RSL Displacements

Explanation:

Each Choice was animated by varying the boundaries of the s & t values for the hump displacement over time.  

Choice 1: Is based on the formula of a circle.
s² + t² = radius²
s² = radius² - t²
s = (radius² - t²)/s
 ///this looks similar to the formula used below.

Choice #1

Choice #2

Choice #3

Choice #4

Choice #5

Code

displacement rsl_tests
	(float	Km = 0.1, 
	/* displacement magnitude */
	top_edge = 0.4,
	lower_edge = 0.6,
	radius = 0.8,
	choice = 1 )
{

float	hump = 0;
normal	n;

/* STEP 1 - make a copy of the surface
normal one unit in length */

n = normalize(N);

/* STEP 2 - calculate an appropriate
value for the displacement */

if(choice == 1){
/* EX #1*/
if(s < (radius -(t * t)) / s) {
    hump = -1;
	}
}
else if(choice == 2){
/* EX #2*/
if(t < top_edge || t > lower_edge ||
	s > top_edge && s < lower_edge){
    hump = 1;
	}
}
else if(choice == 3){
/* EX #3*/
if(t > top_edge && t < lower_edge ||
	s > top_edge && s < lower_edge){
 	hump = 1;
	}
}
else if(choice == 4){
/* EX #4*/
if(t > top_edge && t < lower_edge){
    hump = 1 - s;
	}
}
else if(choice == 5){
/* EX #5*/
if(t > top_edge && t < lower_edge &&
	s > top_edge  && s < lower_edge){
    hump = -1;
	}
}


/* STEP 3 - calculate the new position of the
surface point, "P" based on the value of hump */

P = P - n * hump * Km;

/* STEP 4 - calculate the new orientation
 of the surface normal */

N = calculatenormal(P);
}