text: /*
   *  Copyright 2019-2020 Diligent Graphics LLC
   *  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
   *  
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   *  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 "Texture1DArray_OGL.hpp"
  #include "RenderDeviceGLImpl.hpp"
  #include "DeviceContextGLImpl.hpp"
  #include "GLTypeConversions.hpp"
  #include "BufferGLImpl.hpp"
  
  namespace Diligent
  {
  
  Texture1DArray_OGL::Texture1DArray_OGL(IReferenceCounters*        pRefCounters,
                                         FixedBlockMemoryAllocator& TexViewObjAllocator,
                                         RenderDeviceGLImpl*        pDeviceGL,
                                         GLContextState&            GLState,
                                         const TextureDesc&         TexDesc,
                                         const TextureData*         pInitData /*= nullptr*/,
                                         bool                       bIsDeviceInternal /*= false*/) :
      // clang-format off
      TextureBaseGL
      {
          pRefCounters,
          TexViewObjAllocator,
          pDeviceGL,
          TexDesc,
          GL_TEXTURE_1D_ARRAY,
          pInitData,
          bIsDeviceInternal
      }
  // clang-format on
  {
      if (TexDesc.Usage == USAGE_STAGING)
      {
          // We will use PBO initialized by TextureBaseGL
          return;
      }
  
      GLState.BindTexture(-1, m_BindTarget, m_GlTexture);
  
      //                             levels             format          width             height
      glTexStorage2D(m_BindTarget, m_Desc.MipLevels, m_GLTexFormat, m_Desc.Width, m_Desc.ArraySize);
      CHECK_GL_ERROR_AND_THROW("Failed to allocate storage for the 1D texture array");
      // When target is GL_TEXTURE_1D_ARRAY, calling glTexStorage2D() is equivalent to the following code:
      //for (i = 0; i < levels; i++)
      //{
      //    glTexImage2D(target, i, internalformat, width, height, 0, format, type, NULL);
      //    width = max(1, (width / 2));
      //}
  
      SetDefaultGLParameters();
  
      if (pInitData != nullptr && pInitData->pSubResources != nullptr)
      {
          if (m_Desc.MipLevels * m_Desc.ArraySize == pInitData->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, 1};
                      // UpdateData() is a virtual function. If we try to call it through vtbl from here,
                      // we will get into TextureBaseGL::UpdateData(), because instance of Texture1DArray_OGL
                      // is not fully constructed yet.
                      // To call the required function, we need to explicitly specify the class:
                      Texture1DArray_OGL::UpdateData(GLState, Mip, Slice, DstBox, pInitData->pSubResources[Slice * m_Desc.MipLevels + Mip]);
                  }
              }
          }
          else
          {
              UNEXPECTED("Incorrect number of subresources");
          }
      }
  
      GLState.BindTexture(-1, m_BindTarget, GLObjectWrappers::GLTextureObj::Null());
  }
  
  Texture1DArray_OGL::Texture1DArray_OGL(IReferenceCounters*        pRefCounters,
                                         FixedBlockMemoryAllocator& TexViewObjAllocator,
                                         RenderDeviceGLImpl*        pDeviceGL,
                                         GLContextState&            GLState,
                                         const TextureDesc&         TexDesc,
                                         GLuint                     GLTextureHandle,
                                         bool                       bIsDeviceInternal) :
      // clang-format off
      TextureBaseGL
      {
          pRefCounters,
          TexViewObjAllocator,
          pDeviceGL,
          GLState,
          TexDesc,
          GLTextureHandle,
          GL_TEXTURE_1D_ARRAY,
          bIsDeviceInternal
      }
  // clang-format on
  {
  }
  
  Texture1DArray_OGL::~Texture1DArray_OGL()
  {
  }
  
  void Texture1DArray_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);
      glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
      glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0);
      glPixelStorei(GL_UNPACK_SKIP_ROWS, 0);
  
      glTexSubImage2D(m_BindTarget, MipLevel,
                      DstBox.MinX,
                      Slice,
                      DstBox.MaxX - DstBox.MinX,
                      1,
                      TransferAttribs.PixelFormat, TransferAttribs.DataType,
                      // If a non-zero named buffer object is bound to the GL_PIXEL_UNPACK_BUFFER target, 'data' is treated
                      // as a byte offset into the buffer object's data store.
                      // https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/glTexSubImage2D.xhtml
                      SubresData.pSrcBuffer != nullptr ? reinterpret_cast<void*>(static_cast<size_t>(SubresData.SrcOffset)) : 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::Null());
  }
  
  void Texture1DArray_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 1D array to draw framebuffer");
          glFramebufferTexture(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip);
          CHECK_GL_ERROR("Failed to attach texture 1D 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 1D array to draw framebuffer");
          glFramebufferTextureLayer(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip, ViewDesc.FirstArraySlice);
          CHECK_GL_ERROR("Failed to attach texture 1D array to read framebuffer");
      }
      else
      {
          UNEXPECTED("Only one slice or the entire texture array can be attached to a framebuffer");
      }
  }
  
  } // namespace Diligent
  