//
// 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;

#ifndef GL_ES_VERSION_2_0
        graphics_->SetUBO(0);
        glDeleteBuffers(1, &object_);
#endif
        object_ = 0;
    }

    shadowData_.Reset();
    size_ = 0;
}

void ConstantBuffer::OnDeviceReset()
{
    if (size_)
        SetSize(size_); // Recreate
}

bool ConstantBuffer::SetSize(unsigned size)
{
    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_)
    {
#ifndef GL_ES_VERSION_2_0
        if (!object_)
            glGenBuffers(1, &object_);
        graphics_->SetUBO(object_);
        glBufferData(GL_UNIFORM_BUFFER, size_, shadowData_.Get(), GL_DYNAMIC_DRAW);
#endif
    }

    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_)
    {
#ifndef GL_ES_VERSION_2_0
        graphics_->SetUBO(object_);
        glBufferData(GL_UNIFORM_BUFFER, size_, shadowData_.Get(), GL_DYNAMIC_DRAW);
#endif
        dirty_ = false;
    }
}

}
