Added lerp, lerp_color, approach, and multiapproach lua functions.

src/LuaManager.h

@@ -266,6 +266,11 @@ void LuaFunc_Register_##func( lua_State *L ); \
 void LuaFunc_Register_##func( lua_State *L ) { lua_register( L, #func, LuaFunc_##func ); } \
 REGISTER_WITH_LUA_FUNCTION( LuaFunc_Register_##func );
 
+#define LUAFUNC_REGISTER_COMMON(func_name) \
+void LuaFunc_Register_##func_name(lua_State* L); \
+void LuaFunc_Register_##func_name(lua_State* L) { lua_register(L, #func_name, LuaFunc_##func_name); } \
+REGISTER_WITH_LUA_FUNCTION(LuaFunc_Register_##func_name);
+
 #endif
 
 /*

src/RageTypes.cpp

@@ -74,6 +74,14 @@ RString RageColor::NormalizeColorString( RString sColor )
 	return c.ToString();
 }
 
+void lerp_rage_color(RageColor& out, RageColor const& a, RageColor const& b, float t)
+{
+	out.b= lerp(t, a.b, b.b);
+	out.g= lerp(t, a.g, b.g);
+	out.r= lerp(t, a.r, b.r);
+	out.a= lerp(t, a.a, b.a);
+}
+
 void WeightedAvergeOfRSVs(RageSpriteVertex& average_out, RageSpriteVertex const& rsv1, RageSpriteVertex const& rsv2, float percent_between)
 {
 	average_out.p= lerp(percent_between, rsv1.p, rsv2.p);
@@ -207,8 +215,21 @@ int LuaFunc_color( lua_State *L )
 	c.PushTable( L );
 	return 1;
 }
-void LuaFunc_Register_color( lua_State *L ) { lua_register( L, "color", LuaFunc_color ); }
-REGISTER_WITH_LUA_FUNCTION( LuaFunc_Register_color );
+LUAFUNC_REGISTER_COMMON(color);
+
+int LuaFunc_lerp_color(lua_State *L)
+{
+	// Args:  percent, color, color
+	// Returns:  color
+	float percent= FArg(1);
+	RageColor a, b, c;
+	a.FromStack(L, 2);
+	b.FromStack(L, 3);
+	lerp_rage_color(c, a, b, percent);
+	c.PushTable(L);
+	return 1;
+}
+LUAFUNC_REGISTER_COMMON(lerp_color);
 
 /*
  * Copyright (c) 2006 Glenn Maynard

src/RageTypes.h

@@ -342,6 +342,7 @@ struct RageSpriteVertex	// has color
 	RageVector2 t; // texture coordinates
 };
 
+void lerp_rage_color(RageColor& out, RageColor const& a, RageColor const& b, float t);
 void WeightedAvergeOfRSVs(RageSpriteVertex& average_out, RageSpriteVertex const& rsv1, RageSpriteVertex const& rsv2, float percent_between);
 
 struct RageModelVertex	// doesn't have color.  Relies on material color

src/RageUtil.cpp

@@ -2329,6 +2329,76 @@ LuaFunction( PrettyPercent, PrettyPercent( FArg(1), FArg(2) ) );
 //LuaFunction( IsHexVal, IsHexVal( SArg(1) ) );
 static bool UndocumentedFeature( RString s ){ sm_crash(s); return true; }
 LuaFunction( UndocumentedFeature, UndocumentedFeature(SArg(1)) );
+LuaFunction( lerp, lerp(FArg(1), FArg(2), FArg(3)) );
+
+void luafunc_approach_internal(lua_State* L, int valind, int goalind, int speedind);
+void luafunc_approach_internal(lua_State* L, int valind, int goalind, int speedind, int process_index)
+{
+#define TONUMBER_NICE(dest, num_name, index) \
+	if(!lua_isnumber(L, index)) \
+	{ \
+		luaL_error(L, "approach: " #num_name " for approach %d is not a number.", process_index); \
+	} \
+	dest= lua_tonumber(L, index);
+	float val= 0;
+	float goal= 0;
+	float speed= 0;
+	TONUMBER_NICE(val, current, valind);
+	TONUMBER_NICE(goal, goal, goalind);
+	TONUMBER_NICE(speed, speed, speedind);
+#undef TONUMBER_NICE
+	if(speed < 0)
+	{
+		luaL_error(L, "approach: speed %d is negative.", process_index);
+	}
+	fapproach(val, goal, speed);
+	lua_pushnumber(L, val);
+}
+
+int LuaFunc_approach(lua_State* L);
+int LuaFunc_approach(lua_State* L)
+{
+	// Args:  current, goal, speed
+	// Returns:  new_current
+	luafunc_approach_internal(L, 1, 2, 3, 1);
+	return 1;
+}
+LUAFUNC_REGISTER_COMMON(approach);
+
+int LuaFunc_multiapproach(lua_State* L);
+int LuaFunc_multiapproach(lua_State* L)
+{
+	// Args:  {currents}, {goals}, {speeds}
+	// Returns:  {currents}
+	// Modifies the values in {currents} in place.
+	if(lua_gettop(L) != 3)
+	{
+		luaL_error(L, "multiapproach:  A table of current values, a table of goal values, and a table of speeds must be passed.");
+	}
+	size_t currents_len= lua_objlen(L, 1);
+	size_t goals_len= lua_objlen(L, 2);
+	size_t speeds_len= lua_objlen(L, 3);
+	if(currents_len != goals_len || currents_len != speeds_len)
+	{
+		luaL_error(L, "multiapproach:  There must be the same number of current values, goal values, and speeds.");
+	}
+	if(!lua_istable(L, 1) || !lua_istable(L, 2) || !lua_istable(L, 3))
+	{
+		luaL_error(L, "multiapproach:  current, goal, and speed must all be tables.");
+	}
+	for(size_t i= 1; i <= currents_len; ++i)
+	{
+		lua_rawgeti(L, 1, i);
+		lua_rawgeti(L, 2, i);
+		lua_rawgeti(L, 3, i);
+		luafunc_approach_internal(L, -3, -2, -1, i);
+		lua_rawseti(L, 1, i);
+		lua_pop(L, 3);
+	}
+	lua_pushvalue(L, 1);
+	return 1;
+}
+LUAFUNC_REGISTER_COMMON(multiapproach);
 
 /*
  * Copyright (c) 2001-2005 Chris Danford, Glenn Maynard