Page 208 - DCAP504_Computer Graphics

Unit 13: Advanced Computer Graphics

Let us now analyze ray tracing with the help of following figure 13.10.

Figure 13.10: Ray Tracing

To avoid wastage of time, the rays which were guaranteed to hit the view window and reach the eye
were traced. The point on the view window whose color is to be determined is selected. The color which
passes through the selected point of the view window and reaches the eye is the color assigned to it.
The ray can also be traced backwards by starting at the eye and then passing through the point on the
scene. These two rays would be similar except for their direction. Since, the original ray comes directly
from the light source, the backward ray travels to the light source. When the original ray bounces back
then the backward ray also bounces back. The following figure 13.11 depicts how rays travel backwards
in ray tracing.

Figure 13.11: Ray Tracing

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