Cosine window Cos[Pi x] on [-1/2 1/2] (radical values at exact grid points)
CosineWindow[x]
CosineWindow[x, α]
Plot[CosineWindow[x], {x, -1, 1}]
→ -Graphics-Plot3D[CosineWindow[x]CosineWindow[y], {x, -1, 1}, {y, -1, 1}, PlotRange -> All]
→ -Graphics3D-CosineWindow[0.1]
→ 0.9510565162951535