Added support for DXT1/3/5 and BC5/7 compressed textures via love.image.CompressedData. Some internals are still iffy.

- added a new CompressedData type to love.image
- added love.image.isCompressed(file or data)
- love.graphics.newImage automatically tests for compression when loading a file
- added love.graphics.isSupported strings for DXT, BC5, and BC7

Compressed textures meant to be used on the GPU offer huge performance gains when
- loading the texture from a file
- loading the texture from RAM to VRAM
- loading mipmaps
- rendering

--HG--
branch : image-CompressedData

src/libraries/ddsparse/ddsparse.h

@@ -0,0 +1,139 @@
+/**
+ * Simple DDS data parser for compressed 2D textures.
+ *
+ * Copyright (c) 2013 Alexander Szpakowski.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ **/
+
+#ifndef DDS_PARSE_H
+#define DDS_PARSE_H
+
+#include "ddsinfo.h"
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <vector>
+#include <exception>
+
+namespace dds
+{
+
+// Supported DDS formats.
+enum Format
+{
+	FORMAT_DXT1,
+	FORMAT_DXT3,
+	FORMAT_DXT5,
+	FORMAT_BC5s,    // Signed.
+	FORMAT_BC5u,    // Unsigned.
+	FORMAT_BC7,
+	FORMAT_BC7srgb, // sRGB color space.
+	FORMAT_UNKNOWN
+};
+
+class Parser
+{
+public:
+
+	enum Options
+	{
+		OPTIONS_NONE      = 0x00,
+		OPTIONS_COPY_DATA = 0x01 // Copy texture data internally when parsing.
+	};
+
+	// Represents a single mipmap level of a texture.
+	struct Image
+	{
+		int width;
+		int height;
+		size_t dataSize;
+		const uint8_t *data;
+
+		Image();
+	};
+
+	/**
+	 * Determines whether the input byte data is a valid DDS representation.
+	 **/
+	static bool isDDS(const void *data, size_t dataSize);
+
+	/**
+	 * Constructor.
+	 * Attempts to parse byte data as DDS. May throw std::bad_alloc if out of
+	 * memory.
+	 * @param data     The byte data to parse.
+	 * @param dataSize The size in bytes of the data.
+	 * @param options  Any optional settings (see above.)
+	 **/
+	Parser(const void *data, size_t dataSize, Options opts = OPTIONS_NONE);
+	Parser(const Parser &other);
+
+	~Parser();
+
+	/**
+	 * Gets the format of this texture.
+	 **/
+	Format getFormat() const;
+
+	/**
+	 * Gets the data of this texture at a mipmap level. Mipmap level 0
+	 * represents the base image.
+	 * @param miplevel The mipmap level to get the data of.
+	 * @return Pointer to the image data, or 0 if miplevel is not within the
+	 *         range of [0, numMipmaps).
+	 **/
+	const Image *getImageData(size_t miplevel = 0) const;
+
+	/**
+	 * Gets the number of mipmap levels in this texture.
+	 * Includes the base mip level.
+	 **/
+	size_t getNumMipmaps() const;
+
+	/**
+	 * Gets whether this Parser is using an internal copy of the texture data.
+	 * Accessing texture data from a Parser which hasn't internally copied the
+	 * DDS data will result in undefined behaviour if the original data is deleted.
+	 **/
+	bool ownsData() const;
+
+private:
+
+	Format parseDDSFormat(const dxinfo::DDSPixelFormat &fmt) const;
+	Format parseDX10Format(dxinfo::DXGIFormat fmt) const;
+	size_t parseImageSize(Format fmt, int width, int height) const;
+
+	bool parseTexData(const uint8_t *data, size_t dataSize, Format fmt, int w, int h, int mips);
+
+	bool parseData(const void *data, size_t dataSize);
+
+	// Delete any heap data created by this object.
+	void clearData();
+
+	std::vector<Image> texData;
+	Format format;
+	Options options;
+
+}; // Parser
+
+} // dds
+
+#endif // DDS_PARSE_H