/*     Copyright 2015-2019 Egor Yusov
 *  
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 *  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 OF ANY PROPRIETARY RIGHTS.
 *
 *  In no event and under no legal theory, whether in tort (including negligence), 
 *  contract, or otherwise, unless required by applicable law (such as deliberate 
 *  and grossly negligent acts) or agreed to in writing, shall any Contributor be
 *  liable for any damages, including any direct, indirect, special, incidental, 
 *  or consequential damages of any character arising as a result of this License or 
 *  out of the use or inability to use the software (including but not limited to damages 
 *  for loss of goodwill, work stoppage, computer failure or malfunction, or any and 
 *  all other commercial damages or losses), even if such Contributor has been advised 
 *  of the possibility of such damages.
 */

#include "pch.h"

#include "Texture2DArray_OGL.h"
#include "RenderDeviceGLImpl.h"
#include "DeviceContextGLImpl.h"
#include "GLTypeConversions.h"
#include "GraphicsAccessories.h"
#include "BufferGLImpl.h"

namespace Diligent
{

Texture2DArray_OGL::Texture2DArray_OGL( IReferenceCounters *pRefCounters, 
                                        FixedBlockMemoryAllocator& TexViewObjAllocator,
                                        RenderDeviceGLImpl *pDeviceGL, 
                                        DeviceContextGLImpl *pDeviceContext, 
                                        const TextureDesc& TexDesc, 
                                        const TextureData &InitData /*= TextureData()*/,
									    bool bIsDeviceInternal /*= false*/) : 
    TextureBaseGL(pRefCounters, TexViewObjAllocator, pDeviceGL, TexDesc, TexDesc.SampleCount > 1 ? GL_TEXTURE_2D_MULTISAMPLE_ARRAY : GL_TEXTURE_2D_ARRAY, InitData, bIsDeviceInternal)
{
    auto &ContextState = pDeviceContext->GetContextState();
    ContextState.BindTexture(-1, m_BindTarget, m_GlTexture);

    if( m_Desc.SampleCount > 1 )
    {
        //                                                              format          width         height          depth
        glTexStorage3DMultisample(m_BindTarget, m_Desc.SampleCount, m_GLTexFormat, m_Desc.Width, m_Desc.Height, m_Desc.ArraySize, GL_TRUE);
        // The last parameter specifies whether the image will use identical sample locations and the same number of 
        // samples for all texels in the image, and the sample locations will not depend on the internal format or size 
        // of the image.
        CHECK_GL_ERROR_AND_THROW("Failed to allocate storage for the 2D multisample texture array");
        // * An INVALID_ENUM error is generated if sizedinternalformat is not colorrenderable,
        //   depth - renderable, or stencil - renderable
        // * An INVALID_OPERATION error is generated if samples is greater than the maximum number of samples 
        //   supported for this target and internalformat. The maximum number of samples supported can be 
        //   determined by calling glGetInternalformativ with a pname of GL_SAMPLES

        SetDefaultGLParameters();
    }
    else
    {
        //                             levels             format          width         height          depth
        glTexStorage3D(m_BindTarget, m_Desc.MipLevels, m_GLTexFormat, m_Desc.Width, m_Desc.Height, m_Desc.ArraySize);
        CHECK_GL_ERROR_AND_THROW("Failed to allocate storage for the 2D texture array");
        // When target is GL_TEXTURE_2D_ARRAY, calling glTexStorage3D is equivalent to the following pseudo-code:
        //for (i = 0; i < levels; i++)
        //{
        //    glTexImage3D(target, i, internalformat, width, height, depth, 0, format, type, NULL);
        //    width = max(1, (width / 2));
        //    height = max(1, (height / 2));
        //}

