> 2][index & 3]; index = iceil(ipos.x) + ifloor(ipos.y) * 8; float tr = mat[index >> 2][index & 3]; index = ifloor(ipos.x) + iceil(ipos.y) * 8; float bl = mat[index >> 2][index & 3]; index = iceil(ipos.x) + iceil(ipos.y) * 8; float br = mat[index >> 2][index & 3]; float2 s = frac(ipos); float tA = lerp(tl, tr, s.x); float tB = lerp(bl, br, s.x); worldPosition.y += lerp(tA, tB, s.y); ]]>