Buffer.h

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#pragma once
 
#include "glm/gtc/type_ptr.hpp"
#include "stb_image.h"
 
namespace Karma
{
    enum class ShaderDataType
    {
        None = 0,
        Float,
        Float2,
        Float3,
        Float4,
        Mat3,
        Mat4,
        Int,
        Int2,
        Int3,
        Int4,
        Bool
    };

    static uint32_t ShaderDataTypeSize(ShaderDataType type)
    {
        switch (type)
        {
            case ShaderDataType::Float:
                return 4;
            case ShaderDataType::Float2:
                return 4 * 2;
            case ShaderDataType::Float3:
                return 4 * 3;
            case ShaderDataType::Float4:
                return 4 * 4;
            case ShaderDataType::Mat3:
                return 4 * 3 * 3;
            case ShaderDataType::Mat4:
                return 4 * 4 * 4;
            case ShaderDataType::Int:
                return 4;
            case ShaderDataType::Int2:
                return 4 * 2;
            case ShaderDataType::Int3:
                return 4 * 3;
            case ShaderDataType::Int4:
                return 4 * 4;
            case ShaderDataType::Bool:
                return 4;
            case ShaderDataType::None:
                KR_CORE_WARN("ShaderDataType is none. Size shall be considered 0.");
                return 0;
        }
 
        KR_CORE_ASSERT(false, "Unknown ShaderDataType");
        return 0;
    }

    struct BufferElement
    {
        std::string Name;

        uint64_t Offset;

        uint32_t Size;

        ShaderDataType Type;
        bool Normalized;

        BufferElement(ShaderDataType type, const std::string& name, bool normalized = false, uint64_t offset = 0)
            : Name(name), Type(type), Size(ShaderDataTypeSize(type)), Offset(offset), Normalized(normalized)
        {
        }

        uint32_t GetComponentCount() const
        {
            switch (Type)
            {
                case Karma::ShaderDataType::None:
                    return 0;
                case Karma::ShaderDataType::Float:
                    return 1;
                case Karma::ShaderDataType::Float2:
                    return 2;
                case Karma::ShaderDataType::Float3:
                    return 3;
                case Karma::ShaderDataType::Float4:
                    return 4;
                case Karma::ShaderDataType::Mat3:
                    return 3 * 3;
                case Karma::ShaderDataType::Mat4:
                    return 4 * 4;
                case Karma::ShaderDataType::Int:
                    return 1;
                case Karma::ShaderDataType::Int2:
                    return 2;
                case Karma::ShaderDataType::Int3:
                    return 3;
                case Karma::ShaderDataType::Int4:
                    return 4;
                case Karma::ShaderDataType::Bool:
                    return 1;
            }
 
            KR_CORE_ASSERT(false, "Unknown ShaderDataType!");
            return 0;
        }
    };

    class KARMA_API BufferLayout
    {
    public:
        BufferLayout()
        {
        }

        BufferLayout(const std::initializer_list<BufferElement>& elements)
            : m_Elements(elements)
        {
            CalculateOffsetsAndStride();
        }

        inline uint32_t GetStride() const { return m_Stride; }

        inline const std::vector<BufferElement>& GetElements() const { return m_Elements; }

        inline void PushElement(const BufferElement& element) { m_Elements.push_back(element); CalculateOffsetsAndStride(); }

        std::vector<BufferElement>::iterator begin()
        {
            return m_Elements.begin();
        }

        std::vector<BufferElement>::iterator end()
        {
            return m_Elements.end();
        }

        std::vector<BufferElement>::const_iterator begin() const
        {
            return m_Elements.begin();
        }

        std::vector<BufferElement>::const_iterator end() const
        {
            return m_Elements.end();
        }
 
    private:
        void CalculateOffsetsAndStride()
        {
            uint32_t offset = 0;
            m_Stride = 0;
            for (auto& element : m_Elements)
            {
                element.Offset = offset;
                offset += element.Size;
                m_Stride += element.Size;
            }
        }
 
    private:
        std::vector<BufferElement> m_Elements;
        uint32_t m_Stride = 0;
    };

    class KARMA_API VertexBuffer
    {
    public:
        virtual ~VertexBuffer() = default;
 
        virtual void Bind() const = 0;
        virtual void UnBind() const = 0;
 
        virtual const BufferLayout& GetLayout() const = 0;
        virtual void SetLayout(const BufferLayout& layout) = 0;
 
        static VertexBuffer* Create(float* vertices, uint32_t size);
    };

    class KARMA_API IndexBuffer
    {
    public:
        virtual ~IndexBuffer() = default;
 
        virtual void Bind() const = 0;
        virtual void UnBind() const = 0;
 
        virtual uint32_t GetCount() const = 0;
 
        static IndexBuffer* Create(uint32_t* vertices, uint32_t size);
    };

    class KARMA_API ImageBuffer
    {
    public:
        static ImageBuffer* Create(const char* filename);
        uint32_t GetBindingPointIndex() const
        {
            return m_BindingPoint;
        }
    protected:
        uint32_t m_BindingPoint;
    };

    class KARMA_API UBODataPointer
    {
    public:
        UBODataPointer(const void* data) : m_DataPointer(data)
        {}

        const void* GetDataPointer() const
        {
            return m_DataPointer;
        }
    private:
        const void* m_DataPointer;
    };

    struct KARMA_API UniformBufferObject
    {
        static UniformBufferObject* Create(std::vector<ShaderDataType> dataTypes, uint32_t bindingPointIndex);

        UniformBufferObject(std::vector<ShaderDataType> dataTypes, uint32_t bindingPointIndex);

        virtual ~UniformBufferObject() = default;

        template<typename... T>
        void UpdateUniforms(T&&... uniforms)
        {
            m_UniformList = { uniforms... };
        }
 
        virtual void UpdateCameraUniform() = 0;

        virtual void UploadUniformBuffer(size_t frameIndex = 0) = 0;
 
        uint32_t GetBufferSize() const
        {
            return m_BufferSize;
        }
 
        const std::vector<UBODataPointer>& GetUniformList() const
        {
            return m_UniformList;
        }
 
        const std::vector<ShaderDataType>& GetUniformDataType() const
        {
            return m_UniformDataType;
        }
 
        const std::vector<uint32_t>& GetAlignedOffsets() const
        {
            return m_UniformAlignedOffsets;
        }
 
        const std::vector<uint32_t>& GetUniformSize() const
        {
            return m_UniformSizes;
        }
 
        uint32_t GetBindingPointIndex() const
        {
            return m_BindingPoint;
        }
 
    protected:
        void CalculateOffsetsAndBufferSize();
 
    protected:
        uint32_t m_BufferSize;

        uint32_t m_BindingPoint;

        std::vector<UBODataPointer> m_UniformList;

        std::vector<ShaderDataType> m_UniformDataType;

        std::vector<uint32_t> m_UniformAlignedOffsets;

        std::vector<uint32_t> m_UniformSizes;
 
    private:
        uint32_t ComputeBaseAlignment(ShaderDataType dataType);
    };
}