I am newbie to GLSL and HLSL programming. I am trying to do the below operations using some functions with shader programming. Any suggestions or reference code or links would help.

1)HLSL/GLSL function test to check if two vectors lie on single line
2) HLSL/GLSL function to find the angle between vectors v1 and v2 is acute (less than 90)
3)HLSL/GLSL function to convert linear value to gamma corrected value
4)HLSL/GLSL function to compute lambert diffuse term . Compute Lambert diffuse term where L = light vector, N = normal vector, V = view vector, Kd- diffuse coeff