Refactor panorama again

* Always writes rm2k3e compatible pan_x/pan_y. * Fixes save game compatibility between Player and rm2k3e
CataractJustice · Dec 21, 2018 · 53654dc · 53654dc
1 parent 76b12d9
commit 53654dc
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Showing 2 changed files with 73 additions and 39 deletions.
diff --git a/src/game_map.cpp b/src/game_map.cpp
@@ -372,20 +372,30 @@ void Game_Map::ScrollRight(int distance) {
 	int x = map_info.position_x;
 	AddScreenX(x, distance);
 	map_info.position_x = x;
+	if (distance == 0) {
+		return;
+	}
 	// Unused, except compatibility with RPG_RT
 	auto& pan_x = Main_Data::game_data.screen.pan_x;
 	const auto pan_limit_x = 20 * SCREEN_TILE_WIDTH;
 	pan_x = (pan_x - distance + pan_limit_x) % pan_limit_x;
+
+	Game_Map::Parallax::ScrollRight(distance);
 }
 
 void Game_Map::ScrollDown(int distance) {
 	int y = map_info.position_y;
 	AddScreenY(y, distance);
 	map_info.position_y = y;
+	if (distance == 0) {
+		return;
+	}
 	// Unused, except compatibility with RPG_RT
 	auto& pan_y = Main_Data::game_data.screen.pan_y;
 	const auto pan_limit_y = 10 * SCREEN_TILE_WIDTH;
 	pan_y = (pan_y + distance + pan_limit_y) % pan_limit_y;
+
+	Game_Map::Parallax::ScrollDown(distance);
 }
 
 // Add inc to acc, clamping the result into the range [low, high].
@@ -1472,8 +1482,6 @@ FileRequestAsync* Game_Map::RequestMap(int map_id) {
 /////////////
 
 namespace {
-	int parallax_x;
-	int parallax_y;
 	int parallax_width;
 	int parallax_height;
 }
@@ -1514,47 +1522,71 @@ std::string Game_Map::Parallax::GetName() {
 }
 
 int Game_Map::Parallax::GetX() {
-	return (parallax_x - panorama.pan_x / 2) / TILE_SIZE;
+	return (-panorama.pan_x / TILE_SIZE) / 2;
 }
 
 int Game_Map::Parallax::GetY() {
-	return (parallax_y - panorama.pan_y / 2) / TILE_SIZE;
+	return (-panorama.pan_y / TILE_SIZE) / 2;
 }
 
 void Game_Map::Parallax::Initialize(int width, int height) {
 	parallax_width = width;
 	parallax_height = height;
 
-	UpdatePosition(true);
+	ResetPositionX();
+	ResetPositionY();
 }
 
-void Game_Map::Parallax::UpdatePosition(bool init) {
+void Game_Map::Parallax::ResetPositionX() {
 	Params params = GetParallaxParams();
 
-	// RPG_RT bug:
-	// On loaded save games, RPG_RT will always reset
-	// parallax_x/y to 0 when the map is looping.
-	// We don't emulate this.
+	panorama.pan_x = 0;
+	if (params.scroll_horz || LoopHorizontal())
+		panorama.pan_x = map_info.position_x;
+	else if (GetWidth() > 20 && parallax_width > SCREEN_TARGET_WIDTH)
+		panorama.pan_x = std::min(map_info.position_x,
+				(map_info.position_x / (SCREEN_TILE_WIDTH / TILE_SIZE)) * (parallax_width - SCREEN_TARGET_WIDTH) / (GetWidth() - 20)) * 2;
+}
+
+void Game_Map::Parallax::ResetPositionY() {
+	Params params = GetParallaxParams();
+
+	panorama.pan_y = 0;
+	if (params.scroll_vert || Game_Map::LoopVertical())
+		panorama.pan_y = map_info.position_y;
+	else if (GetHeight() > 15 && parallax_height > SCREEN_TARGET_HEIGHT)
+		panorama.pan_y = std::min(map_info.position_y,
+				(map_info.position_y / (SCREEN_TILE_WIDTH / TILE_SIZE)) * (parallax_height - SCREEN_TARGET_HEIGHT) / (GetHeight() - 15)) * 2;
+}
+
+void Game_Map::Parallax::ScrollRight(int distance) {
+	Params params = GetParallaxParams();
+	if (params.name.empty()) {
+		return;
+	}
+
+	if (params.scroll_horz) {
+		const auto w = parallax_width * TILE_SIZE * 2;
+		panorama.pan_x = (panorama.pan_x + distance + w) % w;
+		return;
+	}
+
+	ResetPositionX();
+}
 