        SetDefaultGLParameters();

        if( InitData.pSubResources )
        {
            if(  m_Desc.MipLevels * m_Desc.ArraySize == InitData.NumSubresources )
            {
                for(Uint32 Slice = 0; Slice < m_Desc.ArraySize; ++Slice)
                {
                    for(Uint32 Mip = 0; Mip < m_Desc.MipLevels; ++Mip)
                    {
                        Box DstBox{0, std::max(m_Desc.Width >>Mip, 1U),
                                   0, std::max(m_Desc.Height>>Mip, 1U)};
                        // UpdateData() is a virtual function. If we try to call it through vtbl from here,
                        // we will get into TextureBaseGL::UpdateData(), because instance of Texture2DArray_OGL
                        // is not fully constructed yet.
                        // To call the required function, we need to explicitly specify the class: 
                        Texture2DArray_OGL::UpdateData(ContextState, Mip, Slice, DstBox, InitData.pSubResources[Slice*m_Desc.MipLevels + Mip]);
                    }
                }
            }
            else
            {
                UNEXPECTED("Incorrect number of subresources");
            }
        }

    }

    ContextState.BindTexture( -1, m_BindTarget, GLObjectWrappers::GLTextureObj(false) );
}

Texture2DArray_OGL::Texture2DArray_OGL( IReferenceCounters *pRefCounters, 
                                        FixedBlockMemoryAllocator& TexViewObjAllocator,     
                                        RenderDeviceGLImpl *pDeviceGL, 
                                        DeviceContextGLImpl *pDeviceContext,
                                        const TextureDesc& TexDesc, 
                                        GLuint GLTextureHandle,
                                        bool bIsDeviceInternal)  : 
    TextureBaseGL(pRefCounters, TexViewObjAllocator, pDeviceGL, pDeviceContext, TexDesc, GLTextureHandle, 
                  TexDesc.SampleCount > 1 ? GL_TEXTURE_2D_MULTISAMPLE_ARRAY : GL_TEXTURE_2D_ARRAY, bIsDeviceInternal)
{
}

Texture2DArray_OGL::~Texture2DArray_OGL()
{
}

void Texture2DArray_OGL::UpdateData(GLContextState &ContextState, Uint32 MipLevel, Uint32 Slice, const Box &DstBox, const TextureSubResData &SubresData)
{
    TextureBaseGL::UpdateData(ContextState, MipLevel, Slice, DstBox, SubresData);

    ContextState.BindTexture(-1, m_BindTarget, m_GlTexture);

    // Bind buffer if it is provided; copy from CPU memory otherwise
    GLuint UnpackBuffer = 0;
    if (SubresData.pSrcBuffer != nullptr)
    {
        auto *pBufferGL = ValidatedCast<BufferGLImpl>(SubresData.pSrcBuffer);
        UnpackBuffer = pBufferGL->GetGLHandle();
    }

    // Transfers to OpenGL memory are called unpack operations
    // If there is a buffer bound to GL_PIXEL_UNPACK_BUFFER target, then all the pixel transfer
    // operations will be performed from this buffer.
    glBindBuffer(GL_PIXEL_UNPACK_BUFFER, UnpackBuffer);

    const auto &TransferAttribs = GetNativePixelTransferAttribs(m_Desc.Format);
    
    glPixelStorei(GL_UNPACK_ALIGNMENT, 4);

