diff --git a/CMakeLists.txt b/CMakeLists.txt
index b3844a6..8bf6a90 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -6,7 +6,7 @@ if (POLICY CMP0091)
 endif ()
 
 project(System3 LANGUAGES CXX)
-set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD 17)
 
 # Generates a static library from pkg_check_modules() result
 function(add_static_library name pkg)
@@ -192,7 +192,6 @@ target_sources(system3 PRIVATE
   src/fm/makofm.cpp
   src/fm/mako_ymfm.cpp
   src/sys/ags.cpp
-  src/sys/ags_bmp.cpp
   src/sys/ags_cursor.cpp
   src/sys/ags_draw.cpp
   src/sys/ags_gl3.cpp
diff --git a/src/sys/ags.cpp b/src/sys/ags.cpp
index 5dcb4a1..d131150 100644
--- a/src/sys/ags.cpp
+++ b/src/sys/ags.cpp
@@ -224,8 +224,7 @@ AGS::AGS(const Config& config, const GameId& game_id) : game_id(game_id)
 	draw_menu = false;
 
 	// CG表示
-	set_cg_dest = false;
-	cg_dest_x = cg_dest_y = 0;
+	cg_dest = std::nullopt;
 	get_palette = extract_palette = extract_cg = true;
 	palette_bank = -1;
 
diff --git a/src/sys/ags.h b/src/sys/ags.h
index 8c93b47..3d3c138 100644
--- a/src/sys/ags.h
+++ b/src/sys/ags.h
@@ -11,6 +11,7 @@
 #include <unordered_set>
 #include <vector>
 #include <memory>
+#include <optional>
 #include <stdio.h>
 #include "common.h"
 #include "game_id.h"
@@ -72,7 +73,6 @@ private:
 	CG load_vsp2l(const std::vector<uint8_t>& data, int transparent); // Little Vampire
 	CG load_gl3(const std::vector<uint8_t>& data, bool set_palette, int transparent);
 	CG load_pms(int page, const std::vector<uint8_t>& data, bool set_palette, int transparent);
-	void load_bmp(const char* file_name);				// あゆみちゃん物語 フルカラー実写版
 	CG load_vsp(const std::vector<uint8_t>& data, bool set_palette, int transparent);
 
 	void draw_char(int dest, int dest_x, int dest_y, uint16 code, TTF_Font* font, uint8 color);
@@ -199,9 +199,7 @@ public:
 	bool draw_menu;
 
 	// CG表示
-	bool set_cg_dest;
-	int cg_dest_x;
-	int cg_dest_y;
+	std::optional<SDL_Point> cg_dest;
 	bool get_palette;
 	bool extract_palette;
 	bool extract_cg;
diff --git a/src/sys/ags_bmp.cpp b/src/sys/ags_bmp.cpp
deleted file mode 100644
index 1900313..0000000
--- a/src/sys/ags_bmp.cpp
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
-	ALICE SOFT SYSTEM 3 for Win32
-
-	[ AGS - bmp loader ]
-*/
-
-#include "ags.h"
-#include "fileio.h"
-
-void AGS::load_bmp(const char* file_name)
-{
-	// ヘッダ取得
-	int sx = 0, sy = 0;
-
-	// Jコマンドの処理
-	if(set_cg_dest) {
-		sx = cg_dest_x;
-		sy = cg_dest_y;
-		set_cg_dest = false;
-	}
-
-	if(extract_cg) {
-		WARNING("not implemented");
-	}
-}
diff --git a/src/sys/ags_cursor.cpp b/src/sys/ags_cursor.cpp
index e125d9e..d3728e5 100644
--- a/src/sys/ags_cursor.cpp
+++ b/src/sys/ags_cursor.cpp
@@ -13,21 +13,15 @@ extern SDL_Renderer* g_renderer;
 void AGS::load_cursor(int page)
 {
 	// カーソルCGをロードする
-	bool j_set = set_cg_dest;
-	int j_x = cg_dest_x;
-	int j_y = cg_dest_y;
+	auto j_backup = cg_dest;
 	int dest = dest_screen;
 
-	set_cg_dest = true;
-	cg_dest_x = 0;
-	cg_dest_y = 0;
+	cg_dest = {0, 0};
 	dest_screen = 1;
 
 	load_cg(page, -1);
 
-	set_cg_dest = j_set;
-	cg_dest_x = j_x;
-	cg_dest_y = j_y;
+	cg_dest = j_backup;
 	dest_screen = dest;
 
