text: /*
   * Copyright (c) Contributors to the Open 3D Engine Project.
   * For complete copyright and license terms please see the LICENSE at the root of this distribution.
   *
   * SPDX-License-Identifier: Apache-2.0 OR MIT
   *
   */
  
  #include <Atom/RHI/RHISystemInterface.h>
  
  #include <Atom/RPI.Reflect/Asset/AssetUtils.h>
  #include <Atom/RPI.Reflect/Shader/ShaderAsset.h>
  
  #include <Atom/RPI.Public/RPIUtils.h>
  #include <Atom/RPI.Public/Shader/Shader.h>
  
  #include <AzFramework/Asset/AssetSystemBus.h>
  
  namespace AZ
  {
      namespace RPI
      {
          namespace Internal
          {
              // The original implementation was from cryhalf's CryConvertFloatToHalf and CryConvertHalfToFloat function
              // Will be replaced with centralized half float API
              struct SHalf
              {
                  explicit SHalf(float floatValue)
                  {
                      AZ::u32 Result;
  
                      AZ::u32 intValue = ((AZ::u32*)(&floatValue))[0];
                      AZ::u32 Sign = (intValue & 0x80000000U) >> 16U;
                      intValue = intValue & 0x7FFFFFFFU;
  
                      if (intValue > 0x47FFEFFFU)
                      {
                          // The number is too large to be represented as a half.  Saturate to infinity.
                          Result = 0x7FFFU;
                      }
                      else
                      {
                          if (intValue < 0x38800000U)
                          {
                              // The number is too small to be represented as a normalized half.
                              // Convert it to a denormalized value.
                              AZ::u32 Shift = 113U - (intValue >> 23U);
                              intValue = (0x800000U | (intValue & 0x7FFFFFU)) >> Shift;
                          }
                          else
                          {
                              // Rebias the exponent to represent the value as a normalized half.
                              intValue += 0xC8000000U;
                          }
  
                          Result = ((intValue + 0x0FFFU + ((intValue >> 13U) & 1U)) >> 13U) & 0x7FFFU;
                      }
                      h = static_cast<AZ::u16>(Result | Sign);
                  }
  
                  operator float() const
                  {
                      AZ::u32 Mantissa;
                      AZ::u32 Exponent;
                      AZ::u32 Result;
  
                      Mantissa = h & 0x03FF;
  
                      if ((h & 0x7C00) != 0)  // The value is normalized
                      {
                          Exponent = ((h >> 10) & 0x1F);
                      }
                      else if (Mantissa != 0)     // The value is denormalized
                      {
                          // Normalize the value in the resulting float
                          Exponent = 1;
  
                          do
                          {
                              Exponent--;
                              Mantissa <<= 1;
                          } while ((Mantissa & 0x0400) == 0);
  
                          Mantissa &= 0x03FF;
                      }
                      else                        // The value is zero
                      {
                          Exponent = static_cast<AZ::u32>(-112);
                      }
  
                      Result = ((h & 0x8000) << 16) | // Sign
                          ((Exponent + 112) << 23) | // Exponent
                          (Mantissa << 13);          // Mantissa
  
                      return *(float*)&Result;
                  }
  
              private:
                  AZ::u16 h;
              };
  
              float ScaleValue(float value, float origMin, float origMax, float scaledMin, float scaledMax)
              {
                  return ((value - origMin) / (origMax - origMin)) * (scaledMax - scaledMin) + scaledMin;
              }
  
