/*
 * Copyright 2011-2023 Branimir Karadzic. All rights reserved.
 * License: https://github.com/bkaradzic/bgfx/blob/master/LICENSE
 */

#ifndef BGFX_UTILS_H_HEADER_GUARD
#define BGFX_UTILS_H_HEADER_GUARD

#include <bx/bounds.h>
#include <bx/pixelformat.h>
#include <bx/string.h>
#include <bgfx/bgfx.h>
#include <bimg/bimg.h>

#include <tinystl/allocator.h>
#include <tinystl/vector.h>
namespace stl = tinystl;


///
void* load(const char* _filePath, uint32_t* _size = NULL);

///
void unload(void* _ptr);

///
bgfx::ShaderHandle loadShader(const char* _name);

///
bgfx::ProgramHandle loadProgram(const char* _vsName, const char* _fsName);

///
bgfx::TextureHandle loadTexture(const char* _name, uint64_t _flags = BGFX_TEXTURE_NONE|BGFX_SAMPLER_NONE, uint8_t _skip = 0, bgfx::TextureInfo* _info = NULL, bimg::Orientation::Enum* _orientation = NULL);

///
bimg::ImageContainer* imageLoad(const char* _filePath, bgfx::TextureFormat::Enum _dstFormat);

///
void calcTangents(void* _vertices, uint16_t _numVertices, bgfx::VertexLayout _layout, const uint16_t* _indices, uint32_t _numIndices);

/// Returns true if both internal transient index and vertex buffer have
/// enough space.
///
/// @param[in] _numVertices Number of vertices.
/// @param[in] _layout Vertex layout.
/// @param[in] _numIndices Number of indices.
///
inline bool checkAvailTransientBuffers(uint32_t _numVertices, const bgfx::VertexLayout& _layout, uint32_t _numIndices)
{
	return _numVertices == bgfx::getAvailTransientVertexBuffer(_numVertices, _layout)
		&& (0 == _numIndices || _numIndices == bgfx::getAvailTransientIndexBuffer(_numIndices) )
		;
}

///
inline uint32_t encodeNormalRgba8(float _x, float _y = 0.0f, float _z = 0.0f, float _w = 0.0f)
{
	const float src[] =
	{
		_x * 0.5f + 0.5f,
		_y * 0.5f + 0.5f,
		_z * 0.5f + 0.5f,
		_w * 0.5f + 0.5f,
	};
	uint32_t dst;
	bx::packRgba8(&dst, src);
	return dst;
}

///
struct MeshState
{
	struct Texture
	{
		uint32_t            m_flags;
		bgfx::UniformHandle m_sampler;
		bgfx::TextureHandle m_texture;
		uint8_t             m_stage;
	};

	Texture             m_textures[4];
	uint64_t            m_state;
	bgfx::ProgramHandle m_program;
	uint8_t             m_numTextures;
	bgfx::ViewId        m_viewId;
};

struct Primitive
{
	uint32_t m_startIndex;
	uint32_t m_numIndices;
	uint32_t m_startVertex;
	uint32_t m_numVertices;

	bx::Sphere m_sphere;
	bx::Aabb   m_aabb;
	bx::Obb    m_obb;
};

typedef stl::vector<Primitive> PrimitiveArray;

struct Group
{
	Group();
	void reset();

	bgfx::VertexBufferHandle m_vbh;
	bgfx::IndexBufferHandle m_ibh;
	uint16_t m_numVertices;
	uint8_t* m_vertices;
	uint32_t m_numIndices;
	uint16_t* m_indices;
	bx::Sphere m_sphere;
	bx::Aabb   m_aabb;
	bx::Obb    m_obb;
	PrimitiveArray m_prims;
};
typedef stl::vector<Group> GroupArray;

struct Mesh
{
	void load(bx::ReaderSeekerI* _reader, bool _ramcopy);
	void unload();
	void submit(bgfx::ViewId _id, bgfx::ProgramHandle _program, const float* _mtx, uint64_t _state) const;
	void submit(const MeshState*const* _state, uint8_t _numPasses, const float* _mtx, uint16_t _numMatrices) const;

	bgfx::VertexLayout m_layout;
	GroupArray m_groups;
};

///
Mesh* meshLoad(const char* _filePath, bool _ramcopy = false);

///
void meshUnload(Mesh* _mesh);

///
MeshState* meshStateCreate();

///
void meshStateDestroy(MeshState* _meshState);

///
void meshSubmit(const Mesh* _mesh, bgfx::ViewId _id, bgfx::ProgramHandle _program, const float* _mtx, uint64_t _state = BGFX_STATE_MASK);

///
void meshSubmit(const Mesh* _mesh, const MeshState*const* _state, uint8_t _numPasses, const float* _mtx, uint16_t _numMatrices = 1);

/// bgfx::RendererType::Enum to name.
bx::StringView getName(bgfx::RendererType::Enum _type);

/// Name to bgfx::RendererType::Enum.
bgfx::RendererType::Enum getType(const bx::StringView& _name);

///
struct Args
{
	Args(int _argc, const char* const* _argv);

	bgfx::RendererType::Enum m_type;
	uint16_t m_pciId;
};

#endif // BGFX_UTILS_H_HEADER_GUARD