So I'm trying to make my teapot scale properly when testing my HLSL shader effect.

currently I have this:


float4x4 scale = {(sin(gTime)*sin(gTime)),0,0,0,
0,sin(gTime)*sin(gTime),0,0,
0,0,sin(gTime)*sin(gTime),0,
0,0,0,1};
where gTime is the time elapsed since the program started.
Basically what I want it to do is scale from about 0.5 of its original state to 1.0 (the original size) constantly.
you could probably guess that what I currently have scales it from 1.0 to 0.0
is also tried using the absolute value and, well, it partially works, only the full scaling takes about 4 seconds and it takes 3 seconds before it moves
can anyone help me scale it smoothly from half its size to its full size using sin, cos, or tan?

sin^2(t) varies from 0 to 1, so to get a scaling factor that varies between 0.5 and 1 you need to have the scaling factor equal to 0.5+0.5*sin^2(t).

Awesome it works and scales properly! Thanks a ton!