Add buffer textures

libs/gfx/include/psemek/gfx/texture.hpp

@@ -3,6 +3,7 @@
 #include <psemek/gfx/gl.hpp>
 #include <psemek/gfx/pixel.hpp>
 #include <psemek/gfx/pixmap.hpp>
+#include <psemek/gfx/buffer.hpp>
 #include <psemek/geom/vector.hpp>
 
 #include <optional>
@@ -158,6 +159,40 @@ namespace psemek::gfx
 		{}
 	};
 
+	struct buffer_texture
+	{
+		buffer_texture();
+		buffer_texture(buffer_texture &&);
+		buffer_texture & operator = (buffer_texture &&);
+		~buffer_texture();
+
+		buffer_texture(buffer_texture const &) = delete;
+		buffer_texture & operator = (buffer_texture const &) = delete;
+
+		static buffer_texture null();
+
+		static constexpr GLenum target = gl::TEXTURE_BUFFER;
+
+		GLuint id() const { return id_; }
+
+		explicit operator bool() const { return id() != 0; }
+
+		void reset();
+
+		void bind() const;
+		void bind(int texture_unit) const;
+
+		void buffer(GLenum internal_format, gfx::buffer const & buffer);
+
+		template <typename Pixel>
+		void buffer(gfx::buffer const & buffer);
+
+	protected:
+		GLuint id_;
+
+		explicit buffer_texture(std::nullptr_t);
+	};
+
 	namespace detail
 	{
 		std::optional<float> max_anisotropy();
@@ -433,6 +468,72 @@ namespace psemek::gfx
 		: id_{0}
 	{}
 
+	inline buffer_texture::buffer_texture()
+	{
+		gl::GenTextures(1, &id_);
+	}
+
+	inline buffer_texture::buffer_texture(buffer_texture && other)
+		: id_(other.id_)
+	{
+		other.id_ = 0;
+	}
+
+	inline buffer_texture & buffer_texture::operator = (buffer_texture && other)
+	{
+		if (this != &other)
+		{
+			reset();
+			id_ = other.id_;
+			other.id_ = 0;
+		}
+
+		return *this;
+	}
+
+	inline buffer_texture::~buffer_texture()
+	{
+		reset();
+	}
+
+	inline buffer_texture buffer_texture::null()
+	{
+		return buffer_texture(nullptr);
+	}
+
+	inline void buffer_texture::reset()
+	{
+		if (id_ != 0)
+			gl::DeleteTextures(1, &id_);
+	}
+
+	inline void buffer_texture::bind() const
+	{
+		gl::BindTexture(target, id_);
+	}
+
+	inline void buffer_texture::bind(int texture_unit) const
+	{
+		gl::ActiveTexture(gl::TEXTURE0 + texture_unit);
+		bind();
+	}
+
+	inline void buffer_texture::buffer(GLenum internal_format, gfx::buffer const & buffer)
+	{
+		bind();
+		gl::TexBuffer(target, internal_format, buffer.id());
+	}
+
+	template <typename Pixel>
+	void buffer_texture::buffer(gfx::buffer const & buffer)
+	{
+		this->buffer(pixel_traits<Pixel>::internal_format, buffer);
+	}
+
+	inline buffer_texture::buffer_texture(std::nullptr_t)
+		: id_(0)
+	{}
+
 	template <std::size_t D>
 	std::size_t mipmap_count(geom::vector<std::size_t, D> const & size)
 	{