Lec 12 - Recursive ray tracing, Shadow volumes & Refraction Flashcards
What is ray tracing?
Start from a pixel in the screen and the camera (i.e. origin of projection system) trace a ray through the pixel, eventually it will reach an object and depending on the properties of the surface (specular/diffuse) it will be traced back to a light source to produce a highlight.
What is recursive ray tracing / backward ray tracing / ray casting?
Similar to ray tracing, except you go from object to object and keep track of the number of objects you are colliding with in attempts to get back to a light source.
How is ray tracing different to the rendering pipeline?
Rendering pipeline normally is fed vertices from which vertex shader creates fragments which are later interpolated by the illumination model. The rastorization phase later draws the pixels. (Starting from model and rastorizing into pixels).
In ray tracing you cast a ray along the vector and follow it along the path and adding up the specular and lambersion components along the way.
What is the complexity of ray tracing?
Cardinality of the problem depends on the number of pixels in the image / view port, as opposed to the number of polygons (pipe line rendering.)
However also depends on the re-reflections catered for (due to recursive nature.)
What is snell’s Law?
look it up coz I can’t put images here :(
What is the stencil buffer?
It is a buffer that is used to store where we want shadows to occur. To drop intensity down on those locations.
What are shadow volumes?
shadow volumes are the volumes of shapes cast by the objects by obstructing the light source as shown in: http://imgur.com/a/KBroF the volume formed by combining the faces of A, B, C is the shadow volume
