/**
 * @file llgltfprimitive.h
 * @brief LL GLTF Implementation
 *
 * $LicenseInfo:firstyear=2024&license=viewergpl$
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 * Copyright (c) 2024, Linden Research, Inc.
 *
 * Second Life Viewer Source Code
 * The source code in this file ("Source Code") is provided by Linden Lab
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 *
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 */

#ifndef LL_LLGLTFPRIMITIVE_H
#define LL_LLGLTFPRIMITIVE_H

#include "hbfastmap.h"
#include "llmemory.h"				// For LL_ALIGNED16_NEW_DELETE
#include "llvertexbuffer.h"
#include "llvolumeoctree.h"

// Saves from including "tinygltf/tiny_gltf.h" here. HB
namespace tinygltf
{
	struct Primitive;
}

namespace LLGLTF
{
	class Asset;

	constexpr U32 ATTRIBUTE_MASK = LLVertexBuffer::MAP_VERTEX |
								   LLVertexBuffer::MAP_NORMAL |
								   LLVertexBuffer::MAP_TEXCOORD0 |
								   LLVertexBuffer::MAP_TANGENT |
								   LLVertexBuffer::MAP_COLOR;

	// Note 16-byte aligned because we use vectors of LLVector4a. HB
	class alignas(16) Primitive
	{
	protected:
		LOG_CLASS(LLGLTF::Primitive);

	public:
		LL_ALIGNED16_NEW_DELETE

		Primitive();
		~Primitive();

		// Creates an octree based on vertex buffer; must be called before
		// buffer is unmapped and after buffer is populated with valid data.
		void createOctree();

		// Gets the LLVolumeTriangle that intersects with the given line
		// segment at the point closest to start. Moves end to the point of
		// intersection. Returns NULL if no intersection.
		// Line segment must be in the same coordinate frame as this Primitive.
		const LLVolumeTriangle* lineSegmentIntersect(const LLVector4a& start,
													 const LLVector4a& end,
													 LLVector4a* interp = NULL,
													 LLVector2* tcoordp = NULL,
													 LLVector4a* normp = NULL,
													 LLVector4a* tgtp = NULL);
		
		const Primitive& operator=(const tinygltf::Primitive& src);

		// Returns true on success, or false on failure. HB
		bool allocateGLResources(Asset& asset);

	public:
		// Aligned members first...
		// CPU copy of mesh data
		std::vector<LLVector4a>			mNormals;
		std::vector<LLVector4a>			mTangents;
		std::vector<LLVector4a>			mPositions;
		std::vector<LLVector4a>			mJoints;
		std::vector<LLVector4a>			mWeights;
		// ... then the rest.
		std::vector<LLVector2>			mTexCoords;
		std::vector<LLColor4U>			mColors;
		std::vector<U32>				mIndexArray;

		// Raycast acceleration structure
		std::vector<LLVolumeTriangle>	mOctreeTriangles;
		LLPointer<LLVolumeOctree>		mOctree;

		// GPU copy of mesh data
		LLPointer<LLVertexBuffer>		mVertexBuffer;

		fast_hmap<std::string, S32>		mAttributes;

		S32								mMaterial;
		U32								mMode;
		U32								mGLMode;
		S32								mIndices;
	};
}

#endif	// LL_LLGLTFPRIMITIVE_H