tracing ray differentials homan igehy speaker: haoji
TRANSCRIPT
Tracing Ray Differentials
Homan Igehy
Speaker: Haoji
• Ray tracing
• ray differentials– derivatives of the ray with respect to image
space coordinates, by applying the derivatives of the functions.
Initial value
Transfer
Reflection
• 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
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.
pixel’s footprint in texture spacebased on the pixel-to-pixel spacing:
• Given this parallelogram, one of several texture filtering methods can be used – mip mapping
• level-of-dital =>