Buffer.h

// Copyright 2022 ShenMian
// License(Apache-2.0)
 
#pragma once
 
#include <cstddef>
#include <span>
 
class Buffer
{
public:
    enum class Type
    {
        Vertex,
        Index,
        Uniform
    };
 
    enum class Usage
    {
        Static,
        Dynamic,
        Stream
    };
 
    Buffer(size_t size, Type type, Usage usage);
 
    template <typename T>
    void write(std::span<T> data, size_t offset = 0);
 
    void write(const void* data, size_t size, size_t offset = 0);
 
    void read(void* data, size_t size, size_t offset = 0);
 
    [[nodiscard]] size_t get_size() const;
 
    [[nodiscard]] Type get_type() const;
 
    [[nodiscard]] Usage get_usage() const;
 
    [[nodiscard]] void* get_data();
 
    virtual void map(size_t size = -1, size_t offset = 0) = 0;
 
    virtual void unmap() = 0;
 
    virtual void flush(size_t size = -1, size_t offset = 0) = 0;
 
protected:
    size_t size_;
    Type   type_;
    Usage  usage_;
    void*  data_ = nullptr;
};
 
template <typename T>
void Buffer::write(std::span<T> data, size_t offset)
{
    write(data.data(), data.size_bytes(), offset);
}