From 1dff26d895ce0400d23a6db51f3ca0cb92d4d459 Mon Sep 17 00:00:00 2001
From: Gary Talent <gary@drinkingtea.net>
Date: Wed, 31 Jan 2024 23:16:41 -0600
Subject: [PATCH] [nostalgia/core] Add getTileCnt and fix getTileIdx

---
 src/nostalgia/modules/core/src/tilesheet.cpp | 21 +++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/nostalgia/modules/core/src/tilesheet.cpp b/src/nostalgia/modules/core/src/tilesheet.cpp
index 67b2c2e0..58ebc156 100644
--- a/src/nostalgia/modules/core/src/tilesheet.cpp
+++ b/src/nostalgia/modules/core/src/tilesheet.cpp
@@ -14,6 +14,7 @@ std::size_t idx(TileSheet::SubSheet const&ss, ox::Point const&pt) noexcept {
 	return ptToIdx(pt, ss.columns);
 }
 
+[[nodiscard]]
 static TileSheet::SubSheet const*getSubsheet(TileSheet::SubSheet const&ss, SubSheetId const id) noexcept {
 	if (ss.id == id) {
 		return &ss;
@@ -26,6 +27,24 @@ static TileSheet::SubSheet const*getSubsheet(TileSheet::SubSheet const&ss, SubSh
 	return {};
 }
 
+[[nodiscard]]
+static size_t getTileCnt(TileSheet::SubSheet const&ss, int const bpp) noexcept {
+	if (ss.subsheets.empty()) {
+		auto const bytesPerTile = bpp == 4 ? 32u : 64u;
+		return ss.pixels.size() / bytesPerTile;
+	} else {
+		size_t out{};
+		for (auto const&child : ss.subsheets) {
+			out += getTileCnt(child, bpp);
+		}
+		return out;
+	}
+}
+
+size_t getTileCnt(TileSheet const&ts) noexcept {
+	return getTileCnt(ts.subsheet, ts.bpp);
+}
+
 TileSheet::SubSheet const*getSubsheet(TileSheet const&ts, SubSheetId const id) noexcept {
 	return getSubsheet(ts.subsheet, id);
 }
@@ -42,7 +61,7 @@ static ox::Optional<size_t> getPixelIdx(
 		if (auto out = getPixelIdx(child, id, idx, bpp)) {
 			return out;
 		}
-		idx += pixelCnt(ss, bpp);
+		idx += pixelCnt(child, bpp);
 	}
 	return {};
 }