Support dynamic loading of SDL libraries

This is mainly to address old issue when one need to have SDL library installed
in order to use our official builds. Some hip distros already installs SDL,
but it's not quite the same across all the variety of the distros.

We also now switching to SDL-2.0, most of the distros have it in repositories
already, so it shouldn't be huge deal to install it if needed.

Reviewers: campbellbarton

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D878

5 files changed, 50 insertions, 13 deletions

diff --git a/source/gameengine/GameLogic/Joystick/SCA_Joystick.cpp b/source/gameengine/GameLogic/Joystick/SCA_Joystick.cpp
index 6e379c91d0c..228adbb942e 100644
--- a/source/gameengine/GameLogic/Joystick/SCA_Joystick.cpp
+++ b/source/gameengine/GameLogic/Joystick/SCA_Joystick.cpp
@@ -41,6 +41,8 @@
 
 #include "BLI_path_util.h"
 
+#define SDL_CHECK(x) ((x) != (void*)0)
+
 SCA_Joystick::SCA_Joystick(short int index)
 	:
 	m_joyindex(index),
@@ -82,6 +84,9 @@ SCA_Joystick *SCA_Joystick::GetInstance( short int joyindex )
 #ifndef WITH_SDL
 	return NULL;
 #else  /* WITH_SDL */
+	if (!SDL_CHECK(SDL_InitSubSystem)) {
+		return NULL;
+	}
 	if (joyindex < 0 || joyindex >= JOYINDEX_MAX) {
 		JOYSTICK_ECHO("Error-invalid joystick index: " << joyindex);
 		return NULL;
@@ -135,8 +140,10 @@ void SCA_Joystick::ReleaseInstance()
 	if (--m_refCount == 0)
 	{
 #ifdef WITH_SDL
-		int i;
-		for (i=0; i<JOYINDEX_MAX; i++) {
+		if (!SDL_CHECK(SDL_QuitSubSystem)) {
+			return;
+		}
+		for (int i=0; i<JOYINDEX_MAX; i++) {
 			if (m_instance[i]) {
 				m_instance[i]->DestroyJoystickDevice();
 				delete m_instance[i];
@@ -191,6 +198,9 @@ bool SCA_Joystick::aAxisIsPositive(int axis_single)
 bool SCA_Joystick::aAnyButtonPressIsPositive(void)
 {
 #ifdef WITH_SDL
+	if (!SDL_CHECK(SDL_JoystickGetButton)) {
+		return false;
+	}
 	/* this is needed for the "all events" option
 	 * so we know if there are no buttons pressed */
 	for (int i=0; i<m_buttonmax; i++)
@@ -206,7 +216,7 @@ bool SCA_Joystick::aButtonPressIsPositive(int button)
 	return false;
 #else
 	bool result;
-	SDL_JoystickGetButton(m_private->m_joystick, button)? result = true:result = false;
+	result = SDL_CHECK(SDL_JoystickGetButton) && SDL_JoystickGetButton(m_private->m_joystick, button);
 	return result;
 #endif
 }
@@ -218,7 +228,7 @@ bool SCA_Joystick::aButtonReleaseIsPositive(int button)
 	return false;
 #else
 	bool result;
-	SDL_JoystickGetButton(m_private->m_joystick, button)? result = false : result = true;
+	result = !(SDL_CHECK(SDL_JoystickGetButton) && SDL_JoystickGetButton(m_private->m_joystick, button));
 	return result;
 #endif
 }
@@ -253,7 +263,7 @@ bool SCA_Joystick::CreateJoystickDevice(void)
 	m_axismax = m_buttonmax = m_hatmax = 0;
 	return false;
 #else /* WITH_SDL */
-	if (m_isinit == false) {
+	if (m_isinit == false && SDL_CHECK(SDL_JoystickOpen)) {
 		if (m_joyindex>=m_joynum) {
 			/* don't print a message, because this is done anyway */
 			//JOYSTICK_ECHO("Joystick-Error: " << SDL_NumJoysticks() << " avaiable joystick(s)");
@@ -293,9 +303,9 @@ void SCA_Joystick::DestroyJoystickDevice(void)
 #ifdef WITH_SDL
 	if (m_isinit) {
 #if SDL_VERSION_ATLEAST(2, 0, 0)
-		if (SDL_JoystickGetAttached(m_private->m_joystick))
+		if (SDL_CHECK(SDL_JoystickGetAttached) && SDL_JoystickGetAttached(m_private->m_joystick))
 #else
-		if (SDL_JoystickOpened(m_joyindex))
+		if (SDL_CHECK(SDL_JoystickOpened) && SDL_JoystickOpened(m_joyindex))
 #endif
 		{
 			JOYSTICK_ECHO("Closing-joystick " << m_joyindex);
@@ -309,13 +319,16 @@ void SCA_Joystick::DestroyJoystickDevice(void)
 int SCA_Joystick::Connected(void)
 {
 #ifdef WITH_SDL
-	if (m_isinit
+	if (m_isinit &&
 #if SDL_VERSION_ATLEAST(2, 0, 0)
-		&& SDL_JoystickGetAttached(m_private->m_joystick))
+	    SDL_CHECK(SDL_JoystickGetAttached) && SDL_JoystickGetAttached(m_private->m_joystick)
 #else
-	    && SDL_JoystickOpened(m_joyindex))
+	    SDL_CHECK(SDL_JoystickOpened) && SDL_JoystickOpened(m_joyindex)
 #endif
+		)
+	{
 		return 1;
+	}
 #endif
 	return 0;
 }
@@ -353,9 +366,9 @@ const char *SCA_Joystick::GetName()
 {
 #ifdef WITH_SDL
 #if SDL_VERSION_ATLEAST(2, 0, 0)
-	return SDL_JoystickName(m_private->m_joystick);
+	return (SDL_CHECK(SDL_JoystickName)) ? SDL_JoystickName(m_private->m_joystick) : "";
 #else
-	return SDL_JoystickName(m_joyindex);
+	return (SDL_CHECK(SDL_JoystickName)) ? SDL_JoystickName(m_joyindex) : "";
 #endif
 #else /* WITH_SDL */
 	return "";
diff --git a/source/gameengine/GameLogic/Joystick/SCA_JoystickEvents.cpp b/source/gameengine/GameLogic/Joystick/SCA_JoystickEvents.cpp
index 38baeaab35e..08f4d97ed1b 100644
--- a/source/gameengine/GameLogic/Joystick/SCA_JoystickEvents.cpp
+++ b/source/gameengine/GameLogic/Joystick/SCA_JoystickEvents.cpp
@@ -85,7 +85,11 @@ void SCA_Joystick::OnNothing(SDL_Event* sdl_event)
 void SCA_Joystick::HandleEvents(void)
 {
 	SDL_Event		sdl_event;
-	
+
+	if (SDL_PollEvent == (void*)0) {
+		return;
+	}
+
 	int i;
 	for (i=0; i<m_joynum; i++) { /* could use JOYINDEX_MAX but no reason to */
 		if (SCA_Joystick::m_instance[i])
diff --git a/source/gameengine/GamePlayer/ghost/CMakeLists.txt b/source/gameengine/GamePlayer/ghost/CMakeLists.txt
index 8ab090eac02..a1bc7e88840 100644
--- a/source/gameengine/GamePlayer/ghost/CMakeLists.txt
+++ b/source/gameengine/GamePlayer/ghost/CMakeLists.txt
@@ -91,4 +91,11 @@ if(WITH_AUDASPACE)
 	add_definitions(-DWITH_AUDASPACE)
 endif()
 
