Tracing Ray Differentials

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Tracing Ray Differentials

• Homan Igehy
• Speaker Haoji

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• Ray tracing
• ray differentials
• derivatives of the ray with respect to image
  space coordinates, by applying the derivatives of
  the functions.

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Initial value
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Transfer
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Reflection
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• If we know the formula for how a ray is affected
  by a phenomenon, then we can differentiate it to
  get a formula for how a ray differential is
  affected without any understanding of the
  phenomenon

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Texture Filtering

• If we can approximate the difference between the
  texture coordinates corresponding to a ray and
  its neighboring rays, then we can find the size
  and shape of a filtering kernel in texture space.

pixels footprint in texture space based on the
pixel-to-pixel spacing
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• Given this parallelogram, one of several texture
  filtering methods can be used
• mip mapping
• level-of-dital gt

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