X-Git-Url: http://git.tdb.fi/?p=libs%2Fgl.git;a=blobdiff_plain;f=source%2Fcore%2Ftexture.h;h=96b17b8910752e0f0f46f7466b2acf7d014e2746;hp=2f647b90cae721837f441a59c4c67e5c5f3f31fd;hb=HEAD;hpb=f19366d32cc29287a2730cfba90893e407754081

diff --git a/source/core/texture.h b/source/core/texture.h
index 2f647b90..96b17b89 100644
--- a/source/core/texture.h
+++ b/source/core/texture.h
@@ -1,6 +1,7 @@
 #ifndef MSP_GL_TEXTURE_H_
 #define MSP_GL_TEXTURE_H_
 
+#include <msp/datafile/dynamicobjectloader.h>
 #include <msp/datafile/objectloader.h>
 #include <msp/graphics/image.h>
 #include "pixelformat.h"
@@ -11,13 +12,20 @@ namespace Msp {
 namespace GL {
 
 /**
-Base class for textures.  This class only defines operations common for all
-texture types and is not instantiable.  For specifying images for textures,
-see one of the dimensioned texture classes.
+Base class for textures.  Most operations are defined in subclasses.
 
-A texture can consinst of a stack of images, called a mipmap.  The dimensions
-of each mipmap level are half that of the previous level.  The mipmap stack
-can be used for texture minification; see the Sampler class for details.
+Memory must be allocated for the texture by calling storage().  Each subclass
+provides this function with parameters appropriate to that type of texture.
+Contents can then be modified using the image() and sub_image() functions
+provided by subclasses.
+
+Most types of textures can consist of a pyramid of images, called a mipmap.
+The dimensions of each mipmap level are half that of the previous level.
+
+Textures can be used as either a data source or target for draw commands.  To
+read from a texture in a shader, it must be paired with a Sampler to determine
+how the texels are accessed.  To draw into a texture, it must be attached to a
+Framebuffer.
 */
 class Texture: public TextureBackend, public Resource
 {
@@ -41,48 +49,66 @@ protected:
 		void load_external_image(Graphics::Image &, const std::string &);
 
 	private:
-		void external_image(const std::string &);
-		void external_image_srgb(const std::string &);
-		void external_image_common(const std::string &);
+		void external_data(const std::string &);
+		void external_image(bool, const std::string &);
 		void generate_mipmap(bool);
 		void image_data(const std::string &);
 		void mipmap_levels(unsigned);
+		void raw_data(const std::string &);
 	};
 
-	enum FormatSwizzle
+public:
+	class GenericLoader: public DataFile::DynamicObjectLoader<Texture>
 	{
-		NO_SWIZZLE,
-		R_TO_LUMINANCE,
-		RG_TO_LUMINANCE_ALPHA,
-		RGB_TO_BGR
+		friend class Texture;
+
+	public:
+		GenericLoader(Collection &c): DynamicObjectLoader<Texture>(&c) { }
+
+	protected:
+		virtual const TypeRegistry &get_type_registry() const { return get_texture_registry(); }
 	};
 
-	PixelFormat format;
-	PixelFormat storage_fmt;
-	FormatSwizzle swizzle;
-	bool use_srgb_format;
-	bool auto_gen_mipmap;
+protected:
+	PixelFormat format = NO_PIXELFORMAT;
+	PixelFormat storage_fmt = NO_PIXELFORMAT;
+	ComponentSwizzle swizzle = NO_SWIZZLE;
+	unsigned n_levels = 0;
+	bool use_srgb_format = false;
+	bool auto_gen_mipmap = false;
 
-	Texture(unsigned, ResourceManager * = 0);
+	Texture(unsigned);
 
 	void set_format(PixelFormat);
+	static unsigned count_levels(unsigned);
+
+	void stage_pixels(void *, const void *, std::size_t);
 
 public:
 	PixelFormat get_format() const { return format; }
 
 	using TextureBackend::generate_mipmap;
 
-	/// Loads a Graphics::Image from a file and uploads it to the texture.
+	/** Replaces contents of an entire mipmap level.  Allocated storage must
+	exist.  The image data is interpreted according to the storage format and
+	must have size matching the selected mipmap level. */
+	virtual void image(unsigned level, const void *) = 0;
+
+	/** Loads an image into the texture from a file. */
 	virtual void load_image(const std::string &, unsigned = 0);
 
-	/** Uploads an image to the texture.  If storage has not been defined, it
-	will be set to match the image.  Otherwise the image must be compatible
-	with the defined storage.  Semantics depend on the type of texture.  */
+	/** Sets the texture's contents from an image.  If storage has not been
+	allocated yet, it will be set to match the image.  Otherwise the image must
+	be compatible with the existing storage.  Subclasses may impose restrictions
+	on the image's dimensions. */
 	virtual void image(const Graphics::Image &, unsigned = 0) = 0;
 
-	virtual std::uint64_t get_data_size() const { return 0; }
+	virtual std::size_t get_data_size() const { return 0; }
 
 	using TextureBackend::set_debug_name;
+
+private:
+	static GenericLoader::TypeRegistry &get_texture_registry();
 };
 
 } // namespace GL