[nostalgia/core] Add clearCbb functions

src/nostalgia/modules/core/include/nostalgia/core/gfx.hpp

@@ -142,6 +142,10 @@ ox::Error loadBgTileSheet(
 		unsigned cbb,
 		TileSheetSet const&set) noexcept;
 
+void clearCbb(Context &ctx, unsigned cbb) noexcept;
+
+void clearCbbs(Context &ctx) noexcept;
+
 ox::Error loadBgTileSheet(
 		Context &ctx,
 		unsigned cbb,

src/nostalgia/modules/core/include/nostalgia/core/studio.hpp

@@ -0,0 +1,11 @@
+/*
+ * Copyright 2016 - 2025 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#pragma once
+
+#include <studio/studio.hpp>
+
+namespace nostalgia::core {
+
+}

src/nostalgia/modules/core/include/nostalgia/core/tilesheet.hpp

@@ -18,6 +18,23 @@
 
 namespace nostalgia::core {
 
+struct SubSheetTemplate {
+	static constexpr auto TypeName = "net.drinkingtea.nostalgia.gfx.SubSheetTemplate";
+	static constexpr auto TypeVersion = 1;
+	ox::String name;
+	int32_t width{};
+	int32_t height{};
+	ox::Vector<SubSheetTemplate> subsheets;
+};
+
+OX_MODEL_BEGIN(SubSheetTemplate)
+	OX_MODEL_FIELD(name)
+	OX_MODEL_FIELD(width)
+	OX_MODEL_FIELD(height)
+	OX_MODEL_FIELD(subsheets)
+OX_MODEL_END()
+
+
 // Predecessor to TileSheet, kept for backward compatibility
 struct TileSheetV1 {
 	static constexpr auto TypeName = "net.drinkingtea.nostalgia.core.NostalgiaGraphic";

src/nostalgia/modules/core/src/gba/gfx.cpp

@@ -63,6 +63,19 @@ ox::Error loadSpritePalette(
 	return {};
 }
 
+void clearCbb(Context&, unsigned const cbb) noexcept {
+	for (auto &v : MEM_BG_TILES[cbb]) {
+		v = 0;
+	}
+}
+
+void clearCbbs(Context &ctx) noexcept {
+	clearCbb(ctx, 0);
+	clearCbb(ctx, 1);
+	clearCbb(ctx, 2);
+	clearCbb(ctx, 3);
+}
+
 static ox::Error loadTileSheetSet(
 		Context &ctx,
 		ox::Span<uint16_t> tileMapTargetMem,

src/nostalgia/modules/core/src/opengl/gfx.cpp

@@ -586,6 +586,18 @@ static void copyPixels(
 	}
 }
 
+void clearCbb(Context &ctx, unsigned const cbb) noexcept {
+	for (auto &v : ctx.cbbs[cbb].pixels) {
+		v = 0;
+	}
+}
+
+void clearCbbs(Context &ctx) noexcept {
+	for (unsigned i = 0 ; i < ctx.cbbs.size(); ++i) {
+		clearCbb(ctx, i);
+	}
+}
+
 ox::Error loadBgTileSheet(
 		Context &ctx,
 		unsigned const cbb,