text: // Copyright 2017 The Dawn Authors
  //
  // 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.
  
  #include "dawn_native/Sampler.h"
  
  #include "dawn_native/Device.h"
  #include "dawn_native/ObjectContentHasher.h"
  #include "dawn_native/ValidationUtils_autogen.h"
  
  #include <cmath>
  
  namespace dawn_native {
  
      MaybeError ValidateSamplerDescriptor(DeviceBase*, const SamplerDescriptor* descriptor) {
          if (descriptor->nextInChain != nullptr) {
              return DAWN_VALIDATION_ERROR("nextInChain must be nullptr");
          }
  
          if (std::isnan(descriptor->lodMinClamp) || std::isnan(descriptor->lodMaxClamp)) {
              return DAWN_VALIDATION_ERROR("LOD clamp bounds must not be NaN");
          }
  
          if (descriptor->lodMinClamp < 0 || descriptor->lodMaxClamp < 0) {
              return DAWN_VALIDATION_ERROR("LOD clamp bounds must be positive");
          }
  
          if (descriptor->lodMinClamp > descriptor->lodMaxClamp) {
              return DAWN_VALIDATION_ERROR(
                  "Min lod clamp value cannot greater than max lod clamp value");
          }
  
          if (descriptor->maxAnisotropy > 1) {
              if (descriptor->minFilter != wgpu::FilterMode::Linear ||
                  descriptor->magFilter != wgpu::FilterMode::Linear ||
                  descriptor->mipmapFilter != wgpu::FilterMode::Linear) {
                  return DAWN_VALIDATION_ERROR(
                      "min, mag, and mipmap filter should be linear when using anisotropic "
                      "filtering");
              }
          } else if (descriptor->maxAnisotropy == 0u) {
              return DAWN_VALIDATION_ERROR("max anisotropy cannot be set to 0");
          }
  
          DAWN_TRY(ValidateFilterMode(descriptor->minFilter));
          DAWN_TRY(ValidateFilterMode(descriptor->magFilter));
          DAWN_TRY(ValidateFilterMode(descriptor->mipmapFilter));
          DAWN_TRY(ValidateAddressMode(descriptor->addressModeU));
          DAWN_TRY(ValidateAddressMode(descriptor->addressModeV));
          DAWN_TRY(ValidateAddressMode(descriptor->addressModeW));
  
          // CompareFunction::Undefined is tagged as invalid because it can't be used, except for the
          // SamplerDescriptor where it is a special value that means the sampler is not a
          // comparison-sampler.
          if (descriptor->compare != wgpu::CompareFunction::Undefined) {
              DAWN_TRY(ValidateCompareFunction(descriptor->compare));
          }
  
          return {};
      }
  
      // SamplerBase
  
      SamplerBase::SamplerBase(DeviceBase* device, const SamplerDescriptor* descriptor)
          : CachedObject(device, kLabelNotImplemented),
            mAddressModeU(descriptor->addressModeU),
            mAddressModeV(descriptor->addressModeV),
            mAddressModeW(descriptor->addressModeW),
            mMagFilter(descriptor->magFilter),
            mMinFilter(descriptor->minFilter),
            mMipmapFilter(descriptor->mipmapFilter),
            mLodMinClamp(descriptor->lodMinClamp),
            mLodMaxClamp(descriptor->lodMaxClamp),
            mCompareFunction(descriptor->compare),
            mMaxAnisotropy(descriptor->maxAnisotropy) {
      }
  
      SamplerBase::SamplerBase(DeviceBase* device, ObjectBase::ErrorTag tag)
          : CachedObject(device, tag) {
      }
  
      SamplerBase::~SamplerBase() {
          if (IsCachedReference()) {
              GetDevice()->UncacheSampler(this);
          }
      }
  
      // static
      SamplerBase* SamplerBase::MakeError(DeviceBase* device) {
          return new SamplerBase(device, ObjectBase::kError);
      }
  
      bool SamplerBase::IsComparison() const {
          return mCompareFunction != wgpu::CompareFunction::Undefined;
      }
  
      bool SamplerBase::IsFiltering() const {
          return mMinFilter == wgpu::FilterMode::Linear || mMagFilter == wgpu::FilterMode::Linear ||
                 mMipmapFilter == wgpu::FilterMode::Linear;
      }
  
      size_t SamplerBase::ComputeContentHash() {
          ObjectContentHasher recorder;
          recorder.Record(mAddressModeU, mAddressModeV, mAddressModeW, mMagFilter, mMinFilter,
                          mMipmapFilter, mLodMinClamp, mLodMaxClamp, mCompareFunction,
                          mMaxAnisotropy);
          return recorder.GetContentHash();
      }
  
      bool SamplerBase::EqualityFunc::operator()(const SamplerBase* a, const SamplerBase* b) const {
          if (a == b) {
              return true;
          }
  
          ASSERT(!std::isnan(a->mLodMinClamp));
          ASSERT(!std::isnan(b->mLodMinClamp));
          ASSERT(!std::isnan(a->mLodMaxClamp));
          ASSERT(!std::isnan(b->mLodMaxClamp));
  
          return a->mAddressModeU == b->mAddressModeU && a->mAddressModeV == b->mAddressModeV &&
                 a->mAddressModeW == b->mAddressModeW && a->mMagFilter == b->mMagFilter &&
                 a->mMinFilter == b->mMinFilter && a->mMipmapFilter == b->mMipmapFilter &&
                 a->mLodMinClamp == b->mLodMinClamp && a->mLodMaxClamp == b->mLodMaxClamp &&
                 a->mCompareFunction == b->mCompareFunction && a->mMaxAnisotropy == b->mMaxAnisotropy;
      }
  
  }  // namespace dawn_native
  