add "ability to move camera" (aka freelook). it requires use of a lua script to actually control the matrix switcheroo

re: #130

desmume/src/gfx3d.cpp

@@ -348,6 +348,9 @@ static u16 dsDiffuse, dsAmbient, dsSpecular, dsEmission;
 //used for indexing the shininess table during parameters to shininess command
 static u8 shininessInd = 0;
 
+// "Freelook" related things
+int freelookMode = 0;
+s32 freelookMatrix[16];
 
 //-----------cached things:
 //these dont need to go into the savestate. they can be regenerated from HW registers
@@ -743,8 +746,27 @@ static void SetVertex()
 	if(polylist->count >= POLYLIST_SIZE) 
 			return;
 
-	GEM_TransformVertex(mtxCurrent[MATRIXMODE_POSITION], coordTransformed); //modelview
+	if(freelookMode == 2)
-	GEM_TransformVertex(mtxCurrent[MATRIXMODE_PROJECTION], coordTransformed); //projection
+	{
+		//adjust projection
+		s32 tmp[16];
+		MatrixCopy(tmp,mtxCurrent[MATRIXMODE_PROJECTION]);
+		MatrixMultiply(tmp, freelookMatrix);
+		GEM_TransformVertex(mtxCurrent[MATRIXMODE_POSITION], coordTransformed); //modelview
+		GEM_TransformVertex(tmp, coordTransformed); //projection
+	}
+	else if(freelookMode == 3)
+	{
+		//use provided projection
+		GEM_TransformVertex(mtxCurrent[MATRIXMODE_POSITION], coordTransformed); //modelview
+		GEM_TransformVertex(freelookMatrix, coordTransformed); //projection
+	}
+	else
+	{
+		//no freelook
+		GEM_TransformVertex(mtxCurrent[MATRIXMODE_POSITION], coordTransformed); //modelview
+		GEM_TransformVertex(mtxCurrent[MATRIXMODE_PROJECTION], coordTransformed); //projection
+	}
 
 	//TODO - culling should be done here.
 	//TODO - viewport transform?
@@ -904,6 +926,15 @@ static void SetVertex()
 	}
 }
 
+static void UpdateProjection()
+{
+	if(freelookMode == 0) return;
+	float floatproj[16];
+	for(int i=0;i<16;i++)
+		floatproj[i] = mtxCurrent[MATRIXMODE_PROJECTION][i]/((float)(1<<12));
+	CallRegistered3dEvent(0,floatproj);
+}
+
 static void gfx3d_glPolygonAttrib_cache()
 {
 	// Light enable/disable
@@ -984,6 +1015,8 @@ static void gfx3d_glPushMatrix()
 			if (index == 1) MMU_new.gxstat.se = 1;
 			index += 1;
 			index &= 1;
+
+			UpdateProjection();
 		}
 		else
 		{
@@ -1031,6 +1064,8 @@ static void gfx3d_glPopMatrix(u32 v)
 			index ^= 1;
 			if (index == 1) MMU_new.gxstat.se = 1;
 			MatrixCopy(mtxCurrent[mode], mtxStackProjection.matrix[0]);
+
+			UpdateProjection();
 		}
 		else
 		{
@@ -1070,6 +1105,7 @@ static void gfx3d_glStoreMatrix(u32 v)
 		if (mode == MATRIXMODE_PROJECTION)
 		{
 			MatrixCopy(mtxStackProjection.matrix[0], mtxCurrent[MATRIXMODE_PROJECTION]);
+			UpdateProjection();
 		}
 		else
 		{
@@ -1102,6 +1138,7 @@ static void gfx3d_glRestoreMatrix(u32 v)
 		if (mode == MATRIXMODE_PROJECTION)
 		{
 			MatrixCopy(mtxCurrent[MATRIXMODE_PROJECTION], mtxStackProjection.matrix[0]);
+			UpdateProjection();
 		}
 		else
 		{

desmume/src/lua-engine.cpp

@@ -3830,6 +3830,38 @@ DEFINE_LUA_FUNCTION(emu_registermenustart, "func")
 	return 1;
 }
 
