your submodules.")
@@ -96,8 +105,8 @@ OPTION(FSO_DEVELOPMENT_MODE "Generate binaries in development mode, only use if
 
 OPTION(FSO_BUILD_QTFRED "Build qtFRED2 binary" OFF)
 
-IF(WIN32 OR APPLE)
-	# On windows and mac the default should be to always build the included libraries
+IF(WIN32 OR APPLE OR ANDROID)
+	# On windows, mac and android the default should be to always build the included libraries
 	SET(FSO_BUILD_INCLUDED_LIBS_DEFAULT ON)
 ELSE()
 	SET(FSO_BUILD_INCLUDED_LIBS_DEFAULT OFF)

code/cfile/cfile.cpp

@@ -185,7 +185,12 @@ int cfile_init(const char *exe_dir, const char *cdrom_dir)
 
 	char buf[CFILE_ROOT_DIRECTORY_LEN];
 
-	strncpy(buf, exe_dir, CFILE_ROOT_DIRECTORY_LEN - 1);
+	#ifndef __ANDROID__
+		strncpy(buf, exe_dir, CFILE_ROOT_DIRECTORY_LEN - 1);
+	#else
+		(void)exe_dir;
+		strncpy(buf, os_get_working_folder_path().c_str(), CFILE_ROOT_DIRECTORY_LEN - 1);
+	#endif
 
 	buf[CFILE_ROOT_DIRECTORY_LEN - 1] = '\0';
 

code/ddsutils/ddsutils.cpp

@@ -74,6 +74,28 @@ static bool conversion_needed(const DDS_HEADER &dds_header)
 	return false;
 }
 
+#ifdef __ANDROID__
+// Auto-determine max texture size based on avail device ram for software decompression
+// 128 for <4GB, 256 for < 8GB, 512 for < 12GB and finally 1024
+static size_t calculate_resize_max_size()
+{
+	size_t size = 1024;
+	size_t ram_mib = SDL_GetSystemRAM();
+
+	if (ram_mib > 0)
+	{
+		if (ram_mib < 4 * 1024) // < 4GB
+			return 128;
+		if (ram_mib < 8 * 1024) // < 8GB
+			return 256;
+		if (ram_mib < 12 * 1024) // < 12GB
+			return 512;
+	}
+
+	return size;
+}
+#endif
+
 // Memory usage for uncompressed textures is quite high. Some MVP assets can
 // require well over a GB of VRAM for a single ship after conversion. To help
 // alleviate this we need to resize those textures where possible. At 1024x1024
@@ -85,7 +107,11 @@ static bool conversion_needed(const DDS_HEADER &dds_header)
 // returns: number of mipmap levels to skip
 static uint conversion_resize(DDS_HEADER &dds_header)
 {
+#ifdef __ANDROID__
+	const size_t MAX_SIZE = calculate_resize_max_size();
+#else
 	const size_t MAX_SIZE = 1024;
+#endif
 	uint width, height, depth, offset = 0;
 
 	if (dds_header.dwMipMapCount <= 1) {

code/external_dll/externalcode.h

@@ -29,6 +29,23 @@ class SCP_ExternalCode
 			return FALSE;
 
 		m_library = SDL_LoadObject(externlib);
+		
+#ifdef __ANDROID__
+		if (m_library == NULL) {
+			auto android_path = SDL_AndroidGetInternalStoragePath();
+			if (android_path != nullptr) {
+				SCP_string android_full_path = android_path;
+				if (android_full_path.back() != DIR_SEPARATOR_CHAR) {
+					android_full_path += DIR_SEPARATOR_CHAR;
+				}
+				android_full_path += SCP_string("natives") + DIR_SEPARATOR_CHAR + externlib;
+				#ifndef NDEBUG
+					mprintf(("Calling SDL_LoadObject with the following path: '%s'\n", android_full_path.c_str()));
+				#endif
+				m_library = SDL_LoadObject(android_full_path.c_str());
+			}
+		}
+#endif
 
