//
// Copyright (c) 2008-2015 the Urho3D project.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//

#include "../../Precompiled.h"

#include "../../Graphics/Graphics.h"
#include "../../Graphics/GraphicsImpl.h"
#include "../../Graphics/ConstantBuffer.h"
#include "../../IO/Log.h"

#include "../../DebugNew.h"

namespace Atomic
{

ConstantBuffer::ConstantBuffer(Context* context) :
    Object(context),
    GPUObject(GetSubsystem<Graphics>())
{
}

ConstantBuffer::~ConstantBuffer()
{
    Release();
}

void ConstantBuffer::Release()
{
    if (object_)
    {
        if (!graphics_)
            return;

        ((ID3D11Buffer*)object_)->Release();
        object_ = 0;
    }

    shadowData_.Reset();
    size_ = 0;
}

bool ConstantBuffer::SetSize(unsigned size)
{
    Release();

    if (!size)
    {
        LOGERROR("Can not create zero-sized constant buffer");
        return false;
    }

    // Round up to next 16 bytes
    size += 15;
    size &= 0xfffffff0;

    size_ = size;
    dirty_ = false;
    shadowData_ = new unsigned char[size_];
    memset(shadowData_.Get(), 0, size_);

    if (graphics_)
    {
        D3D11_BUFFER_DESC bufferDesc;
        memset(&bufferDesc, 0, sizeof bufferDesc);

        bufferDesc.ByteWidth = size_;
        bufferDesc.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
        bufferDesc.CPUAccessFlags = 0;
        bufferDesc.Usage = D3D11_USAGE_DEFAULT;

        graphics_->GetImpl()->GetDevice()->CreateBuffer(&bufferDesc, 0, (ID3D11Buffer**)&object_);

        if (!object_)
        {
            LOGERROR("Failed to create constant buffer");
            return false;
        }
    }

    return true;
}

void ConstantBuffer::SetParameter(unsigned offset, unsigned size, const void* data)
{
    if (offset + size > size_)
        return; // Would overflow the buffer

    memcpy(&shadowData_[offset], data, size);
    dirty_ = true;
}

void ConstantBuffer::SetVector3ArrayParameter(unsigned offset, unsigned rows, const void* data)
{
    if (offset + rows * 4 * sizeof(float) > size_)
        return; // Would overflow the buffer

    float* dest = (float*)&shadowData_[offset];
    const float* src = (const float*)data;

    while (rows--)
    {
        *dest++ = *src++;
        *dest++ = *src++;
        *dest++ = *src++;
        ++dest; // Skip over the w coordinate
    }

    dirty_ = true;
}

void ConstantBuffer::Apply()
{
    if (dirty_ && object_)
    {
        graphics_->GetImpl()->GetDeviceContext()->UpdateSubresource((ID3D11Buffer*)object_, 0, 0, shadowData_.Get(), 0, 0);
        dirty_ = false;
    }
}

}