var get_height(var Px, var Py, int SW, CONTACT* c1)
{
//P = point that we want the height of (x,y,0)
//SW = vertex number of terrain ent closest towards the lower left corner of the square
//c1 = pointer to our terrain vertex info

VECTOR P;

VECTOR Triangle[3];
VECTOR temp_vec;
ANGLE temp_ang;
VECTOR Director[2];

VECTOR formula;
var ind_term;

//1

//TRANSFORM SKIN PIXEL COORDS TO LOCAL ENT COORD SYSTEM
vec_set(P,vector(Px,Py,0));
P.x-= 256;
P.y = 256-P.y;

//2

//retrieve first point of containing triangle (base corner)
Triangle[0].x=(c1.v)[SW].x;
Triangle[0].y=(c1.v)[SW].z;
Triangle[0].z=(c1.v)[SW].y;

//3

//retrieve second point of containing triangle (diagonal to base)
Triangle[1].x=(c1.v)[SW-32].x;
Triangle[1].y=(c1.v)[SW-32].z;
Triangle[1].z=(c1.v)[SW-32].y;

//4

//determine third point of containing triangle (varying point)
vec_set (temp_vec, P);
//5
vec_sub (temp_vec,Triangle[0].x);
//6
vec_to_angle (temp_ang.pan,temp_vec);

//7

//retrieve third point of containing triangle (varying point)
if(temp_ang.pan>45)
{
Triangle[2].x = (c1.v)[SW-33].x;
Triangle[2].y = (c1.v)[SW-33].z;
Triangle[2].z = (c1.v)[SW-33].y;

}
else
{
Triangle[2].x = (c1.v)[SW+1].x;
Triangle[2].y = (c1.v)[SW+1].z;
Triangle[2].z = (c1.v)[SW+1].y;

}

//8

//calculate the triangle's plane normal for the formula coeficients
vec_set(Director[0],Triangle[1]);
vec_sub(Director[0],Triangle[0]);
vec_set(Director[1],Triangle[2]);
vec_sub(Director[1],Triangle[0]);
//9
vec_cross(formula,Director[0],Director[1]);
//10
//set the independant term of the formula
ind_term=(-1*formula.x*Triangle[0].x)+(-1*formula.y*Triangle[0].y)+(-1*formula.z*Triangle[0].z);
//11
//calculate our point's height plugging our values into the formula
P.z=(-1*((formula.x*P.x)+(formula.y*P.y)+ind_term))/formula.z;
//12
return(P.z);
//NONE
}