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/modules/graphics/opengl/Image.h

@@ -26,6 +26,7 @@
 #include "common/math.h"
 #include "common/config.h"
 #include "image/ImageData.h"
+#include "image/CompressedData.h"
 #include "graphics/Image.h"
 
 // OpenGL
@@ -52,10 +53,17 @@ public:
 	 * Creates a new Image. Not that anything is ready to use
 	 * before load is called.
 	 *
-	 * @param file The file from which to load the image.
+	 * @param data The data from which to load the image.
 	 **/
 	Image(love::image::ImageData *data);
 
+	/**
+	 * Creates a new Image with compressed image data.
+	 *
+	 * @param cdata The compressed data from which to load the image.
+	 **/
+	Image(love::image::CompressedData *cdata);
+
 	/**
 	 * Destructor. Deletes the hardware texture and other resources.
 	 **/
@@ -126,6 +134,9 @@ public:
 	static bool hasMipmapSupport();
 	static bool hasMipmapSharpnessSupport();
 
+	static bool hasCompressedTextureSupport();
+	static bool hasCompressedTextureSupport(image::CompressedData::TextureType type);
+
 private:
 
 	void drawv(const Matrix &t, const vertex *v) const;
@@ -138,6 +149,9 @@ private:
 	// The ImageData from which the texture is created.
 	love::image::ImageData *data;
 
+	// Or the Compressed Image Data from which the texture is created.
+	love::image::CompressedData *cdata;
+
 	// Width and height of the hardware texture.
 	float width, height;
 
@@ -153,12 +167,16 @@ private:
 	// True if mipmaps have been created for this Image.
 	bool mipmapsCreated;
 
+	bool isCompressed;
+
 	// The image's filter mode
 	Image::Filter filter;
 
 	// The image's wrap mode
 	Image::Wrap wrap;
 
+	void preload();
+
 	bool loadVolatilePOT();
 	bool loadVolatileNPOT();
 
@@ -169,6 +187,8 @@ private:
 	static FilterMode defaultMipmapFilter;
 	static float defaultMipmapSharpness;
 
+	GLenum getCompressedFormat(image::CompressedData::TextureType type) const;
+
 }; // Image
 
 } // opengl