 	// フォントの生成
diff --git a/src/sys/ags_draw.cpp b/src/sys/ags_draw.cpp
index d3cc560..157150e 100644
--- a/src/sys/ags_draw.cpp
+++ b/src/sys/ags_draw.cpp
@@ -34,9 +34,7 @@ void mosaic(SDL_Surface* sf) {
 void AGS::load_cg(int page, int transparent)
 {
 	if (bmp_prefix) {
-		char file_name[16];
-		snprintf(file_name, sizeof(file_name), "%s%03d.BMP", bmp_prefix, page);
-		load_bmp(file_name);
+		WARNING("not implemented");
 		return;
 	}
 	std::vector<uint8_t> data = acg.load(page);
@@ -93,6 +91,14 @@ void AGS::load_cg(int page, int transparent)
 		}
 		break;
 	}
+
+	// J command
+	if (cg_dest.has_value()) {
+		cg.x = cg_dest->x;
+		cg.y = cg_dest->y;
+		cg_dest = std::nullopt;
+	}
+
 	if (extract_cg && cg.surface()) {
 		SDL_SetSurfacePalette(cg.surface(), screen_palette);
 		if (censor_list.count(page)) {
diff --git a/src/sys/ags_gl3.cpp b/src/sys/ags_gl3.cpp
index 551ebc4..83cf2fb 100644
--- a/src/sys/ags_gl3.cpp
+++ b/src/sys/ags_gl3.cpp
@@ -17,13 +17,6 @@ CG AGS::load_gl3(const std::vector<uint8_t>& data, bool set_palette, int transpa
 	int height = data[0x34] | (data[0x35] << 8);
 	uint8 base = 0;
 
-	// Jコマンドの処理
-	if(set_cg_dest) {
-		sx = cg_dest_x >> 3;
-		sy = cg_dest_y;
-		set_cg_dest = false;
-	}
-
 	// Zコマンドの処理
 	if(palette_bank != -1) {
 		base = (palette_bank & 0x0f) << 4;
diff --git a/src/sys/ags_gm3.cpp b/src/sys/ags_gm3.cpp
index 58c6e20..78c9d95 100644
--- a/src/sys/ags_gm3.cpp
+++ b/src/sys/ags_gm3.cpp
@@ -17,13 +17,6 @@ CG AGS::load_gm3(const std::vector<uint8_t>& data, int transparent)
 	int height = data[0x34] | (data[0x35] << 8);
 	uint8 base = 0;
 
-	// Jコマンドの処理
-	if(set_cg_dest) {
-		sx = cg_dest_x >> 3;
-		sy = cg_dest_y;
-		set_cg_dest = false;
-	}
-
 	// Zコマンドの処理
 	if(palette_bank != -1) {
 		base = (palette_bank & 0x0f) << 4;
diff --git a/src/sys/ags_pms.cpp b/src/sys/ags_pms.cpp
index cff23ad..b2d061c 100644
--- a/src/sys/ags_pms.cpp
+++ b/src/sys/ags_pms.cpp
@@ -19,15 +19,6 @@ CG AGS::load_pms(int page, const std::vector<uint8_t>& data, bool set_palette, i
 	int height = ey - sy + 1;
 	uint16_t mask = data[0xa] | (data[0xb] << 8);
 
-	// Jコマンドの処理
-	if(set_cg_dest) {
-		sx = cg_dest_x;
-		sy = cg_dest_y;
-		ex = sx + width - 1;
-		ey = sy + height - 1;
-		set_cg_dest = false;
-	}
-
 	if(get_palette) {
 		SDL_Color colors[256];
 		int p = 0x20;
diff --git a/src/sys/ags_vsp.cpp b/src/sys/ags_vsp.cpp
index be52499..695e14d 100644
--- a/src/sys/ags_vsp.cpp
+++ b/src/sys/ags_vsp.cpp
@@ -37,15 +37,6 @@ CG AGS::load_vsp(const std::vector<uint8_t>& data, bool set_palette, int transpa
 	int height = ey - sy;
 	uint8 base = (data[9] & 0x0f) << 4;
 
-	// Jコマンドの処理
-	if(set_cg_dest) {
-		sx = cg_dest_x >> 3;
-		sy = cg_dest_y;
-		ex = sx + width;
-		ey = sy + height;
-		set_cg_dest = false;
-	}
-
 	// Zコマンドの処理
 	if (game_id.is(GameId::AMBIVALENZ_FD) || game_id.is(GameId::AMBIVALENZ_CD)) {
 		// Z 0,numを無視する
diff --git a/src/sys/ags_vsp2l.cpp b/src/sys/ags_vsp2l.cpp
index 48bd721..cb8eaba 100644
--- a/src/sys/ags_vsp2l.cpp
+++ b/src/sys/ags_vsp2l.cpp
@@ -18,15 +18,6 @@ CG AGS::load_vsp2l(const std::vector<uint8_t>& data, int transparent)
 	int height = ey - sy;
 	uint8 base = 0;//(data[9] & 0x0f) << 4;
 
-	// Jコマンドの処理
-	if(set_cg_dest) {
-		sx = cg_dest_x >> 3;
-		sy = cg_dest_y;
-		ex = sx + width;
-		ey = sy + height;
-		set_cg_dest = false;
-	}
-
 	// Zコマンドの処理
 	if(palette_bank != -1) {
 		base = (palette_bank & 0x0f) << 4;
diff --git a/src/sys/nact_sys3.cpp b/src/sys/nact_sys3.cpp
index 2249643..6b0f106 100644
--- a/src/sys/nact_sys3.cpp
+++ b/src/sys/nact_sys3.cpp
@@ -374,9 +374,7 @@ void NACT_Sys3::cmd_j()
 	TRACE("J %d,%d:", x, y);
 
 	// x方向はカラム単位で切り捨て
-	ags->cg_dest_x = column ? x * 8 : x & 0xfff8;
-	ags->cg_dest_y = y;
-	ags->set_cg_dest = true;
+	ags->cg_dest = {column ? x * 8 : x & 0xfff8, y};
 }
 
 void NACT_Sys3::cmd_k()