CoolVLViewer/indra/newview/llpatchvertexarray.h

/**
 * @file llpatchvertexarray.h
 * @brief description of LLPatchVertexArray class
 *
 * $LicenseInfo:firstyear=2001&license=viewergpl$
 *
 * Copyright (c) 2001-2009, 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
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 * http://secondlifegrid.net/programs/open_source/licensing/flossexception
 *
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 */

#ifndef LL_LLPATCHVERTEXARRAY_H
#define LL_LLPATCHVERTEXARRAY_H

#include "llerror.h"

// A LLPatchVertexArray is really just a structure of vertex arrays for
// rendering a "patch" of a certain size.
//
// A "patch" is currently a sub-square of a larger square array of data we call
// a "surface".
class LLPatchVertexArray
{
protected:
	LOG_CLASS(LLPatchVertexArray);

public:
	LLPatchVertexArray();
	LLPatchVertexArray(U32 surface_width, U32 patch_width,
					   F32 meters_per_grid);

	~LLPatchVertexArray();

	void create(U32 surface_width, U32 patch_width, F32 meters_per_grid);
	void destroy();
	void init();

public:
	U32		mSurfaceWidth;	// Grid points on one side of a LLSurface
	U32		mPatchWidth;	// Grid points on one side of a LLPatch
	U32		mPatchOrder;	// 2^mPatchOrder >= mPatchWidth

	U32*	mRenderLevelp;	// Look-up table  : render_stride -> render_level
	U32*	mRenderStridep; // Look-up table : render_level -> render_stride

	// We want to be able to render a patch from multiple resolutions.
	// The lowest resolution has two triangles, and the highest has
	// 2*mPatchWidth*mPatchWidth triangles.
	//
	// mPatchWidth is not hard-coded, so we do not know how much memory to
	// allocate to the vertex arrays until it is set. Once it is set, we will
	// calculate how much total memory to allocate for the vertex arrays, and
	// then keep track of their lengths and locations in the memory bank.
	//
	// A Patch has three regions that need vertex arrays: middle, north, and
	// east. For each region there are three items that must be kept track of:
	// data, offset, and length.
};

#endif