//
// Urho3D Engine
// Copyright (c) 2008-2012 Lasse Öörni
//
// 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.
//

#pragma once

#include "ArrayPtr.h"
#include "GPUObject.h"
#include "Object.h"
#include "GraphicsDefs.h"

/// Hardware index buffer.
class IndexBuffer : public Object, public GPUObject
{
    OBJECT(IndexBuffer);
    
public:
    /// Construct.
    IndexBuffer(Context* context);
    /// Destruct.
    virtual ~IndexBuffer();
    
    /// Save data and release the buffer.
    virtual void OnDeviceLost();
    /// Recreate the buffer from saved data.
    virtual void OnDeviceReset();
    /// Release the buffer.
    virtual void Release();
    
    /// Set buffer size and dynamic mode. Previous data will be lost.
    bool SetSize(unsigned indexCount, bool largeIndices, bool dynamic = false);
    /// Set all data in the buffer.
    bool SetData(const void* data);
    /// Set a data range in the buffer.
    bool SetDataRange(const void* data, unsigned start, unsigned count);
    /// Lock a data range in the buffer. Return pointer to locked data if successful.
    void* Lock(unsigned start, unsigned count, LockMode mode);
    /// Unlock buffer.
    void Unlock();
    /// Clear data lost flag. No-op on OpenGL.
    void ClearDataLost();
    
    /// Return whether is dynamic.
    bool IsDynamic() const { return dynamic_; }
    /// Return whether data is lost. Always false on OpenGL.
    bool IsDataLost() const { return false; }
    /// Return number of indices.
    unsigned GetIndexCount() const {return indexCount_; }
    /// Return index size.
    unsigned GetIndexSize() const { return indexSize_; }
    /// Return used vertex range from index range.
    bool GetUsedVertexRange(unsigned start, unsigned count, unsigned& minVertex, unsigned& vertexCount);
    
private:
    /// Create buffer.
    bool Create();
    
    /// Fallback data when operating with a null graphics subsystem.
    SharedArrayPtr<unsigned char> fallbackData_;
    /// Save data when OpenGL context needs to be destroyed and recreated.
    SharedArrayPtr<unsigned char> saveData_;
    /// Memory area for discard locking.
    void* discardLockData_;
    /// Number of indices.
    unsigned indexCount_;
    /// Index size.
    unsigned indexSize_;
    /// Discard lock range start.
    unsigned discardLockStart_;
    /// Discard lock vertex count.
    unsigned discardLockCount_;
    /// Dynamic flag.
    bool dynamic_;
    /// Buffer locked flag.
    bool locked_;
};