/** 
 * @file llvertexbuffer.h
 * @brief LLVertexBuffer wrapper for OpengGL vertex buffer objects
 *
 * $LicenseInfo:firstyear=2003&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LL_LLVERTEXBUFFER_H
#define LL_LLVERTEXBUFFER_H

#include "llgl.h"
#include "v2math.h"
#include "v3math.h"
#include "v4math.h"
#include "v4coloru.h"
#include "llstrider.h"
#include "llrender.h"
#include "lltrace.h"
#include <set>
#include <vector>
#include <list>

#define LL_MAX_VERTEX_ATTRIB_LOCATION 64

//============================================================================
// NOTES
// Threading:
//  All constructors should take an 'create' paramater which should only be
//  'true' when called from the main thread. Otherwise createGLBuffer() will
//  be called as soon as getVertexPointer(), etc is called (which MUST ONLY be
//  called from the main (i.e OpenGL) thread)


//============================================================================
// base class 
class LLPrivateMemoryPool;
class LLVertexBuffer final : public LLRefCount
{
public:
	struct MappedRegion
	{
        U32 mStart;
        U32 mEnd;
	};

	LLVertexBuffer(const LLVertexBuffer& rhs)
	{
		*this = rhs;
	}

	const LLVertexBuffer& operator=(const LLVertexBuffer& rhs)
	{
		LL_ERRS() << "Illegal operation!" << LL_ENDL;
		return *this;
	}

	static void initClass(LLWindow* window);
	static void cleanupClass();
	static void setupClientArrays(U32 data_mask);
	static void drawArrays(U32 mode, const std::vector<LLVector3>& pos);
	static void drawElements(U32 mode, const LLVector4a* pos, const LLVector2* tc, U32 num_indices, const U16* indicesp);

 	static void unbind(); //unbind any bound vertex buffer

	//get the size of a vertex with the given typemask
	static U32 calcVertexSize(const U32& typemask);

	//get the size of a buffer with the given typemask and vertex count
	//fill offsets with the offset of each vertex component array into the buffer
	// indexed by the following enum
	static U32 calcOffsets(const U32& typemask, U32* offsets, U32 num_vertices);

	//WARNING -- when updating these enums you MUST 
	// 1 - update LLVertexBuffer::sTypeSize
    // 2 - update LLVertexBuffer::vb_type_name
	// 3 - add a strider accessor
	// 4 - modify LLVertexBuffer::setupVertexBuffer
	// 6 - modify LLViewerShaderMgr::mReservedAttribs
	
    // clang-format off
    enum AttributeType {                      // Shader attribute name, set in LLShaderMgr::initAttribsAndUniforms()
        TYPE_VERTEX = 0,        //  "position"
        TYPE_NORMAL,            //  "normal"
        TYPE_TEXCOORD0,         //  "texcoord0"
        TYPE_TEXCOORD1,         //  "texcoord1"
        TYPE_TEXCOORD2,         //  "texcoord2"
        TYPE_TEXCOORD3,         //  "texcoord3"
        TYPE_COLOR,             //  "diffuse_color"
        TYPE_EMISSIVE,          //  "emissive"
        TYPE_TANGENT,           //  "tangent"
        TYPE_WEIGHT,            //  "weight"
        TYPE_WEIGHT4,           //  "weight4"
        TYPE_CLOTHWEIGHT,       //  "clothing"
        TYPE_TEXTURE_INDEX,     //  "texture_index"
        TYPE_MAX,   // TYPE_MAX is the size/boundary marker for attributes that go in the vertex buffer
        TYPE_INDEX,	// TYPE_INDEX is beyond _MAX because it lives in a separate (index) buffer	
    };
    // clang-format on

    enum {
		MAP_VERTEX = (1<<TYPE_VERTEX),
		MAP_NORMAL = (1<<TYPE_NORMAL),
		MAP_TEXCOORD0 = (1<<TYPE_TEXCOORD0),
		MAP_TEXCOORD1 = (1<<TYPE_TEXCOORD1),
		MAP_TEXCOORD2 = (1<<TYPE_TEXCOORD2),
		MAP_TEXCOORD3 = (1<<TYPE_TEXCOORD3),
		MAP_COLOR = (1<<TYPE_COLOR),
		MAP_EMISSIVE = (1<<TYPE_EMISSIVE),
		MAP_TANGENT = (1<<TYPE_TANGENT),
		MAP_WEIGHT = (1<<TYPE_WEIGHT),
		MAP_WEIGHT4 = (1<<TYPE_WEIGHT4),
		MAP_CLOTHWEIGHT = (1<<TYPE_CLOTHWEIGHT),
		MAP_TEXTURE_INDEX = (1<<TYPE_TEXTURE_INDEX),
	};
	
protected:
	friend class LLRender;

	~LLVertexBuffer(); // use unref()

	void setupVertexBuffer();

	void	genBuffer(U32 size);
	void	genIndices(U32 size);
	bool	createGLBuffer(U32 size);
	bool	createGLIndices(U32 size);
	void 	destroyGLBuffer();
	void 	destroyGLIndices();
	bool	updateNumVerts(U32 nverts);
	bool	updateNumIndices(U32 nindices); 

public:
	LLVertexBuffer(U32 typemask);
	
    // allocate buffer
    bool	allocateBuffer(U32 nverts, U32 nindices);

	// map for data access (see also getFooStrider below)
	U8*		mapVertexBuffer(AttributeType type, U32 index, S32 count = -1);
	U8*		mapIndexBuffer(U32 index, S32 count = -1);
    void	unmapBuffer();