              float RetrieveFloatValue(const AZ::u8* mem, size_t index, AZ::RHI::Format format)
              {
                  switch (format)
                  {
                  case AZ::RHI::Format::R8_UNORM:
                  case AZ::RHI::Format::A8_UNORM:
                  {
                      return mem[index] / static_cast<float>(std::numeric_limits<AZ::u8>::max());
                  }
                  case AZ::RHI::Format::R8_SNORM:
                  {
                      // Scale the value from AZ::s8 min/max to -1 to 1
                      // We need to treat -128 and -127 the same, so that we get a symmetric
                      // range of -127 to 127 with complementary scaled values of -1 to 1
                      auto actualMem = reinterpret_cast<const AZ::s8*>(mem);
                      AZ::s8 signedMax = std::numeric_limits<AZ::s8>::max();
                      AZ::s8 signedMin = aznumeric_cast<AZ::s8>(-signedMax);
                      return ScaleValue(AZStd::max(actualMem[index], signedMin), signedMin, signedMax, -1.0f, 1.0f);
                  }
                  case AZ::RHI::Format::D16_UNORM:
                  case AZ::RHI::Format::R16_UNORM:
                  {
                      return mem[index] / static_cast<float>(std::numeric_limits<AZ::u16>::max());
                  }
                  case AZ::RHI::Format::R16_SNORM:
                  {
                      // Scale the value from AZ::s16 min/max to -1 to 1
                      // We need to treat -32768 and -32767 the same, so that we get a symmetric
                      // range of -32767 to 32767 with complementary scaled values of -1 to 1
                      auto actualMem = reinterpret_cast<const AZ::s16*>(mem);
                      AZ::s16 signedMax = std::numeric_limits<AZ::s16>::max();
                      AZ::s16 signedMin = aznumeric_cast<AZ::s16>(-signedMax);
                      return ScaleValue(AZStd::max(actualMem[index], signedMin), signedMin, signedMax, -1.0f, 1.0f);
                  }
                  case AZ::RHI::Format::R16_FLOAT:
                  {
                      auto actualMem = reinterpret_cast<const float*>(mem);
                      return SHalf(actualMem[index]);
                  }
                  case AZ::RHI::Format::D32_FLOAT:
                  case AZ::RHI::Format::R32_FLOAT:
                  {
                      auto actualMem = reinterpret_cast<const float*>(mem);
                      return actualMem[index];
                  }
                  default:
                      AZ_Assert(false, "Unsupported pixel format");
                      return 0.0f;
                  }
              }
  
              AZ::u32 RetrieveUintValue(const AZ::u8* mem, size_t index, AZ::RHI::Format format)
              {
                  switch (format)
                  {
                  case AZ::RHI::Format::R8_UINT:
                  {
                      return mem[index] / static_cast<AZ::u32>(std::numeric_limits<AZ::u8>::max());
                  }
                  case AZ::RHI::Format::R16_UINT:
                  {
                      auto actualMem = reinterpret_cast<const AZ::u16*>(mem);
                      return actualMem[index] / static_cast<AZ::u32>(std::numeric_limits<AZ::u16>::max());
                  }
                  case AZ::RHI::Format::R32_UINT:
                  {
                      auto actualMem = reinterpret_cast<const AZ::u32*>(mem);
                      return actualMem[index];
                  }
                  default:
                      AZ_Assert(false, "Unsupported pixel format");
                      return 0;
                  }
              }
  
              AZ::s32 RetrieveIntValue(const AZ::u8* mem, size_t index, AZ::RHI::Format format)
              {
                  switch (format)
                  {
                  case AZ::RHI::Format::R8_SINT:
                  {
                      return mem[index] / static_cast<AZ::s32>(std::numeric_limits<AZ::s8>::max());
                  }
                  case AZ::RHI::Format::R16_SINT:
                  {
                      auto actualMem = reinterpret_cast<const AZ::s16*>(mem);
                      return actualMem[index] / static_cast<AZ::s32>(std::numeric_limits<AZ::s16>::max());
                  }
                  case AZ::RHI::Format::R32_SINT:
                  {
                      auto actualMem = reinterpret_cast<const AZ::s32*>(mem);
                      return actualMem[index];
                  }
                  default:
                      AZ_Assert(false, "Unsupported pixel format");
                      return 0;
                  }
              }
  
