Refactor Buffer internals.

Allows buffers created with love.graphics.newBuffer to only allocate VRAM data. Previously they had a copy of their contents in RAM.
Also makes it easier to implement Buffers in other graphics APIs and to implement more types of Buffers in the future.

src/modules/graphics/Text.h

@@ -22,6 +22,7 @@
 
 // LOVE
 #include "common/config.h"
+#include "common/Range.h"
 #include "Drawable.h"
 #include "Font.h"
 #include "Buffer.h"
@@ -73,9 +74,9 @@ private:
 		Font::ColoredCodepoints codepoints;
 		float wrap;
 		Font::AlignMode align;
-		Font::TextInfo text_info;
-		bool use_matrix;
-		bool append_vertices;
+		Font::TextInfo textInfo;
+		bool useMatrix;
+		bool appendVertices;
 		Matrix4 matrix;
 	};
 
@@ -88,16 +89,18 @@ private:
 	VertexAttributes vertexAttributes;
 	BufferBindings vertexBuffers;
 
-	StrongRef<Buffer> vertex_buffer;
+	StrongRef<Buffer> vertexBuffer;
+	uint8 *vertexData;
+	Range modifiedVertices;
 
-	std::vector<Font::DrawCommand> draw_commands;
+	std::vector<Font::DrawCommand> drawCommands;
 
-	std::vector<TextData> text_data;
+	std::vector<TextData> textData;
 
-	size_t vert_offset;
+	size_t vertOffset;
 	
 	// Used so we know when the font's texture cache is invalidated.
-	uint32 texture_cache_id;
+	uint32 textureCacheID;
 	
 }; // Text