Interp2 problem with brightness

Thia is the code that we use:

[xmg1,ymg1]=meshgrid(-10:0.8:10,-10:0.8:10);
[xmg2,ymg2]=meshgrid(-2:0.2:2,-2:0.2:2);

txi=-10:0.05:10;
tyi=-10:0.05:10;
[xr,yr]=meshgrid(txi,tyi);

z1=(cos(xmg1)+sin(ymg1))*xmg1*ymg1;          %ordinate della funzione
figure(1)
lt1=interp2(xmg1,ymg1,z1,xr,yr,'linear');
surf(xr,yr,lt1),title('Interpolazione lineare 2D')

[Jan]

You forgot to ask a question.

[KSSV]

Try

shading interp 

after the surf command