              template<typename T>
              T GetSubImagePixelValueInternal(const AZ::Data::Asset<AZ::RPI::StreamingImageAsset>& imageAsset, uint32_t x, uint32_t y, uint32_t componentIndex, uint32_t mip, uint32_t slice)
              {
                  AZStd::array values{ aznumeric_cast<T>(0) };
  
                  auto topLeft = AZStd::make_pair(x, y);
                  auto bottomRight = AZStd::make_pair(x + 1, y + 1);
                  GetSubImagePixelValues(imageAsset, topLeft, bottomRight, AZStd::span<T>(values), componentIndex, mip, slice);
  
                  return values[0];
              }
          }
  
          Data::AssetId GetShaderAssetId(const AZStd::string& shaderFilePath, bool isCritical)
          {
              Data::AssetId shaderAssetId;
  
              Data::AssetCatalogRequestBus::BroadcastResult(
                  shaderAssetId,
                  &Data::AssetCatalogRequestBus::Events::GetAssetIdByPath,
                  shaderFilePath.c_str(),
                  azrtti_typeid<ShaderAsset>(),
                  false
              );
  
              if (!shaderAssetId.IsValid())
              {
                  if (isCritical)
                  {
                      Data::Asset<RPI::ShaderAsset> shaderAsset = RPI::AssetUtils::LoadCriticalAsset<RPI::ShaderAsset>(shaderFilePath);
                      if (shaderAsset.IsReady())
                      {
                          return shaderAsset.GetId();
                      }
                      else
                      {
                          AZ_Error("RPI Utils", false, "Could not load critical shader [%s]", shaderFilePath.c_str());
                      }
                  }
  
                  AZ_Error("RPI Utils", false, "Failed to get asset id for shader [%s]", shaderFilePath.c_str());
              }
  
              return shaderAssetId;
          }
  
          Data::Asset<ShaderAsset> FindShaderAsset(Data::AssetId shaderAssetId, [[maybe_unused]] const AZStd::string& shaderFilePath)
          {
              if (!shaderAssetId.IsValid())
              {
                  return Data::Asset<ShaderAsset>();
              }
  
              auto shaderAsset = Data::AssetManager::Instance().GetAsset<ShaderAsset>(shaderAssetId, AZ::Data::AssetLoadBehavior::PreLoad);
  
              shaderAsset.BlockUntilLoadComplete();
  
              if (!shaderAsset.IsReady())
              {
                  AZ_Error("RPI Utils", false, "Failed to find shader asset [%s] with asset ID [%s]", shaderFilePath.c_str(), shaderAssetId.ToString<AZStd::string>().c_str());
                  return Data::Asset<ShaderAsset>();
              }
  
              return shaderAsset;
          }
  
          Data::Instance<Shader> LoadShader(Data::AssetId shaderAssetId, const AZStd::string& shaderFilePath, const AZStd::string& supervariantName)
          {
              auto shaderAsset = FindShaderAsset(shaderAssetId, shaderFilePath);
              if (!shaderAsset)
              {
                  return nullptr;
              }
  
              Data::Instance<Shader> shader = Shader::FindOrCreate(shaderAsset, AZ::Name(supervariantName));
              if (!shader)
              {
                  AZ_Error("RPI Utils", false, "Failed to find or create a shader instance from shader asset [%s] with asset ID [%s]", shaderFilePath.c_str(), shaderAssetId.ToString<AZStd::string>().c_str());
                  return nullptr;
              }
  
              return shader;
          }
  
          Data::Asset<ShaderAsset> FindShaderAsset(const AZStd::string& shaderFilePath)
          {
              return FindShaderAsset(GetShaderAssetId(shaderFilePath), shaderFilePath);
          }
  
          Data::Asset<ShaderAsset> FindCriticalShaderAsset(const AZStd::string& shaderFilePath)
          {
              const bool isCritical = true;
              return FindShaderAsset(GetShaderAssetId(shaderFilePath, isCritical), shaderFilePath);
          }
  