 #ifndef NDEBUG
 		if (m_library == NULL)

code/graphics/2d.cpp

@@ -220,7 +220,11 @@ const auto LightingOption __UNUSED = options::OptionBuilder<int>("Graphics.Light
                      .parser(parse_lighting_func)
                      .finish();
 
+#ifndef __ANDROID__
 os::ViewportState Gr_configured_window_state = os::ViewportState::Fullscreen;
+#else
+os::ViewportState Gr_configured_window_state = os::ViewportState::Borderless;
+#endif
 
 static bool mode_change_func(os::ViewportState state, bool initial)
 {

code/graphics/opengl/es_compatibility.h

@@ -353,6 +353,7 @@ static inline void glQueryCounter(GLuint id, GLenum target)
 	#else
 		(void)id;
 	#endif
+		(void)target;
 }
 
 // glGetCompressedTexImage not present on GLES and no equivalent

code/graphics/opengl/gropengl.cpp

@@ -6,7 +6,7 @@
 #include <direct.h>
 #endif
 
-#if !defined __APPLE_CC__ && defined SCP_UNIX
+#if !defined __APPLE_CC__ && !defined __ANDROID__ && defined SCP_UNIX
 #include<glad/glad_glx.h>
 //Required because X defines none and always, which is used later
 #undef None
@@ -1339,7 +1339,7 @@ bool gr_opengl_init(std::unique_ptr<os::GraphicsOperations>&& graphicsOps)
 		Error(LOCATION, "Failed to load OpenGL!");
 	}
 
-#if !defined __APPLE_CC__ && defined SCP_UNIX
+#if !defined __APPLE_CC__ && !defined __ANDROID__ && defined SCP_UNIX
 	if (!gladLoadGLXLoader(GL_context->getLoaderFunction(), nullptr, 0)) {
 		Error(LOCATION, "Failed to load GLX!");
 	}

code/osapi/osapi.cpp

@@ -28,6 +28,13 @@
 #include <sys/types.h>
 #endif
 
+#ifdef __ANDROID__
+#include <SDL_system.h>
+#include <SDL.h>
+#include <jni.h>
+#include "options/Option.h"
+#endif
+
 namespace
 {
 	const char* ORGANIZATION_NAME = "HardLightProductions";
@@ -840,3 +847,126 @@ SCP_string os_get_config_path(const SCP_string& subpath)
 	return ss.str();
 }
 
