Ray Tracing

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Ray Tracing

• CS 351-50
• Nov. 19, 2003

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Turner Whitted
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No Bounces
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One Bounce
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Two Bounces
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Reflection Ray
n
I incident ray -d N normal vector R
reflected ray
R
-I
q
q
( -I . N) N
( -I . N) N
N
-I - (-I . N) N
-I (-I . N) N
R
-I
q
q
R ( -I . N) N I (-I . N) N
I - 2 (I . N) N
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Adding an object transparency
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Refraction
n sin q nt sin f
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Index of Refraction gt 1
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Index of Refraction lt 1
total internal reflection
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Algorithm

• Trace (ray)
• For each object in scene
• intersect (ray, object)
• If no intersections
• return background_color
• For each light
• for each object in scene
• intersect(shadowRay, object)
• Accumulate local illumination
• Trace (ReflectionRay)
• Trace (TransmissionRay)
• Accumulate global illumination
• Return illumination

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Sampling
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Ray Tracing Demos
http//www.siggraph.org/education/materials/HyperG
raph/raytrace/rt_java/raytrace.html
http//www.cs.berkeley.edu/efros/java/tracer/trac
er.html
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Sampling Demo
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Texture Materials
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Links

• http//www.acm.org/tog/GraphicsGems/

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