Constructing Image Based on Data Sets

Hi,

I do have some data sets from where I generate image. The source of these datasets are varied along Z axis. I used around 4 of them. These source I need to project on a XY plane to construct image. This plane composed of 100*100 pixel.

The equation is calculating the intensity for each pixel

I=S*cos(alphaT)^3*cos(alphaR)^3

Each time one source is active and other source non-active mode.Where alpha is the angleT between the source and pixel position. and alphaR is the angle between the pixel to other 3 non-active source. I have coordinate of all source and coordinate of pixel.if We think the right box , it is a combination of huge

number of XY plane if you cut the box verically. My question is

1) which equation I need to choose for calculating the angle between the source and pixel of that XY plane?

2) if possible MATLAB code for this calculation.