+/*
+	  Special functions for Android
+*/
+
+#ifdef __ANDROID__
+// Helper to get a static method from a java class and clear the exception
+// if the method is not found. This is needed to avoid crashing on the next JNI request.
+static jmethodID android_get_static_method(JNIEnv* e, jclass cls, const char* name, const char* sig)
+{
+	jmethodID m = e->GetStaticMethodID(cls, name, sig);
+	if (e->ExceptionCheck()) {
+		e->ExceptionClear();
+		m = nullptr;
+		mprintf(("OSAPI : Method: %s. Not found on GameActivity! Signature: %s. \n", name, sig));
+	}
+	return m;
+}
+
+SCP_string os_get_working_folder_path()
+{
+	SCP_string wfp{};
+	 
+	//Get the JNI Environment pointer and current Activity instance via SDL
+    JNIEnv* env = (JNIEnv*)SDL_AndroidGetJNIEnv();
+    jobject activity = (jobject)SDL_AndroidGetActivity();
+    
+    if (env && activity) {
+    	// Locate the Java class (GameActivity on KnossosNET)
+    	jclass ga = env->GetObjectClass(activity);
+    	if(ga) {
+    		// Get the methodID (activity, methodName, signature);
+    		// "()Ljava/lang/String;" means it takes no paramenters and returns a string 
+    		jmethodID methodId = android_get_static_method (env, ga, "getWorkingFolder", "()Ljava/lang/String;");
+			if (methodId) {
+				jstring jString = (jstring)env->CallStaticObjectMethod(ga, methodId);
+				if (jString) {
+					const char* workingFolder = env->GetStringUTFChars(jString, 0);
+					wfp = SCP_string(workingFolder);
+					env->ReleaseStringUTFChars(jString, workingFolder);
+					env->DeleteLocalRef(jString);
+				} else {
+					mprintf(("os_get_working_folder_path: Couldn't get the jString.\n"));
+				}
+			} else {
+				mprintf(("os_get_working_folder_path: Couldn't get the methodID.\n"));
+			}
+			env->DeleteLocalRef(ga);
+    	} else {
+    		mprintf(("os_get_working_folder_path: Couldn't get java class.\n"));
+    	}
+    } else {
+    	mprintf(("os_get_working_folder_path: Couldn't get JNI enviroment or activity.\n"));
+    }
+    
+	if (wfp.empty()) {
+		mprintf(("Couldn't get working folder path from Java class, reverting to SDL default.\n"));
+		// Fallback to app space on internal storage
+		const char* fallbackPath = SDL_AndroidGetExternalStoragePath();
+		if (fallbackPath) {
+			wfp = SCP_string(fallbackPath);
+			wfp += "/files/"; 
+		}
+	}
+	
+	// Ensure path ends with a dir separator
+	if (!wfp.empty() && (wfp.back() != DIR_SEPARATOR_CHAR)) {
+		wfp += DIR_SEPARATOR_CHAR;
+	}
+	mprintf(("Using working folder: %s\n", wfp.c_str()));
+	return wfp;
+}
+
+void os_touch_overlay_toggle(bool status)
+{
+	//Get the JNI Environment pointer and current Activity instance via SDL
+    JNIEnv* env = (JNIEnv*)SDL_AndroidGetJNIEnv();
+    jobject activity = (jobject)SDL_AndroidGetActivity();
+    
+    if (env && activity) {
+    	// Locate the Java class (GameActivity on KnossosNET)
+    	jclass ga = env->GetObjectClass(activity);
+    	if(ga) {
+			jmethodID methodId = android_get_static_method (env, ga, status ? "enableOverlay" : "disableOverlay", "()V");
+			if (methodId) {
+				env->CallStaticVoidMethod(ga, methodId); 
+			} else {
+				mprintf(("os_touch_overlay_toggle: Couldn't get the methodID.\n"));
+			}
+			env->DeleteLocalRef(ga);
+    	} else {
+    		mprintf(("os_touch_overlay_toggle: Couldn't get java class.\n"));
+    	}
+    } else {
+    	mprintf(("os_touch_overlay_toggle: Couldn't get JNI enviroment or activity.\n"));
+    }
+}
+
+static bool touch_ui_change(bool new_val, bool initial)
+{
+	if (initial) {
+		return false;
+	}
+	os_touch_overlay_toggle(new_val);
+	return true;
+}
+
+static auto TouchOverlayOption = options::OptionBuilder<bool>("Input.TouchOverlay",
+	std::pair<const char*, int>{"Touch Overlay", -1},
+	std::pair<const char*, int>{"Enable or disable the Touch Overlay", -1})
+	.category(std::make_pair("Input", 1827))
+	.level(options::ExpertLevel::Beginner)
+	.change_listener(touch_ui_change)
+	.default_val(true)
+	.importance(0)
+	.finish();
+	
+void os_touch_overlay_init()
+{
+	os_touch_overlay_toggle(TouchOverlayOption->getValue());
+}
+
+#endif
+

code/osapi/osapi.h

@@ -91,6 +91,20 @@ bool os_is_legacy_mode();
  */
 SCP_string os_get_config_path(const SCP_string& subpath = "");
 
+/*
+	 Special functions for Android
+*/
+#ifdef __ANDROID__
+// Get working folder absolute path from Android Java Class
+SCP_string os_get_working_folder_path();
+
+// Calls to display the touch overlay depending on its last state
+void os_touch_overlay_init();
+
+// Enable or disable the touch UI overlay
+void os_touch_overlay_toggle(bool status);
+#endif
+
 namespace os
 {
 	/**

code/sound/openal.h

@@ -3,7 +3,7 @@
 #define _AL_H
 
 
-#if defined(__APPLE__)
+#if defined(__APPLE__) || defined(__ANDROID__)
 #include "al.h"
 #include "alc.h"
 #else