          Data::Instance<Shader> LoadShader(const AZStd::string& shaderFilePath, const AZStd::string& supervariantName)
          {
              return LoadShader(GetShaderAssetId(shaderFilePath), shaderFilePath, supervariantName);
          }
  
          Data::Instance<Shader> LoadCriticalShader(const AZStd::string& shaderFilePath, const AZStd::string& supervariantName)
          {
              const bool isCritical = true;
              return LoadShader(GetShaderAssetId(shaderFilePath, isCritical), shaderFilePath, supervariantName);
          }
  
          AZ::Data::Instance<RPI::StreamingImage> LoadStreamingTexture(AZStd::string_view path)
          {
              AzFramework::AssetSystem::AssetStatus status = AzFramework::AssetSystem::AssetStatus_Unknown;
              AzFramework::AssetSystemRequestBus::BroadcastResult(
                  status, &AzFramework::AssetSystemRequestBus::Events::CompileAssetSync, path);
  
              // When running with no Asset Processor (for example in release), CompileAssetSync will return AssetStatus_Unknown.
              AZ_Error(
                  "RPIUtils",
                  status == AzFramework::AssetSystem::AssetStatus_Compiled || status == AzFramework::AssetSystem::AssetStatus_Unknown,
                  "Could not compile image at '%s'", path.data());
  
              Data::AssetId streamingImageAssetId;
              Data::AssetCatalogRequestBus::BroadcastResult(
                  streamingImageAssetId, &Data::AssetCatalogRequestBus::Events::GetAssetIdByPath,
                  path.data(), azrtti_typeid<RPI::StreamingImageAsset>(), false);
              if (!streamingImageAssetId.IsValid())
              {
                  AZ_Error("RPI Utils", false, "Failed to get streaming image asset id with path " AZ_STRING_FORMAT, AZ_STRING_ARG(path));
                  return AZ::Data::Instance<RPI::StreamingImage>();
              }
  
              auto streamingImageAsset = Data::AssetManager::Instance().GetAsset<RPI::StreamingImageAsset>(streamingImageAssetId, AZ::Data::AssetLoadBehavior::PreLoad);
  
              streamingImageAsset.BlockUntilLoadComplete();
  
              if (!streamingImageAsset.IsReady())
              {
                  AZ_Error("RPI Utils", false, "Failed to get streaming image asset: " AZ_STRING_FORMAT, AZ_STRING_ARG(path));
                  return AZ::Data::Instance<RPI::StreamingImage>();
              }
  
              return RPI::StreamingImage::FindOrCreate(streamingImageAsset);
          }
  
          //! A helper function for GetComputeShaderNumThreads(), to consolidate error messages, etc.
          static bool GetAttributeArgumentByIndex(const Data::Asset<ShaderAsset>& shaderAsset, const AZ::Name& attributeName, const RHI::ShaderStageAttributeArguments& args, const size_t argIndex, uint16_t* value, AZStd::string& errorMsg)
          {
              if (value)
              {
                  const auto numArguments = args.size();
                  if (numArguments > argIndex)
                  {
                      if (args[argIndex].type() == azrtti_typeid<int>())
                      {
                          *value = aznumeric_caster(AZStd::any_cast<int>(args[argIndex]));
                      }
                      else
                      {
                          errorMsg = AZStd::string::format("Was expecting argument '%zu' in attribute '%s' to be of type 'int' from shader asset '%s'", argIndex, attributeName.GetCStr(), shaderAsset.GetHint().c_str());
                          return false;
                      }
                  }
                  else
                  {
                       errorMsg = AZStd::string::format("Was expecting at least '%zu' arguments in attribute '%s' from shader asset '%s'", argIndex + 1, attributeName.GetCStr(), shaderAsset.GetHint().c_str());
                       return false;
                  }
              }
              return true;
          }
  
