Motion Blur Weight
A parameter that lets the developer and user control the weight of each sample in the final output of a motion blurred frame.
The Default value decides the initial value of the slider. A value of 0 means that the behavior of the motion blur algorithm is unaltered, with the weight of each sample given by:
Weight = 1 / Total # of samples
The Weight multiplier value indicates the maximum factor the weight of each sample can be increased by. A value of 3.0 means that the weight of each sample can be increased by 300%.
The user only customizes the first value, ranging from 0 to 1, through a slider. As the value of the slider increases from 0 to 1, the weight of each sample increases as follows:
Weight * ( 1.0 + multiplier * slider_value )
Where Weight is as defined above (1 / # of samples). The equation makes it clear that when slider_value is 0, the weight is unchanged. When slider_value is 1, the Weight is increased by 1.0 + 3.0 * 1.0 = 3.0, a 300% increase.
The weight of any sample is clamped so that it may never be greater than 1, no matter what combination of slider_value and multiplier is being used.