in driver program

in init()

• declare an object of type Scene
• have this Scene object call readScene( )
• have this Scene object call setUp( ), which
  • assigns values to N and theta
  • calculates values for
    • H
    • W
    • vectors n, u, v
  • normalizes vectors n, u, v
• assigns ray's start position to be eye's position

in display( )

• clears the screen
• calls rayTracer( )
• flushes the buffer

in scene_tools:

in rayTracer( )

for each row,
     for each column,

• calculates ray's direction
• sets pixelColor to the value returned by shader( ), for this ray
• calls shadePixel(this_column, this_row, pixelColor)

in shader( )

• calls getFirstHit for this ray, which

for each Primitive in list of primitives in this scene,

• sets itRay to be the inverse transform of ray with this primitive, using the primitive's inverse transformation matrix, M.
• if this primitive is a sphere,
  • declares