          AZ::Outcome<void, AZStd::string> GetComputeShaderNumThreads(const Data::Asset<ShaderAsset>& shaderAsset, const AZ::Name& attributeName, uint16_t* numThreadsX, uint16_t* numThreadsY, uint16_t* numThreadsZ)
          {
              // Set default 1, 1, 1 now. In case of errors later this is what the caller will get.
              if (numThreadsX)
              {
                  *numThreadsX = 1;
              }
              if (numThreadsY)
              {
                  *numThreadsY = 1;
              }
              if (numThreadsZ)
              {
                  *numThreadsZ = 1;
              }
              const auto numThreads = shaderAsset->GetAttribute(RHI::ShaderStage::Compute, attributeName);
              if (!numThreads)
              {
                  return AZ::Failure(AZStd::string::format("Couldn't find attribute '%s' in shader asset '%s'", attributeName.GetCStr(), shaderAsset.GetHint().c_str()));
              }
              const RHI::ShaderStageAttributeArguments& args = *numThreads;
              AZStd::string errorMsg;
              if (!GetAttributeArgumentByIndex(shaderAsset, attributeName, args, 0, numThreadsX, errorMsg))
              {
                  return AZ::Failure(errorMsg);
              }
              if (!GetAttributeArgumentByIndex(shaderAsset, attributeName, args, 1, numThreadsY, errorMsg))
              {
                  return AZ::Failure(errorMsg);
              }
              if (!GetAttributeArgumentByIndex(shaderAsset, attributeName, args, 2, numThreadsZ, errorMsg))
              {
                  return AZ::Failure(errorMsg);
              }
              return AZ::Success();
          }
  
          AZ::Outcome<void, AZStd::string> GetComputeShaderNumThreads(const Data::Asset<ShaderAsset>& shaderAsset, uint16_t* numThreadsX, uint16_t* numThreadsY, uint16_t* numThreadsZ)
          {
              return GetComputeShaderNumThreads(shaderAsset, Name{ "numthreads" }, numThreadsX, numThreadsY, numThreadsZ);
          }
  
          AZ::Outcome<void, AZStd::string> GetComputeShaderNumThreads(const Data::Asset<ShaderAsset>& shaderAsset, RHI::DispatchDirect& dispatchDirect)
          {
              return GetComputeShaderNumThreads(shaderAsset, &dispatchDirect.m_threadsPerGroupX, &dispatchDirect.m_threadsPerGroupY, &dispatchDirect.m_threadsPerGroupZ);
          }
  
          template<>
          float GetSubImagePixelValue<float>(const AZ::Data::Asset<AZ::RPI::StreamingImageAsset>& imageAsset, uint32_t x, uint32_t y, uint32_t componentIndex, uint32_t mip, uint32_t slice)
          {
              return Internal::GetSubImagePixelValueInternal<float>(imageAsset, x, y, componentIndex, mip, slice);
          }
  
          template<>
          AZ::u32 GetSubImagePixelValue<AZ::u32>(const AZ::Data::Asset<AZ::RPI::StreamingImageAsset>& imageAsset, uint32_t x, uint32_t y, uint32_t componentIndex, uint32_t mip, uint32_t slice)
          {
              return Internal::GetSubImagePixelValueInternal<AZ::u32>(imageAsset, x, y, componentIndex, mip, slice);
          }
  
          template<>
          AZ::s32 GetSubImagePixelValue<AZ::s32>(const AZ::Data::Asset<AZ::RPI::StreamingImageAsset>& imageAsset, uint32_t x, uint32_t y, uint32_t componentIndex, uint32_t mip, uint32_t slice)
          {
              return Internal::GetSubImagePixelValueInternal<AZ::s32>(imageAsset, x, y, componentIndex, mip, slice);
          }
  
          bool GetSubImagePixelValues(const AZ::Data::Asset<AZ::RPI::StreamingImageAsset>& imageAsset, AZStd::pair<uint32_t, uint32_t> topLeft, AZStd::pair<uint32_t, uint32_t> bottomRight, AZStd::span<float> outValues, uint32_t componentIndex, uint32_t mip, uint32_t slice)
          {
              // TODO: Use the component index
              (void)componentIndex;
  