    if( TransferAttribs.IsCompressed )
    {
        auto MipWidth  = std::max(m_Desc.Width  >> MipLevel, 1U);
        auto MipHeight = std::max(m_Desc.Height >> MipLevel, 1U);
        VERIFY( (DstBox.MinX % 4) == 0 && (DstBox.MinY % 4) == 0    &&
                ((DstBox.MaxX % 4) == 0 || DstBox.MaxX == MipWidth) && 
                ((DstBox.MaxY % 4) == 0 || DstBox.MaxY == MipHeight), 
                "Compressed texture update region must be 4 pixel-aligned" );
#ifdef _DEBUG
        {
            const auto& FmtAttribs = GetTextureFormatAttribs(m_Desc.Format);
            auto BlockBytesInRow = ((DstBox.MaxX - DstBox.MinX + 3)/4) * Uint32{FmtAttribs.ComponentSize};
            VERIFY( SubresData.Stride == BlockBytesInRow,
                    "Compressed data stride (", SubresData.Stride, " must match the size of a row of compressed blocks (", BlockBytesInRow, ")" );
        }
#endif
        //glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
        //glPixelStorei(GL_UNPACK_COMPRESSED_BLOCK_WIDTH, 0);
        auto UpdateRegionWidth  = DstBox.MaxX - DstBox.MinX;
        auto UpdateRegionHeight = DstBox.MaxY - DstBox.MinY;
        UpdateRegionWidth  = std::min(UpdateRegionWidth,  MipWidth  - DstBox.MinX);
        UpdateRegionHeight = std::min(UpdateRegionHeight, MipHeight - DstBox.MinY);
        glCompressedTexSubImage3D(m_BindTarget, MipLevel, 
                        DstBox.MinX, 
                        DstBox.MinY, 
                        Slice,
                        UpdateRegionWidth, 
                        UpdateRegionHeight,
                        1,
                        // The format must be the same compressed-texture format previously 
                        // specified by glTexStorage2D() (thank you OpenGL for another useless 
                        // parameter that is nothing but the source of confusion), otherwise
                        // INVALID_OPERATION error is generated.
                        m_GLTexFormat, 
                        // An INVALID_VALUE error is generated if imageSize is not consistent with
                        // the format, dimensions, and contents of the compressed image( too little or
                        // too much data ),
                        ((DstBox.MaxY - DstBox.MinY + 3)/4) * SubresData.Stride,
                        SubresData.pData);
    }
    else
    {
        const auto TexFmtInfo = GetTextureFormatAttribs(m_Desc.Format);
        const auto PixelSize = Uint32{TexFmtInfo.NumComponents} * Uint32{TexFmtInfo.ComponentSize};
        VERIFY( (SubresData.Stride % PixelSize)==0, "Data stride is not multiple of pixel size" );
        glPixelStorei(GL_UNPACK_ROW_LENGTH, SubresData.Stride / PixelSize);
        glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0);
        glPixelStorei(GL_UNPACK_SKIP_ROWS, 0 );

        glTexSubImage3D(m_BindTarget, MipLevel, 
                        DstBox.MinX, 
                        DstBox.MinY,
                        Slice,
                        DstBox.MaxX - DstBox.MinX, 
                        DstBox.MaxY - DstBox.MinY, 
                        1,
                        TransferAttribs.PixelFormat, TransferAttribs.DataType, 
                        SubresData.pData);
    }
    CHECK_GL_ERROR("Failed to update subimage data");

    if(UnpackBuffer != 0)
        glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);

    ContextState.BindTexture( -1, m_BindTarget, GLObjectWrappers::GLTextureObj(false) );
}

void Texture2DArray_OGL::AttachToFramebuffer( const TextureViewDesc& ViewDesc, GLenum AttachmentPoint )
{
    if( ViewDesc.NumArraySlices == m_Desc.ArraySize )
    {
        glFramebufferTexture( GL_DRAW_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip );
        CHECK_GL_ERROR( "Failed to attach texture 2D array to draw framebuffer" );
        glFramebufferTexture( GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip );
        CHECK_GL_ERROR( "Failed to attach texture 2D array to read framebuffer" );
    }
    else if( ViewDesc.NumArraySlices == 1 )
    {
        // Texture name must either be zero or the name of an existing 3D texture, 1D or 2D array texture, 
        // cube map array texture, or multisample array texture.
        glFramebufferTextureLayer( GL_DRAW_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip, ViewDesc.FirstArraySlice );
        CHECK_GL_ERROR( "Failed to attach texture 2D array to draw framebuffer" );
        glFramebufferTextureLayer( GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip, ViewDesc.FirstArraySlice );
        CHECK_GL_ERROR( "Failed to attach texture 2D array to read framebuffer" );
    }
    else
    {
        UNEXPECTED( "Only one slice or the entire texture array can be attached to a framebuffer" );
    }
}

}
