From 03da9d4eaa09fb60b660913de0b2a3dc1f466f95 Mon Sep 17 00:00:00 2001
From: scawful <justin.scofield@outlook.com>
Date: Sun, 10 Nov 2024 11:28:51 -0500
Subject: [PATCH] Add sheet_offset parameter to ComposeTile16 and update sheet
 ID validation

---
 src/app/gfx/tilesheet.cc |  9 +++++----
 src/app/gfx/tilesheet.h  | 11 ++++++++++-
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/src/app/gfx/tilesheet.cc b/src/app/gfx/tilesheet.cc
index c5991c11..0f0470f0 100644
--- a/src/app/gfx/tilesheet.cc
+++ b/src/app/gfx/tilesheet.cc
@@ -63,7 +63,8 @@ void Tilesheet::ComposeTile16(const std::vector<uint8_t>& graphics_buffer,
                               const TileInfo& top_left,
                               const TileInfo& top_right,
                               const TileInfo& bottom_left,
-                              const TileInfo& bottom_right) {
+                              const TileInfo& bottom_right, int sheet_offset) {
+  sheet_offset_ = sheet_offset;
   // Calculate the base position for this Tile16 in the full-size bitmap
   int tiles_per_row = bitmap_->width() / tile_width_;
   int tile16_row = num_tiles_ / tiles_per_row;
@@ -123,13 +124,13 @@ std::vector<uint8_t> Tilesheet::FetchTileDataFromGraphicsBuffer(
 
   // Calculate the position in the graphics_buffer_ based on tile_id
   std::vector<uint8_t> tile_data(0x40, 0x00);
-  int sheet = (tile_id / tiles_per_sheet) % 4 + 212;
+  int sheet = (tile_id / tiles_per_sheet) % 4 + sheet_offset_;
   int position_in_sheet = tile_id % tiles_per_sheet;
   int row_in_sheet = position_in_sheet / tiles_per_row;
   int column_in_sheet = position_in_sheet % tiles_per_row;
 
-  // Ensure that the sheet ID is between 212 and 215
-  assert(sheet >= 212 && sheet <= 215);
+  // Ensure that the sheet ID is between 212 and 215 if using full gfx buffer
+  assert(sheet >= sheet_offset_ && sheet <= sheet_offset_ + 3);
 
   // Copy the tile data from the graphics_buffer_ to tile_data
   for (int y = 0; y < 8; ++y) {
diff --git a/src/app/gfx/tilesheet.h b/src/app/gfx/tilesheet.h
index abcb9273..94fec6dc 100644
--- a/src/app/gfx/tilesheet.h
+++ b/src/app/gfx/tilesheet.h
@@ -37,7 +37,8 @@ class Tilesheet {
 
   void ComposeTile16(const std::vector<uint8_t>& graphics_buffer,
                      const TileInfo& top_left, const TileInfo& top_right,
-                     const TileInfo& bottom_left, const TileInfo& bottom_right);
+                     const TileInfo& bottom_left, const TileInfo& bottom_right,
+                     int sheet_offset = 0);
 
   void ComposeAndPlaceTilePart(const std::vector<uint8_t>& graphics_buffer,
                                const TileInfo& tile_info, int baseX, int baseY);
@@ -84,6 +85,13 @@ class Tilesheet {
   auto tile_type() const { return tile_type_; }
   auto tile_info() const { return tile_info_; }
   auto mutable_tile_info() { return tile_info_; }
+  void clear() {
+    palette_.clear();
+    internal_data_.clear();
+    tile_info_.clear();
+    bitmap_.reset();
+    num_tiles_ = 0;
+  }
 
  private:
   int CalculateTileIndex(int x, int y) {
@@ -115,6 +123,7 @@ class Tilesheet {
   int num_tiles_ = 0;
   int tile_width_ = 0;
   int tile_height_ = 0;
+  int sheet_offset_ = 0;
   TileType tile_type_;
 };