I wish to implement soft shadows produced by area lights in my raytracer. I’m having trouble generating the random samples. So I have a scene in which I have an area light (represented as a circle) whose world (x,y,z) coordinates of the center are given, the radius is given, the normal of the plane on which the circle lies is given, as well as the color and attenuation factors.
The sampling scheme I wish to use is the following: generate samples on the quadrilateral that encompasses the circle and discard points outside the circle until the required number of samples within the circle have been found. I’m having trouble understanding how I can transform the 3D coordinates of the center of the circle to its 2D representation (I don’t think I can assume that the projection of the circle is on the x-y axis and thus just get rid of the z-component). I think the plane normal information should be used but I’m not sure how.
Any and all suggestions are appreciated.
Please see answer to related topic: Determine if 3D point is inside 2D Circle