void SetAlpha(float alpha){
Vec4 param = mMaterial->GetMaterialParameter(3);
mAlpha = param.w = alpha;
mMaterial->SetMaterialParameter(3, param);
mMaterialParamDest[3].w = alpha;
mMaterialParamDest[2].w = alpha;
}
void PrepareInterpolation(float time, SkySpherePtr startFrom){
MaterialPtr srcMaterial = mMaterial;
if (startFrom)
srcMaterial = startFrom->GetMaterial();
for (int i = 0; i < 5; i++)
{
mMaterialParamCur[i] = srcMaterial->GetMaterialParameter(i);
}
mInterpolationTime = time;
mCurInterpolationTime = 0;
mInterpolating = true;
}