4 files changed, 98 insertions, 0 deletions
diff --git a/lib/nes/common/CMakeLists.txt b/lib/nes/common/CMakeLists.txt
new file mode 100644
index 0000000..69ae435
--- /dev/null
+++ b/lib/nes/common/CMakeLists.txt
@@ -0,0 +1,6 @@
+target_sources(
+	nes
+	PRIVATE
+		debug.hh
+		rgb.hh
+		display.hh)
+\ No newline at end of file
diff --git a/lib/nes/common/debug.hh b/lib/nes/common/debug.hh
new file mode 100644
index 0000000..409d55a
--- /dev/null
+++ b/lib/nes/common/debug.hh
@@ -0,0 +1,15 @@
+#pragma once
+
+#ifdef NES_ENABLE_DEBUG_OUTPUT
+
+#include <spdlog/spdlog.h>
+
+#define NES_DEBUG_LOG(name, ...) \
+  spdlog::info("[" #name "] " __VA_ARGS__)
+
+#else
+
+#define NES_DEBUG_LOG(name, fmt, ...) \
+  (void)0
+
+#endif
+\ No newline at end of file
diff --git a/lib/nes/common/display.hh b/lib/nes/common/display.hh
new file mode 100644
index 0000000..ca78a85
--- /dev/null
+++ b/lib/nes/common/display.hh
@@ -0,0 +1,44 @@
+#pragma once
+
+#include "nes/common/rgb.hh"
+
+namespace nes
+{
+	class rgb;
+
+	/// Abstraction of the display logic.
+	class display
+	{
+	public:
+		static constexpr auto width = unsigned{ 256 };
+		static constexpr auto height = unsigned{ 240 };
+
+		virtual ~display() = default;
+
+		display(display const&) = delete;
+		display(display&&) = delete;
+		auto operator=(display const&) -> display& = delete;
+		auto operator=(display&&) -> display& = delete;
+
+		/// Switch between front and back buffers.
+		virtual auto switch_buffers() -> void = 0;
+		/// Update the pixel at the given position in the back buffer.
+		virtual auto set(unsigned x, unsigned y, rgb value) -> void = 0;
+		/// Load the pixel value at the given position in the back buffer.
+		virtual auto get(unsigned x, unsigned y) const -> rgb = 0;
+		/// Clear the entire back buffer with a color.
+		virtual auto clear(rgb const color) -> void
+		{
+			for (auto y = unsigned{ 0 }; y < height; ++y)
+			{
+				for (auto x = unsigned{ 0 }; x < width; ++x)
+				{
+					set(x, y, color);
+				}
+			}
+		}
+
+	protected:
+		explicit display() = default;
+	};
+} // namespace nes
+\ No newline at end of file
diff --git a/lib/nes/common/rgb.hh b/lib/nes/common/rgb.hh
new file mode 100644
index 0000000..d62c70c
--- /dev/null
+++ b/lib/nes/common/rgb.hh
@@ -0,0 +1,33 @@
+#pragma once
+
+#include <cstdint>
+
+namespace nes
+{
+	/// An RGB value.
+	class rgb
+	{
+	public:
+		explicit rgb() = default;
+
+		explicit rgb(std::uint8_t const r, std::uint8_t const g, std::uint8_t const b)
+			: r{ r }
+			, g{ g }
+			, b{ b }
+		{
+		}
+
+		static auto from_hex(std::uint32_t const hex) -> rgb
+		{
+			auto res = rgb{};
+			res.r = (hex & 0x00FF0000) >> 16;
+			res.g = (hex & 0x0000FF00) >> 8;
+			res.b = (hex & 0x000000FF) >> 0;
+			return res;
+		}
+
+		std::uint8_t r{ 0 };
+		std::uint8_t g{ 0 };
+		std::uint8_t b{ 0 };
+	};
+} // namespace nes
+\ No newline at end of file