How to calculate incident light on surface with multiple orientations?

[Jman99]

Lets say you have a light source with a uniform beam of known intensity per meter square incident on a surface and the surface is tilted both vertically and horizontally.
The surface is on a platform and tilted directly up and the angle of incidence is 45 degrees while the platform is also rotated horizontally at 22 degrees (angle of incidence 22 degrees here?).
How to calculate the intensity? Is it just multiplying both the cosines of each angles by the intensity?

 

[sophiecentaur]

Is it just multiplying both the cosines of each angles by the intensity?

A good indication of the light energy flux would be the projected area - i.e. what you suggest.