generic_buffer.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
 *                                                                           *
 * Copyright(C) 2021-2025                                                    *
 * Visual Computing Lab                                                      *
 * ISTI - Italian National Research Council                                  *
 *                                                                           *
 * All rights reserved.                                                      *
 *                                                                           *
 * This program is free software; you can redistribute it and/or modify      *
 * it under the terms of the Mozilla Public License Version 2.0 as published *
 * by the Mozilla Foundation; either version 2 of the License, or            *
 * (at your option) any later version.                                       *
 *                                                                           *
 * This program 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              *
 * Mozilla Public License Version 2.0                                        *
 * (https://www.mozilla.org/en-US/MPL/2.0/) for more details.                *
 ****************************************************************************/
 
#ifndef VCL_BGFX_BUFFERS_GENERIC_BUFFER_H
#define VCL_BGFX_BUFFERS_GENERIC_BUFFER_H
 
#include <vclib/types.h>
 
#include <bgfx/bgfx.h>
 
#include <utility>
 
namespace vcl {
 
template<typename BufferHandleType>
class GenericBuffer
{
protected:
    BufferHandleType mHandle = BGFX_INVALID_HANDLE;
 
public:
    bool isValid() const { return bgfx::isValid(mHandle); }
 
    void destroy()
    {
        if (bgfx::isValid(mHandle)) {
            bgfx::destroy(mHandle);
            mHandle = BGFX_INVALID_HANDLE;
        }
    }
 
protected:
    GenericBuffer() = default;
 
    // Copying a GenericBuffer is not allowed
    GenericBuffer(const GenericBuffer& other) = delete;
 
    GenericBuffer(GenericBuffer&& other) noexcept { swap(other); }
 
    ~GenericBuffer() { destroy(); }
 
    // Copying a GenericBuffer is not allowed
    GenericBuffer& operator=(const GenericBuffer& other) = delete;
 
    GenericBuffer& operator=(GenericBuffer&& other) noexcept
    {
        swap(other);
        return *this;
    }
 
    void swap(GenericBuffer& other)
    {
        using std::swap;
        swap(mHandle, other.mHandle);
    }
 
    friend void swap(GenericBuffer& a, GenericBuffer& b) { a.swap(b); }
 
protected:
    static uint64_t flagsForAccess(bgfx::Access::Enum access)
    {
        switch (access) {
        case bgfx::Access::Read: return BGFX_BUFFER_COMPUTE_READ;
        case bgfx::Access::Write: return BGFX_BUFFER_COMPUTE_WRITE;
        case bgfx::Access::ReadWrite: return BGFX_BUFFER_COMPUTE_READ_WRITE;
        default: return BGFX_BUFFER_NONE;
        }
    }
 
    static bgfx::AttribType::Enum attributeType(PrimitiveType type)
    {
        switch (type) {
        case PrimitiveType::CHAR:
        case PrimitiveType::UCHAR: return bgfx::AttribType::Uint8;
        case PrimitiveType::SHORT:
        case PrimitiveType::USHORT: return bgfx::AttribType::Int16;
        case PrimitiveType::FLOAT: return bgfx::AttribType::Float;
        default:
            assert(0); // not supported
            return bgfx::AttribType::Count;
        }
    }
 
    static uint64_t flagsForType(PrimitiveType type)
    {
        switch (type) {
        case PrimitiveType::INT:
        case PrimitiveType::UINT: return BGFX_BUFFER_INDEX32;
        case PrimitiveType::FLOAT:
            return BGFX_BUFFER_COMPUTE_FORMAT_32X1 |
                   BGFX_BUFFER_COMPUTE_TYPE_FLOAT;
        case PrimitiveType::DOUBLE: assert(0); // not supported
        default: return BGFX_BUFFER_NONE;
        }
    }
};
 
} // namespace vcl
 
#endif // VCL_BGFX_BUFFERS_GENERIC_BUFFER_H