+DEFINE_LUA_FUNCTION(emu_set3dtransform, "mode, matrix")
+{
+	extern int freelookMode;
+	extern s32 freelookMatrix[16];
+
+	int mode = luaL_checkinteger(L,1);
+	freelookMode = mode;
+	if(mode == 2 || mode == 3)
+	{
+		for(int i=0;i<16;i++)
+		{
+			lua_rawgeti(L, 2, i+1);
+			freelookMatrix[i] = (s32)(lua_tonumber(L,-1)*(1<<12));
+			lua_pop(L,1);
+		}
+	}
+
+	return 0;
+}
+
+DEFINE_LUA_FUNCTION(emu_register3devent, "func")
+{
+	if (!lua_isnil(L,1))
+		luaL_checktype(L, 1, LUA_TFUNCTION);
+	lua_settop(L,1);
+	lua_getfield(L, LUA_REGISTRYINDEX, luaCallIDStrings[LUACALL_REGISTER3DEVENT]);
+	lua_insert(L,1);
+	lua_setfield(L, LUA_REGISTRYINDEX, luaCallIDStrings[LUACALL_REGISTER3DEVENT]);
+	StopScriptIfFinished(luaStateToUIDMap[L->l_G->mainthread]);
+	return 1;
+}
+
 // TODO
 /*
 DEFINE_LUA_FUNCTION(emu_loadrom, "filename")
@@ -4674,6 +4706,8 @@ static const struct luaL_reg emulib [] =
 	{"addmenu", emu_addmenu},
 	{"setmenuiteminfo", emu_setmenuiteminfo},
 	{"registermenustart", emu_registermenustart},
+	{"register3devent", emu_register3devent},
+	{"set3dtransform", emu_set3dtransform},
 	// alternative names
 //	{"openrom", emu_loadrom},
 	{NULL, NULL}
@@ -5683,7 +5717,7 @@ bool AnyLuaActive()
 	return false;
 }
 
-void CallRegisteredLuaFunctions(LuaCallID calltype)
+void _CallRegisteredLuaFunctions(LuaCallID calltype, int (*beforeCallback)(lua_State*, void*), void* beforeCallbackArg)
 {
 	assert((unsigned int)calltype < (unsigned int)LUACALL_COUNT);
 	const char* idstring = luaCallIDStrings[calltype];
@@ -5720,7 +5754,9 @@ void CallRegisteredLuaFunctions(LuaCallID calltype)
 				bool wasRunning = info.running;
 				info.running = true;
 				RefreshScriptSpeedStatus();
-				int errorcode = lua_pcall(L, 0, 0, 0);
+				int nargs = 0;
+				if(beforeCallback) nargs = beforeCallback(L,beforeCallbackArg);
+				int errorcode = lua_pcall(L, nargs, 0, 0);
 				info.running = wasRunning;
 				RefreshScriptSpeedStatus();
 				if (errorcode)
@@ -5744,6 +5780,45 @@ void CallRegisteredLuaFunctions(LuaCallID calltype)
 	}
 }
 
+void CallRegisteredLuaFunctions(LuaCallID calltype)
+{
+	_CallRegisteredLuaFunctions(calltype, NULL, NULL);
+}
+
+static struct {
+	int which;
+	void* arg;
+} todo3devent;
+
+int CallRegistered3dEvent_callback(lua_State* L, void* userarg)
+{
+	if(todo3devent.which == 0)
+	{
+		float* mat = (float*)todo3devent.arg;
+		lua_newtable(L);
+		for(int i=0;i<16;i++)
+		{
+			lua_pushnumber(L,mat[i]);
+			lua_rawseti(L,-2,i+1);
+		}
+		lua_setfield(L,LUA_GLOBALSINDEX,"registered3devent_arg");
+
+		lua_pushnumber(L,todo3devent.which);
+		lua_setfield(L,LUA_GLOBALSINDEX,"registered3devent_which");
+
+		return 0;
+	}
+
+	return 0;
+}
+
+void CallRegistered3dEvent(int which, void* arg)
+{
+	todo3devent.which = which;
+	todo3devent.arg = arg;
+	_CallRegisteredLuaFunctions(LUACALL_REGISTER3DEVENT, &CallRegistered3dEvent_callback, NULL);
+}
+
 void CallRegisteredLuaSaveFunctions(int savestateNumber, LuaSaveData& saveData)
 {
 	const char* idstring = luaCallIDStrings[LUACALL_BEFORESAVE];

desmume/src/lua-engine.h

@@ -37,6 +37,7 @@ enum LuaCallID
 	LUACALL_AFTERLOAD,
 	LUACALL_ONSTART,
 	LUACALL_ONINITMENU,
+	LUACALL_REGISTER3DEVENT,
 
 	LUACALL_SCRIPT_HOTKEY_1,
 	LUACALL_SCRIPT_HOTKEY_2,
@@ -58,6 +59,7 @@ enum LuaCallID
 	LUACALL_COUNT
 };
 void CallRegisteredLuaFunctions(LuaCallID calltype);
+void CallRegistered3dEvent(int which, void* arg);
 
 enum LuaMemHookType
 {