	// set for rendering
    // assumes (and will assert on) the following:
    //      - this buffer has no pending unampBuffer call
    //      - a shader is currently bound
    //      - This buffer has sufficient attributes within it to satisfy the needs of the currently bound shader
	void	setBuffer();
    		
	// Only call each getVertexPointer, etc, once before calling unmapBuffer()
	// call unmapBuffer() after calls to getXXXStrider() before any cals to setBuffer()
	// example:
	//   vb->getVertexBuffer(verts);
	//   vb->getNormalStrider(norms);
	//   setVertsNorms(verts, norms);
	//   vb->unmapBuffer();
	bool getVertexStrider(LLStrider<LLVector3>& strider, U32 index=0, S32 count = -1);
	bool getVertexStrider(LLStrider<LLVector4a>& strider, U32 index=0, S32 count = -1);
	bool getIndexStrider(LLStrider<U16>& strider, U32 index=0, S32 count = -1);
	bool getTexCoord0Strider(LLStrider<LLVector2>& strider, U32 index=0, S32 count = -1);
	bool getTexCoord1Strider(LLStrider<LLVector2>& strider, U32 index=0, S32 count = -1);
	bool getTexCoord2Strider(LLStrider<LLVector2>& strider, U32 index=0, S32 count = -1);
	bool getNormalStrider(LLStrider<LLVector3>& strider, U32 index=0, S32 count = -1);
	bool getNormalStrider(LLStrider<LLVector4a>& strider, U32 index = 0, S32 count = -1);
	bool getTangentStrider(LLStrider<LLVector3>& strider, U32 index=0, S32 count = -1);
	bool getTangentStrider(LLStrider<LLVector4a>& strider, U32 index=0, S32 count = -1);
	bool getColorStrider(LLStrider<LLColor4U>& strider, U32 index=0, S32 count = -1);
	bool getEmissiveStrider(LLStrider<LLColor4U>& strider, U32 index=0, S32 count = -1);
	bool getWeightStrider(LLStrider<F32>& strider, U32 index=0, S32 count = -1);
	bool getWeight4Strider(LLStrider<LLVector4>& strider, U32 index=0, S32 count = -1);
	bool getClothWeightStrider(LLStrider<LLVector4>& strider, U32 index=0, S32 count = -1);
	
    void setPositionData(const LLVector4a* data);
    void setTexCoordData(const LLVector2* data);
    void setColorData(const LLColor4U* data);


	U32 getNumVerts() const					{ return mNumVerts; }
	U32 getNumIndices() const				{ return mNumIndices; }
	
	U32 getTypeMask() const					{ return mTypeMask; }
	bool hasDataType(AttributeType type) const		{ return ((1 << type) & getTypeMask()); }
    U32 getSize() const                     { return mSize; }
	U32 getIndicesSize() const				{ return mIndicesSize; }
	U8* getMappedData() const				{ return mMappedData; }
	U8* getMappedIndices() const			{ return mMappedIndexData; }
	U32 getOffset(AttributeType type) const			{ return mOffsets[type]; }
	
    // these functions assume (and assert on) the current VBO being bound
    // Detailed error checking can be enabled by setting gDebugGL to true
	void draw(U32 mode, U32 count, U32 indices_offset) const;
	void drawArrays(U32 mode, U32 offset, U32 count) const;
    void drawRange(U32 mode, U32 start, U32 end, U32 count, U32 indices_offset) const;

	//for debugging, validate data in given range is valid
	bool validateRange(U32 start, U32 end, U32 count, U32 offset) const;

	#ifdef LL_PROFILER_ENABLE_RENDER_DOC
	void setLabel(const char* label);
	#endif
	

protected:	
    U32		mGLBuffer = 0;		// GL VBO handle
    U32		mGLIndices = 0;		// GL IBO handle
    U32		mNumVerts = 0;		// Number of vertices allocated
    U32		mNumIndices = 0;	// Number of indices allocated
    U32		mOffsets[TYPE_MAX]; // byte offsets into mMappedData of each attribute

    U8* mMappedData = nullptr;	// pointer to currently mapped data (NULL if unmapped)
    U8* mMappedIndexData = nullptr;	// pointer to currently mapped indices (NULL if unmapped)

    U32		mTypeMask = 0;      // bitmask of present vertex attributes
	
	U32		mSize = 0;          // size in bytes of mMappedData
	U32		mIndicesSize = 0;   // size in bytes of mMappedIndexData

	std::vector<MappedRegion> mMappedVertexRegions;  // list of mMappedData byte ranges that must be sent to GL
	std::vector<MappedRegion> mMappedIndexRegions;   // list of mMappedIndexData byte ranges that must be sent to GL

private:
    // DEPRECATED
    // These function signatures are deprecated, but for some reason 
    // there are classes in an external package that depend on LLVertexBuffer
    
    // TODO: move these classes into viewer repository
    friend class LLNavShapeVBOManager;
    friend class LLNavMeshVBOManager;
    
    LLVertexBuffer(U32 typemask, U32 usage)
        : LLVertexBuffer(typemask)
    {}

    bool	allocateBuffer(S32 nverts, S32 nindices, BOOL create) { return allocateBuffer(nverts, nindices); }

public:

    static U64 getBytesAllocated();
	static const U32 sTypeSize[TYPE_MAX];
	static const U32 sGLMode[LLRender::NUM_MODES];
	static U32 sGLRenderBuffer;
	static U32 sGLRenderIndices;
	static U32 sLastMask;
	static U32 sVertexCount;
};

#ifdef LL_PROFILER_ENABLE_RENDER_DOC
#define LL_LABEL_VERTEX_BUFFER(buf, name) buf->setLabel(name)
#else
#define LL_LABEL_VERTEX_BUFFER(buf, name)
#endif


#endif // LL_LLVERTEXBUFFER_H