/*
 * cylindrical projection model
 */

x : m_view - c_view$
y : tan(c_nick - m_nick)$ 
x_rot : y * sin(c_tilt) + x * cos(c_tilt)$
y_rot : y * cos(c_tilt) - x * sin(c_tilt)$
x_scale : x_rot * scale$
y_scale : y_rot * scale$

/*
 * Some mangling for C code generation
 */

x_expand : trigexpand(x_scale)$
y_expand : trigexpand(y_scale)$

args: "(double c_view, double c_nick, double c_tilt, double scale, double k0, double k1, double m_view, double m_nick)"$

printfunc(name, expression) := sprint("double ProjectionCylindrical::", name, args, "{ return ", string(subst(pow, "^", expression)), ";}", "
")$

printfunc("mac_x", x_expand)$
printfunc("mac_y", y_expand)$

printfunc("mac_x_dc_view", diff(x_expand, c_view))$
printfunc("mac_x_dc_nick", diff(x_expand, c_nick))$
printfunc("mac_x_dc_tilt", diff(x_expand, c_tilt))$
printfunc("mac_x_dscale", diff(x_expand, scale))$
printfunc("mac_x_dk0", diff(x_expand, k0))$
printfunc("mac_x_dk1", diff(x_expand, k1))$
printfunc("mac_y_dc_view", diff(y_expand, c_view))$
printfunc("mac_y_dc_nick", diff(y_expand, c_nick))$
printfunc("mac_y_dc_tilt", diff(y_expand, c_tilt))$
printfunc("mac_y_dscale", diff(y_expand, scale))$
printfunc("mac_y_dk0", diff(y_expand, k0))$
printfunc("mac_y_dk1", diff(y_expand, k1))$