-	if (init || !Game_Map::LoopHorizontal()) {
-		if (params.scroll_horz || LoopHorizontal())
-			parallax_x = -map_info.position_x / 2;
-		else if (GetWidth() > 20 && parallax_width > SCREEN_TARGET_WIDTH)
-			parallax_x = -std::min(map_info.position_x,
-					(map_info.position_x / (SCREEN_TILE_WIDTH / TILE_SIZE)) * (parallax_width - SCREEN_TARGET_WIDTH) / (GetWidth() - 20));
-		else
-			parallax_x = 0;
+void Game_Map::Parallax::ScrollDown(int distance) {
+	Params params = GetParallaxParams();
+	if (params.name.empty()) {
+		return;
 	}
 
-	if (init || !Game_Map::LoopVertical()) {
-		if (params.scroll_vert || Game_Map::LoopVertical())
-			parallax_y = -map_info.position_y / 2;
-		else if (GetHeight() > 15 && parallax_height > SCREEN_TARGET_HEIGHT)
-			parallax_y = -std::min(map_info.position_y,
-					(map_info.position_y / (SCREEN_TILE_WIDTH / TILE_SIZE)) * (parallax_height - SCREEN_TARGET_HEIGHT) / (GetHeight() - 15));
-		else
-			parallax_y = 0;
+	if (params.scroll_vert) {
+		const auto h = parallax_height * TILE_SIZE * 2;
+		panorama.pan_y = (panorama.pan_y + distance + h) % h;
+		return;
 	}
+
+	ResetPositionY();
 }
 
 void Game_Map::Parallax::Update() {
@@ -1563,24 +1595,22 @@ void Game_Map::Parallax::Update() {
 	if (params.name.empty())
 		return;
 
-	UpdatePosition();
-
 	auto scroll_amt = [](int speed) {
-		if (speed > 0) return 1 << (speed - 1);
-		if (speed < 0) return -(1 << (-speed - 1));
-		return 0;
+		return speed < 0 ? (1 << -speed) : -(1 << speed);
 	};
 
-
-	if (params.scroll_horz && params.scroll_horz_auto) {
+	if (params.scroll_horz
+			&& params.scroll_horz_auto
+			&& params.scroll_horz_speed != 0) {
 		const auto w = parallax_width * TILE_SIZE * 2;
-		panorama.pan_x -= scroll_amt(params.scroll_horz_speed) * 2;
-		panorama.pan_x = (panorama.pan_x + w) % w;
+		panorama.pan_x = (panorama.pan_x + scroll_amt(params.scroll_horz_speed) + w) % w;
 	}
-	if (params.scroll_vert && params.scroll_vert_auto) {
+
+	if (params.scroll_vert
+			&& params.scroll_vert_auto
+			&& params.scroll_vert_speed != 0) {
 		const auto h = parallax_height * TILE_SIZE * 2;
-		panorama.pan_y -= scroll_amt(params.scroll_vert_speed) * 2;
-		panorama.pan_y = (panorama.pan_y + h) % h;
+		panorama.pan_y = (panorama.pan_y + scroll_amt(params.scroll_vert_speed) + h) % h;
 	}
 }
 

diff --git a/src/game_map.h b/src/game_map.h
@@ -656,7 +656,11 @@ namespace Game_Map {
 		 *
 		 * @param init if true will always reset position, even on looping maps
 		 */
-		void UpdatePosition(bool init = false);
+		void ResetPositionX();
+		void ResetPositionY();
+
+		void ScrollRight(int distance);
+		void ScrollDown(int distance);
 
 		/** Update autoscrolling BG (call every frame). */
 		void Update();