              if (!imageAsset.IsReady())
              {
                  return false;
              }
  
              auto imageData = imageAsset->GetSubImageData(mip, slice);
              if (imageData.empty())
              {
                  return false;
              }
  
              const AZ::RHI::ImageDescriptor imageDescriptor = imageAsset->GetImageDescriptor();
              auto width = imageDescriptor.m_size.m_width;
              const uint32_t pixelSize = AZ::RHI::GetFormatSize(imageDescriptor.m_format);
  
              size_t outValuesIndex = 0;
              for (uint32_t y = topLeft.second; y < bottomRight.second; ++y)
              {
                  for (uint32_t x = topLeft.first; x < bottomRight.first; ++x)
                  {
                      size_t imageDataIndex = (y * width + x) * pixelSize;
  
                      auto& outValue = outValues[outValuesIndex++];
                      outValue = Internal::RetrieveFloatValue(imageData.data(), imageDataIndex, imageDescriptor.m_format);
                  }
              }
  
              return true;
          }
  
          bool GetSubImagePixelValues(const AZ::Data::Asset<AZ::RPI::StreamingImageAsset>& imageAsset, AZStd::pair<uint32_t, uint32_t> topLeft, AZStd::pair<uint32_t, uint32_t> bottomRight, AZStd::span<AZ::u32> outValues, uint32_t componentIndex, uint32_t mip, uint32_t slice)
          {
              // TODO: Use the component index
              (void)componentIndex;
  
              if (!imageAsset.IsReady())
              {
                  return false;
              }
  
              auto imageData = imageAsset->GetSubImageData(mip, slice);
              if (imageData.empty())
              {
                  return false;
              }
  
              const AZ::RHI::ImageDescriptor imageDescriptor = imageAsset->GetImageDescriptor();
              auto width = imageDescriptor.m_size.m_width;
              const uint32_t pixelSize = AZ::RHI::GetFormatSize(imageDescriptor.m_format);
  
              size_t outValuesIndex = 0;
              for (uint32_t y = topLeft.second; y < bottomRight.second; ++y)
              {
                  for (uint32_t x = topLeft.first; x < bottomRight.first; ++x)
                  {
                      size_t imageDataIndex = (y * width + x) * pixelSize;
  
                      auto& outValue = outValues[outValuesIndex++];
                      outValue = Internal::RetrieveUintValue(imageData.data(), imageDataIndex, imageDescriptor.m_format);
                  }
              }
  
              return true;
          }
  
          bool GetSubImagePixelValues(const AZ::Data::Asset<AZ::RPI::StreamingImageAsset>& imageAsset, AZStd::pair<uint32_t, uint32_t> topLeft, AZStd::pair<uint32_t, uint32_t> bottomRight, AZStd::span<AZ::s32> outValues, uint32_t componentIndex, uint32_t mip, uint32_t slice)
          {
              // TODO: Use the component index
              (void)componentIndex;
  
              if (!imageAsset.IsReady())
              {
                  return false;
              }
  
              auto imageData = imageAsset->GetSubImageData(mip, slice);
              if (imageData.empty())
              {
                  return false;
              }
  
              const AZ::RHI::ImageDescriptor imageDescriptor = imageAsset->GetImageDescriptor();
              auto width = imageDescriptor.m_size.m_width;
              const uint32_t pixelSize = AZ::RHI::GetFormatSize(imageDescriptor.m_format);
  
              size_t outValuesIndex = 0;
              for (uint32_t y = topLeft.second; y < bottomRight.second; ++y)
              {
                  for (uint32_t x = topLeft.first; x < bottomRight.first; ++x)
                  {
                      size_t imageDataIndex = (y * width + x) * pixelSize;
  
                      auto& outValue = outValues[outValuesIndex++];
                      outValue = Internal::RetrieveIntValue(imageData.data(), imageDataIndex, imageDescriptor.m_format);
                  }
              }
  
              return true;
          }
      }
  }
  