TextureView.h

#pragma once
 
#include <CesiumGltf/KhrTextureTransform.h>
#include <CesiumGltf/Sampler.h>
#include <CesiumGltf/TextureInfo.h>
#include <CesiumImage/ImageAsset.h>
#include <CesiumUtility/IntrusivePointer.h>
 
#include <vector>
 
namespace CesiumGltf {
 
struct Model;

struct TextureViewOptions {
  bool applyKhrTextureTransformExtension = false;

  bool makeImageCopy = false;
};

enum class TextureViewStatus {
  Valid,

  ErrorUninitialized,

  ErrorInvalidTexture,

  ErrorInvalidSampler,

  ErrorInvalidImage,

  ErrorEmptyImage,

  ErrorInvalidBytesPerChannel,
};

class TextureView {
public:
  TextureView() noexcept;

  TextureView(
      const Model& model,
      const TextureInfo& textureInfo,
      const TextureViewOptions& options = TextureViewOptions()) noexcept;

  TextureView(
      const Sampler& sampler,
      const CesiumImage::ImageAsset& image,
      int64_t textureCoordinateSetIndex,
      const ExtensionKhrTextureTransform* pKhrTextureTransformExtension =
          nullptr,
      const TextureViewOptions& options = TextureViewOptions()) noexcept;

  TextureViewStatus getTextureViewStatus() const noexcept {
    return this->_textureViewStatus;
  }

  int64_t getTexCoordSetIndex() const noexcept {
    if (this->_applyTextureTransform && this->_textureTransform) {
      return this->_textureTransform->getTexCoordSetIndex().value_or(
          this->_texCoordSetIndex);
    }
    return this->_texCoordSetIndex;
  }

  const Sampler* getSampler() const noexcept { return this->_pSampler; }

  const CesiumImage::ImageAsset* getImage() const noexcept {
    if (this->_pImageCopy) {
      return this->_pImageCopy.get();
    }
    return this->_pImage.get();
  }

  std::optional<KhrTextureTransform> getTextureTransform() const noexcept {
    return this->_textureTransform;
  }

  std::vector<uint8_t> sampleNearestPixel(
      double u,
      double v,
      const std::vector<int64_t>& channels) const noexcept;
 
private:
  TextureViewStatus _textureViewStatus;
 
  const Sampler* _pSampler;
  CesiumUtility::IntrusivePointer<CesiumImage::ImageAsset> _pImage;
  int64_t _texCoordSetIndex;
 
  bool _applyTextureTransform;
  std::optional<KhrTextureTransform> _textureTransform;
 
  CesiumUtility::IntrusivePointer<CesiumImage::ImageAsset> _pImageCopy;
};
} // namespace CesiumGltf