Imported existing code

indra/newview/llworldmipmap.h

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+/** 
+ * @file llworldmipmap.h
+ * @brief Data storage for the S3 mipmap of the entire world.
+ *
+ * $LicenseInfo:firstyear=2003&license=viewergpl$
+ * 
+ * Copyright (c) 2003-2009, Linden Research, Inc.
+ * 
+ * Second Life Viewer Source Code
+ * The source code in this file ("Source Code") is provided by Linden Lab
+ * to you under the terms of the GNU General Public License, version 2.0
+ * ("GPL"), unless you have obtained a separate licensing agreement
+ * ("Other License"), formally executed by you and Linden Lab.  Terms of
+ * the GPL can be found in doc/GPL-license.txt in this distribution, or
+ * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
+ * 
+ * There are special exceptions to the terms and conditions of the GPL as
+ * it is applied to this Source Code. View the full text of the exception
+ * in the file doc/FLOSS-exception.txt in this software distribution, or
+ * online at
+ * http://secondlifegrid.net/programs/open_source/licensing/flossexception
+ * 
+ * By copying, modifying or distributing this software, you acknowledge
+ * that you have read and understood your obligations described above,
+ * and agree to abide by those obligations.
+ * 
+ * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
+ * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
+ * COMPLETENESS OR PERFORMANCE.
+ * $/LicenseInfo$
+ */
+
+#ifndef LL_LLWORLDMIPMAP_H
+#define LL_LLWORLDMIPMAP_H
+
+#include <map>
+
+#include "llmemory.h"			// LLPointer
+#include "indra_constants.h"	// REGION_WIDTH_UNITS
+#include "llregionhandle.h"		// to_region_handle()
+
+class LLViewerImage;
+
+// LLWorldMipmap : Mipmap handling of all the tiles used to render the world at any resolution.
+// This class provides a clean structured access to the hierarchy of tiles stored in the 
+// Amazon S3 repository and abstracts its directory/file structure.
+// The interface of this class though still assumes that the caller knows the general level/tiles
+// structure (at least, that it exists...) but doesn't requite the caller to know the details of it.
+// IOW, you need to know that rendering levels exists as well as grid coordinates for regions, 
+// but you can ignore where those tiles are located, how to get them, etc...
+// The class API gives you back LLPointer<LLViewerImage> per tile.
+
+// See llworldmipmapview.cpp for the implementation of a class who knows how to render an LLWorldMipmap.
+
+// Implementation notes:
+// - On the S3 servers, the tiles are rendered in 2 flavors: Objects and Terrain.
+// - For the moment, LLWorldMipmap implements access only to the Objects tiles.
+class LLWorldMipmap
+{
+public:
+	// Parameters of the mipmap
+	static const S32 MAP_LEVELS = 8;		// Number of subresolution levels computed by the mapserver
+	static const S32 MAP_TILE_SIZE = 256;	// Width in pixels of the tiles computed by the mapserver
+
+	LLWorldMipmap();
+	~LLWorldMipmap();
+
+	// Clear up the maps and release all image handles
+	void	reset();
+	// Manage the boost levels between loops (typically draw() loops)
+	void	equalizeBoostLevels();
+	// Drop the boost levels to none (used when hiding the map)
+	void	dropBoostLevels();
+	// Get the tile smart pointer, does the loading if necessary
+	LLPointer<LLViewerImage> getObjectsTile(U32 grid_x, U32 grid_y, S32 level, bool load = true);
+
+	// Helper functions: those are here as they depend solely on the topology of the mipmap though they don't access it
+	// Convert sim scale (given in sim width in display pixels) into a mipmap level
+	static S32  scaleToLevel(F32 scale);
+	// Convert world coordinates to mipmap grid coordinates at a given level
+	static void globalToMipmap(F64 global_x, F64 global_y, S32 level, U32* grid_x, U32* grid_y);
+
+private:
+	// Get a handle (key) from grid coordinates
+	U64		convertGridToHandle(U32 grid_x, U32 grid_y) { return to_region_handle(grid_x * REGION_WIDTH_UNITS, grid_y * REGION_WIDTH_UNITS); }
+	// Load the relevant tile from S3
+	LLPointer<LLViewerImage> loadObjectsTile(U32 grid_x, U32 grid_y, S32 level);
+	// Clear a level from its "missing" tiles
+	void cleanMissedTilesFromLevel(S32 level);
+
+	// The mipmap is organized by resolution level (MAP_LEVELS of them). Each resolution level is an std::map
+	// using a region_handle as a key and storing a smart pointer to the image as a value.
+	typedef std::map<U64, LLPointer<LLViewerImage> > sublevel_tiles_t;
+	sublevel_tiles_t mWorldObjectsMipMap[MAP_LEVELS];
+//	sublevel_tiles_t mWorldTerrainMipMap[MAP_LEVELS];
+
+	S32 mCurrentLevel;		// The level last accessed by a getObjectsTile()
+};
+
+#endif // LL_LLWORLDMIPMAP_H