[nostalgia/core/studio] Add scrolling support to TileSheetEditor

src/nostalgia/core/gfx.hpp

@@ -6,10 +6,12 @@
 
 #include <ox/std/types.hpp>
 #include <ox/model/def.hpp>
+#include <nostalgia/common/point.hpp>
 #include <nostalgia/common/size.hpp>
 
 #include "color.hpp"
 #include "context.hpp"
+#include "ptidxconv.hpp"
 
 namespace nostalgia::core {
 
@@ -36,6 +38,46 @@ struct NostalgiaGraphic {
 	ox::FileAddress defaultPalette;
 	NostalgiaPalette pal;
 	ox::Vector<uint8_t> pixels;
+
+	[[nodiscard]]
+	constexpr auto getPixel4Bpp(const common::Point &pt) const noexcept {
+		oxAssert(bpp == 4, "NostalgiaGraphic::getPixel4Bpp: wrong bpp");
+		const auto idx = ptToIdx(pt, this->columns);
+		if (idx & 1) {
+			return this->pixels[idx / 2];
+		} else {
+			return this->pixels[idx / 2];
+		}
+	}
+
+	[[nodiscard]]
+	constexpr auto getPixel8Bpp(const common::Point &pt) const noexcept {
+		oxAssert(bpp == 8, "NostalgiaGraphic::getPixel8Bpp: wrong bpp");
+		const auto idx = ptToIdx(pt, this->columns);
+		return this->pixels[idx];
+	}
+
+	[[nodiscard]]
+	constexpr auto getPixel(const common::Point &pt) const noexcept {
+		if (this->bpp == 4) {
+			return getPixel4Bpp(pt);
+		} else {
+			return getPixel8Bpp(pt);
+		}
+	}
+
+	constexpr void setPixel(const common::Point &pt, uint8_t palIdx) noexcept {
+		const auto idx = ptToIdx(pt, this->columns);
+		if (bpp == 4) {
+			if (idx & 1) {
+				pixels[idx / 2] &= 0b0000'1111 | (palIdx << 4);
+			} else {
+				pixels[idx / 2] &= 0b1111'0000 | (palIdx);
+			}
+		} else {
+			this->pixels[idx] = palIdx;
+		}
+	}
 };
 
 oxModelBegin(NostalgiaPalette)