+if(WITH_SDL AND WITH_SDL_DYNLOAD)
+	list(APPEND INC
+		../../../../extern/sdlew/include
+	)
+	add_definitions(-DWITH_SDL_DYNLOAD)
+endif()
+
 blender_add_lib_nolist(ge_player_ghost "${SRC}" "${INC}" "${INC_SYS}")
diff --git a/source/gameengine/GamePlayer/ghost/GPG_ghost.cpp b/source/gameengine/GamePlayer/ghost/GPG_ghost.cpp
index 3bb5f17841d..1a6501fae6e 100644
--- a/source/gameengine/GamePlayer/ghost/GPG_ghost.cpp
+++ b/source/gameengine/GamePlayer/ghost/GPG_ghost.cpp
@@ -114,6 +114,10 @@ extern char datatoc_bmonofont_ttf[];
 #endif // !defined(DEBUG)
 #endif // WIN32
 
+#ifdef WITH_SDL_DYNLOAD
+#  include "sdlew.h"
+#endif
+
 const int kMinWindowWidth = 100;
 const int kMinWindowHeight = 100;
 
@@ -421,6 +425,11 @@ int main(int argc, char** argv)
 	signal (SIGFPE, SIG_IGN);
 #endif /* __alpha__ */
 #endif /* __linux__ */
+
+#ifdef WITH_SDL_DYNLOAD
+	sdlewInit();
+#endif
+
 	BLI_init_program_path(argv[0]);
 	BLI_temp_dir_init(NULL);
 	
diff --git a/source/gameengine/GamePlayer/ghost/SConscript b/source/gameengine/GamePlayer/ghost/SConscript
index d4c31889a5e..610abcd0357 100644
--- a/source/gameengine/GamePlayer/ghost/SConscript
+++ b/source/gameengine/GamePlayer/ghost/SConscript
@@ -87,4 +87,8 @@ if env['WITH_BF_FFMPEG']:
 if env['WITH_BF_INTERNATIONAL']:
     defs.append('WITH_INTERNATIONAL')
 
+if env['WITH_BF_SDL'] and env['WITH_BF_SDL_DYNLOAD']:
+    defs.append('WITH_SDL_DYNLOAD')
+    incs += ['#extern/sdlew/include']
+
 env.BlenderLib (libname='ge_player_ghost', sources=source_files, includes = incs, defines = defs, libtype=['player'],priority=[0], cxx_compileflags=env['BGE_CXXFLAGS'])